No abstract

We studied the selective formation of 3,5-and 2,5-pyrazinone via a transamidation-cyclization reaction. The equilibrium between acyl amides changed depending on the solvent, acidity, and substituents. Furthermore, selective transformation of 2,5-pyrazinone was accomplished by using a substrate with a secondary amine.Hydrogen ion exponent (pH) was measured on a Horiba F-13 and electrode was used with Horiba 9677-10D. N-( -Oxoacetyl diamines 1 were prepared according to our previously reported procedure. 8

AlkaloidsAlkaloids U 0600 Synthesis of Marine Bisindole Alkaloids, Hamacanthins A and B Through Intramolecular Transamidation-Cyclization. -(KAWASAKI*, T.; KOUKO, T.; TOTSUKA, H.; HIRAMATSU, K.; Tetrahedron Lett. 44 (2003) 49, 8849-8852; Meiji Pharm. Univ., Kiyose, Tokyo 204, Japan; Eng.) -Mais 11-185