Phthalimide → 8-chloro-1-(2-phthalimidoethyl)-6-phenyl-4H-s-triazolo[4,3-a][1,4]benzodiazepine ethyl acetate

Participants

Reaction Steps

A stirred mixture of 8-chloro-6-phenyl-1-(2-hydroxyethyl)-4H-s-triazolo[4,3-a][1,4]benzodiazepine (0.677 g., 0.002 mole), phthalimide (0.324 g., 0.0022 mole), triphenylphosphine (0.576 g., 0.0022 mole) and dry tetrahydrofuran (20 ml.), under nitrogen, is treated with diethyl azodicarboxylate (0.383 g., 0.0022 mole) and stirred at ambient temperature (22°-25° C.) for 24 hours. The mixture is concentrated in vacuo and the residue chromatographed on silica gel (50 g.) with 3% methanol-97% chloroform. The product thus obtained is crystallized from ethyl acetate to give 8-chloro-1-(2-phthalimidoethyl)-6-phenyl-4H-s-triazolo[4,3-a][1,4]benzodiazepine ethyl acetate solvate of melting point 223.5°-226° C.

Provenance & Evidence