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Ethylamine

Q: What are some common uses and applications of Ethylamine?

Ethylamine has a variety of applications in the chemical industry. It is used as a building block in the synthesis of various organic compounds, including pharmaceuticals, pesticides, and other specialty chemicals. Ethylamine also finds use as a pH regulator, a reducing agent, and a catalyst in various chemical reactions.

Q: What are the different variations or types of Ethylamine?

Ethylamine primarily exists in its base form as a colorless gas. However, it can also be found in solution, typically as an aqueous solution. The concentration of Ethylamine in these solutions can vary depending on the specific application or formulation.

Q: What are some common challenges or considerations when using Ethylamine?

Ethylamine is a flammable and odorous gas, so proper handling and storage precautions are necessary. It can also be corrosive to certain materials, so compatibility with equipment and containers must be evaluated. Additionally, Ethylamine is a volatile compound, so evaporation and containment may be a consideration in some applications.

Ethylamine is a primary aliphatic amine with the chemical formula C2H7N.
It is a colorless, flammable gas with a fishy odor, commonly used in the synthesis of various organic compounds and pharmaceuticals.
Ethylamine plays a role in biochemical processes and has applications in the chemical industry.
Researchers can discover optimized Ethylamine research protocols using PubCompare.ai's AI-powered platform, which helps locate relevant literature, preprints, and patents, and leverages AI-driven comparisons to identify the best protocols and products for enhanced reproducibility and acccuracy.
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Most cited protocols related to «Ethylamine»

Detailed Protocol for AMOEBA Force Field

Cited 10 times

The atomic polarizabilities are listed for each AMOEBA atom type in Table 1. The values are the same as those derived by Thole⁶² except for aromatic carbon and hydrogen atoms which have been systematically refined using a series of aromatic systems, including a small carbon nanotube (see Table 3). The molecular polarizabilities computed using the current model are compared to experimental values for selected compounds in Table 2. Reducing the damping factor from Thole’s original value of 0.567 to AMOEBA’s 0.39 is critical to correctly reproducing water cluster energetics.¹⁸ On the other hand, AMOEBA’s greater damping leads to a slight systematic underestimation of molecular polarizabilities. However, given the simplicity of the model, the agreement is generally satisfactory for both average polarizabilities and their anisotropies. As described above, polarization groups are defined for purposes of treating intramolecular polarization. Typically a functional group is treated as a single polarization group. For example, methylamine is a group by itself, while ethylamine has two groups: –CH₂NH₂ and CH₃–. The groups are specified in AMOEBA parameter files in the following format: “polarize A α 0.390 B C”, where α is the polarizability for atom type A; 0.39 is the damping coefficient in Eq (2); B and C are possible bonded atom types that belong to the same polarization group as atom type A.
The permanent atomic multipoles were derived for each molecule from ab initio QM calculations. Ab initio geometry optimization and a subsequent single-point energy evaluation were performed at the MP2/6-311G(1d,1p) level using Gaussian 03.⁷⁸ For small molecules with less than six heavy atoms, Distributed Multipole Analysis (DMA v1.2⁷⁹) was used to compute the atomic multipole moments in the global frame using the density matrix from the QM calculation. Next, the TINKER POLEDIT program rotates the atomic multipoles into a local frame and extracts Thole-based intramolecular polarization to produce permanent atomic multipole (PAM) parameters. Thus, when the AMOEBA polarization model is applied to the permanent atomic moments, the original ab initio-derived DMA is recovered. Finally, the POTENTIAL program from the TINKER package is used to optimize the permanent atomic multipole parameters by fitting to the electrostatic potential on a grid of points outside the vdW envelope of the molecule. The reference potential for the fitting step is typically derived from a single point calculation at the MP2/aug-cc-pVTZ level. Only a partial optimization to the potential grid is used to keep the atomic moments close to their DMA-derived values while still providing an improved molecular potential. The fitting approach is also useful for molecules containing symmetry-averaged atoms of the same atomic multipole type. In this case, simple arithmetic averaging would degrade the quality of the PAM. For example, in dimethyl- or trimethylamine, all the methyl hydrogen atoms are indistinguishable and adopt the same atom type. The DMA multipole values for these atoms are somewhat different due their non-equivalence in any single conformation, and PAM derived by simple averaging would lead to a large error in the molecular dipole moment. The potential-optimized PAM, where methyl hydrogens are constrained to adopt equivalent values, will reproduce almost exactly both the ab initio potential and the molecular multipole moments. Our standard procedure is to use a molecular potential grid consisting of a 2 Å shell beginning 1 Å out from the vdW surface. The DMA monopole values are generally fixed during the potential fitting procedure.
This electrostatic parameterization protocol is particularly important for larger molecules and for molecules with high symmetry. It is known that the original DMA approach tends to give “unphysical’ multipole values for large molecules when diffuse functions are included in the basis set even though the resulting electrostatic potential is correct. A recent modification of DMA⁸⁰ has been put forward to address this issue. However, in our hands, the multipoles from the modified scheme seem less transferable between conformations. The above protocol allows derivation of PAM corresponding to larger basis sets than would be practical with the original DMA method. Note this procedure is different from restrained potential fits commonly used to fit fixed atomic charge models, as the starting DMA values are already quite reasonable and the fitting can be considered as a small perturbation biased toward the larger basis set potential. The overall procedure has been extensively tested in a small molecule hydration study^{81 (link)} and will be used in future AMOEBA parameterization efforts.
Empirical vdW parameters were determined by fitting to both gas and liquid phase properties. The gas phase properties include homodimer binding energy (BSSE corrected) and structure from ab initio calculations at the MP2/aug-cc-pVTZ level or above. Liquid properties include experimental density and heat of vaporization of neat liquids. The vdW parameters were first estimated by comparing structure and energy of the AMOEBA-optimized dimer with ab initio results, and then fine-tuned to reproduce the experimental liquid density and heat of vaporization via molecular dynamics simulation. Additional homodimers at alternative configurations, heterodimers with water, and liquid properties were computed post facto for the purpose of validation. A more generic force field atom classification for vdW parameters was enforced to ensure the transferability. Table 1 lists the common vdW atom classes used by AMOEBA, together with the corresponding vdW parameters and polarizabilities. The vdW atom classes are also used to define parameters for all of the valence potential energy terms. The parameters for bonded terms, initially transferred from MM3, are optimized to reproduce ab initio geometries and vibration frequencies. In the final parameterization step, after all other parameters are fixed, torsional parameters were obtained by fitting to ab initio conformational energy profiles at the MP2/6-311++(2d,2p) level of theory.

Ren P., Wu C, & Ponder J.W. (2011). Polarizable Atomic Multipole-based Molecular Mechanics for Organic Molecules. Journal of chemical theory and computation, 7(10), 3143-3161.

