反应详情

A mixture of 5.7 g. (0.02 mole) of 7-chloro-2-hydrazino-5-phenyl-3H-1,4-benzodiazepine, 3 ml. (0.04 mole) of methyl pyruvate and 50 ml. of methanol is stirred, under nitrogen, for 17 hours at room temperature, by which time the solid has dissolved. Three ml. more methyl pyruvate is added and the solution is allowed to stand for 7 hours more. After filtration and evaporation in vacuo (50° C./0.5 mm.) a brown gum is obtained which is chromatographed on silica gel and eluted with 1% methanol in chloroform. Evaporation of the combined fractions containing the product (as indicated by thin layer chromatography) gives a gum which is crystallized from a mixture of chloroform and ether. A yield of 3.5 g. (67%) of 7-chloro-2-[[1-methoxycarbonyl)ethylidene]hydrazino]-5-phenyl-3H-1,4-benzodiazepine is obtained as nearly white crystals of melting point 156°-157° C. Melt solvate indicates the product contained 1.95% CHCl3 even after prolonged drying in vacuo.

1. additionA mixture of 5.7 g
2. dissolutionhas dissolved
3. filtrationAfter filtration and evaporation in vacuo (50° C./0.5 mm.) a brown gum
4. customis obtained which
5. customis chromatographed on silica gel
6. washeluted with 1% methanol in chloroform
7. customEvaporation of the combined fractions
8. additioncontaining the product (as indicated by thin layer chromatography)
9. customgives a gum which
10. customis crystallized from a mixture of chloroform and ether