> Phenomena > Natural Phenomenon or Process > Acylation

Acylation

Acylation is a chemical process in which an acyl group (such as an acetyl or benzoyl group) is introduced into a molecule.
This reaction is widely used in organic synthesis and medicinal chemistry to modify the structure and properties of compounds.
Acylation can be performed on a variety of substrates, including alcohols, amines, and aromatic compounds, and is a key step in the synthesis of many pharmaceutical drugs and other important chemicals.
Researchers studying acylation reactions can use PubCompare.ai's AI-powered platform to effortlessly locate the best protocols from literature, preprints, and patents, and identify the most effective methods and products to streamline their research and accelerate their discoveries.
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Most cited protocols related to «Acylation»

Revealing Diterpene Ester Isomers in Euphorbia dendroides

The examination of the LC-MS² data (MSV000080502) from the Euphorbia dendroides plant extract showed the presence of numerous chromatographic peaks for ions in the range m/z 500–900, corresponding to diterpene ester derivatives. These specialized metabolites consist of a polyhydroxylated diterpene core acylated with various acidic moieties, that are typically found as positional isomers based on their acylation pattern. The extracted ion chromatogram (EIC) for the ion m/z 589.31 in the Euphorbia dendroides extract data (Supplementary Fig. 7) shows the presence of at least seven distinct LC-MS peaks between 24.5 and 27.3 min, including five peaks with an associated MS² spectra. The analysis of the extract and the fractions where these molecules were originally isolated (fractions 13 and 14) with classical MN resulted in a molecular network with two nodes for the m/z 589.31 ions (Fig. 2a and Supplementary Fig. 8). These MS² spectra (cluster index 5352 and 5354) resulted from merging 96 fragmentation spectra spanning from 23.6 to 26.5 min by MS-Cluster (Fig. 2b and Supplementary Fig. 9). Close examination of the clustered spectra revealed that while all MS² spectra for the precursor m/z 589.31 present fragment ions m/z 501.26, 423.21, 335.16, and 295.17, three distinct spectral types could be established based on the ions relative intensities (Supplementary Fig. 10). FBMN of the dataset with MZmine processing (see the GNPS job) enabled the differentiation of the MS² spectra of seven isomers (Figure 2b and Supplementary Fig. 11 for the molecular network view). A detailed discussion on the differences observed between the two methods can be found in the Supporting Information (Supplementary Note 2 and Supplementary Table 1). Interestingly, in the original study^{7 (link)} OpenMS was used for FBMN and resulted in the observation of three different positional isomers instead of seven, which shows that different processing methods and/or parameters can lead to different results with FBMN. These three isomers were subsequently isolated and differed by the position of one double bond on the C-12 acyl chain, or from carbon C-4 configuration^{7 (link)}. Because FBMN connects the accurate relative abundance of the ions across the fractions and the molecular networks, it allowed to create bioactivity-based molecular networks^{7 (link)}, which were used to predict and target potentially antiviral compounds. For detailed description of the extraction, mass spectrometry analysis, and structural elucidation, see the original manuscript^{7 (link)}. The MZmine project and parameters used can be accessed on the MassIVE submission (MSV000080502).

Nothias L.F., Petras D., Schmid R., Dührkop K., Rainer J., Sarvepalli A., Protsyuk I., Ernst M., Tsugawa H., Fleischauer M., Aicheler F., Aksenov A., Alka O., Allard P.M., Barsch A., Cachet X., Caraballo M., Silva R.R., Dang T., Garg N., Gauglitz J.M., Gurevich A., Isaac G., Jarmusch A.K., Kameník Z., Kang K.B., Kessler N., Koester I., Korf A., Gouellec A.L., Ludwig M., H. C.M., McCall L.I., McSayles J., Meyer S.W., Mohimani H., Morsy M., Moyne O., Neumann S., Neuweger H., Nguyen N.H., Nothias-Esposito M., Paolini J., Phelan V.V., Pluskal T., Quinn R.A., Rogers S., Shrestha B., Tripathi A., van der Hooft J.J., Vargas F., Weldon K.C., Witting M., Yang H., Zhang Z., Zubeil F., Kohlbacher O., Böcker S., Alexandrov T., Bandeira N., Wang M, & Dorrestein P.C. (2020). Feature-Based Molecular Networking in the GNPS Analysis Environment. Nature methods, 17(9), 905-908.

Publication 2020

Acids Acylation Antiviral Agents Carbon Chromatography derivatives Diterpenes Esters Euphorbia Isomerism Mass Spectrometry Plants

Enzymatic Reaction Pathway Determination

With a reaction coordinate driving method and an iterative energy minimization procedure,29 the enzyme reaction path was determined by the pseudobond QM/MM calculations at B3LYP/6-31G*:AMBER level, in which the QM calculations were performed at the B3LYP/6-31G* level of theory by using a modified version of Gaussian0345 and the MM calculations were performed by using a modified version of AMBER program.⁴⁸ Normal mode analyses were performed to characterize the reactant, intermediates, transition states, and final product. In addition, single-point energy calculations were carried out at the QM/MM(B3LYP/6-31+G*:AMBER) level on the QM/MM-optimized geometries to evaluate the energy barriers. Throughout the QM/MM calculations, the boundary carbon atoms were treated with improved pseudobond parameters.26 (link) No cutoff for nonbonded interactions was used in the QM/MM calculations. For QM subsystem, the convergence criterion for geometry optimizations follows the original Gaussian03 defaults. For MM subsystem, the geometry optimization convergence criterion is when the RMS energy gradient is less than 0.1 kcal·mol⁻¹·Å⁻¹. Prior to QM/MM calculations, the MM subsystem was relaxed by performing ∼500 steps of energy minimization with AMBER8 program. Then, atoms within 20 Å of the C^ζ atom of (−)-cocaine benzoyl were allowed to move while all the other atoms outside this range were frozen in all QM/MM calculations, resulting in 2,981 movable atoms in QM/MM calculations for acylation and 3,089 movable atoms in QM/MM calculations for deacylation.

Liu J., Hamza A, & Zhan C.G. (2009). Fundamental Reaction Mechanism and Free Energy Profile for (−)-Cocaine Hydrolysis Catalyzed by Cocaine Esterase. Journal of the American Chemical Society, 131(33), 11964-11975.

Publication 2009

Acylation Amber Carbon Cocaine Enzymes Freezing

Synthesis of PNHAV Hydrogel Polymers

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Publication 2018

2-hydroxyethyl methacrylate acryloyl chloride Acylation Bath Cold Temperature dilactide dioxane Ethyl Ether Free Radicals Hydrogels Methanol Molar n-hexane Peroxide, Benzoyl Polymerization Polymers Vacuum

Genetic Determinants of Antimicrobial Resistance in Gonorrhea

Previously reported genetic determinants conferring reduced antimicrobial susceptibility to the different agents are shown in Table 1. Using WGS, SNPs and resultant amino acid substitutions were determined following mapping to the NCCP11945 reference genome (NC_011035.1) and quality filtering as in De Silva et al.,¹⁶ (link) with the exception of the penA and penB genes and mtrR promoter variants, which were more variable, and were therefore identified from Velvet²¹ (link)de novo assemblies using BLAST and subsequently aligned using MUSCLE.²² (link) BLAST searches of de novo assemblies were used to determine the presence/absence of accessory genes. To identify rRNA variants, sequence reads were mapped against a single copy of the NCCP11945 23S RNA gene using BWA mem²³ (link) with default settings. Base counts were determined using SAMtools,²⁴ (link) enabling estimation of the proportion of gene copies with relevant mutations.

