L phenylalanine methyl ester hydrochloride

Silver oxide, anhydrous sodium sulfate, iodomethane, iodomethane-d₃, l-phenylalanine methyl ester hydrochloride, mass spectrometric grade formic acid (~98%), and HPLC grade trifluoroacetic acid (99.0%) were obtained from Sigma-Aldrich; HPLC grade methanol, acetonitrile, ethyl acetate, and water from Fisher Scientific; Deuterium oxide (99.8%) and HPLC grade dichloromethane from Acros; l-alanyl-l-proline, N-(tert-butoxycarbonyl)-d-alanine, l-proline tert-butyl ester hydrochloride, d-proline tert-butyl ester hydrochloride, and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) hydrochloride from Tokyo Chemical Industry. A Fisher Scientific vortex mixer was used for mixing and a Sorvall Legend Micro 21R microcentrifuge used for centrifugation of 1.5 mL Eppendorf tubes. A Corning Laboratory stirrer was used for mixing chemical reactions. Human plasma (Na₂-EDTA) was obtained from Bioreclamation and stored at −80 °C. An Argonaut SPE DRY™ 96 DUAL evaporator was used for solvent evaporation.

L-phenylalanine methyl ester hydrochloride, methacryloyl chloride, 2-hydroxyethyl methacrylate, ethylene dimethacrylate, poly(vinyl alcohol) (fully hydrolyzed), ammonium persulfate (APS) (ACS reagent, ≥98.0%), sodium dodecyl sulfate (ACS reagent, ≥99.0%), sodium bisulfite, sodium carbonate, sodium nitrite, potassium carbonate, and amlodipine besylate were obtained from Sigma-Aldrich^® (Munich, Germany).

N-Boc-l-phenylalanine, l-phenylalanine methyl ester hydrochloride, d-phenylalanine
methyl ester hydrochloride, and 2-(naphthalen-2-yloxy)acetic acid
were obtained from Sigma-Aldrich; glucono-δ-lactone, 1,4-dioxane,
and lithium hydroxide were purchased from Alfa Aesar; diethyl ether, N-methylmorpholine, sodium hydroxide, and hydrochloric acid
were received from Honeywell; acetonitrile, chloroform, tetrahydrofuran,
and sodium chloride were acquired from Fisher Scientific; hydrogen
chloride (ca 4 mol/L in 1,4-dioxane) was obtained from Tokyo Chemical
Industry; magnesium sulfate, dichloromethane, trifluoroacetic acid,
and isobutyl chloroformate were purchased from VWR International,
Fluorochem, and Thermo Scientific, respectively. All chemicals were
used directly without further treatment. Deionized water was used
throughout this research.
Full synthetic protocols and characterization
data for the two gelators used here are described in the Supporting
Information (Figures S1–S18).