Ammonia → HCID 23454279, compound

Participants

Reaction Steps

110 g (0.5 mol) of 8-chloro-5,6,7,8-tetrahydro-2-quinolone hydrochloride are heated with 500 ml of water to about 90° C. with agitation, thus obtaining after a short time a transparent solution which is then neutralized with 75 ml of concentrated ammonia. After cooling of the solution, 105 g of 8-hydroxy-5,6,7,8-tetrahydro-2-quinolone trihydrate areisolated having a melting point of 192° C., which correspond to a yield of 85.7% of theory. 105 g (0.48 mol) of trihydrate are heated with 2liters of chloroform while stirring, the hydration water is removed in the form of an azeotropic mixture, and the chloroform phase of the distillate is recycled to the flask. After this operation is complete, 350 g of manganese dioxide (precipitated in an active form) are added to the chloroform solution in portions and in such a manner that the reaction temperature does not exceed 40° C. Intense agitation is continued at this temperature for 3 hours. Subsequently, the batch is separated fromthe manganese dioxide, the chloroform is distilled off, and 65 g of light brown 8-oxo-5,6,7,8-tetrahydro-2-quinolone, corresponding to a yield of 83% of theory, are isolated, which after recrystallization from cyclohexanone has a melting point of 253° C. in a closed vial.

Provenance & Evidence