TETRAHYDRO-4(1H)-PYRIMIDINONE RING FORMATION OF BELLENAMINE, A BIOGENIC-AMINE, WITH CARBONYL-COMPOUNDS

Bellenamine, (R)-3.6-diamino-N-(aminomethyl)hexanamide in a neutral aq ueous solution at 37-degrees-C formed a new tetrahydro-4(1H)-pyrimidin one compound, N1,N3-methylenebellenamine by the reaction with self-gen erated formaldehyde. The structure was elucidated by NMR spectral anal yses. Two tetrahydro-4(1H)-pyrimidinone compounds. N1,N3-methylenebell enamine and (R)-6-(3-aminopropyl)tetrahydro-4(1H)-pyrimidinone (tentat ively named cyclized bellenamine) were synthesized from bellenamine an d D-beta-lysinamide, respectively, with an equimolar amount of formali n in good yields. However, formation of a 5-membered ring 4-imidazolid inone compound by the reaction of L-lysinamide with formalin was a ver y low yield. Reaction of bellenamine with acetaldehyde gave a mixture of four diastereomeric aldol adducts. By the reaction with acetone or diacetone alcohol. two stereoisomeric diacetone adducts. (2R,9aS)- and ethylocta-hydro-4H-pyrimido[1,6-a]pyrimidin-4-one, were obtained. Alt hough these adducts were difficult to separate, the (2R,9aR) diastereo mer was more stable than the other in acidic aqueous solution.