Publication 2011

Comprehensive Multi-omics Profiling of Cellular Metabolism

Cited 8 times

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Publication 2015

Synthesis of N6-Substituted Adenosine Analogues

Cited 5 times

DBU (1.5 mmol) was added dropwise to a stirred solution of inosine (1 mmol) and BOP (1.2 mmol) in DMF; the mixture was then heated at 40 °C. After the consumption of starting material (approximately 40 min, as assessed by TLC), the reaction was cooled to room temperature and the appropriate amine (5 mmol) was added dropwise and the reaction was stirred overnight. The crude product mixture was concentrated under reduced pressure, then diluted with ethyl acetate and was washed with water (3 × 10 mL). The organic layer was dried (anhydrous MgSO₄) and concentrated under vacuum. The resulted solid was recrystallised twice from iso-propanol.
N⁶-Methyladenosine (1). The desired product was prepared according to General Procedure A; white solid (250 mg, 90%). m.p 214.5 °C; ¹H-NMR (500 MHz, D₂O) δ 2.93 (s, 3H), 3.74 (dd, J = 13.0, 3.5 Hz, 1H), 3.83 (dd, J = 13.0, 2.5 Hz, 1H), 4.20 (q, J = 3.0 Hz, 1H), 4.32 (dd, J = 5.0, 3.0 Hz, 1H), 4.66 (t, J = 5.5 Hz, 1H), 5.90 (d, J = 6.0 Hz, 1H), 8.02 (s, 1H), 8.11 (s, 1H); ¹³C-NMR (126 MHz, D₂O) δ 27.5, 62.1, 71.1, 74.0, 88.36, 88.39, 120.0, 140.1, 152.9, 155.6. HRMS (ESI) m/z: calculated for C₁₁H₁₆O₄N₅ [M + H]⁺ 282.1197, observed: 282.1196.
3′,5′-O-(Di-tert-butyl)silyl-2′-O-dimethyl(tert-butyl)silylinosine (2). The desired compound was prepared according to a modified version of the reported procedure [22 (link)]. To a stirred suspension of inosine (2.12 g, 8 mmol) in 40 mL anhydrous DMF at 0 °C, di-t-butylsilyl ditrifluoromethanesulfonate (3.0 mL, 8.8 mmol) was added dropwise under an N₂ atmosphere. After consumption of starting material (30 min, as assessed by TLC), the reaction was quenched immediately with imidazole (2.7 g, 40 mmol) at 0 °C. After 5 min, the reaction was warmed to room temperature. t-Butyldimethylsilyl chloride (1.5 g, 9.6 mmol) was then added portionwise and the reaction was refluxed at 60 °C for 12 h. The suspension was then cooled to room temperature, water was added, and the precipitate was collected by suction filtration. The filtrate was discarded, and the white precipitate was washed with cold methanol. The methanol layer was evaporated under reduced pressure and the product was crystallised from CH₂Cl₂ to give a white solid (4.0 g, 98%). m.p 191–193.4 °C. TLC R_f 0.45 (3:2 cyclohexane/ethyl acetate); ¹H NMR (600 MHz, CDCl₃) δ 0.17 (s, 3H), 0.18 (s, 3H), 0.96 (s, 9H), 1.07 (s, 9H), 1.10 (s, 9H), 4.02–4.09 (m, 1H), 4.25 (td, J = 10.0, 5.0 Hz, 1H), 4.38 (dd, J = 9.5, 4.5 Hz, 1H), 4.45–4.58 (m, 2H), 5.96 (s, 1H), 7.87 (s, 1H), 8.11 (s, 1H), 12.56 (s, 1H); ¹³C NMR (151 MHz, CDCl₃) δ −5.0, −4.3, 18.3, 20.4, 22.8, 25.9, 27.0, 27.5, 67.8, 74.8, 75.89, 75.94, 92.3, 125.5, 138.3, 144.7, 148.1, 158.9; HRMS (ESI) m/z: calculated for C₂₄H₄₃O₄N₅²⁸Si₂ [M + H]⁺ 523.2767, observed: 523.2756.
3′,5′-O-Bis(tert-butyl)silyl-2′-O-(tert-butyldimethyl)silyl-N⁶-methyladenosine (3). The desired compound was prepared according to a modified version of the reported procedure [10 (link)]. To a stirred solution of 3′,5′-O-Bis(tert-butylsilyl)-2′-O-(tert-butyldimethylsilyl)inosine (2; 663 mg, 1.2 mmol) and BOP (0.64 g, 1.44 mmol) in 20 mL of THF, DBU (0.3 mL, 1.8 mmol) was added dropwise and the mixture was heated at 40 °C. After the consumption of the starting material (40 min, as assessed by TLC), the reaction was cooled to room temperature and methylamine (0.3 mL, 6.0 mmol) was added dropwise and the reaction was stirred overnight. The crude product mixture was concentrated under reduced pressure and diluted with ethyl acetate and was washed with water (3 × 10 mL). The organic layer was dried (anhydrous MgSO₄) and concentrated under vacuum. The residue was purified by column chromatography (9:1 to 3:2 cyclohexane/ethyl acetate) which resulted in an oil (665 mg, 98%). TLC R_f 0.20 (7:3 cyclohexane/ethyl acetate); ¹H NMR (400 MHz, CDCl₃) δ 0.00 (s, 3H) 0.02 (s, 3H) 0.78 (s, 9H) 0.90 (s, 9H) 0.94 (s, 9H) 3.05 (d, J = 1.0 Hz, 3H) 3.86–3.90 (m, 1H) 4.02–4.10 (m, 1H) 4.34 (dd, J = 9.0, 5.0 Hz, 1 H) 4.38–4.44 (m, 1 H) 4.47 (d, J = 4.5 Hz, 1 H) 5.76 (b.s, 2 H) 7.62 (s, 1 H) 8.22 (s, 1 H); ¹³C NMR (101 MHz, CDCl₃) δ −5.0, −4.3, 18.3, 20.4, 22.8, 25.9, 27.1, 27.5, 27.6, 67.9, 74.6, 75.5, 75.8, 92.4, 120.5, 125.0, 138.0, 153.4, 155.5; HRMS (ESI) m/z: calculated for C₂₅H₄₆O₄N₅²⁸Si₂ [M + H]⁺ 536.3082, observed: 536.3078. Analytical data are consistent with those reported [4 (link)].
2′-O-(tert-Butyldimethyl)silyl-N⁶-methyladenosine (4). The desired compound was prepared according to the reported procedure [4 (link)]. To a stirred solution of 3′,5′-O-Bis(tert-butylsilyl)-2′-O-(tert-butyldimethylsilyl)-N⁶-methyladenosine (3; 240 mg, 0.45 mmol) in 4 mL of CH₂Cl₂ at −15 °C, a cooled solution of (HF)_x·pyridine (0.06 mL, 2.3 mmol) in 365 μL pyridine was added. The reaction temperature was maintained at -15 °C and stirred for 12 h. The reaction was diluted with CH₂Cl₂, then washed first with sat. aq. NaHCO₃ solution, then with water (3 × 10 mL). The organic layer was dried (anhydrous MgSO₄) and concentrated under reduced pressure. The residue was purified by column chromatography (9:1 to 3:2 cyclohexane/ethyl acetate) which resulted in oil (160 mg, 90%). TLC R_f 0.15 (2:3 hexane/ethyl acetate); ¹H-NMR (400 MHz, CDCl₃) δ 0.00 (s, 3H), 0.02 (s, 3H), 0.94 (s, 9H), 3.42 (d, J = 1.0 Hz, 3H), 3.89 (dd, J = 10.5, 9.0 Hz, 1H), 4.01–4.11 (m, 1H), 4.34 (dd, J = 9.0, 5.0 Hz, 1H), 4.41 (dd, J = 9.0, 5.0 Hz, 1H), 4.47 (d, J = 5.0 Hz, 1H), 5.76 (s, 2H), 7.62 (s, 1H), 8.22 (s, 1H); ¹³C NMR (101 MHz, CDCl₃) δ −5.4, −5.3, 17.9, 25.6, 25.8, 27.5, 63.5, 73.1, 74.4, 87.8, 91.3, 119.7, 140.0, 140.1, 152.9, 155.8; HRMS (ESI) m/z: calculated for C₁₇H₃₀O₄N₅²⁸Si [M + H]⁺ 396.2062, observed: 396.2068. Analytical data are consistent with those reported [4 (link)].
