June 1975 ÍI3 Studies of Thieno[2,3-í>] pyrazines in Preparation of Pyrazino[2',3':4,5]thieno[3, 2-d]pyrimidines and Related Moleeules (1) SW Schneller*and FW Clough Department of Chemistry, University of South Florida, Tampa, Florida ... and KD Ross, J. Heterocyclic Chem., 9 ...