Table 1

Susceptibility-modifying genetic elements.¹¹ (link)

Gene/element	Characteristic	Summary	Reference	AZM	CFX	CIP	PEN	TET
penA	allele	reduced β-lactam acetylation of PBP2	¹¹ (link)^,³² (link)^,³³ (link)		✓		✓
	SNPs: A311V, I312M, V316T, V316P, T483S, A501V, N512Y, G545S, A501P, A501V, A501T, G542S, P551S, P551L	penA alleles were defined as described in the Methods section, and represent commonly occurring combinations of SNPs	¹¹ (link)^,²⁵ (link)		✓
	SNPs: D345a, F504L, A510V, A516G, H541N, P551S, P551L, P552V, K555Q, I556V, I566V, N573a, A574V, A311V, I312M, V316T, V316P, T483S, A501V, N512Y, G545S, A501P, A501V, A501T, G542S, P551S, P551L	additional contributions of individual SNPs were also investigated	¹¹ (link)^,³⁴ (link)				✓
mtrR promoter disruption	deletion of A in repeat (–35A)	overexpression of MtrCDE efflux pump	³⁵ (link)^,³⁶ (link)	✓	✓		✓	✓
	A → C in repeat (–38)		⁶ (link)^,³⁷ (link)
	2 bp insertion		³⁶ (link)
	mtr120	novel promoter for MtrCDE efflux pump expression	³⁸ (link)	✓	✓		✓	✓
mtrR	A39T	overexpression of MtrCDE efflux pump	³⁹ (link)	✓	✓		✓	✓
	G45D		³⁹ (link)
	truncation		¹³ (link)
penB (porB1b)	G120K	reduced influx	⁴⁰ (link)		✓		✓	✓
penB (porB1b)	A121D/N	reduced influx	⁴⁰ (link)		✓		✓	✓
ponA (ponA1 allele)	L421P	reduced β-lactam acylation of PBP1	⁴¹ (link)		✓		✓
pilQ	E666K	reduced influx via pore-forming secretin PilQ	⁴² (link)		✓		✓
bla_TEM	bla_TEM-1/bla_TEM-135-encoding plasmids	penicillinase	⁴³ (link)^,⁴⁴ (link)				✓
23S rRNA	C2611T	four copies of these genes present, increasing resistance with increased number of copies with SNPs via decreased binding to 50S ribosome	⁴⁵ (link)	✓
23S rRNA	A2059G		⁴⁶ (link)	✓
erm(B), erm(C), erm(F)	presence	methylate 23S RNA to block binding	⁴⁷ (link)	✓
macAB	promoter mutation	efflux pump overexpression	⁴⁸ (link)	✓
mef	presence	efflux pump	⁴⁹ (link)	✓
ere(A), ere(B)	presence	macrolide esterase	³⁷ (link)	✓
gyrA	S91F	reduced quinolone binding to DNA gyrase	¹³ (link)^,⁵⁰ (link)			✓
gyrA	D95N/G	reduced quinolone binding to DNA gyrase	¹³ (link)^,⁵⁰ (link)			✓
parC	D86N	reduced quinolone binding to topoisomerase IV	¹³ (link)			✓
	S87R/I/W		¹³ (link)
	S88P		¹³ (link)^,⁵⁰ (link)
	E91K		¹³ (link)^,⁵⁰ (link)
norM	promoter mutation	overexpression of efflux pump	⁵¹ (link)			✓
rpsJ	V57M	reduced affinity of 30S ribosome for tetracycline	⁵² (link)					✓
tetM plasmid	Dutch/American plasmid	TetM resembles elongation factor G, binds 30S ribotype and prevents tetracycline binding	⁵³ (link)^,⁵⁴ (link)					✓

AZM, azithromycin; CFX, cefixime; CIP, ciprofloxacin; PEN, penicillin; TET, tetracycline.

Ticked boxes indicate that the genetic determinant affects the indicated antimicrobial. The A → C nucleotide substitution 38 bases upstream of mtrR is found in WHO-P like and mosaic Neisseria meningitidis-like mtrR promoter sequences.⁶ (link)

Eyre D.W., De Silva D., Cole K., Peters J., Cole M.J., Grad Y.H., Demczuk W., Martin I., Mulvey M.R., Crook D.W., Walker A.S., Peto T.E, & Paul J. (2017). WGS to predict antibiotic MICs for Neisseria gonorrhoeae. Journal of Antimicrobial Chemotherapy, 72(7), 1937-1947.

Publication 2017

Acetylation Acylation Alleles Amino Acid Substitution Azithromycin Cardiac Arrest Cefixime Ciprofloxacin Gene Components Genes Lactams Microbicides MTRR protein, human Muscle Tissue Mutation Neisseria meningitidis Nucleotides Penicillins Peptide Elongation Factor G Quinolones Reproduction Ribosomal RNA Ribosomes Ribotype Secretin Single Nucleotide Polymorphism Strains Susceptibility, Disease Tetracycline

Quantification of Protein S-Acylation in Adipocytes

Prior to harvesting, 3T3-L1 adipocytes were incubated overnight in medium containing 5.55 mM D-Glucose. Subsequently, cells were collected in buffer A (25 mM HEPES, 25 mM NaCl, 1 mM EDTA, pH 7.4 and protease inhibitor cocktail) and passed five to ten times through a 26G needle. Following disruption, the cell fraction was centrifuged at 800 × g for 5 minutes at 4 °C, and the recovered supernatant was then subjected to an additional centrifugation step at 136,000 × g for 60 min at 4 °C. The pellet containing the membrane fraction was then resuspended in 100 μl buffer A containing 0.5% Triton X-100 (v/v). In order to block free SH groups with S-methyl methanethiosulfonate (MMTS), 200 μl of blocking buffer (100 mM HEPES, 1 mM EDTA, 87.5 mM SDS and 1–1.5% (v/v) MMTS) was added to the resuspended proteins and incubated for 4 h at 40 °C with frequent vortexing. Subsequently, 3 volumes of ice-cold 100% acetone was added to the blocking protein mixture and incubated for 20 minutes at −20 °C and then centrifuged at 5,000 × g for 10 minutes at 4 °C to pellet precipitated proteins. The pellet was washed five times in 1 ml of 70% (v/v) acetone and resuspended in buffer B (100 mM HEPES, 1 mM EDTA, 35 mM SDS). A fraction of the solubilised pellet was saved as the input. For treatment with hydroxylamine (HA) and capture by Thiopropyl Sepharose® beads, 2 M HA was added together with the beads (previously activated for 15 min with dH₂O) to a final concentration of 0.5 M HA and 10% (w/v) beads. As a negative control, 2 M Tris was used instead of HA. These samples were then incubated overnight at room temperature with end-over-end mixing. The supernatant was removed and retained as the “unbound” fraction. The remaining beads were washed five times with 1 ml buffer B. Subsequently, the proteins were eluted from the beads by two consecutive incubations in 100 μl SDS sample buffer containing 50 mM dithiothreitol (DTT) for 15 minutes at room temperature and then 5 minutes at 95 °C. The eluted proteins were the “bound” fraction. Before subjecting all samples to SDS-PAGE, the final volumes of the bound and unbound fractions were equalised. For quantification of S-acylation, we used the following equation: [Bound(HA)/(Bound(HA) + Unbound(HA)] − [Bound (Tris)/(Bound(Tris) + Unbound(Tris)].

Werno M.W, & Chamberlain L.H. (2015). S-acylation of the Insulin-Responsive Aminopeptidase (IRAP): Quantitative analysis and Identification of Modified Cysteines. Scientific Reports, 5, 12413.

Publication 2015

3T3-L1 Cells Acetone Acylation Adipocytes Buffers Cells Centrifugation Cold Temperature Dithiothreitol Edetic Acid G-800 Glucose HEPES Hydroxylamine methyl methanethiosulfonate Needles Protease Inhibitors Proteins SDS-PAGE Sodium Chloride thiopropyl-sepharose Tissue, Membrane Triton X-100 Tromethamine

Most recents protocols related to «Acylation»

Synthesis of Cephem, Carbacephem, Penem, and Carbapenem Cannabinoid Conjugates

Not available on PMC !

Example 1

Cephem Conjugates

Cephem ether linked β-lactam antibiotic cannabinoid conjugate components are synthesized according to the following Scheme. The CAS numbers for the two key building blocks is shown. Reaction conditions follow standard conditions for amine acylation in the first step to attach the cephem side chain, for alkylation of a phenol group of a cannabinoid in the second step with optional use of a catalyst or enhancer such as NaI, followed by standard removal of the p-methoxybenzyl protecting group in the third step to furnish the product. A di-alkylated product may also be obtained.

[Figure (not displayed)]

Carbacephem Conjugates

Carbacephem ether linked β-lactam antibiotic cannabinoid conjugate components are synthesized according to the following Scheme. The general starting material [177472-75-2] was reported in racemic form as [54296-34-3] (Journal of the American Chemical Society (1974), 96(24), 7584) and is elaborated to the iodide intermediate after installing a side chain of choice using a previously reported process (WO 96/04247). Alkylation of CBD with the iodide followed by deprotection, both steps under standard conditions, provides the desired product.

