Ammonia → HCID 10291701, compound

Participants

Reaction Conditions

Reaction Steps

A mixture of 1-acetyl-4-piperidinepropionic acid (1.99 g, 9.99 mmol), 1,2,5,6-tetrahydro-4H-pyrrolo[3,2,1-ij]quinoline-4-one (1.73 g, 9.99 mmol) and polyphosphoric acid (24 g) was stirred at about 105° C. for 7 hours under nitrogen. Cold water (16 mL) at about 5° C. was slowly added dropwise thereto at −40 to 70° C. and 25% aqueous ammonia was added dropwise thereto at 40 to 50° C. to adjust pH to 8.5. A mixture of toluene-acetonitrile (1:1) (20 mL) was added. The layers were separated, a mixture of toluene-acetonitrile (1:1) (10 mL) was added to the aqueous layer, and the layers were separated. The organic layers were combined, and concentrated to a volume of the solution of ⅕. Diisoporpyl ether (7 mL) was added to the residue to precipitate crystals. The mixture was stirred at about 25° C. for about 1 hour and then at 0 to 5° C. for about 1 hour. Precipitated crystals were separated, washed with diisopropyl ether (3 mL) and dried to obtain 3.47 g (yield 98.6%) of the desired compound as crystals.

Provenance & Evidence