Isotellurazoles, synthesis

Isothiazoles, Isoselenazoles, and Isotellurazoles Synthesis.—Several new methods for the synthesis of isothiazoles and benziso-thiazoles have been reported. Nitrile sulphides are probable intermediates in one such synthesis they are produced by the thermolysis of l,3,4-oxathiazol-2-ones... 

S824). More recently, this method was employed for the synthesis of 3-methyl-5-vinyl isotellurazole If (87H1587). It was assumed that the reaction occurs through the intermediate oxime-O-sulfonic acids 2. 

Disubstituted isotellurazoles 1 (4-11%) and bis((3-acylvinyl)tellurides 3 (3-10%) were isolated in very low yields from the reaction mixture as the products of nucleophilic addition of telluride anion to the triple bond of the initial ethynyl ketones (83S824). This method cannot be applied to the synthesis of 3//-isotellurazoles. When a-acetylenic aldehydes were used instead of ethynyl ketones, bis((3-cyanovinyl)tellurides 4 obtained in 14-20% yields were the only products (83S824). 

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See also in sourсe #XX -- [ , ]

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