Selective Synthesis and Structural Elucidation of S-Acyl- and N-Acylcysteines

Abstract

N-(Acyl)-1H-benzotriazoles 6a-f react with l-cysteine 5 at 20 degrees C to give exclusively (i) N-acyl-l-cysteines 8a-e in the presence of triethylamine in CH(3)CN-H(2)O (3:1), but (ii) S-acyl-l-cysteines 7a-e in CH(3)CN-H(2)O (5:1) in the absence of base. Structures 7b, 7d and 8b, 8d are supported by 2D NMR spectroscopic methods including gDQCOSY, gHMQC, gHMBC, and (1)H-(15)N CIGAR-gHMBC experiments. The structure of compound 8d was also supported by single-crystal X-ray diffraction.

Unusual hydrogen bonding inL-cysteine hydrogen fluoride

“…Dashed black lines represent hydrogen bonds. Table S1 in the Supporting information) (Chapman & Bryce, 2007;Shan & Huang, 1999;Fujii et al, 2005;, 2009, 2011Kolesov et al, 2008;Gö rbitz & Dalhus, 1996;Minkov et al, , 2012Drebushchak et al, 2008;Kumar & Nangia, 2013;Katritzky et al, 2009). The corresponding C3b-O1b and C3b-O2b bond lengths in the B molecule differ from each other, and from the mean zwitterionic values, d min (C-O) = 1.244 (6) Å and d max (C-O) = 1.257 (6) Å .…”

Similarity analysis, synthesis, and bioassay of antibacterial cyclic peptidomimetics

“…The methodology used for the regioselective syntheses of S - and N -acylcysteines was developed recently in our group by using N -acylbenzotriazoles under mild reaction conditions [37]. Utilizing this methodology, 35a was coupled with two equiv of free cysteine in aqueous acetonitrile at 20 °C over 12 h to give bis( S -acylcysteine) 36 in 64% yield.…”

“…A synthetic route seems highly relevant, since N -acylbenzotriazoles have been reported elsewhere [35–37] to be stable, easy-to-handle acylating agents and have found numerous applications for advantageous N-, O-, C- and S-acylations.…”

Synthesis of Coumarin Conjugates of Biological Thiols for Fluorescent Detection and Estimation

“…Compounds 4a,f,k that are derived from cysteine and 4d,i,n from L-penicillamine were synthesized according to our previously reported method (Method C). 16 Treatment of GSH (1b) with one equivalent of 1-acyl-1H-benzotriazoles 3a-c in the presence of one equivalent of potassium bicarbonate at 20°C in aqueous methanol for 15 minutes gave exclusively S-acylglutathiones 4b,g,l (Method A). 17 However, captopril thioesters 4c,h,m were prepared when N-acylbenzotriazoles 3a-c were added to a solution of captopril (1c) in a solution of acetonitrile (20 mL) and water (10 mL) in the presence of triethylamine for one hour (Method B).…”

“…Method C: 16 To a solution of the corresponding biological thiol 8, 57.0, 111.2, 115.0, 118.7, 122.5, 126.6, 131.2, 142.5, 153.6, 173.2, 196.5. Anal. Calcd for C 13 H 11 NO 5 S: C,53.24;H,3.78;N,4.78.…”