[Figure (not displayed)]

Penem Conjugates

Penem ether linked β-lactam antibiotic cannabinoid conjugate components are synthesized according to the following Scheme. The starting material [145354-22-9], prepared as reported (Journal of Organic Chemistry, 58(1), 272-4; 1993), is reacted with CBD under standard alkylating conditions. The silyl ether TBS protecting group is then removed followed by deallylation under known conditions to give the desired product.

[Figure (not displayed)]

Carbapenem Conjugates

Carbapenem ether linked β-lactam antibiotic cannabinoid conjugate components are synthesized according to the following Scheme. The starting material [136324-03-3] is reacted with CBD under standard alkylating conditions. The silyl ether TES protecting group is then removed followed by removal of the p-methoxybenzyl ester protecting group under known conditions to give the desired product.

[Figure (not displayed)]

US11877988B2. Conjugate molecules (2024-01-23). Diverse Biotech, Inc. [US]. Inventors: Paul Hershberger [US], Philip Arlen [US].

Patent 2024

Acylation Adjustment Disorders Alkylation Amines Cannabinoids carbacephems Carbapenems Esters Ethers Iodides Monobactams Penem Phenol

Synthesis of Cyclic Peptide Analogs

Not available on PMC !

Example 2

Tertiary propargylamine bridges were introduced into the peptide by initial incorporation of aza-propargylglycine and ε-N-alkyl-lysine residues into the GHRP-6 peptide sequence, followed by copper-catalyzed macrocyclization using an aldehyde linchpin. The A³-macrocyclization was examined immediately after introduction of the azapropargylglycine residue, as well as after completing the peptide sequence. To seek a diversity-oriented synthesis, two strategies were employed, in which an ε-N-alkyl-lysine residue was introduced respectively at the C-terminal and a central residue of the peptide sequence. With the ε-N-alkyl-lysine residue at the C-terminal, the macrocycle ring-size diversity was varied by azapropargyiglycine position scanning, in which the azapropargylglycyl residue was marched systematically to the N-terminal of the GHRP-6 sequence prior to macrocyclization with formaldehyde. With the ε-N-alkyl-lysine residue centred in the sequence, the influence of various & amino substituents was examined on macrocyclization.

The important step for the effective diversity-oriented synthesis of cyclic azapeptides by A³-macrocyclization was development of solid-phase methods to install the azapropargyiglycine residue and ε-N-alkyl-lysine residue into the peptide sequence prior to the copper-catalyzed macrocyclization using an aldehyde linchpin. The azapropargyiglycine can be inserted by submonomer synthesis of azapeptides on solid phase.^[13]The ε-N-alkylated lysine was prepared in solution and then coupled to the resin-bound peptide; however, solid-phase ε-N-alkylation of lysine was also performed by Mitsunobu chemistry on the corresponding ε-N-o-nitrobenzenesulfonyl (o-NBS) amine.^[20]

As a proof-of-concept of the A³-macrocyclization, cyclic azatripeptide 8 was pursued by placing ε-N-methyl lysine at the peptide C-terminal and inserting aza-propargyiglycine at the i+2 position. Prior to attachment to Rink amide resin, Fmoc-Lys(methyl, o-NBS)—OH 1 was synthesized from Boc-Lys-OH in solution. After Fmoc group removals and elongation with Fmoc-D-Phe-OH using DIC and HOBt, dipeptide 2a was acylated by the active carbazate prepared from benzophenone hydrazone and N,N′-disuccinimidyl carbonate (DSC) to provide semicarbazone 3a.^[14]Propargylation was performed using Cs₂CO₃(300 mol %) and proparyl bromide (600 mol %) to furnish the aza-propargyiglycine 4a in good purity as accessed by LCMS analysis of a cleaved aliquot. After removal of the o-NBS-group with 2-mercaptoethanol and DBU, secondary ε-N-methylamine 5a was ready to test the A³-macrocyclization. Macrocycle 6a was prepared successfully by treating aza-peptide 5a with CuI (20 mol %) and 37% aqueous formaldehyde (600 mol %) in DMSO at rt for 24 h, as verified by LCMS analysis. Elongation of macrocycle 6a to cyclic GHRP-6 analog 8 was accomplished by removal of the semicarbazone with hydroxylamine hydrochloride in pyridine, acylation of the resulting semicarbazide 7a using the symmetric anhydride from treating Fmoc-Ala-OH with DIC, and standard solid-phase peptide synthesis, deprotection and resin cleavage. GHRP-6 macrocycle 8 was isolated in 3.5% overall yield after purification by preparative HPLC. Employing the same strategy, macrocycle 9 was obtained in 2.4% overall yield.

[Figure (not displayed)]

With macrocyclic GHRP-6 analogs 8 and 9 in hand, ring-size scope was investigated by systematically moving the azapropargylglycine residue towards the N-terminal of the sequence. Moreover, the ε-N-alkyl-lysine residue was prepared on solid phase by a method designed to expand the diversity of the ε-amine substituent. After coupling Fmoc-Lys(o-NBS)—OH 10^[19]to RINK amide resin and peptide elongation, semicarbazones 11a-d were synthesized. Chemoselective modification of the ε-N-o-(NBS)amine nitrogen was achieved by employing Mitsunobu chemistry to alkylate the former. Treatment of sulphonamide 11a-d with allyl alcohol, PPh₃, and diisopropyl azodicarboxylate (DIAD) provided selectively ε-N-(allyl)lysinyl peptides 12a-d as verified by LCMS analysis of cleaved aliquots. Subsequently, propargylation of semicarbazone was performed using Cs₂CO₃(300 mol %) and proparyl bromide (600 mol %) to yield aza-propargylglycine peptides 13a-d. A³-Macrocyclization was then performed using the same conditions as discussed above to provide respectively 16-, 19, 21, and 24-membered macrocycles 15a-d as verified by LCMS analysis. After cyclization, semicarbazone removal, semicarbazide acylation, peptide elongation and resin cleavage were performed as described above to afford cyclic GHRP-6 analogs 17 and 18 after purification by preparative HPLC (Table 1). Coupling to semicarbazide macrocycles 16c and 16d was however unsuccessful in the syntheses of the corresponding cyclic GHRP-6 analogs. Steric hindrance inhibited apparently, the coupling to the semicarbazide of the larger ring-sizes. Semicarbazide 16d was however cleaved from resin to give cyclic aza-hexapeptide 19 with a N-terminal semicarbazide after purification by preparative HPLC.

[Figure (not displayed)]
[Figure (not displayed)]
[Figure (not displayed)]

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Failure to elongate semicarbazides 16c and 16d after cyclization promoted investigation of a strategy featuring elongation of the complete linear peptide prior to A3-macrocyclization as the penultimate step before simultaneous deprotection and resin cleavage. Semicarbazone 13a was thus treated with hydroxylamine hydrochloride to liberate the semicarbazide 20a, and the linear peptide was elongated as described for its cyclic counterpart above. Aza-hexapeptide 21a was treated with DBU and 2-mercaptoethanol to selectively remove the o-NBS group. Subsequently, aza-hexapeptide 23a was effectively converted to macrocycle 17 using the standard A³-macrocyclization conditions. Resin cleavage gave cyclic azapeptide 17 in about 2-fold higher yield (1.2%) than the earlier approach, involving peptide elongation after cyclization.

Employing the peptide elongation/A³-macrocyclization approach, linear peptides 22b-d were also successfully converted into macrocyclic aza-GHRP-6 analogs 18, 24 and 25. Cyclic azapeptides 24 and 25 were respectively prepared with N-terminal alanine residues to avoid racemization during coupling to the semicarbazide with histidine, and to add an N-terminal basic amine that may favor biological activity.

The diversity of the ε-amine substituent was explored by the synthesis of cyclic azatetrapeptides 30-32 employing different alcohols as electrophiles in the Mitsunobu reaction: methanol, allyl alcohol and isopropyl alcohol. An ε-N-alkylated lysine was inserted in the peptide sequence to replace the tryptophan residue and an azapropargylglycine was placed at the i+3 position to replace the histidine residue in the GHRP-6 sequence. Cyclic analog 33 was synthesized with an additional alanine in the N-terminal for comparison with analog 31 to study the importance of the N-terminal basic amine.

[Figure (not displayed)]

Cyclic azapeptide GHRP-6 analogs were synthesized by the A³-macrocyclization method in yields and purities suitable for biological evaluation (Table 1).