5′-O-(4,4′-Dimethoxytrityl)−2′-O-dimethyl(tert-butyl)silyl-N6-methyladenosine (5). The desired compound was prepared according to the reported procedure [4 (link)]. To a stirred solution of 2′-O-dimethyl(tert-butyl)silyl-N6-methyladenosine (4) (2.6 g, 6.6 mmol) in 4 mL anhydrous pyridine at 0 °C, DMTrCl (2.7 g, 8.0 mmol) was added portionwise at regular intervals for 12 h. The reaction was quenched by addition of an excess of anhydrous methanol (0.5 mL) at room temperature. After 1 h, the solution was concentrated under vacuum. The crude solid was first dissolved and fractioned between aqueous NaHCO₃ and ethyl acetate; the organic layer was then washed with water (3 × 10 mL). The organic layer was dried (MgSO₄) and concentrated under vacuum. The residue was purified by column chromatography (9:1 to 3:2 cyclohexane/ethyl acetate) resulted in a green oil (3.9 g, 85%). TLC R_f 0.45 (2:3 cyclohexane/ethyl acetate); ¹H-NMR (400 MHz, CDCl₃) δ −0.13 (s, 3H) 0.00 (s, 3H) 0.86 (s, 9H) 2.77 (d, J = 4.0 Hz, 1H) 3.17 (s, 3H) 3.36–3.43 (m, 1H) 3.54 (dd, J = 10.5, 3.5 Hz, 1H) 3.80 (s, 6 H) 4.27 (d, J = 3.5 Hz, 1H) 4.33–4.37 (m, 1H) 5.02 (t, J = 5.5 Hz, 1H) 5.85 (d, J = 4.5 Hz, 1H) 6.04 (b.s, 2H) 6.83 (d, J = 9.0 Hz, 4H) 7.18–7.28 (m, 3H) 7.36 (d, J = 8.0 Hz, 4H) 7.47 (dd, J = 8.5 Hz, 1.5, 2H) 7.98 (s, 1H) 8.35 (s, 1H); ¹³C NMR (101 MHz, CDCl₃) δ −5.6, −5.5, 18.3, 25.8, 25.9, 55.2, 60.4, 63.0, 73.6, 75.5, 85.0, 87.5, 89.2, 113.4, 120.0, 127.3, 128.1, 128.3, 130.39, 130.45, 135.9, 138.0, 145.0, 153.0, 155.4, 158.89, 158.91; HRMS (ESI) m/z: calculated for C₃₈H₄₈O₆N₅²⁸Si [M + H]⁺ 698.3368, observed: 698.3359. Analytical data are consistent with those reported [4 (link)].
5′-O-(4,4′-Dimethoxytrityl)-(3′-O-[(2cyanoethyl)(N,N-diisopropylamino)phosphino]−2′-O-dimethyl(tert-butyl)silyl-N⁶-methyladenosine (6). The desired compound was prepared according to the reported procedure [4 (link)]. To a stirred solution of 5′-O-(4,4′-dimethoxytrityl)−2′-O-dimethyl(tert-butyl)silyl-N⁶-methyladenosine (5, 500 mg, 0.7 mmol) in anhydrous CH₂Cl₂ in an over-dried flask under argon, DIPEA (1.3 mL, 7.2 mmol) was added dropwise and the reaction mixture was allowed to stir at 0 °C for 10 min. (2-Cyanoethyl)-N,N-diisopropylchlorophosphoramidite (0.40 mL, 1.8 mmol) was added to the reaction mixture dropwise at 0 °C under an argon atmosphere. The reaction was stirred at 0 °C for 30 min, then gradually (about 30 min) warmed to room temperature. After another five hours under an inert atmosphere, the reaction mixture was treated with a saturated aq. KCl solution, then evaporated by rotary evaporation. The desired product was separated by silica gel column chromatography (1:1:0.01 hexane/ethyl acetate/pyridine) resulting in a colourless oil (520 mg, 80%) yield. TLC R_f 0.40 (1:1:0.01 hexane/ethyl acetate/pyridine); ¹H NMR (700 MHz, CD₂Cl₂-d₂) Major peaks are listed. δ −0.15 (s, 3H), −0.01 (s, 3H), 0.82 (s, 9H), 1.10 (s,3H), 1.11 (s, 3H), 1.22 (s, 3H), 1.22 (s, 3H), 1.65 (s, 2H), 2.62–2.74 (m, 2H), 3.19 (s, 3H), 3.36 (dd, J = 10.5, 4.5 Hz, 1H), 3.54 (dd, J = 10.5, 4.0 Hz, 1H), 3.82 (s, 6H), 3.85–3.93 (m, 1H), 3.95–4.10 (m, 1H), 4.41–4.49 (m, 1H), 5.12 (dd, J = 6.1, 4.4 Hz, 1H), 5.33–5.40 (m, 2H), 5.79 (s, 1H), 5.99 (d, J = 6.0 Hz, 1H), 6.78–6.90 (m, 4H), 7.23–7.29 (m, 1H), 7.28–7.34 (m, 2H), 7.34–7.40 (m, 4H), 7.47–7.52 (m, 2H), 7.94 (s, 1H), 8.25 (s, 1H); ¹³C NMR (176 MHz, CD₂Cl₂) Major peaks are listed. δ −5.4, −5.0, 0.8, 17.8, 20.4, 20.44, 21.1, 24.37, 24.4, 25.4, 25.44, 42.9, 43.0, 55.2, 58.8, 58.9, 63.5, 72.8, 72.9, 74.7, 74.7, 83.46, 83.48, 86.5, 88.4, 113.1, 117.8, 125.2, 126.8, 127.8, 128.1, 128.2, 129.0, 130.10, 130.14, 135.7, 139.0, 144.9, 153.0, 155.5, 158.6, 158.7; ³¹P-NMR (202 MHz, CD₂Cl₂) δ 148.0, 150.8.
N⁶,N⁶-Dimethyladenosine (11a). The desired product was prepared according to General Procedure A; white solid (250 mg, 85%). ¹H NMR (600 MHz, D₂O) δ 3.06 (s, 6H), 3.75 (dd, J = 13.0, 3.5 Hz, 1H), 3.85 (dd, J = 13.0, 2.5 Hz, 1H), 4.19 (q, J = 3.0 Hz, 1H), 4.29–4.33 (t, J = 4.5 Hz, 1H), 4.59 (t, J = 5.5 Hz, 1H), 5.82 (d, J = 6.0 Hz, 1H), 7.78 (b.s, 1H), 8.00 (s, 1H); ¹³C-NMR (151 MHz, D₂O) δ 38.7, 61.4, 70.5, 73.7, 85.5, 88.2, 118.9, 138.2, 148.2, 151.3, 153.6; HRMS (ESI) m/z: calculated for C₁₂H₁₈O₄N₅ [M + H]⁺ 296.1353, observed: 296.1352.
N⁶-Ethyladenosine (11b). The desired product was prepared according to General Procedure A; Ethylamine was prepared in-situ. To a stirred solution of ethylamine hydrochloride (1.1 g, 13.7 mmol) in 10 mL of ethanol in 50 mL round bottom flask, Ag₂O (3.8 g, 16.4 mmol) was added and the mixture was stirred at room temperature under N₂ for 1 h. The precipitate was collected by suction filtration; the resultant solution was then added to the stirred mixture of inosine, BOP and DBU. Yellowish solid (90 mg, 30%). ¹H NMR (600 MHz, D₂O + DMSO-d₆) δ 2.63 (t, J = 2.0 Hz, 3H), 3.53 (b.s, 2H), 3.77 (dd, J = 13.0, 3.5 Hz, 1H), 3.85 (dd, J = 13.0, 3.0 Hz, 1H), 4.23 (q, J = 3.0 Hz, 1H), 4.35 (dd, J = 5.0, 3.0 Hz, 1H), 5.98 (d, J = 6.5 Hz, 1H), 8.18 (s, 1H), 8.24 (s, 1H), (1H under solvent peak); ¹³C-NMR (151 MHz, D₂O + DMSO-d₆) δ 13.9, 61.6, 70.8, 73.7, 86.0, 88.3, 117.6, 130.0, 140.1, 152.7, 154.6, (1C under solvent peak); HRMS (ESI) m/z: calculated for C₁₂H₁₈O₄N₅ [M + H]⁺ 296.1308, observed: 296.1353.
