Triethylamine → HCID 67959040, compound

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Reaction Steps

As per scheme-9, 2-picolinic acid hydrazide (9-a) is reacted with pyruvic acid chloride in the presence of organic base such as triethylamine in dichloromethane at a temperature 0° C. to 5° C. for up to 3 hr. The reaction mixture is further treated with p-toluene sulfonyl chloride and is allowed to stir at ambient temperature for up to 16 hr to provide pyridine-1,3,4-oxadiazole compound 9-b. The compound 9-b, thus obtained, is reacted with reducing agent sodium borohydride in methanol or ethanol at a temperature 35° C. to provide pyridine-1,3,4-oxadiazole ethanol (9-c). The compound 9-c is reacted with methanesulfonylchloride in the presence of triethylamine in dichloromethane at a temperature ranging from 0° C. to 15° C. to provide corresponding methanesulfonyl ester of pyridinyl-1,3,4-oxadiazolyl-ethanol, which is converted to corresponding pyridine-1,3,4-oxadiazolyl ethyl bromide (9-d) by treating sulfonyl ester with lithium bromide in acetone at reflux temperature.

Provenance & Evidence