TABLE 1

Yields and purity of the cyclic azapeptide GHRP-6 analogs

CyclicSyntheticIsolated

AnalogApproachYield (%)Purity^[a]HRMS

8I3.5 99%809.4201(809.4206)

9I2.4 99%924.4627(924.4628)

17I and (II)0.5(1.5)99%835.4376(835.4362)

18I and (II)0.4(1.1)99%950.4787(950.4784)

19I0.5 94%884.4549(884.4566)

24II0.9 99%769.4140(769.4144)

25II1.1 97%955.4942(955.4937)

26II2.0%99%997.5031(997.5043)

27II1.6%99%926.4658(926.4671)

31I1.5 96%826.4718(826.4723)

32I1.2 97%828.4875(828.4879)

33II0.9 94%897.5092(897.5094)

34II2.5%98%939.5186(939.5199)

35II1.4%96%868.4804(868.4828)

^[a]Determined by LCMS analysis as described above.

Synthesis of Cyclic Analogs MPE-110, MPE-111, MPE-074 and MPE-048

Solution-Phase Chemistry

Ornithine Building Block Synthesis

[Figure (not displayed)]

Fmoc-Orn(o-NBS)—OH (RGO1):

Fmoc-Orn(Boc)-OH (2.02 g, 4.44 mmol) was dissolved in CH₂Cl₂(30 mL) treated with TFA (20 mL) stirred at room temperature for 3 hours, and the volatiles were removed by rotary evaporation. The resulting yellow oil was co-evaporated with toluene to give a residue that was dissolved in THF (40 mL) and water (40 mL) and treated with iPr₂NEt (7.70 mL, 44.2 mmol) and o-NBSCl (1.13 g, 5.08 mmol) in one portion. The reaction was stirred at room temperature for 3 hours, diluted with EtOAc (100 mL) and sequentially washed with aqueous HCl (1 M, 100 mL×3), water (100 mL) and brine (100 mL). The organic layer was dried over MgSO₄and the volatiles were removed by rotary evaporation to give sulfonamide RGO1 (2.4 g, quant.) as a light yellow solid. The amino acid was used without further purification.

¹H NMR (300 MHz, DMSO) δ 8.10 (t, J=5.6 Hz, 1H), 8.03-7.92 (m, 2H), 7.92-7.81 (m, 4H), 7.72 (d, J=7.4 Hz, 2H), 7.61 (d, J=8.0 Hz, 1H), 7.41 (t, J=7.2 Hz, 2H), 7.32 (t, J=7.1 Hz, 2H), 4.34-4.16 (m, 3H), 3.89 (td, J=8.7, 4.6 Hz, 1H), 2.90 (q, J=6.3 Hz, 2H), 1.73 (s, 1H), 1.65-1.43 (m, 3H). ¹³C NMR (75 MHz, DMSO) δ 173.7, 156.1, 147.8, 143.8, 140.7, 134.0, 132.7, 132.6, 129.4, 127.7, 127.1, 125.3, 124.4, 120.1, 65.6, 53.5, 46.7, 42.3, 27.9, 26.0. LCMS (10-90% MeOH containing 0.1% formic acid over 10 min) R_t=11.04 min. ESI-MS m/z calcd for C₂₆H₂₆N₃O₈S⁺ [M+H]⁺ 540.1, found 540.1. Melting point: 108-110° C.

Solid-Phase Chemistry

Fmoc-based peptide synthesis was performed using standard conditions (W. D. Lubell, J. W. Blankenship, G. Fridkin, and R. Kaul (2005) “Peptides.” Science of Synthesis 21.11, Chemistry of Amides. Thieme, Stuttgart, 713-809) on an automated shaker using polystyrene Rink amide resin. The loading was calculated from the UV absorbance for Fmoc-deprotection after the coupling of the first amino acid. Couplings of amino acids (3 equiv.) were performed in DMF using DIC (3 equiv.) and HOBt (3 equiv.) for 3-6 hours. Fmoc-deprotections were performed by treating the resin with 20% piperidine in DMF for 30 min. The resin was washed after each coupling and deprotection step sequentially with DMF (×3), MeOH (×3) THF (×3) and CH₂Cl₂(×3).

Lysine as AA1

[Figure (not displayed)]

Fmoc-Lys(o-NBS)-Rink Amide Resin RGO7:

On Rink amide resin (3.00 g) in a syringe fitted with a Teflon™ filter, Fmoc removal was performed by treating the resin with a solution of 20% piperidine in DMF over 30 min. The resin was filtered and washed sequentially with DMF (×3), MeOH (×3) and CH₂Cl₂(×3). Fmoc-Lys(o-NBS)—OH (1.62 g, 2.93 mmol) was dissolved in DMF (20 mL) and treated with DIC (0.7 mL, 4.52 mmol) and HOBt (611 mg, 4.52 mmol), stirred for 3 min. and added to the syringe containing the resin. The mixture was shaken for 14 hours. The resin was then filtered and sequentially washed with DMF (×3), MeOH (×3) and CH₂Cl₂(×3). The resin was dried and the loading was measured at 0.345 mmol/g resin.

[Figure (not displayed)]

Fmoc-Lys(o-NBS, Allyl)-Rink Amide Resin RGO8:

Vacuum dried Fmoc-Lys(o-NBS)-resin RGO7 (0.441 mmol) was placed in a syringe fitted with a Teflon™ filter, suspended in THF (dry, 5 mL) and treated sequentially with solutions of allyl alcohol (206 μL, 3.03 mmol) in THF (dry, 1 mL), PPh₃(397 mg, 1.51 mmol) in THF (dry, 1 mL), and DIAD (298 μL, 1.51 mmol) in THF (dry, 1 mL). The mixture in the syringe was shaken for 90 min. The resin was filtered and sequentially washed with DMF (×3), MeOH (×3), THF (×3) and CH₂Cl₂(×3). Examination by LCMS of a cleaved resin sample (5 mg) showed complete allylation: LCMS (30-95% MeOH containing 0.1% formic acid in water containing 0.1% formic acid over 10 min) R_t=8.65 min. ESI-MS m/z calcd for C₃₀H₃₃N₄O₇S⁺ [M+H]⁺593.2, found 593.2.

[Figure (not displayed)]

Boc-Ala-D-Pra-Ala-Trp(Boc)-D-Phe-Lys(o-NBS, Allyl)-Rink Amide Resin RGO99:

LCMS (30-95% MeOH containing 0.1% formic acid in water containing 0.1% formic acid over 10 min) R_t=5.73 min. ESI-MS m/z calcd for C₄₆H₅₇N₁₀O₁₀S⁺ [M−2Boc+H]⁺941.4, found 941.4.

[Figure (not displayed)]

Boc-Ala-L-Pra-Ala-Trp(Boc)-D-Phe-Lys(o-NBS, Allyl)-Rink Amide Resin RGO100:

LCMS (30-95% MeOH containing 0.1% formic acid in water containing 0.1% formic acid over 10 min) R_t=5.77 min. ESI-MS m/z calcd for C₄₆H₅₇N₁₀O₁₀S⁺ [M−2Boc+H]⁺941.4, found 941.4.

[Figure (not displayed)]

Boc-Ala-D-Pra-D-Trp(Boc)-Ala-Trp-D-Phe-Lys(o-NBS, Allyl)-Rink Amide Resin RGO65:

LCMS (30-95% MeOH containing 0.1% formic acid in water containing 0.1% formic acid over 10 min) R_t=6.48 min. ESI-MS m/z calcd for C₅₇H₆₇N₁₂O₁₁S⁺ [M−3Boc+H]⁺1127.5, found 1127.5.

[Figure (not displayed)]

Boc-Ala-L-Pra-D-Trp(Boc)-Ala-Trp-D-Phe-Lys(o-NBS, Allyl)-Rink Amide Resin RGO66:

LCMS (30-95% MeOH containing 0.1% formic acid in water containing 0.1% formic acid over 10 min) R_t=6.66 min. ESI-MS m/z calcd for C₅₇H₆₇N₁₂O₁₁S⁺ [M−3Boc+H]⁺1127.5, found 1127.5.

