Hydrochloric Acid → ethyl N-((7-chloro-2,3-dihydro-2-methyl-4-benzofuranylhydrazono)cyanoacetyl)carbamate

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Reaction Steps

A mixture of 9.18 g of 32A, 10 mL of 12N hydrochloric acid and 10 mL of water was heated on a steam bath for 1 hour, then 10 mL of water was added and the mixture was stirred at room temperature overnight. Then 30 mL of water was added, the mixture was cooled to 0° C. and stirred while a solution of 3.45 g of sodium nitrite in 10 mL of water was added dropwise over 15 minutes, then was stirred for 1 hour at 0° C. The resulting mixture was added slowly to a stirred mixture of 7.8 g of N-cyanoacetylurethane, 35 mL of pyridine and 900 mL of water, at 0° C. The resulting mixture was stirred at 0° C. for 1.5 hours, and filtered. The collected solid phase was washed with water, dried under reduced pressure and recrystallized from acetone/petroleum ether to give ethyl N-((7-chloro-2,3-dihydro-2-methyl- 4-benzofuranylhydrazono)cyanoacetyl)carbamate (32B), as a solid, m.p.: 175°-177° C. (with decomposition).

Provenance & Evidence