1.3- Thiazetidine-2-ones

A sulfa drug derivative of 1,3-thiazetidine-2-one is said to have a different... 

The synthesis and reactions of imino-1,3-thiazetidine-2-ones, 2-thiones, and exomethylene derivatives have been discussed in Sections XXVI and... 

In contrast, 1,3-diarylsulfonyl thioureas are transformed into 1,3-thiazetidin-2-ones [2087a] ... 

In contrast, the reaction of 1-arenesulfony 1-3-aryIthioureas (V, R = R = aryl), with carbonyl chloride affords the four-membered ring 1,3-thiazetidine-2-ones (IX) almost exclusively ( ). The compounds (IX) are also formed as minor by-products in the reaction of aliphatic and aromatic 1,3-disubstituted thioureas with carbonyl chloride ( ). 

A stereoselective one-pot synthesis of substituted 1,2-thiazetidine 1,1-dioxides (P-sultams) 55 started from heterocyclic pentafluorophenyl (PFP) sulfonates <06OL5513>. 

Fused 5-imino-l,2,4-dithiazolidine-3-thiones and 3-imines (100) take up nucleophiles on one sulfur atom, releasing the XCS structural unit of the heterocycle (Scheme 15) <85JCS(P1)1007>. Nonfused analogues (101) give up one sulfur atom to the nucleophile, the rest of heterocycle closing to form a 1,3-thiazetidine ring (102) (Scheme 16) <87ZC142>. 

The present review is concerned with four-membered heterocycles that contain one sulfur atom either alone or associated with another heteroatom. The classes of compounds that will be discussed are the thietanes (1) and thietes (2), the 1,2-oxathietanes (3), the / -sultines and -sultones (4 and 5), the 1,2- and 1,3-thiazetidines (6 and 7) and thiazetes (8), the 1,2- and 1,3-thia-phosphetanes (9 and 10), and the 1,3-silathietanes and 1,3-selenathietanes (11 and 12). 

The UV spectra of 1,2-thiazetidinone oxides have been recorded by Beeken and Korte. Measured in cyclohexane or chloroform, the N-substituted cyclohexyl- (35), phenyl-, and aryl-substituted 4,4-bisphenyl-l,2-thiazetidin-3-one 1,1-oxides showed an average absorption band at = 240 nm... 

A 2 -H 2 cycloaddition of diphenylketenes with tosylated sulfurdiitnides 162 produces the l,2-thiazetidin-3-one as well as the isomer 1,2-thiadiazolin-3-one (Eq. 32) Reaction of a ketene with N-sulfinylaniline in acetone at... 

Ring-opening polymerization of 1,2-thiazetidines, because of their highly strained ring structure, is often investigated for eventual technological applications. Imai et al. have produced a new class of polyamide-polysulfon-amide, using this technique. 4,4-Dimethyl-l,2-thiazetidin-3-one 1,1-dioxide... 

Four-membered ring adducts from 2n + 2n cycloaddition of keten-imines to sulfur dioxide. Isolation of l,2-thiazetidin-3-one 1-oxides. jS-Sultames. Simple method for synthesis of substituted 1,2-thia-zetidin 1,1-dioxide. ... 

Simple saltams, 1,2-thiazetidine 1,1-dioxides, are known to polymerize thermally (73MI51500), although in one case the alkene product was reported to be formed with retention of stereochemistry (Scheme 11) (75BCJ480). 

One example of an iminoalkylidene-l,3-thiazetidine thermolysis is reported to fragment in the opposite direction to give isothiocyanate and ketenimine (Scheme 14) (70JOC3470). 

The hydrolyses of l-imino-l,2-thiazetidin-3-ones, which are themselves the result of addition of ketenes to sulfur diimides, are usually characterized by loss of the imino sulfur linkage (Scheme 24) (69TL447,70TL1427). However, one account where the iminothiazetidine... 

Treatment of 1,2-thiazetidine dioxides with nucleophiles, base (75BCJ480) or methoxide (72LA(763)46) also cleaves the N—S bond (Scheme 34), although at least one account reports carbon-nitrogen scission (70BCJ3543). 

The intermediacy of a 4-imino- 1,2-oxathietane 2-oxide from the addition of sulfur dioxide to ketenimines was inferred from the trapping with methanol. The final isolated product in absence of methanol, l,2-thiazetidin-3-one 1-oxide, was established by X-ray (Scheme 42) (81CC350). 

Two examples of thioureas have been reported to give imino-l,3-thiazetidin-2-ones, one (66AG(E)704> in 97%, the other (64CB1232) in 35% yield, presumably by y-halo displacement (Scheme 70). 

Two studies of amination of mixed diacid chlorides to give l,2-thiazetidin-3-ones are known (Scheme 114) (62HCA717,76BSF277). 

It has been reported that amines (32JCSH42) or imines (53JCS143), when reacted with formaldehyde and hydrogen sulfide, give rise to N-substituted 1,3-thiazetidines. However, in at least one case the structure was established to be an eight-membered ring dimer, which calls into question the structure of these compounds. 

Bis(trifluoromethyl)thioketene reacts with some imines to form 1,3-thiazetidines (78JOC2500). One derivative has been used by Dupont in surface treatment of water-repellent textiles (71USP3592811). 

Thioureas are useful in the preparation of two four-membered ring systems thietanes and l,3-thiazetidin-4-ones. Thietanes (3) can be... 

The reaction between l,3-diaryl-2-thioureas and phosgene or thio-phosgene has been reported to yield 2-arylimino-3-aryl-l,3-thiazetidin-4-ones (5)9 or thiones (6).10 Recent studies on the reaction between... 

N,N-Disubstituted sulfur diimides, diaryl (69TL447), di-f-butyl (72JOC3810) and bis-p-tolylsulfonyl (70TL1427), are reported to add [2+2] to diphenylketene. The initially formed l-imino-4,4-diphenyl-l,2-thiazetidin-3-one derivatives are relatively unstable and rearrange thermally to five-membered rings at 70 °C (Scheme 9). 

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