Thiazolinium salts and their reactions with nucleophiles

Abstract

this was unstable; other quaternisations could not be carried out. (17) n = 2 (19) 1.2 = 2 (18) Pi? = 3 (20) t a = 3Acyl derivatives of 2-thiazoline-2-thiol (I 1) may be obtained by treatment with acyl halides but it appears not to have been established unequivocally whether these are in fact S-acyl derivatives 596 (2-acylthio-2-thiazolines) (16) or N-acyl derivatives 'i-9 (3-acylthiazolidine-2-thiones), e.g. ( 21). The position of the G Oband in their i.r. spectra does not permit unequivocal distinction between SCOR and N-COR, but the U.V. spectra of these compounds are unaffected by added acid, and they do not form picrates; these properties are similar to those of the corresponding iN-alkyl compounds, e.g. ( 25), but contrast with those of the S-alkyl compounds, e.g. (13).Attempts to make a 2-thiazolin-2-yl disulphide by oxidation of 2-thiazoline-2-thiol (1 1) with hydrogen peroxide were unsuccessful. Though 5,5-dimethyl-2-thiazoline-2-thiol is said to yield the disulphide (28), in our hands 2-thiazoline-2-thiol (1 1), under similar conditions, yielded the thiazolinylthiazolidine-2-thione (29). However, the reported characterisation of compound ( 28) c D (27) R = H (29) R = H (28) R = Me (30) R = Me rests on a nitrogen analysis only, and this fits structure

Overview of the Chemistry of 2-Thiazolines

“…89,90 The most useful alkylating agents are those having an excellent leaving group (iodide and p-toluenesulfonate derivatives). [89][90][91][92][93] With less reactive nucleophiles such as bromide, lower yields are obtained (entries 21 and 22). Low molecular weight alkyl halides such as methyl iodide afforded good yields (Table 7, entries 1-16).…”

“…With 2-methyl-thiazoline care has to be taken to avoid formation of cyanine-type compounds. 90 Substitution by bulky groups on the 2 position of thiazolines also resulted in lower alkylation yield (Table 7, entry 6). Functionalized thiazolinium salts having a carboxylic ester function were also prepared by this procedure.…”

“…The thiazolinium salts 200 were simply prepared by N -alkylation of the corresponding thiazolines 199 (Scheme , Table ) under moisture-free conditions. , The most useful alkylating agents are those having an excellent leaving group (iodide and p -toluenesulfonate derivatives). − With less reactive nucleophiles such as bromide, lower yields are obtained (entries 21 and 22). Low molecular weight alkyl halides such as methyl iodide afforded good yields (Table , entries 1−16).…”

Noncovalent Bonds, Spectral and Thermal Properties of Substituted Thiazolo[2,3-b][1,3]thiazinium Triiodides

“…The use of such heterocyclic systems as thiazolo [2,3-a]isoquinolinium cations [40] is very promising in this regard. Syntheses of the related systems, such as 2H-benzo [4,5]thiazolo [2,3-b] [1,3] thiazin-5-ium, are superficially described in the literature [41], and only a few examples of 3,5,6,7-tetrahydro-2H-thiazolo [2,3-b] [1,3]thiazin-4-ium synthesis and transformation have been described [42][43][44] in the context of their biological activity.…”

Structure of 2-(2-thioxo-1,3-thiazolidin-3-yl)-4,5-dihydro-1,3-thiazolium aquatrichlorozincate(II)

“…HC1, we have noted the formation of a new, rather unexpected, compound of overall composition (dihydrothiazollumylthiazolidine-2-thione)+.ZnCl3(H20) -. Clark & Sykes (1971) prepared ttzt by treating 4,5-dihydro-1,3-thiazole-2-thiol with H20 2 and suggested that it is probably formed by oxidation of the 2-thiol group of one molecule of the dihydrothiazole followed by nucleophilic attack by the N atom of a second molecule, with the oxygenated S atom acting as a good leaving group. The ttzt ligand is also one of the major products of the reaction of the thallium(I) salt of ttz with thiophosgene (Fujita, Nagao, Seno, Takao, Miyasaka, Kimura & Watson, 1981).…”