Hydrochloric Acid → HCID 19045313, compound

Participants

Reaction Steps

Triethyl orthoformate (75 ml, 67 mg, 0.45 mmol) was added to a stirred suspension of 6,7-diamino-3,4-dihydro-1'-[2-(4-cyanophenyl)ethyl]spiro[(2H)-1-benzopyran-2,4'-piperidine]-4-one (56 mg, 0.15 mmol) and p-toluensulfonic acid (monohydrate, 10 mg) in ethyl acetate (5 ml). The mixture was heated under reflux for 1 hour, further triethyl orthoformate (75 ml) was added and the mixture was heated under reflux for 1.5 hour. The mixture was cooled and aqueous HCl (1N, 5 ml) was added. The mixture was stirred for 15 minutes, poured into aqueous sodium hydrogen carbonate (saturated, 25 ml) and extracted with dichloromethane (3×25 ml). The combined organic fractions were dried (Na2SO4) and evaporated under reduced pressure. The residue was purified by column chromatography on silica gel, eluting with CH2Cl2 /MeOH/NH3 (Aq.) (95:5:0.5) to give a yellow solid which was suspended in ethanol (1 ml) and treated with ethanolic HCl (6M, 0.2 ml). The mixture was stirred for 1 hour, cooled and the precipitate was collected and dried in vacuo to give the title compound as a tan solid (40 mg, 55%), m.p >250° C.

Provenance & Evidence