Phosgene → 4-chlorocarbonyl-4,9-dihydro-3-methyl-10H-thieno[3,4-b][1,5]benzodiazepin-10-one

Participants

Reaction Steps

8.2 g (0.036 mol) of 4,9-dihydro-3-methyl-10H-thieno[3,4-b][1,5]benzodiazepin-10-one were suspended in 365 ml of dichloromethane and after the addition of 40 ml (0.08 mol) of a 20% phosgene solution in toluene the mixture was stirred for 7 days at ambient temperature. The solution formed was washed three times, each time with 80 ml of water, dried over sodium sulphate and the solvent was eliminated in vacuo. The desired compound was freed from contaminants by column chromatography on MN silica gel 60 (70-230 mesh ASTM) using dichloromethane/ethyl acetate/petroleum ether 5/5/4 (v/v) as eluant. 6.1 g (58% of theory) of colourless crystals were obtained, m.p. 238°-239° C., RF 0.77 (Macherey-Nagel, PolygramRSIL G/UV254, pre-coated plastic sheets for TLC, eluant: dichloromethane/ethyl acetate/petroleum ether 5/5/4 v/v).

Provenance & Evidence