Methyl chloroformate → 6-Bromo-2-(3-aminopropyl)phthalazin-1(2H)-one

Participants

Reaction Steps

6-Bromo-2-(3-carboxypropyl)phthalazin-1(2H)-one (9.3 gm, 0.03 mole, prepared in Example XIV) was dissolved in 185 ml acetone by adding 4.7 ml triethylamine (0.0335 mole). The slightly cloudy solution was clarified, cooled to <10° C. and 3.8 gm methyl chloroformate (0.04 mole) was added over about 5 minutes. Stirred with cooling for another 30 minutes, then added a solution of 4 gm sodium azide (0.062 mole) in 25 ml water. Stirred for 30 minutes, added to 400 ml ice water and extracted three times with 80 ml methylene dichloride. This solution was dried, 4 ml of trifluoroacetic acid was added, and the solution refluxed for 18 hours. Methanol (100 ml) was added and the solution shaken with dilute potassium carbonate solution to free the base. The resulting solution was acidified with 10 ml of 30% HBr in acetic acid, diluted with 900 ml ether, filtered and washed with ethyl acetate. The product weighed 6.3 gm and showed a single spot on tlc, Rf =0.28 (using 10% methanol in chloroform on an ammonia treated silica plate).

Provenance & Evidence