Acyl with thiols

Aminosodium salt and acylated with 1 H-tetrazole-1 -acetyl chloride. The acetoxy group is then displaced by reaction with 5-methyl-1,3-4-thi-adiazole-2-thiol in buffer solution. The product acid is converted to the sodium salt by NaHCOa. 

Acyl halides react with thiols, in the presence of zinc, to give the corresponding thio ester. ... 

Kusumoto and coworkers have found that the treatment of hemiacetal 1 with trifluoro- or trichloroacetic anhydride 94 (1 equiv) and trimethylsilyl perchlorate (0.2 equiv) selectively provides the corresponding anomeric ester intermediate 91 [152], Hemiacetal acylation occurs even in the presence of the alcohol acceptor. With Lewis acid assistance, the glycosyl ester intermediate is displaced to provide disaccharide products in good yields. This transformation allowed the synthesis of disaccharides 98 (81%) and 99 (91%). In some cases, acetic anhydride has been used as the electrophilic activator of hemiacetal donors and the reaction with thiol acceptors yields S-linked glycosides [153,154],... 

An easily accessible DA CSP derived from L-A-(2-naphthyl)valine (80) was used to separate appropriately derivatized amines, amino alcohols and thiols, derivatization consisting of N-, O- and 5-acylation with 3,5-dinitrobenzoyl chloride or 3,5-dinitrophenyl... 

In one synthesis of this drug, L-proline (11-2) is acylated with the acid chloride (11-1) obtained from the addition of hydrogen chloride to the double bond in methacrylic acid followed by reaction with thionyl chloride to give amide (11-3) as a mixture of diastereomers. The pure 2S isomer is then isolated from the mixture by fractionation as the dicyclohexylamine salt. Treatment of that compound with ammonium hydrosulfide leads to the displacement of chlorine by a thiol group and the formation of captopril (11-4) [13]. 

Entry 1, Table 13.17), the acylation of support-bound thiols (Entries 2 and 3), and the acylation of thiols with support-bound carboxylic acids (Entry 4, Table 13.17). Thiol esters are stable towards acids (e.g. 50% TFA in DCM), but are readily cleaved by nucleophiles and are reduced to alcohols by treatment with LiBH4 [170]. 

Peptide thioesters (Section 15.1.10) are generally prepared by coupling protected amino acids or peptides with thiols and are used for enzymatic hydrolysis. Peptide dithioesters, used to study the structures of endothiopeptides (Section 15.1.11), may be prepared by the reaction of peptide nitriles with thiols followed by thiolysis (Pinner reaction). Peptide vinyl sulfones (Section 15.1.12), inhibitors of various cysteine proteases, are prepared from N-protected C-terminal aldehydes with sulfonylphosphonates. Peptide nitriles (Section 15.1.13) prepared by dehydration of peptide amides, acylation of a-amino nitriles, or the reaction of Mannich adducts with alkali cyanides, are relatively weak inhibitors of serine proteases. 

Figure 4. Cyclic voltammetry at three scan rates for Au macroelectrodes in 1.0 M NaC104 at pH 1.5 buffer (phosphate) derivatized with only acyl ferrocene thiol, 4c, (5.2 x 10 10 mol/cm2) (top) only quinone thiol. 5, (5.6 x 10 10 mol/cm2) (middle) and a mixture of 4c and 5 at 2.8 x 10 1( mol/cm2 and 2.8 x 10 1( mol/cm, respectively (bottom). Reproduced with permission from ref. 1. Copyright 1991 American Association for the Advancment of Science.

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