N⁶-Cyclopropyladenosine (11c). The desired product was prepared according to General Procedure A; white solid (222 mg, 72%). ¹H-NMR (700 MHz, DMSO-d₆ + D₂O) δ 0.62–0.71 (m, 2H), 0.88 (dd, J = 7.0, 2.0 Hz, 2H), 3.00 (bs, 1H), 3.67 (dd, J = 12.0, 3.5 Hz, 1H), 3.77 (dd, J = 12.0, 3.5 Hz, 1H), 4.21–4.28 (m, 1H), 4.67 (t, J = 5.5 Hz, 1H), 5.97 (d, J = 6.0 Hz, 1H), 8.32 (s, 1H), 8.41 (s, 1H), (1 proton under solvent); ¹³C NMR (176 MHz, DMSO-d₆ + D₂O) δ 7.0, 61.9, 70.8, 70.9, 73.9, 86.2, 86.3, 88.4, 119.8, 140.3, 140.4, 152.7, 155.9; HRMS (ESI) m/z: calculated for C₁₃H₁₈O₄N₅ [M + H]⁺ 308.1353, observed: 308.1351.
O⁶-Methylinosine (11d). DBU (1.5 mmol) was added dropwise to a stirred solution of inosine (1 mmol), BOP (1.2 mmol) in THF; the mixture was heated at 40 °C. After the consumption of starting material (40 min, as assessed by TLC), the reaction mixture was concentrated under reduced pressure and an excess of MeOH was added to the flask and the reaction was stirred at 40 °C overnight. The crude product mixture was concentrated under reduced pressure and diluted with ethyl acetate, then washed with water (3 × 10 mL). The organic layer was dried (MgSO₄) and concentrated under vacuum. The crude mixture was purified (99:1 to 9:1 ethyl acetate/methanol) by column chromatography which resulted in a white solid (0.2 g, 72%). TLC R_f 0.3 (9:1 CH₂Cl₂/MeOH); ¹H-NMR (600 MHz, DMSO-d₆) δ 3.58 (ddd, J = 12.0, 6.0, 4.0 Hz, 1H), 3.69 (dt, J = 12.0, 4.5 Hz, 1H), 3.98 (q, J = 4.0 Hz, 1H), 4.11 (s, 3H), 4.17 (q, J = 4.5 Hz, 1H), 4.60 (q, J = 5.5 Hz, 1H), 5.13 (t, J = 5.5 Hz, 1H), 5.22 (d, J = 5.0 Hz, 1H), 5.50 (d, J = 6.0 Hz, 1H), 6.00 (d, J = 5.5 Hz, 1H), 8.57 (s, 1H), 8.63 (s, 1H); ¹³C-NMR (151 MHz, DMSO-d₆) δ 54.5, 61.8, 70.8, 74.2, 86.2, 88.2, 121.6, 142.9, 152.2, 152.24, 160.9; calculated for C₁₁H₁₃O₅N₄ [M + H]⁺ 283.0934, observed: 283.0932.
N⁶-(2-Hydroxyethyl)adenosine (11e). The desired product was prepared according to General Procedure A; white solid (190 mg, 61%). ¹H-NMR (600 MHz, DMSO-d₆) δ 3.57 (dd, J = 12.0, 4.0 Hz, 1H), 3.67 (dd, J = 12.0, 3.5 Hz, 1H), 4.13–4.21 (m, 1H), 4.51–4.64 (m, 3H), 5.96 (d, J = 6.0 Hz, 1H), 8.49 (s, 1H), 8.52 (s, 1H) (4 protons under the residual water peak); ¹³C NMR (151 MHz, DMSO-d₆) δ 61.6, 63.4, 70.7, 74.0, 86.1, 88.2, 121.5, 142.7, 152.0, 152.2, 160.6; HRMS (ESI) m/z: calculated for C₁₂H₁₈O₅N₅ [M + H]⁺312.1302, observed: 312.1297.
N⁶,N⁶-Methyl(2-hydroxyethyl)adenosine (11f). The desired product was prepared according to General Procedure A; white solid (293 mg, 90%). ¹H-NMR (700 MHz, DMSO-d₆) δ 3.56 (ddd, J = 12.0, 7.0, 3.5 Hz, 1H), 3.61–4.43 (m, 6H), 4.59 (q, J = 6.0 Hz, 1H), 4.75 (t, J = 5.5 Hz, 1H), 5.18 (d, J = 5.0 Hz, 1H), 5.37 (dd, J = 7.0, 4.5 Hz, 1H), 5.45 (d, J = 6.0 Hz, 1H), 5.91 (d, J = 6.0 Hz, 1H), 8.22 (s, 1H), 8.37 (s, 1H) (3 methyl protons and one hydroxyl group under the residual water peak in DMSO); ¹³C NMR (176 MHz, DMSO-d₆) δ 37.3, 52.7, 60.0, 62.0, 71.0, 73.9, 86.2, 88.3, 120.1, 139.2, 150.4, 152.2, 154.6; HRMS (ESI) m/z: calculated for C₁₃H₂₀O₅N₅ [M + H]⁺ 326.1459, observed: 326.1459.
N⁶,N⁶-Ethyl(2-hydroxyethyl)adenosine (11g). The desired product was prepared according to General Procedure A; white solid (275 mg, 85%). ¹H-NMR (700 MHz, D₂O) δ 1.18 (t, J = 7.0 Hz, 3H), 2.53 (d, J = 9 Hz, 1H)3.75 (dd, J = 13.0, 3.5 Hz, 1H), 3.78–4.09 (m, 7H), 4.21 (q, J = 3.5 Hz, 1H), 4.34 (dd, J = 5.0, 3.5 Hz, 1H), 5.98 (d, J = 6.0 Hz, 1H), 8.13 (s, 1H), 8.17 (s, 1H) ¹³C-NMR (176 MHz, D₂O) δ 15.4, 44.6, 59.6, 61.1, 61.5, 70.6, 73.5, 85.8, 88.1, 119.3, 138.7, 149.2, 152.0, 154.1; HRMS (ESI) m/z: calculated for C₁₄H₂₂O₅N₅ [M + H]⁺ 340.1617, observed: 340.1615.
2′,3′,5′-O-Tris(tert-butyldimethyl)silylinosine (12). To a stirred solution of inosine (3.75 g, 13.24 mmol) and imidazole (3.6 g, 53.0 mmol) in anhydrous DMF in a 50 mL round bottom flask, TBDMSCl (6.6 g, 43.7 mmol) was added portionwise. The reaction was heated at 60 °C for 12 h. The suspension was cooled to room temperature, water was added and the precipitate was collected by suction filtration. The filtrate was discarded, and the white precipitate was washed with cold methanol. The methanol layer was evaporated under vacuum; the product was crystallised as a white solid from CH₂C1₂ (7.8 g, 94%). TLC R_f 0.6 (1:9 MeOH/CH₂Cl₂); ¹H-NMR (400 MHz, CDCl₃) δ −0.31 (s, 3H), −0.16 (s, 3H), −0.04 (s, 3H), −0.03 (s, 3H), 0.00 (s, 3H), 0.01 (s, 3H), 0.68 (s, 9H), 0.79 (s, 9H), 0.82 (s, 9H), 3.66 (dd, J = 11.5, 2.5 Hz, 1H), 3.86 (dd, J = 11.5, 4.0 Hz, 1H), 4.00 (q, J = 3.5 Hz, 1H), 4.17 (t, J = 4.0 Hz, 1H), 4.38 (t, J = 4.5 Hz, 1H), 5.88 (d, J = 5.0 Hz, 1H), 7.97 (s, 1H), 8.09 (s, 1H), 12.83 (s, 1H); ¹³C NMR (101 MHz, CDCl₃) δ −5.4, −5.0, −4.70, −4.66, −4.4, 17.9, 18.1, 18.6, 25.7, 25.8, 26.1, 62.4, 71.8, 85.5, 88.3, 125.0, 139.1, 144.5, 148.9. 159.2; HRMS (ESI) m/z: calculated for C₂₈H₅₅O₅N₄²⁸Si₃ [M + H]⁺ 611.3474, observed: 611.3468.