[Figure (not displayed)]

Boc-Ala-D-Pra-Ala-Trp(Boc)-D-Phe-Lys(Allyl)-Rink Amide Resin RGO104:

o-NBS-protected hexapeptide RGO99 (˜600 mg, 0.156 mmol) in a syringe fitted with a Teflon™ filter was swollen in DMF (5 mL) and treated with DBU (210 μL, 1.40 mmol) and 2-mercaptoethanol (50 μL, 0.71 mmol). The mixture in the syringe was shaken for 1 h. The resin was filtered and sequentially washed with DMF (×3), MeOH (×3), THF (×3) and CH₂Cl₂(×3). Examination by LCMS of a cleaved resin sample (5 mg) showed complete o-NBS-removal: LCMS (30-95% MeOH containing 0.1% formic acid in water containing 0.1% formic acid over 10 min) R_t=1.50 min. ESI-MS m/z calcd for C₄₀H₅₄N₉O₆⁺ [M−2Boc+H]⁺756.4, found 756.4.

[Figure (not displayed)]

Boc-Ala-L-Pra-Ala-Trp(Boc)-D-Phe-Lys(Allyl)-Rink Amide Resin RGO105:

o-NBS-protected hexapeptide RGO100 (˜600 mg, 0.14 mmol) in a syringe fitted with a Teflon™ filter was swollen in DMF (5 mL) and treated with DBU (210 μL, 1.40 mmol) and 2-mercaptoethanol (50 μL, 0.71 mmol). The mixture in the syringe was shaken for 1 h. The resin was filtered and sequentially washed with DMF (×3), MeOH (×3), THF (×3) and CH₂Cl₂(×3). Examination by LCMS of a cleaved resin sample (5 mg) showed complete o-NBS-removal: LCMS (30-95% MeOH containing 0.1% formic acid in water containing 0.1% formic acid over 10 min) R_t=1.51 min. ESI-MS m/z calcd for C₄₀H₅₄N₉O₆⁺ [M−2Boc+H]⁺756.4, found 756.4.

[Figure (not displayed)]

Boc-Ala-D-Pra-D-Trp(Boc)-Ala-Trp(Boc)-D-Phe-Lys(allyl)-Rink Amide Resin RGO69:

o-NBS-protected heptapeptide RGO65 (˜300 mg, 0.10 mmol) in a syringe fitted with a Teflon™ filter was swollen in DMF (6 mL) and treated with DBU (150 μL, 1.00 mmol) and 2-mercaptoethanol (35 μL, 0.50 mmol). The mixture in the syringe was shaken for 1 h. The resin was filtered and sequentially washed with DMF (×3), MeOH (×3), THF (×3) and CH₂Cl₂(×3). Examination by LCMS of a cleaved resin sample (5 mg) showed complete o-NBS-removal: LCMS (20-80% MeOH containing 0.1% formic acid in water containing 0.1% formic acid over 10 min) R_t=4.79 min. ESI-MS m/z calcd for C₅₁H₆₄N₁₁O₇⁺ [M−3Boc+H]⁺942.5, found 942.5.

[Figure (not displayed)]

Boc-Ala-L-Pra-D-Trp(Boc)-Ala-Trp(Boc)-D-Phe-Lys(Allyl)-Rink Amide Resin RGO70:

o-NBS-protected heptapeptide RGO66 (˜300 mg, 0.09 mmol) in a syringe fitted with a Teflon™ filter was swollen in DMF (6 mL) and treated with DBU (130 μL, 0.87 mmol) and 2-mercaptoethanol (30 μL, 0.43 mmol). The mixture in the syringe was shaken for 1 h. The resin was filtered and sequentially washed with DMF (×3), MeOH (×3), THF (×3) and CH₂Cl₂(×3). Examination by LCMS of a cleaved resin sample (5 mg) showed complete o-NBS-removal: LCMS (20-80% MeOH containing 0.1% formic acid in water containing 0.1% formic acid over 10 min) R_t=5.05 min. ESI-MS m/z calcd for C₅₁H₆₄N₁₁O₇⁺ [M−3Boc+H]⁺942.5, found 942.5.

[Figure (not displayed)]

Cyclic Peptide MPE-110:

Hexapeptide resin RGO104 (˜600 mg, 0.156 mmol) was swollen in DMSO (6 mL) for 30 min in a syringe tube equipped with Teflon™ filter, and stopper, treated with CuI (5.0 mg, 0.03 mmol) and aqueous formaldehyde (70 μL, 0.94 mmol, 37% in H₂O), shaken on an automated shaker for 30 h, and filtered. After filtration, the resin was washed sequentially with AcOH/H₂O/DMF (5:15:80, v/v/v, ×3), DMF (×3), THF (×3), MeOH (×3), and DCM (×3). Examination by LCMS of a cleaved resin sample (5 mg) showed complete conversion, and a peak with molecular ion consistent with cyclic hexapeptide MPE-110 was observed: MS m/z calcd for Ca₄₁H₅₄N₉O₆⁺ [M+H]⁺ 768.4, found 768.4.

Resin-bound cyclic peptide MPE-110 was deprotected and cleaved from the support using a freshly made solution of TFA/H₂O/TES (95:2.5:2.5, v/v/v, 5 mL) at rt for 2 h. The resin was filtered and rinsed with TFA (5 mL). The filtrate and rinses were concentrated until a crude oil persisted, from which a precipitate was obtained by addition of cold ether (10 mL). After centrifugation (1200 rpm for 10 min), the supernatant was removed and the crude peptide precipitate was taken up in aqueous MeOH (10% v/v) and freeze-dried prior to purification. The resulting light brown fluffy material was purified by preparative HPLC to give cyclic pentapeptide MPE-110 (2.0 mg, 2%) as white fluffy material.

LCMS analysis of cyclic peptide MPE-110 was performed using a linear gradient of a) 10-90% of MeOH containing 0.1% formic acid in H₂O (0.1% formic acid) over 10 min, then at 10% MeOH (0.1% formic acid) for 5 min, R_t=4.24 min; b) 10-90% MeCN containing 0.1% formic acid in H₂O containing 0.1% formic acid over 10 min, then at 10% MeCN (0.1% formic acid) for 5 min, R_t=1.70 min; HRMS m/z. calcd for C₄₁H₅₄N₉O₆⁺ [M+H]⁺768.4192, found 768.4176.

[Figure (not displayed)]

Cyclic Peptide MPE-111:

Hexapeptide resin RGO105 (˜600 mg, 0.14 mmol) was swollen in DMSO (6 mL) for 30 min in a syringe tube equipped with Teflon™ filter, and stopper, treated with CuI (5.0 mg, 0.03 mmol) and aqueous formaldehyde (60 μL, 0.84 mmol, 37% in H₂O), shaken on an automated shaker for 30 h, and filtered. After filtration, the resin was washed sequentially with AcOH/H₂O/DMF (5:15:80, v/v/v, ×3), DMF (×3), THF (×3), MeOH (×3), and DCM (×3). Examination by LCMS of a cleaved resin sample (5 mg) showed complete conversion, and a peak with molecular ion consistent with cyclic hexapeptide MPE-111 was observed: MS m/z. calcd for C₄₁H₅₄N₉O₆⁺ [M+H]⁺ 768.4, found 768.4.

Resin-bound cyclic peptide MPE-111 was deprotected and cleaved from the support using a freshly made solution of TFA/H₂O/TES (95:2.5:2.5, v/v/v, 5 mL) at rt for 2 h. The resin was filtered and rinsed with TFA (5 mL). The filtrate and rinses were concentrated until a crude oil persisted, from which a precipitate was obtained by addition of cold ether (10 mL). After centrifugation (1200 rpm for 10 min), the supernatant was removed and the crude peptide precipitate was taken up in aqueous MeOH (10% v/v) and freeze-dried prior to purification. The resulting light brown fluffy material was purified by preparative HPLC to give cyclic hexapeptide MPE-111 (2.9 mg, 3%) as white fluffy material.

LCMS analysis of cyclic peptide MPE-111 was performed using a linear gradient of a) 10-90% of MeOH containing 0.1% formic acid in H₂O (0.1% formic acid) over 10 min, then at 10% MeOH (0.1% formic acid) for 5 min, R_t=4.50 min; b) 10-90% MeCN containing 0.1% formic acid in H₂O containing 0.1% formic acid over 10 min, then at 10% MeCN (0.1% formic acid) for 5 min, R_t=2.03 min; HRMS m/z. calcd for C₄₁H₅₄N₉O₆⁺ [M+H]⁺ 768.4192, found 768.4172.

