Reaction of 1,2- and 1,3-dicarbonyl compounds with 1,3-diamines: some new 1,4-diazepines

Glyoxal sodium hydrogen sulphite addition compound reacts with 2,4-diaminopentane dihydrochloride to yield 5,7-dimethylhexahydro-1,4-diazepin-2-one, but glyoxal monohydrate reacts with 1,3-diaminopropane and 2,4-diaminopentane under alkaline conditions to produce more complex substances. Cyclohexane-1,2-dione condenses with 1,3-diaminopropane to form 2,3,4,6,7,8-hexahydro-1H-1,5-benzodiazepine, but di-imines formed from two molecules of dicarbonyl compound and one of diamine result from the reactions of 1,3-diamino-propane with benzil, camphorquinone, and isatin. Complex products are obtained from o-quinones and diaminopropane. 1,3-diketones and 1,3-diamines react to produce open-chain compounds formed from two molecules of ketone and one of amine. 2,3-Dihydro-1H-1,4-diazepine is apparently formed from malonaldehyde and ethylenediamine, but 1,2-diaminocyclohexane reacts with malonaldehyde to give 1,2-bis(2-formylvinylamino)cyclohexane.