
TY  - JOUR
A1  - Crow, WD 
A1  - Gosney, I 
T1  - Isothiazole chemistry. VI. Reactions of carbanions with N-Ethyl-3-isothiazolone
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1969
VL  - 22
IS  - 4
SP  - 765
EP  - 774
KW  - 
UR  - https://doi.org/10.1071/CH9690765 
N2  - N-Ethyl-3-isothiazolone undergoes cleavage of the S-N bond when subjected to nucleophilic attack by carbanions, yielding a series of cis-3-alkylmercapto-acrylamides. Under basic conditions the reaction is shown to be reversible, the stability of the product being apparently dependent upon the degree of substitution at the carbanion site. Resonance-stabilized carbanions derived from primary carbon acids E-CH3 (E = electrophile) react with two moles of the isothiazolone to give E- CH(S-CH=CH-CONHEt)2 as well as E-CH2-S-CH=CH-CONHEt, whereas those derived from secondary carbon acids (E-CH2R) give only the product E- CHR-S-CH=CH=CONHEt. When carbanions from tertiary carbon acids E-CHR2 are employed, no stable product incorporating the carbon acid is obtained; a competing side reaction of the base on N-ethyl-3-isothiazolone itself results in the formation of a dimer (C5H7ONS)2.     It is proposed that the formation and subsequent stability of the products of carbanion attack depend upon their ability to form a carbanion adjacent to the sulphur atom, and that, in the absence of such a carbanion site, reversion to starting materials will be brought about by bases. Factors relevant to this are discussed. 
ER  -