[Figure (not displayed)]

Cyclic Peptide MPE-074:

Heptapeptide resin RGO69 (˜300 mg, 0.10 mmol) was swollen in DMSO (5 mL) for 30 min in a syringe tube equipped with Teflon™ filter, and stopper, treated with CuI (4.0 mg, 0.02 mmol) and aqueous formaldehyde (50 μL, 0.69 mmol, 37% in H₂O), shaken on an automated shaker for 29 h, and filtered. After filtration, the resin was washed sequentially with AcOH/H₂O/DMF (5:15:80, v/v/v, ×3), DMF (×3), THF (×3), MeOH (×3), and DCM (×3). Examination by LCMS of a cleaved resin sample (5 mg) showed complete conversion, and a peak with molecular ion consistent with cyclic heptapeptide MPE-074 was observed: MS m/z calcd for C₅₂H₆₃N₁₁NaO₇⁺ [M+Na]⁺976.5, found 976.4.

Resin-bound cyclic peptide MPE-074 was deprotected and cleaved from the support using a freshly made solution of TFA/H₂O/TES (95:2.5:2.5, v/v/v, 5 mL) at rt for 2 h. The resin was filtered and rinsed with TFA (5 mL). The filtrate and rinses were concentrated until a crude oil persisted, from which a precipitate was obtained by addition of cold ether (10 mL). After centrifugation (1200 rpm for 10 min), the supernatant was removed and the crude peptide precipitate was taken up in aqueous MeOH (10% v/v) and freeze-dried prior to purification. The resulting light brown fluffy material was purified by preparative HPLC to give cyclic heptapeptide MPE-074 (0.7 mg, 1%) as white fluffy material.

LCMS analysis of cyclic peptide MPE-074 was performed using a linear gradient of a) 10-90% of MeOH containing 0.1% formic acid in H₂O (0.1% formic acid) over 10 min, then at 10% MeOH (0.1% formic acid) for 5 min, R_t=1.72 min; b) 10-90% MeCN containing 0.1% formic acid in H₂O containing 0.1% formic acid over 10 min, then at 10% MeCN (0.1% formic acid) for 5 min, R_t=4.24 min; HRMS m/z calcd for C₅₂H₆₃N₁₁NaO₇⁺ [M+Na]⁺976.4804, found 976.4817.

[Figure (not displayed)]

Cyclic Peptide MPE-075:

Heptapeptide resin RGO69 (˜300 mg, 0.09 mmol) was swollen in DMSO (5 mL) for 30 min in a syringe tube equipped with Teflon™ filter, and stopper, treated with CuI (3.0 mg, 0.02 mmol) and aqueous formaldehyde (50 μL, 0.69 mmol, 37% in H₂O), shaken on an automated shaker for 29 h, and filtered. After filtration, the resin was washed sequentially with AcOH/H₂O/DMF (5:15:80, v/v/v, ×3), DMF (×3), THF (×3), MeOH (×3), and DCM (×3). Examination by LCMS of a cleaved resin sample (5 mg) showed complete conversion, and a peak with molecular ion consistent with cyclic heptapeptide MPE-075 was observed: MS m/z calcd for C₅₂H₆₄N₁₁O₇⁺ [M+H]⁺ 954.5, found 954.5.

Resin-bound cyclic peptide MPE-075 was deprotected and cleaved from the support using a freshly made solution of TFA/H₂O/TES (95:2.5:2.5, v/v/v, 5 mL) at rt for 2 h. The resin was filtered and rinsed with TFA (5 mL). The filtrate and rinses were concentrated until a crude oil persisted, from which a precipitate was obtained by addition of cold ether (10 mL). After centrifugation (1200 rpm for 10 min), the supernatant was removed and the crude peptide precipitate was taken up in aqueous MeOH (10% v/v) and freeze-dried prior to purification. The resulting light brown fluffy material was purified by preparative HPLC to give cyclic heptapeptide MPE-075 (1.5 mg, 2%) as a white fluffy material.

LCMS analysis of cyclic peptide MPE-075 was performed using a linear gradient of a) 10-90% of MeOH containing 0.1% formic acid in H₂O (0.1% formic acid) over 10 min, then at 10% MeOH (0.1% formic acid) for 5 min, R_t=1.89 min; b) 10-90% MeCN containing 0.1% formic acid in H₂O containing 0.1% formic acid over 10 min, then at 10% MeCN (0.1% formic acid) for 5 min, R_t=4.47 min; HRMS m/z calcd for C₅₂H₆₄N₁₁O₇⁺ [M+H]⁺ 954.4985, found 954.4973.

Ornithine as AA1

[Figure (not displayed)]

Fmoc-Orn(o-NBS)-Rink Amide Resin RGO3:

Rink amide resin (2.51 g) was placed in a syringe fitted with a Teflon™ filter. The Fmoc group was removed by treating the resin with a solution of 20% piperidine in DMF over 30 min. The resin was filtered and washed sequentially with DMF (×3), MeOH (×3) and CH₂Cl₂(×3). Fmoc-Orn(o-NBS)—OH (1.33 g, 2.46 mmol) was dissolved in DMF (20 mL) and treated with DIC (0.57 mL, 3.68 mmol) and HOBt (494 mg, 3.66 mmol) and stirred for 3 min, before being transferred to the syringe containing the swollen resin, and the mixture was shaken for 14 hours. The resin was filtered and washed sequentially with DMF (×3), MeOH (×3) and CH₂Cl₂(×3). The resin was dried and the loading was measured to 0.187 mmol/g resin.

[Figure (not displayed)]

Fmoc-Orn(o-NBS, Allyl)-Rink Amide Resin RGO4:

Vacuum dried Fmoc-Orn(o-NBS)-resin (0.362 mmol) was placed in a syringe fitted with a Teflon™ filter, suspended in THF (dry, 20 mL) and treated sequentially with solutions of allyl alcohol (250 μL, 3.68 mmol) in THF (dry, 1 mL), PPh₃(482 mg, 1.84 mmol) in THF (dry, 2 mL) and DIAD (360 μL, 1.83 mmol) in THF (dry, 1 mL). The resin mixture in the syringe was shaken for 90 min. The resin was filtered and washed sequentially with DMF (×3), MeOH (×3), THF (×3) and CH₂Cl₂(×3). Examination by LCMS of a cleaved resin sample (5 mg) showed complete allylation: LCMS (30-95% MeOH containing 0.1% formic acid in water containing 0.1% formic acid over 10 min) R_t=8.47 min. ESI-MS m/z calcd for C₂₉H₃₁N₄O₇S⁺ [M+H]⁺579.2, found 579.2.

[Figure (not displayed)]

Fmoc-D-Trp(Boc)-Ala-Trp(Boc)-D-Phe-Orn(o-NBS, Allyl)-Rink Amide Resin RGO22:

LCMS (30-95% MeOH containing 0.1% formic acid in water containing 0.1% formic acid over 10 min) R_t=6.13 min. ESI-MS m/z calcd for C₄₈H₅₅N₁₀O₉S⁺ [M-Fmoc-2Boc+H]⁺947.4, found 947.3.

[Figure (not displayed)]

Fmoc-azaPra-D-Trp(Boc)-Ala-Trp(Boc)-D-Phe-Orn(o-NBS, Allyl)-Rink Amide Resin RGO79:

N′-Propargyl-fluorenylmethylcarbazate (248 mg, 0.849 mmol, prepared by alkylation of fluorenylmethylcarbazate with propargyibromide as —N(R¹⁰)— described below) was dissolved in CH₂Cl₂(dry, 40 mL) under argon atmosphere. The solution was cooled to 0° C., treated with a 20% solution of phosgene in toluene (1 mL, 1.87 mmol), warmed to rt, stirred 50 min, and the volatiles were removed by rotary evaporation. The residue was re-dissolved in CH₂Cl₂(10 mL) and the volatiles were once again removed by rotary evaporation. The resulting white solid was dissolved in CH₂Cl₂(dry, 7 mL) and added to the Fmoc-deprotected pentapeptide RGO22 in a syringe fitted with a Teflon™ filter. The mixture in the syringe was shaken for 28 h. The resin was filtered and washed sequentially with DMF (×3), MeOH (×3), THF (×3) and CH₂Cl₂(×3). Examination by LCMS of a cleaved resin sample (5 mg) showed complete coupling: LCMS (30-95% MeOH containing 0.1% formic acid in water containing 0.1% formic acid over 10 min) R_t=8.26 min. ESI-MS m/z calcd for C₅₂H₅₉N₁₂O₁₀S⁺ [M-Fmoc-2Boc+H]⁺1043.4, found 1043.3.

