Thiirane carboxylic acid

Thiete structures have been suggested as fragmentation products in the mass spectra of a thietane fused to a 3-lactam, an ortho disulfide of a thiolbenzoate ester, -propanethiol, thiirane carboxylic acid esters, isothiazoles, thiazoles, 1,3-dithiole 2-thiones, 1,3-dithiolene-2-ones, S-ethyl thio-benzoate, and thianaphthene sulfones. Tetramethylthiete may have been formed on thermolysis of the p-toluenesulfonyl-hydrazone of 2,2,4,4-tetramethyl-3-thietanone. " Thiete 2-thione may be an intermediate in the decomposition of 1,2-ditholium salts by the action of bases. " 2,2-Diphenyl-2H-thiete is suggested as an intermediate in the reaction of diphenyldiazomethane with 1,2,3-benzo-thiadiazole which yields 9-phenylthioxanthene and three other products. ... 

Thiirans.— The first examples of optically active thiiran carboxylic acid derivatives have been described. Optically pure methyl (5)-thiiran carboxylate was prepared from methyl (/ )-cysteinate by deaminative cyclization (Scheme 55). 

A simple synthesis of chiral thiiran carboxylic acids from cysteine derivatives has been described by Maycock and Stoodley. Diazotization of methyl (if)-cysteinate (106) gave (107), whilst under the same conditions (i )-cysteine (108) gave a mixture of the (5) and R) enantiomers (109) and (110). 

Thiiranes (episulfides) have been suggested as intermediates in the reaction of thionyl chloride with various substrates including ketones and carboxylic acids.54 However, apart from one claim, later corrected, no such compounds have been isolated.55,56... 

Aziridines (three-membered saturated nitrogen-containing rings) are also found in anti-tumour agents, such as the mitomycins. Thiiranes also occur naturally, as plant products such as thiirane-2-carboxylic acid, isolated from asparagus. 

Olefin derivatives with electron-attracting substituents, such as, for example, acrylic compounds and dienes, as well as lactams, lactones, oxiranes, thiiranes, isocyanates, and A -carboxy anhydrides of a-amino acids, a-hydroxy carboxylic acids, and a-thiol carboxylic acids can be polymerized anionically ... 

Acyl-group transfer polymerization of thiiranes using carboxylic acid derivatives and quaternary onium salts is a relatively new method for controlled polymer synthesis from various thiiranes.In this mechanism, an acyl-group is transferred in each propagating step to give the corresponding polythiirane with an S-acyl end group (Scheme 30). 

Thiiran-2-carboxylic acid methyl ester, A 22.3 C4HA... 

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