Dimethyl Sulfate → 3-Methyl Flunitrazepam

Participants

Reaction Steps

95 g (0.30 M) of rac-5-(o-fluorophenyl)-1,3-dihydro-3-methyl-7-nitro-2H-1,4-benzodiazepin-2-one are dissolved in 1 liter of absolute acetone and treated with 60 g of powdered potassium carbonate and 43 g of dimethyl sulphate. The mixture is stirred at room temperature for 4 hours and left to stand in a refrigerator for 48 hours. The mixture is then concentrated, treated with ice-water and extracted several times with methylene chloride. The organic solution is dried over sodium sulphate, filtered and concentrated. The residue is crystallised from ethyl acetate/petroleum ether, there being obtained rac-5-(o-fluorophenyl)-1,3-dihydro-1,3-dimethyl-7-nitro-2H-1,4-benzodiazepin-2-one which melts at 154°-156° C.

Provenance & Evidence