2-Chloro-5-methylthiazole, reaction with

Reactions with aldehydes and ketones in the 1,2-dimethylimidazole series. Side-chain lithiation of a 2-chloro-methylthiazole 574 leads to epoxides 575 (Scheme 122) <2003T1381>. Exposure of triazole 576 to LDA and then benzonitrile generates the bicyclic 577 <2003EJM959>. 

Halomethyl thiazoles are highly useful synthetic intermediates. Many reactions involve abstraction of an acidic halomethyl proton. For example, the transformation of 2-chloromethyl-4-methylthiazole 123 (among other chloro-alkyl thiazoles) into the corresponding epoxide 124 by lithiation with -butyllithium was followed by reaction with the appropriate ketone (Scheme 45) <2003T1381>. 

Examples in which heterocyclic haloarenes have been used include the photostimulated reactions of 2-chlorothiazole, 2-chloro-4-methylthiazole and 2-chloro-5-methylthiazole with pinacolone potassium enolate which lead to the formation of mono- and bis-2-thia-zolyl ketones672 and a study of the reactions of 3-halo-2-amino derivatives of benzo[ ]thio-phene with the potassium salts of acetophenone, pinacolone and cyclohexanone which indicated that, under S l conditions, mainly reduction products were formed673. 

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