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The syntheses of several N-aryl-3-amino-4-nitroisothiazol-5(2H)-imines 12 from 3,3-diamino-2-nitrothioacrylamides 11 are reported (Scheme 3). In polar solvents, a spontaneous isomerization of some of the prepared isothiazol-5(2H)-imines 12 yielded benzothiazoles 13 (Scheme 4). In the case of 2-alkyl-substituted derivatives of type 12, the isomerization occurred only at higher temperatures. Electronic influences of different substituents on the rate of the isomerization were studied, and a polar reaction mechanism is proposed in Scheme 6. The structures of 12e and 13e were established by X-ray crystallography. Conformational analyses of 3-(methylamino)-2-nitro-N-phenyl-3-(pyrrolidin-l-yl)thioacry~amide (1 1 I) by NMR and X-ray methods were performed with the aim of explaining the distinct behavior of this amide towards Br, or diethyl azodicarboxylate.

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ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

An Unexpected Isomerization of N-Aryl-3-amino-4-nitroisothiazol-5(2H)-imines to 2-(Benzothiazol-2-yl)-2-nitroethene-1,1-diamines. -Cyclization of thioacrylamides of type (I) (11 examples) yields the corresponding isothiazoles (II), which isomerize spontaneously in polar solvents to give the benzothiazoles (III). -(MOYA ARGILAGOS, D.; GARCIA TRIMINO, M. I.; MACIAS CABRERA, A.; LINDEN, A.; HEIMGARTNER, H.; Helv.

The reaction of N,N'‐dimethyl‐2‐nitroethene‐1,1‐diamine (8) with α,ß‐unsaturated acyl isothiocyanates 9 affords 3,3‐diamino‐2‐nitroacrylthioamides 10 (Scheme 2) in moderate‐to‐good yields. Cyclization of 10 under acidic conditions gives 1,3‐thiazin‐4‐one derivatives of type 11. Oxidative cyclization of 10 with diethyl azodicaboxylate leads to 4‐nitro‐1,2‐thiazol‐5(2H)‐imine derivatives 12.