Nordiazepam → 7-chloro-1,3-dihydro-1-[3-(2-methyl-1,3-dioxolan-2-yl)propyl]-5-phenyl-2H-1,4-benzodiazepin-2-one

Participants

Reaction Conditions

Reaction Steps

A solution of 54.2 g. of 7-chloro-1,3-dihydro-5-phenyl-2H-1,4-benzodiazepin-2-one in 500 ml. of dimethylformamide is treated under an atmosphere of argon at 0° C. with 32.8 g. of potassium tertiary butylate and the mixture is then stirred in an ice-bath for 30 minutes. Then, at 10°-15° C. there is added a solution of 66 g. of 2-(3-chloropropyl)-2-methyl-1,3-dioxolan in 100 ml. of dimethylformamide, the mixture is stirred at 20°-25° C. for 30 minutes and subsequently heated to 100° C. for 30 minutes. The mixture is cooled and poured on to 2.5 liters of ice-water. The separated oily product is extracted with methylene chloride and the organic phase washed with a saturated aqueous sodium chloride solution, dried over sodium sulfate and concentrated to dryness. The residue crystallizes upon trituration with ether, and there is obtained 7-chloro-1,3-dihydro-1-[3-(2-methyl-1,3 -dioxolan-2-yl)propyl]-5-phenyl-2H-1,4-benzodiazepin-2-one having a melting point of 152°-153° C. Recrystallization from ethanol does not increase the melting point.

Provenance & Evidence