2′,3′,5′-O-Tris[dimethyl(tert-butyl)silyl]-N⁶-(2-hydroxyethyl)adenosine (13a). To a stirred solution of 2′,3′,5′-O-tris(tert-butyldimethyl)silylinosine (12; 0.1 g, 0.16 mmol) and PyBOP (0.1 g, 0.2 mmol) in 10 mL of THF in a 50 mL round bottom flask, DIPEA (42 μL, 0.24 mmol) was added dropwise and the mixture was heated at 40 °C. After the consumption of the starting material (40 min, as assessed by TLC), the reaction was cooled to room temperature and ethanolamine (0.2 mL, 0.35 mmol) was added dropwise; the reaction was then stirred overnight. The crude product mixture was concentrated under reduced pressure and then diluted with ethyl acetate and was washed with water (3 × 10 mL). The organic layer was dried (MgSO₄) and concentrated under reduced pressure. The residue was purified by column chromatography (99:1 to 94:6 CH₂Cl₂/MeOH) which resulted in oil (95 mg, 90%). ¹H NMR (500 MHz, CD₃OD) δ −0.28 (s, 3H), −0.02 (s, 3H), 0.17 (s, 6H), 0.18 (s, 6H), 0.79 (s, 9H), 0.98 (s, 9H), 0.99 (s, 9H), 3.71–3.84 (m, 4H), 3.85 (dd, J = 11.5, 3.0 Hz, 1H), 4.06 (dd, J = 11.0, 4.5 Hz, 1H), 4.15 (dt, J = 5.0, 3.0 Hz, 1H), 4.40 (dd, J = 4.5, 2.5 Hz, 1H), 4.83 (dd, J = 6.0, 4.5 Hz, 1H), 4.89 (s, 5H), 6.07 (d, J = 6.0 Hz, 1H), 8.26 (s, 1H), 8.31 (s, 1H), (-OH peak under solvent peak); ¹³C-NMR (126 MHz, CD₃OD) δ −6.6, −6.5, −6.3, −5.6, −5.6, −5.5, 17.4, 17.6, 18.0, 24.9, 25.1, 25.2, 45.97, 46.0, 60.4, 62.7, 72.7, 76.0, 86.2, 87.7, 119.5, 139.3, 148.6, 152.5, 155.0; HRMS (ESI) m/z: calculated for C₃₀H₆₀O₅N₅²⁸Si₃ [M + H]⁺ 635.3713, observed: 635.3797.
2′,3′,5′-O-Tris[dimethyl(tert-butyl)silyl]-N⁶,N⁶-methyl(2-hydroxyethyl)adenosine (13b). To a stirred solution of 2′,3′,5′-O-tris(tert-butyldimethyl)silylinosine (12; 1 g, 1.64 mmol) and BOP (0.9 g, 1.96 mmol) in 25 mL of EtOH in a 50 mL round bottom flask, DBU (0.3 mL, 1.97 mmol) was added dropwise; the mixture was heated at 40 °C. After the consumption of the starting material (40 min, TLC), the reaction was cooled to room temperature and methylethanolamine (0.65 mL, 8.2 mmol) was added dropwise; the reaction was then stirred overnight. The crude product mixture was concentrated under reduced pressure, then diluted with ethyl acetate and was washed with water (3 × 10 mL). The organic layer was dried (anhydrous MgSO₄) and concentrated under reduced pressure. The residue was purified by column chromatography (99:1 to 94:6 CH₂Cl₂/MeOH) which resulted in oil (0.82 g, 80%). TLC R_f 0.6 (6:94 MeOH/CH₂Cl₂). ¹H-NMR (600 MHz, CDCl₃) δ −0.29 (s, 3H), −0.14 (s, 3H), −0.01 (s, 3H), 0.00 (s, 3H), 0.02 (s, 3H), 0.03 (s, 3H), 0.71 (s, 9H), 0.83 (s, 9H), 0.85 (s, 9H), 3.42 (s, 3H), 3.67 (dd, J = 11.5, 3.0 Hz, 1H), 3.87 (t, J = 5.0 Hz, 2H), 3.92 (dd, J = 11.4, 4.0 Hz, 1H), 3.94–4.09 (m, 4H), 4.21 (t, J = 4.0 Hz, 1H), 4.58 (t, J = 4.5 Hz, 1H), 5.92 (d, J = 5.0 Hz, 1H), 7.97 (s, 1H), 8.20 (s, 1H); ¹³C-NMR (151 MHz, CDCl₃) δ −5.38, −5.36, −5.0, −4.72, −4.70, −4.4, 17.9, 18.1, 18.5, 25.7, 25.9, 26.1, 53.8, 61.6, 62.5, 71.9, 75.6, 85.3, 88.3, 120.4, 137.7, 150.5, 152.2, 155.6; HRMS (ESI) m/z: calculated for C₃₁H₆₂O₅N₅²⁸Si₃ [M + H]⁺ 668.4053, observed: 668.4042.
2′,3′,5′-O-Tris[dimethyl(tert-butyl)silyl]-N⁶,N⁶-ethyl(2-hydroxyethyl)adenosine (13c). To a stirred solution of 2′,3′,5′-O-tris(tert-butyldimethyl)silylinosine (12; 1 g, 1.64 mmol) and BOP (0.87 g, 1.96 mmol) in 25 mL of EtOH in a 50 mL round bottom flask, DBU (0.3 mL, 2.0 mmol) was added dropwise and the mixture was heated at 40 °C. After the consumption of the starting material (40 min, as assessed by TLC), the reaction was cooled to room temperature and ethylethanolamine (0.65 mL, 8.2 mmol) was added dropwise; the reaction was then stirred overnight. The crude product mixture was concentrated under reduced pressure, then diluted with ethyl acetate and washed with water (3 × 10 mL). The organic layer was dried (anhydrous MgSO₄) and concentrated under reduced pressure. The residue was purified by column chromatography (99:1 to 94:6 CH₂Cl₂/MeOH) which resulted in an oil (960 mg, 86%). TLC R_f 0.5 (6:94 MeOH/CH₂Cl₂); ¹H NMR (600 MHz, CDCl₃) δ −0.30 (s, 3H), −0.15 (s, 3H), −0.02 (s, 3H), −0.01 (s, 3H), 0.00 (s, 3H), 0.01 (s, 3H), 0.69 (s, 9H), 0.82 (s, 9H), 0.83 (s, 9H), 1.18 (t, J = 7.0 Hz, 3H), 3.66 (dd, J = 11.0, 3.0 Hz, 1H), 3.72–4.15 (m, 8H), 4.21 (t, J = 4.0 Hz, 1H), 4.59 (t, J = 5.0 Hz, 1H), 4.67–5.17 (m, 1H), 5.89 (d, J = 5.0 Hz, 1H), 8.05 (s, 1H), 8.16 (s, 1H); ¹³C NMR (151 MHz, CDCl₃) δ −5.39, −5.38, −5.0, −4.72, −4.70, −4.4, 13.3, 17.9, 18.1, 18.5, 25.7, 25.8, 26.0, 44.6, 51.6, 62.5, 62.6, 71.9, 75.5, 85.2, 88.3, 120.1, 137.8, 150.5, 152.1, 155.0. HRMS (ESI) m/z: calculated for C₃₂H₆₄O₅N₅²⁸Si₃ [M + H]⁺ 682.4209, observed: 682.4201.
2′,3′,5′-O-Tris[dimethyl(tert-butyl)silyl]-N¹,N⁶-ethanoadenosine (15a). To a stirred solution of 2′,3′,5′-O-tris[dimethyl(tert-butyl)silyl]-N¹,N⁶-(2-hydroxyethyl)adenosine (13a; 1.3 g, 2 mmol) and Et₃N (1.4 mL, 10 mmol) in 30 mL of anhydrous DMF in a 50 mL round bottom flask, methyltriphenoxyphosphonium iodide (1 g, 2.4 mmol) was added and the mixture was stirred at room temperature for 1 h. Anhydrous methanol was added and the crude product mixture was concentrated under reduced pressure, then diluted with ethyl acetate and washed with NaHCO₃ and water (3 × 10 mL). The organic layer was dried (MgSO₄) and concentrated under reduced pressure. The residue was purified by column chromatography (99:1 to 85:15 CH₂Cl_2/MeOH) resulting in an oil (0.75 g, 60%). ¹H-NMR (600 MHz, CDCl₃) δ −0.18 (s, 3H), −0.07 (s, 3H), 0.00 (s, 3H), 0.01 (s, 3H), 0.05 (s, 3H), 0.06 (s, 3H), 0.75 (s, 9H), 0.83 (s, 9H), 0.87 (s, 9H), 3.71 (dd, J = 11.5, 2.5 Hz, 1H), 3.93 (dd, J = 11.5, 3.0 Hz, 1H), 4.06 (dt, J = 5.5, 3.0 Hz, 1H), 4.18 (t, J = 4.5 Hz, 1H), 4.26–4.40 (m, 3H), 4.90–4.95 (m, 2H), 5.92 (d, J = 4.0 Hz, 1H), 8.38 (s, 1H), 8.51 (s, 1H); ¹³C NMR (151 MHz, CDCl₃) δ −5.3, −5.27, −4.8, −4.6, −4.4, −4.2, 17.9, 18.0, 18.5, 25.7, 25.8, 26.1, 26.4, 26.5, 46.28, 46.33, 46.4, 49.1, 62.0, 71.1, 76.7, 85.2, 89.0, 117.6, 142.3, 143.4, 149.0, 151.3; HRMS (ESI) m/z: calculated for C₃₀H₅₈O₄N₅²⁸Si₃ [M + H]⁺ 636.3767, observed: 636.3791.
