Preparation, spectral and physicochemical characteristics of methylamide Nα-phenylthiocarbamoyl derivatives of naturally occurring amino acids

Abstract

The methylamide Nα-phenylthiocarbamoyl derivatives of encoded amino acids II were prepared either by the addition of phenylisothiocyanate to amino acid methylamides or by the treatment of amino acid phenylthiohydantoins (5-alkyl-3-phenyl-2-thioxo-4-imidazolinones) I with methylamine. The derivatives were prepared of 19 amino acids and their melting points, 1H NMR, 13C NMR, mass, ultraviolet and infrared spectra were measured.

Insight into β-hairpin stability: a structural and thermodynamic study of diastereomeric β-hairpin mimeticsElectronic supplementary information (ESI) available: temperature and concentration-dependent chemical shifts and melting curves of the investigated molecules in different solvents and details of the X-ray analysis. See http://www.rsc.org/suppdata/nj/b1/b111241d/

“…(S)-N-Acetylvaline was prepared by acetylation of (S)-valine under sonochemical conditions. 45 (S)-Alaninemethylamide was obtained by transamidation of (S)-alanine methyl ester following literature procedures. 46 Subjecting 2-iodoaniline (1) to Sonogashira coupling with (trimethylsilyl)acetylene afforded 2-[(trimethylsilyl)ethynyl]aniline (2) in excellent yield, 41 desilylation by potassium fluoride 47 yielded 2-ethynylaniline (3).…”

“…(S)-Valine (470.6 mg, 4 mmol) was dissolved in water (10 mL) and was sonicated for 6 min. 45 Acetic acid anhydride (0.75 mL, 8 mmol) was added at 0, 2, and 4 min. Then, the mixture was concentrated on a rotatory evaporator.…”

Design and Synthesis of New PotentC2-Symmetric HIV-1 Protease Inhibitors. Use ofl-Mannaric Acid as a Peptidomimetic Scaffold

“…N 1, N 6-Di[(1 S ,2 S )-2-methyl-1-(methylcarbamoyl)butyl]-(2 R ,3 R ,4 R ,5 R )-2,5-di(benzyloxy)-3, 4-dihydroxyhexanediamide (48). Prepared using isolucine methylamide according to method IV using chloroform−methanol (20:1) as eluent to give (34.4 mg, 46%). [α] D = −6.8° ( c = 0.50, CHCl 3 ).…”

“…)-2,5-di(benzyloxy)-3,4-dihydroxyhexanediamide (33). The title compound was prepared in 32% yield (75 mg, 0.13 mmol) according to method III, using 6-amino-m-cresol.…”