Stannous Chloride → 5-(4-fluorophenyl)-8-methyl-11H-1,3-dioxolo[4,5-h]imidazo[1,2-c][2,3]benzodiazepine

Participants

Reaction Conditions

Reaction Steps

First 200 mg of 5-(4-aminophenyl)-8-methyl-11H-1,3-dioxolo[4,5-h]imidazo[1,2-c][2,3]benzodiazepine is added to a solution of 6 ml of hydrogen fluoride-pyridine complex (1:1) under argon, and then 51 mg of sodium nitrite is added at 0-5° C. After stirring at 5-10° C. for 40 minutes, 117 mg of tin(II) chloride and 190 mg of tetrabutylammonium dihydrogen trifluoride are added to the preparation. It is then heated for 3 hours to a bath temperature of 100° C. After cooling, it is added to ice water and extracted three times with ethyl acetate and three times with methylene chloride. The collected organic phase is dried, filtered, concentrated by evaporation and chromatographed on silica gel first with methylene chloride:ethanol=10:1, then a second time with acetone:ethyl acetate=3:1 and then a third time with methylene chloride:ethanol=95:5. 106 mg of 5-(4-fluorophenyl)-8-methyl-11H-1,3-dioxolo[4,5-h]imidazo[1,2-c][2,3]benzodiazepine with a melting point of 190° C. is obtained.

Provenance & Evidence