N¹,N⁶-Ethanoadenosine (16a). To a stirred solution of 2′,3′,5′-O-tris[dimethyl(tert-butyl)silyl]-N⁶-ethanoadenosine (15a, 470 mg, 0.74 mmol) in CH₂Cl₂, 3HF.Et₃N (361 µL, 2.2 mmol) was added dropwise. The solution was left to stir for 48 h. The mixture was reduced under pressure and was purified by column chromatography (99:1 to 9:1 ethyl acetate/methanol) which resulted in a white solid (150 mg, 70%). ¹H NMR (700 MHz, DMSO-d₆) δ 3.49–3.57 (m, 2H), 3.60–3.68 (m, 1H), 3.86–3.97 (m, 3H), 4.08–4.16 (m, 3H), 4.44 (t, J = 5.0 Hz, 1H), 5.11–5.21 (m, 2H), 5.46 (s, 1H), 5.78 (d, J = 6.0 Hz, 1H), 8.09 (s, 1H), 8.17 (s, 1H); ¹³C-NMR (176 MHz, DMSO-d₆) δ 46.5, 53.3, 61.9, 70.8, 74.5, 86.1, 88.0, 120.0, 138.5, 145.2, 145.4, 150.2; HRMS (ESI) m/z: calculated for C₁₂H₁₆O₄N₅ [M + H]⁺ 294.1197, observed: 294.1191.
2′,3′,5′-O-Tris[dimethyl(tert-butyl)silyl]-N⁶,N¹,N⁶-methylethanoadenosine (15b). To a stirred solution of 2′,3′,5′-O-tris[dimethyl(tert-butyl)silyl]-N⁶,N⁶-methyl(2-hydroxyethyl)adenosine (13b; 0.5 g, 0.75 mmol) and Et₃N (0.54 mL, 3.75 mmol) in 30 mL of anhydrous DMF in a 50 mL round bottom flask, methyltriphenoxyphosphonium iodide (0.85 g, 1.9 mmol) was added and the mixture was stirred at room temperature for 1 h. Anhydrous methanol was added and the crude product mixture was concentrated under reduced pressure, then diluted with ethyl acetate and washed with NaHCO₃ and water (3 × 10 mL). The organic layer was dried (anhydrous MgSO₄), then concentrated under reduced pressure. The residue was purified by alumina column chromatography (99:1 to 90:10 CH₃Cl/MeOH) which resulted in an oil. ¹H NMR (600 MHz, CDCl₃) δ −0.20 (s, 3H), −0.12 (s, 3H), −0.08 (s, 3H), −0.07 (s, 3H), 0.00 (s, 3H), 0.01 (s, 3H), 0.70 (s, 9H), 0.75 (s, 9H), 0.81 (s, 9H), 3.57 (s, 3H), 3.65 (dd, J = 11.5, 2.0 Hz, 1H), 3.88 (dd, J = 11.5, 3.0 Hz, 1H), 4.00 (dt, J = 5.0, 2.5 Hz, 1H), 4.12 (dd, J = 5.5, 4.0 Hz, 1H), 4.17–4.26 (m, 2H), 4.35–4.42 (m, 1H), 5.05–5.3 (m, 2H), 5.87 (d, J = 3.5 Hz, 1H), 8.43 (s, 1H), 8.50 (s, 1H); ¹³C NMR (151 MHz, CDCl₃) δ −5.4, −5.2, −4.8, −4.6, −4.5, −4.2, 17.9, 18.1, 18.6, 25.7, 25.8, 26.2, 34.6, 45.9, 49.1, 51.6, 61.7, 70.7, 85.0, 89.3, 115.4, 117.0, 129.5, 142.8, 143.7, 149.9, 150.1; HRMS (ESI) m/z: calculated for C₃₁H₆₀O₄N₅²⁸Si₃ [M] 650.3947, observed: 650.3924.
2′,3′,5′-O-Tris[dimethyl(tert-butyl)silyl]-N⁶,N¹,N⁶-ethylethanoadenosine (15c). To a stirred solution of 2′,3′,5′-O-tris[dimethyl(tert-butyl)silyl]-N⁶,N⁶-ethyl(2-hydroxyethyl)adenosine (15c; 0.4 g, 0.6 mmol) and Et₃N ( 0.4 mL, 3 mmol) in 20 mL of anhydrous DMF in a 50 mL round bottom flask, methyltriphenoxyphosphonium iodide (0.6 g, 1.2 mmol) was added; the mixture was stirred at room temperature for 1 h. Anhydrous methanol was added and the crude product mixture was concentrated under reduced pressure and then diluted with ethyl acetate and was washed subsequently with NaHCO₃ and water (3 × 10 mL). The organic layer was dried (anhydrous MgSO₄) and concentrated under reduced pressure. The residue was purified by alumina column chromatography (99:1 to 95:5 CH₂Cl₂/MeOH) which resulted in a solid (0.26 g, 36%). mp 195 °C; ¹H-NMR (600 MHz, CDCl₃) δ −0.25 (s, 3H), −0.18 (s, 3H), −0.03 (s, 3H), −0.01 (s, 3H), 0.00 (s, 3H), 0.01 (s, 3H), 0.70 (s, 9H), 0.74 (s, 9H), 0.83 (s, 9H), 1.33 (t, J = 7.0 Hz, 3H), 3.2 (q, J = 7.0 Hz, 2H), 3.65 (dd, J = 12.0, 2.0 Hz, 1H), 3.88 (dd, J = 12.0, 3.0 Hz, 1H), 4.00 (dt, J = 5.0, 2.5 Hz, 1H), 4.23–4.28 (m, 2H), 4.59 (t, J = 5.0 Hz, 1H), 4.69 (t, J = 5.0 Hz, 1H) 5.0–5.18 (m, 2H), 5.83 (d, J = 5.0 Hz, 1H), 8.34 (s, 1H), 8.46 (s, 1H); ¹³C-NMR (151 MHz, CDCl₃) δ −5.3, −5.0, −5.0, −4.6, −4.6, −4.2, 13.0, 17.9, 18.1, 18.5, 25.7, 25.8, 26.2, 35.6, 48.4, 51.6, 61.7, 70.7, 73.4, 85.0, 89.3, 115.4, 144.8, 149.9, 150.0, 152.0; HRMS (ESI) m/z: calculated for C₃₁H₆₀O₄N₅²⁸Si₃ [M] 664.3886, observed: 664.3896.
N⁶,N¹,N⁶-Methylethanoadenosine (16b). To a stirred solution of 2′,3′,5′-O-tris[dimethyl(tert-butyl)silyl]-N⁶,N⁶-methylethanoadenosine (15b; 500 mg, 0.8 mmol) in CH₂Cl₂, 3HF.Et₃N (0.4 mL, 2.3 mmol) was added dropwise. The solution was stirred for 48 h. The mixture was reduced under pressure, then purified by alumina column chromatography (99:1 to 9:1 ethyl acetate/methanol) which resulted in a white solid (54 mg, 22%). mp 202.5 °C; ¹H-NMR (600 MHz, DMSO-d₆) δ 3.01 (s, 3H), 3.29 (m, 1H), 3.38 (dt, J = 12.5, 4.5 Hz, 1H), 3.68 (q, J = 4.0 Hz, 1H), 3.76–3.84 (m, 2H), 3.87 (b.s, 1H), 4.18 (q, J = 5.0 Hz, 1H), 4.43 (t, J = 9.5 Hz, 1H), 4.79 (t, J = 5.5 Hz, 1H), 5.01 (s, 1H), 5.28–5.37 (m, 2H), 5.68 (d, J = 5.0 Hz, 1H), 8.50 (s, 1H), 8.52 (s, 1H); ¹³C-NMR (151 MHz, D₂O) δ 36.4, 50.5, 53.4, 63.6, 72.6, 77.1, 88.6, 90.8, 119.0, 145.7, 148.0, 152.2, 152.3; HRMS (ESI) m/z: calculated for C₁₃H₁₈O₄N₅ [M]⁺ 308.1353, observed: 308.1353.
N⁶,N¹,N⁶-Ethylethanoadenosine (16c). To a stirred solution of 2′,3′,5′-O-tris[dimethyl(tert-butyl)silyl]-N⁶,N⁶-methylethanoadenosine (15c; 470 mg, 0.74 mmol) in CH₂Cl₂, 3HF.Et₃N (360 µL, 2.2 mmol)was added dropwise. The solution was left to stir for 48 h. The mixture was reduced under pressure and was purified by alumina column chromatography (99:1 to 9:1 ethyl acetate/methanol) which resulted in a white solid (65 mg, 30%). mp 210 °C; ¹H-NMR (600 MHz, DMSO-d₆) δ 1.15 (t, J = 7.0 Hz, 3H), 2.88 (q, J = 7.0 Hz, 2H), δ 3.49–3.57 (m, 2H), 3.36 (dt, J = 12.5 Hz, 4.0 Hz, 1H), 3.54 (q, J = 4.0 Hz, 1H), 3.76–3.84 (m, 2H), 3.95 (b.s, 1H), 4.15–4.27 (m, 1H), 4.34–4.43 (m, 1H), 5.1 (b.s, 1H), 5.43–5.57 (m, 2H), 6.0 (d, J = 5.0 Hz, 1H), 8.48 (s, 1H), 8.63 (s, 1H); ¹³C-NMR (151 MHz, DMSO-d₆) δ 13.0, 32.4, 48.3, 52.3, 62.4, 70.4, 75.3, 85.4, 90.8, 119.0, 146.4, 148.2, 151.9, 152.0; HRMS (ESI) m/z: calculated for C₁₃H₁₈O₄N₅ [M]⁺ 322.1518, observed: 322.1515.

