From Thione-S-imides

From Thione-S-imides (Type D).— The first synthesis of compounds incorporating the thione-S-imide (RiC S NR ) system has been announced, and some of their novel reactions have been enumerated. Amongst them, the cycloaddition of N-isobutenylpyrrolidine (20) to (19) yields a 1 1 adduct, formulated as the isothiazolidine (21).  

From Aminocrotonic Esters (Type E).— A novel direct ring synthesis of 5-hydroxyisothiazoles involves the condensation of a p-aminocrotonic ester (22) with perchloromethanethiol in the presence of base the heterocyclic products (23) are obtained directly (30—40%), presumably by the reaction sequence shown.  

Type F Synthesis.— The substituted 5-ethoxythiocarbonylthiophen (24) functions as a thioacylating agent, converting malonic dinitrile into the 

Further examples of isothiazoles have been produced by well-established syntheses. A comparative study examining four distinct routes has provided mono-, di-, and tri-methylisothiazoles. Directions have been given for the synthesis of the parent compound of the series, isothiazole, from propynaP in improved yield. 

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From Thione S-Imides (Type D). Further details of the cycloadditions between activated alkenes and thione S-imides (see Vol. 1, p. 112, ref 16) have been reported. ... 

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