[Figure (not displayed)]

Boc-Ala-azaPra-D-Trp(Boc)-Ala-Trp(Boc)-D-Phe-Orn(o-NBS, Allyl)-Rink Amide RGO29:

Coupling onto the semicarbazide RGO79 was performed by using amino acid symmetric anhydrides that were generated in situ (J. Zhang, C. Proulx, A. Tomberg, W. D. Lubell, Org. Lett. 2013, 16, 298-301). The procedure was repeated twice on semicarbazide RGO79. Examination by LCMS of a cleaved resin sample (5 mg) showed complete coupling: LCMS (30-95% MeOH containing 0.1% formic acid in water containing 0.1% formic acid over 10 min) R_t=6.39 min. ESI-MS m/z calcd for C₅₅H₆₄N₁₃O₁₁S⁺ [M−3Boc+H]⁺1114.5, found 1114.4.

[Figure (not displayed)]

Boc-Ala-azaPra-D-Trp(Boc)-Ala-Trp(Boc)-D-Phe-Orn(Allyl)-Rink Amide RGO30:

o-NBS-protected hetapeptide RGO29 (˜1 g, 0.2 mmol) in a syringe fitted with a Teflon™ filter was swollen in DMF (6 mL) and DBU (300 μL, 2.01 mmol) and treated with 2-mercaptoethanol (70 μL, 1.00 mmol). The mixture in the syringe was shaken for 1 h. The resin was filtered and washed sequentially with DMF (×3), MeOH (×3), THF (×3) and CH₂Cl₂(×3). Examination by LCMS of a cleaved resin sample (5 mg) showed complete o-NBS-removal: LCMS (30-95% MeOH containing 0.1% formic acid in water containing 0.1% formic acid over 10 min) R_t=4.49 min. ESI-MS m/z calcd for C₄₉H₆₁N₁₂O₇⁺ [M−3Boc+2Na]²⁺487.2, found 487.3.

[Figure (not displayed)]

Cyclic Azapeptide MPE-048:

Azaheptapeptide resin RGO30 (˜1 g, 0.2 mmol) was swollen in DMSO (8 mL) for 30 min in a syringe tube equipped with Teflon™ filter, and stopper, treated with CuI (7.0 mg, 0.04 mmol) and aqueous formaldehyde (90 μL, 1.2 mmol, 37% in H₂O), shaken on an automated shaker for 31 h, and filtered. After filtration, the resin was washed sequentially with AcOH/H₂O/DMF (5:15:80, v/v/v, ×3), DMF (×3), THF (×3), MeOH (×3), and DCM (×3). Examination by LCMS of a cleaved resin sample (5 mg) showed complete conversion, and a peak with molecular ion consistent with cyclic azaheptapeptide MPE-048 was observed: MS m/z calcd for C₅₀H₆₁N₁₂O₇⁺[M+H]⁺941.5, found 941.4.

Resin-bound cyclic azapeptide MPE-048 was deprotected and cleaved from the support using a freshly made solution of TFA/H₂O/TES (95:2.5:2.5, v/v/v, 5 mL) at rt for 2 h. The resin was filtered and rinsed with TFA (5 mL). The filtrate and rinses were concentrated until a crude oil persisted, from which a precipitate was obtained by addition of cold ether (10 mL). After centrifugation (1200 rpm for 10 min), the supernatant was removed and the crude peptide precipitate was taken up in aqueous MeOH (10% v/v) and freeze-dried prior to purification. The resulting light brown fluffy material was purified by preparative HPLC to give cyclic azaheptapeptide MPE-048 (1.3 mg, 1%) as white fluffy material.

LCMS analysis of cyclic peptide MPE-048 was performed using a linear gradient of a) 10-90% of MeOH containing 0.1% formic acid in H₂O (0.1% formic acid) over 10 min, then at 10% MeOH (0.1% formic acid) for 5 min, R_t=1.80 min; b10-90% MeCN containing 0.1% formic acid in H₂O containing 0.1% formic acid over 10 min, then at 10% MeCN (0.1% formic acid) for 5 min, R_t=4.30 min; HRMS m/z calcd for C₅₀H₆₀N₁₂O₇Na⁺ [M+Na]⁺963.4600, found 963.4573.

Synthesis of Cyclic Analogs MPE-189, MPE-201, MPE-202, and MPE-203

Synthesis of Carbazates 2 and 3

[Figure (not displayed)]

To a well-stirred solution of fluorenylmethyl carbazate (1, 1 eq., 2.8 g, 11 mmol, prepared according to reference 1) and DIEA (2 eq., 2.85 g, 3.64 mL, 22 mmol) in dry DMF (280 mL) at 0° C., a solution of 3-bromopropyne (0.9 eq., 1.47 g, 1.07 mL, 9.91 mmol, 80 wt. % in toluene) in dry DMF (10 mL) was added drop-wise by cannula over 30 min. The cooling bath was removed. The reaction mixture was allowed to warm to room temperature and stirred for 16 h. The volatiles were evaporated. The residue was partitioned between EtOAc and brine. The aqueous layer was separated and extracted with EtOAc. The combined organic layer was dried over Na₂SO₄, filtered, and evaporated. The residue was purified by silica gel chromatography eluting with 40% EtOAc in hexane as solvent system to obtain N′-propargyl-fluorenylmethylcarbazate 3 (1.8 g, 62%), as white solid: R_f0.42 (60% EtOAc); mp 148-149° C.; ¹H NMR (500 MHz, DMSO-d₆) δ 8.82 (s, 1H), 7.89 (d, J=7.5 Hz, 2H), 7.70 (d, J=7.4 Hz, 2H), 7.50-7.43 (m, 2H), 7.37-7.28 (m, 2H), 4.89 (q, J=4.6 Hz, 1H), 4.29 (d, J=6.9 Hz, 2H), 4.22 (t, J=6.1 Hz, 1H), 3.48 (s, 2H), 3.09 (t, J=2.3 Hz, 1H); ¹³C NMR (125 MHz, DMSO-d₆) δ 156.7, 143.8, 140.7, 127.7 (2C), 127.1 (2C), 125.3 (2C), 120.1 (2C), 81.2, 74.2, 65.6 (2C), 46.6, 39.6 (2C). IR (neat) vmax/cm-1 3304, 3290, 2947, 1699, 1561, 1489, 1448, 1265, 1159, 1021; HRMS m/z calculated for C₁₈H₁₇N₂O₂[M+H]⁺293.1285; found 293.1275.

US11879021B2. Cyclic peptides and uses thereof (2024-01-23). UNIVERSITÉ DE MONTRÉAL [CA]. Inventors: William D. Lubell [CA], Huy Ong [CA], Jinqiang Zhang [CN], Dilan Mukandila Mulumba [CA], Sylvie Marleau [CA], Ragnhild Gaard Ohm [DK], Ahsanullah [CA], Samy Omri [CA], Ramesh Chingle [US].

Patent 2024

1-hydroxybenzotriazole 1H NMR 2-Mercaptoethanol 5A peptide Acylation Alanine Alcohols Aldehydes Alkylation allyl alcohol Amides Amines Amino Acids Anabolism Anhydrides Argon Atmosphere Bath benzophenone Biopharmaceuticals brine Bromides Cannula carbamylhydrazine carbazate Carbon-13 Magnetic Resonance Spectroscopy Carbonates Cardiac Arrest Centrifugation Chromatography Cold Temperature Copper Cyclic Peptides Cyclization Cytokinesis Dipeptides Ethers Filtration Formaldehyde formic acid Freezing Gel Chromatography growth hormone releasing hexapeptide H 1285 Hexanes High-Performance Liquid Chromatographies Histidine Hydrazones Hydroxylamine Hydroxylamine Hydrochloride Isopropyl Alcohol Light Lincomycin Methanol methylamine N,N-diisopropylethylamine N-propargyl Nitrogen Ornithine Peptide Biosynthesis Peptides Petroleum Phosgene piperidine polypeptide C Polystyrenes propargylamine propargylglycine pyridine pyridine hydrochloride Resins, Plant Rink amide resin Semicarbazides Semicarbazones Silica Gel Silicon Dioxide Solvents Sulfate, Magnesium Sulfonamides Sulfoxide, Dimethyl Syringes Teflon tert-butoxycarbonylalanine Toluene Training Programs Tryptophan Vacuum

Chitosan Nanofibers for Tissue Engineering

Not available on PMC !