Shishodia S, & Schofield C.J. (2020). Improved Synthesis of Phosphoramidite-Protected N6-Methyladenosine via BOP-Mediated SNAr Reaction. Molecules, 26(1), 147.

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Publication 2020

Dual-Functional Nitric Oxide-Releasing Peptide Amphiphiles

Cited 4 times

Two types of PAs; PA-YIGSR [CH₃(CH₂)₁₄CONH-GTAGLIGQ-YIGSR] and PA-KKKKK [CH₃(CH₂)₁₄CONH-GTAGLIGQ-KKKKK], were prepared using the Fmoc chemistry in the Advanced Chemtech Apex 396 peptide synthesizer (AAPPTec, Louisville, KY, USA) and subsequently alkylated at the N-termini with palmitic acid by a manual coupling reaction for 24 hours at room temperature [60 (link)]. To alkylate with palmitic acid, a mixture of o-benzotriazole-N, N, N, N'-tetramethyluronium hexafluoro phosphate, di-isopropyl-ethylamine, and dimethylformamide was used, cleavage and deprotection were achieved using a mixture of trifluoroacetic acid, deionized water, triisopropylsilane, and anisole (40:1:1:1) for 3 hours at room temperature. The PAs precipitated in cold ether were lyophilized and characterized by matrix-assisted laser desorption ionization time of flight mass spectrometry. PA-YIGSR was composed of an endothelial cell adhesive ligand (YIGSR) coupled with a matrix metalloprotease-2 (MMP-2) degradable sequence (GTAGLIGQ) to form PA-YIGSR. PA-KKKKK contained a NO donor poly-lysine (KKKKK) linked to the MMP-2 degradable sequence, forming PA-KKKKK. A mixture of PA-YIGSR and PA-KKKKK at a 9:1 molar ratio was reacted with NO gas to generate PA-YK-NO [47 (link)]. For gelation process, 50 μL of a 2% wt stock PA-YK-NO solution was mixed with 15 μL of calcium chloride and 25 μL of phosphate-buffered saline (PBS) and incubated at 37°C for 30 min.

Moon C.Y., Nam O.H., Kim M., Lee H.S., Kaushik S.N., Cruz Walma D.A., Jun H.W., Cheon K, & Choi S.C. (2018). Effects of the nitric oxide releasing biomimetic nanomatrix gel on pulp-dentin regeneration: Pilot study. PLoS ONE, 13(10), e0205534.

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Publication 2018

anisole benzotriazole Calcium chloride Cold Temperature Cytokinesis Dimethylformamide Endothelial Cells Ethers ethylamine Ligands Lysine MMP2 protein, human Molar Palmitic Acid Peptides Phosphates Poly A Saline Solution Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization Tissue Donors Trifluoroacetic Acid tyrosyl-isoleucyl-glycyl-seryl-arginine

Synthesis and Characterization of Heptazine Derivatives

Cited 4 times

Heating at temperatures above 300 °C was carried out in a custom-made resistive furnace, using a Eurotherm 2408 temperature controller. Where applicable, percentage molar yields are calculated assuming the ideal formula of C₆N₉H₃ for melon. Crystalline melem (1)39 (link), crystalline melon (10)4 (link), amorphous melem65 (link), amorphous melon18 (link), tri(diethylamino)heptazine (3)66 , potassium cyamelurate (6)67 (link), cyameluric acid (7)68 , tri(p-tolyl)heptazine (8)69 (link), tri(p-benzoic acid)heptazine (9)69 (link) and potassium melonate38 (5) were synthesized following literature methods and their characterizations are consistent with those previously reported.
Heptazine triphthalimide (4) was prepared following the literature method65 (link), except that unreacted melem was not removed by Soxhlet extraction with nitromethane because of safety concerns.
Cyameluric trichloride was prepared following an adapted procedure70 . Potassium cyamelurate (24.4 g) was refluxed in a mixture of PCl₅ (6.81 g) and POCl₃ (10 ml) until gas evolution has ceased. Unreacted PCl₅ and POCl₃ were boiled or sublimed off by heating under vacuum. The yellow product was not purified from the side product KCl as it is easier to remove in the subsequent syntheses. Yield 34.1 g (molar yield not provided as residual KCl was not removed). Characterization with FTIR is consistent with literature70 .
Tri(ethylamino)heptazine (2) was synthesized by mixing under argon a solution of cyameluric trichloride (1.386 g) in tetrahydrofuran (THF, 20 ml, anhydrous) and ethylamine in THF (8.5 ml, 2 M L⁻¹), and then refluxed for 2 h. The solvent and unreacted ethylamine were evaporated off and the resulting solid was re-dispersed in water, refluxed for 1 h, isolated by filtration, and then washed repeatedly with water and dried. The product was further purified by recrystallization from hot glacial acetic acid. Yield: 933 mg (62%). ¹H NMR (DMSO): δ=2.50 (CH₂), 1.07 ppm (CH₃). FTIR: 3,222, 3,080, 3,029, 2,971, 2,933, 1,641, 1,571, 1,494, 1,433, 1,398, 1,373, 1,346, 1,308, 1,286, 1,178, 1,144, 1,100, 1,069 and 797 cm⁻¹.
Transition and lanthanum metal complexes of melonate were prepared by mixing stoichiometric amounts of potassium melonate and the metal salt, both as aqueous solutions (20 mM). The metal salts employed are: (5a) AgNO₃, (5b) CeCl₃·6H₂O, (5c) Co(NO₃)₂·6H₂O, (5d) Cr(NO₃)₃·9H₂O, (5e) Cu(AcO)₂·H₂O, (5f) Fe(NO₃)₂·nH₂O, (5g) La(NO₃)₃·6H₂O, (5h) Mn(AcO)₂·4H₂O, (5i) Nd₂(SO₄)₃, (5j) Ni(NO₃)₂·6H₂O, (5k) (NH₃)₄Pt(NO₃)₂, (5l) Tb(NO₃)₃ and (5m) Zn(AcO)₂·2H₂O. The complex precipitated immediately upon mixing the metal salt and the ligand. The complex was isolated by filtration, washed with copious amounts of water, and then dried at 60 °C in a vacuum oven. Product yields were above 90% to quantitative. Characterizations are shown in Supplementary Figs 6–8.
Amorphous melon with the cyanamide functionalization was prepared following the original synthesis of potassium melonate38 , except that the water-insoluble solid was collected. In detail, melon (800 mg) was thoroughly ground with KSCN (1.6 g, dried at 140 °C in vacuum) and loaded in an alumina boat. In a tube furnace, this mixture was heated under argon to 400 °C at 30 °C min⁻¹ ramp for 1 h, and then to 500 °C at 30 °C min⁻¹ ramp for 30 min. The resulting yellow mass was suspended in water and the insoluble product was isolated by centrifugation, washed with copious amount of water and dried at 60 °C in a vacuum oven. Yield from 800 mg melon is 350–450 mg (35–45% assuming the formula C₇N₁₀H_1.4K_0.6, see elemental analyses in Supplementary Table 4).
As post-synthetic annealing may lead to a significant improvement in the photocatalytic activity of melon, we prepared another control sample to verify that the large outperformance of KSCN-treated melon is not attributed to this heating step. Melon in a ceramic boat was heated under argon to 400 °C at 30 °C min⁻¹ ramp for 1 h, and then 500 °C at 30 °C min⁻¹ ramp for 30 min. This sample is denoted as ‘amorphous melon (extra heating step)' in Fig. 1a.

