Thiazetidine-2-ones, synthesis

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

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. ... 

Intramolecular cyclization of 2-aminoethanesulfonyl halides gives 1,2-thiazetidine 1,1-dioxides ((3 sultams), as exemplified in the synthesis of 429. ° Treatment of 2-halosulfonylethanoyl halides with ammonia or primary amines yields 1,2-thiazetidin-3-one 1,1-dioxides, which are mixed sulfonic-carboxylic imides 430. A 3-imino derivative has also been obtained. ... 

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

A new synthesis of 6-arylamino-2-heteroarylimino-l,2-dihydro-l,3,5-triazines from 2,4-bis-(heteroarylimino)-l,3-diazetidines and amidines has been developed by Molina et al. The formation of the triazines was explained as an initial addition of the imino nitrogen of the amidine to the exocyclic C=N bond, followed by formation of an open chain intermediate. This intermediate cyclized, followed by elimination of 4-amino-6-methyl-3-methylthio-l,2,4-triazin-5(47/)-one to give the triazine product (Scheme 62) <87S150>. 1,3,5-Triazines (207) and (208) have been prepared from 2-acylimino-l,3-thiazetidines (204) by treatment with iso thioureas or guanidines respectively (Scheme 63) <91JHC177>. 

The synthesis of A -substituted 4,4-dimethyl-l,2-thiazetidin-3-one 1,1-dioxides 42 (R = CH2R ) and a new ba.se catalysed rearrangement of this compound to thiazolidin-4-one I, I-dioxides 43 is reported <97HCA671>. 

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