Example 5

To further explore the potential of the electrospun chitosan nanofibers in tissue engineering applications, osteoblast proliferation on the membrane of electrospun chitosan nanofibers was examined by Celltiter Glo Assay Kit. As shown in FIG. 12, there was no statistical difference in the day 5 growth of cells on chitosan compared with acylated (acetyl- and butyryl-) and deacylated electrospun chitosan nanofiber membranes, suggesting the electrospun chitosan nanofibers membranes were non-toxic.

The cell morphology on the materials was visualized with fluorescence microscope after osteoblast cells were cultured on the top of the materials for 5 days. The cells grown on the electrospun chitosan nanofibers showed characteristic shapes associated with osteoblast cells, such as elongated/stretched shape, suggesting the material did not interfere with the growth of the osteoblasts.

These surprising results suggested that the problems with dissolution and swelling observed with electrospun chitosan fiber membranes can be solved by the reversible acylation method. The mechanisms behind the process were elucidated based on the data obtained from the FTIR, XPS and SEM analyses. The acylation method could potentially be used to synthesize other modified chitoan nanofibrous material containing acyl moieties as well.

US11878088B2. Chitosan nanofiber compositions, compositions comprising modified chitosan, and methods of use (2024-01-23). The University of Memphis Research Foundation [US]. Inventors: Joel D. Bumgardner [US], Hengjie Su [US], Tomoko Fujiwara [US], Daniel G. Abebe [US], Kwei-Yu Liu [US].

Patent 2024

Acylation Biological Assay Cell Proliferation Cells Chitosan Fibrosis Microscopy, Fluorescence Osteoblasts Somatostatin-Secreting Cells Spectroscopy, Fourier Transform Infrared Tissue, Membrane

Synthesis of PCAN Component 4 from Pt Dicarbonates

Not available on PMC !

Example 45

PCAN component 4 can be synthesized as follows. Related Pt dicarbonates (129551-82-2, 129551-94-6, 160953-30-0, Inorganic Chemistry (1995), 34(5), 1015-2, EP 328274 A1 19890816) have been made from [62928-11-4] and pyrocarbonates. Acylation of OH groups on Pt⁴⁺ is well known. Accordingly, reaction of CBD and [62928-11-4] with phosgene or an appropriate surrogate reagent system forms the carbonate link between the cannabinoid and platinum. Alternatively, Pt⁴⁺ OH groups can react with alkyl carbonates to form new alkyl carbonates; thus, it may also be possible to generate the reagent where both X groups are CBD and react it with the Pt reagent.

[Figure (not displayed)]

US11877988B2. Conjugate molecules (2024-01-23). Diverse Biotech, Inc. [US]. Inventors: Paul Hershberger [US], Philip Arlen [US].

Patent 2024

Acylation Anabolism Cannabinoids Carbonates Phosgene Platinum

Synthesis of 13C-Labeled Aromatic Compounds

The compound with a ¹³C label in each position of the aromatic ring is prepared in a Friedel–Crafts acylation of ¹³C-labelled phenol with 2-bromoacetyl chloride,^{47 (link)} followed by reaction with NH₄SCN. The same reaction is used for the preparation of the derivative with a ¹³C label in the LG, using KS¹³CN instead. For synthesis and characterization details, see the ESI and Fig. S1–S7.† NMR, high resolution mass spectrometry (HRMS) and IR spectroscopy confirmed the isotope incorporation. For the laser experiments, the samples are dissolved in D₂O (Eurisotop) and acetonitrile (MeCN; Sigma-Aldrich), and dried with a molecular sieve before use.

van Wilderen L.J., Kern-Michler D., Neumann C., Reinfelds M., von Cosel J., Horz M., Burghardt I., Heckel A, & Bredenbeck J. (2023). Choose your leaving group: selective photodeprotection in a mixture of pHP-caged compounds by VIPER excitation. Chemical Science, 14(10), 2624-2630.

Publication 2023

acetonitrile Acylation Anabolism Chlorides Isotopes Mass Spectrometry Phenol Spectrum Analysis

Top products related to «Acylation»

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Superscript III is a reverse transcriptase enzyme produced by Thermo Fisher Scientific. It is designed for cDNA synthesis from RNA templates during the process of reverse transcription.

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The 2-D Quant Kit is a laboratory equipment used for protein quantification. It provides a simple and accurate method for determining the concentration of proteins in complex biological samples.

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The Zorbax SB-C18 column is a high-performance liquid chromatography (HPLC) column designed for the separation and analysis of a wide range of compounds. It features a silica-based stationary phase with n-octadecylsilane (C18) ligands, which provides reversible phase chromatography for the separation of both polar and non-polar analytes.

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Ab104139 is a primary antibody product offered by Abcam. It is intended for use in various research applications. The core function of this product is to bind to a specific target, but a detailed description cannot be provided while maintaining an unbiased and factual approach.

What are the most common types of acylation reactions?

Acylation reactions can involve a variety of substrates, including alcohols, amines, and aromatic compounds. Some of the most common types of acylation include acetylation, benzoylation, and formylation, where an acetyl, benzoyl, or formyl group is introduced into the target molecule, respectively. The specific type of acylation used often depends on the desired structural modifications and the properties needed for the final compound.

What are some common challenges researchers face when optimizing acylation protocols?

Researchers studying acylation may encounter challenges such as achieving complete conversion, minimizing side reactions, controlling regioselectivity, and ensuring high purity of the final product. The reaction conditions, stoichiometry, and choice of acylating agent can all significantly impact the outcome of the acylation. Additionally, scale-up from lab to production scale can introduce further complexities that need to be addressed.

How can PubCompare.ai help researchers optimize their acylation protocols?

PubCompare.ai's AI-powered platform can assist researchers in optimizing their acylation protocols in several ways. First, it allows you to quickly screen the literature, preprints, and patents to identify the most effective acylation methods for your specific research goals. The platform's AI-driven analysis can highlight key differences in protocol effectiveness, enabling you to choose the best option for reproducibility and accuracy. Additionally, PubCompare.ai's intuitive tools can help you streamline your research and accelerate your discoveries by guiding you towards the most efficient and effective acylation protocols.

What are some common applications of acylation reactions in organic synthesis and medicinal chemistry?

Acylation reactions are widely used in organic synthesis and medicinal chemistry to modify the structure and properties of compounds. Some common applications include the synthesis of pharmaceuticals, the preparation of prodrugs, the introduction of protective groups, and the derivatization of natural products or biomolecules. Acylation can be a key step in the synthesis of many important chemicals, as it allows for the introduction of specific functional groups that can impart desirable pharmacological, physicochemical, or reactivity characteristics to the final product.

How can researchers use PubCompare.ai to identify the most effective acylation protocols from the literature?

Researchers can leverage PubCompare.ai's AI-powered platform to quickly and efficiently identify the most effective acylation protocols from the literature, preprints, and patents. The platform's advanced search and filtration tools allow you to easily find relevant protocols, while the AI-driven analysis can highlight key differences in factors like reaction yield, reaction time, and selectivity. This enables you to make informed decisions about which acylation protocols are best suited for your specific research needs and goals. With PubCompare.ai, you can streamline your literature search, optimize your experimental design, and accelerate your discoveries in the field of acylation chemistry.

More about "Acylation"

Acylation is a fundamental chemical process that involves the introduction of an acyl group, such as an acetyl or benzoyl moiety, into a molecule.
This versatile reaction is widely utilized in organic synthesis and medicinal chemistry to modify the structure and properties of compounds.
Acylation can be performed on a variety of substrates, including alcohols, amines, and aromatic compounds, making it a crucial step in the synthesis of many pharmaceutical drugs and other important chemicals.
Researchers studying acylation reactions can leverage the power of PubCompare.ai's AI-powered platform to effortlessly locate the best protocols from literature, preprints, and patents.
This platform enables researchers to identify the most effective methods and products, streamlining their research and accelerating their discoveries.
Synonyms and related terms for acylation include acetylation, benzoylation, and esterification.
The process may involve the use of reagents such as Superscript III, 2-D Quant Kit, N,N-dimethylformamide (DMF), piperidine, benzoyl cyanide, and thionyl chloride.
Analytical tools like Xcalibur software and Zorbax SB-C18 column can be employed to characterize and purify the acylated products.
By harnessing the insights and capabilities of PubCompare.ai's intuitive tools, scientists can optimize their acylation research protocols and make breakthroughs more efficiently.
The platform's AI-driven comparisons and data-driven insights can help researchers identify the most effective methods and products, ultimately accelerating their scientific discoveries.