Lau V.W., Moudrakovski I., Botari T., Weinberger S., Mesch M.B., Duppel V., Senker J., Blum V, & Lotsch B.V. (2016). Rational design of carbon nitride photocatalysts by identification of cyanamide defects as catalytically relevant sites. Nature Communications, 7, 12165.

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Publication 2016

Most recents protocols related to «Ethylamine»

Theanine Extraction and Analysis

The hot water was employed to extract theanine from various tissues of tea leaves, described by the previous method [33 (link)]. To investigate the involvement of CsGGT4 in the production and degradation of theanine, samples were collected and examined utilizing HPLC–MS/MS and GC/MS techniques, following established protocols in a previous study [19 (link)]. The instrument parameters and methods employed were in accordance with Dong et al. [61 (link)].

Chang M., Sun Y., Fang K., Fu M., Ma J., Gao Y., Chen Q., Liu L., Zhang Z., Wan X, & Sun J. (2024). CsMYB73 negatively regulates theanine accumulation mediated by CsGGT2 and CsGGT4 in tea shoots (Camellia sinensis). Horticulture Research, 11(3), uhae012.

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Publication 2024

Synthesis of Substituted Benzyl Ether Derivative

Compound 35 (30 mg; 0.099 mmol); K₂CO₃ (27 mg; 0.198 mmol); ethyl iodide (16 μl; 0.198 mmol) in dry CH₃CN (2 mL). After filtration and evaporation, the residue was purified by preparative TLC cHx/DEA (9 : 1.5) to get pure product 43 as a yellow oil. Yield 96%. ¹H NMR (600 MHz, CDCl₃) δ: 7.45–7.42 (m, 2H), 7.40–7.35 (m, 4H), 7.34–7.26 (m, 6H), 7.25–7.21 (m, 1H), 6.96–6.89 (m, 2H), 5.05 (s, 2H), 3.56 (s, 2H), 3.52 (s, 2H), 2.50 (q, J = 7.1 Hz, 2H), 1.06 (t, J = 7.1 Hz, 3H). ¹³C NMR (151 MHz, CDCl₃) δ: 157.8, 140.0, 137.2, 132.2, 129.9, 128.7, 128.6, 128.1, 127.9, 127.5, 126.7, 114.5, 70.0, 57.5, 57.0, 46.9, 11.8. ESI-HRMS m/z calcd for C₂₃H₂₆NO⁺ [M + H]⁺ 332.2009, found 332.2018; 98.67% purity.

Pidany F., Kroustkova J., Jenco J., Breiterova K.H., Muckova L., Novakova L., Kunes J., Fibigar J., Kucera T., Novak M., Sorf A., Hrabinova M., Pulkrabkova L., Janousek J., Soukup O., Jun D., Korabecny J, & Cahlikova L. (2024). Carltonine-derived compounds for targeted butyrylcholinesterase inhibition. RSC Medicinal Chemistry, 15(5), 1601-1625.

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Publication 2024

Alkylation of Compound 14 to Produce 19

Compound 14 (25 mg; 0.082 mmol); K₂CO₃ (23 mg; 0.164 mmol); ethyl iodide (13 μl; 0.164 mmol) in dry CH₃CN (2 mL). After filtration and evaporation, the residue was purified by preparative TLC using mobile phase cHx/DEA (9 : 0.5) to get pure product 19 as a yellow oil. Yield 80%. ¹H NMR (500 MHz, CDCl₃) δ: 7.50–7.45 (m, 2H), 7.44–7.30 (m, 7H), 7.29–7.21 (m, 2H), 7.11–7.07 (m, 1H), 7.02–6.97 (m, 1H), 6.91–6.85 (m, 1H), 5.09 (s, 2H), 3.60 (s, 2H), 3.58 (s, 2H), 2.58–2.49 (m, 2H), 1.09 (t, J = 7.1 Hz, 3H). ¹³C NMR (126 MHz, CDCl₃) δ: 158.8, 141.6, 139.7, 137.1, 129.1, 128.7, 128.5, 128.1, 127.9, 127.5, 126.8, 121.3, 115.1, 113.2, 69.9, 57.7, 57.6, 47.1, 11.8. ESI-HRMS m/z calcd for C₂₃H₂₆NO⁺ [M + H]⁺ 332.2009, found 332.2014; 99.55% purity.

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Publication 2024

Synthesis of Bis(4-Methoxybenzyl)Diselane Derivative

(The reaction
was
carried out under a nitrogen atmosphere.) Sodium borohydride
(0.4 g, 10.6 mmol) was added portionwise to a solution of 1,2-bis(4-methoxybenzyl)diselane
(1.0 g, 2.5 mmol) in EtOH/DMF (30 mL, 1:1, v/v), and the reaction
mixture was stirred for 2 h at room temperature. 2-Bromoethylamine
hydrobromide (1.3 g, 6.3 mmol) was then dissolved in EtOH (5 mL) and
added dropwise at 0 °C. The solution was warmed to room temperature
and stirred overnight. The solvent was removed to dryness under a
stream of nitrogen. The obtained product was dissolved in a saturated
aqueous solution of NaHCO₃, and the aqueous layer was extracted
with ethyl acetate (3×). The organic layer was washed with brine
and dried over anhydrous MgSO₄. The solvent was removed
on a rotary evaporator to give a white solid product. Yield 0.55 g
(90%). ¹H NMR (500 MHz, MeOD): δ = 7.24–7.22
(m, 2H), 6.85–6.83 (m, 2H), 3.78 (s, 2H), 3.77 (s, 3H), 2.80
(t, J = 6.9 Hz, 2H), 2.60 (t, J =
6.9 Hz, 2H); ¹³C{¹H} NMR (126 MHz, MeOD): δ
= 158.7, 131.3, 129.6, 113.5, 54.3, 40.6, 25.5, 25.0; ⁷⁷Se NMR (114 MHz, MeOD): δ = 217.8; calculated m/z [M + H]⁺: 246.0392; found m/z [M + H]⁺: 246.0344 for C₁₀H₁₅NOSe.

Pehlivan Ö., Wojtkowiak K., Jezierska A., Waliczek M, & Stefanowicz P. (2024). Photochemical Transformations of Peptides Containing the N-(2-Selenoethyl)glycine Moiety. ACS Omega, 9(14), 16775-16791.

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Publication 2024

Siglec Ligand Conjugation to PEG-DSPE

NHS coupling
of NH₂–PEG₍₄₅₎-DSPE to NHS-trinitrophenyl
was performed as described in the Supporting Information (Figure S22). Conjugation of NHS-PEG₍₄₅₎-DSPE to Siglec-3
ligand–ethylamine, Siglec-7 ligand–ethylamine, and Siglec-9
ligand–ethylamine was performed following the literature method.^{51 (link),52 (link)} Schematics of these syntheses are shown in the Supporting Information (Figures S23–S25).

McCord K.A., Wang C., Anhalt M., Poon W.W., Gavin A.L., Wu P, & Macauley M.S. (2024). Dissecting the Ability of Siglecs To Antagonize Fcγ Receptors. ACS Central Science, 10(2), 315-330.

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Publication 2024

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N,N-dimethylformamide is a clear, colorless liquid organic compound with the chemical formula (CH3)2NC(O)H. It is a common laboratory solvent used in various chemical reactions and processes.

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Formic acid is a colorless, pungent-smelling liquid chemical compound. It is the simplest carboxylic acid, with the chemical formula HCOOH. Formic acid is widely used in various industrial and laboratory applications.

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