REACTIONS OF THIOL ESTERS WITH HALOGENS AND SOME N-HALO AND O-HALO COMPOUNDS

Abstract

S-Phenyl thioacetate (1) quantitatively reacted with 1/2 mole of bromine (or chlorine), yielding acetyl bromide (or chloride) and phenyl disulfide. With iodine, 1 formed a complex, which reacted with an alcohol (MeOH, Me3CCH2OH, PhCH2OH), forming the corresponding ester; a catalytic amount of iodine was sufficient for this transesterification. 1 reacted quantitatively with 1-chlorobenzotriazole. The reaction of 1 with t-butyl hypochlorite yielded t-butyl acetate (70%) and acetyl chloride(30%).

Preparation of N,N-Dimethyl-N′-Arylureas Using S,S-Dimethyl Dithio­carbonate as a Carbonylating Reagent

“…As indicated in Scheme 2, it may be that N,N-dimethylcarbamoyl chloride (5) is obtained through the formation of the chlorine-thiocarbamate 3 intermediate complexes 9 and 13; this is consistent with the literature regarding the reactions of halogen (chlorine and bromine) with thiol esters, 21 and with what we recently hypothesized for the re-actions of chlorine with S-methyl N-alkylthiocarbamates. 19b The mechanism proposed in Scheme 2 is also supported by the presence of dimethyl disulfide (4) in the reaction mixtures and by the reaction of 5 with methanesulfenyl chloride (11) (Scheme 3).…”

Preparation of 2-halogeno S-phenyl thioesters from 2-phenylsulphony -2-phenylthiooxiranes. Crystal structures of 2-phenylsulphonyloxiranes

“…92.5-93. 5 (E)-3-/sopropyl-2-phenylsulphonyi-2-phenyi~hiooxirane 4b. The alkene was 8b (0.74 mmol scale), and the reaction mixture was stirred at -18 "C for 2 h. Chromatography was carried out using light petroleum+thyl acetate (10: 1) as eluent to yield (E)-3-isopropyi-2-phenylsulphonyl-2-pheny/thiooxirane 4b as a colourless oil which eventually solidified (0.242 g, 98%), m.p.…”

“…76-76. 5 General Procedure for Work-up Used in the Preparation of Oxiranes 4b, 4e, 4f, 14b and 14f by Anion Formation.-Aqueous ammonium chloride ( 5 cm3; 10%) was added and the mixture was warmed to room temp. The organic layer was separated and the aqueous layer was washed with dichloromethane (3 x 15 cm3).…”

The reduction of oxidized methionine residues in peptide thioesters with NH4I–Me2S

“…In order to minimize the formation of iodine and iodosulfonium ions, which have been reported to induce side reactions like Trp dimerizations to 2,2 indolylindoline derivatives, 19 Me 2 S was previously found to accelerate the reaction and serve as an efficient coreductant leading to the formation of dimethyl sulfoxide and iodide. Although it is well documented that iodine promotes the cleavage of thioesters to acids, 20 we envisioned that a careful optimization of the reaction conditions and the use of Me 2 S as coreductant could avoid the formation of iodine and thereby lead to a selective nucleophilic reduction of the methionine sulfoxide 2 to 1 while leaving the thioester intact.…”