Abstract: There are disclosed certain 2-alkyl-4-substituted 6H-7,8-dihydrothiapyrano[3,2-d]pyrimidines which have oral hypoglycermic activity and with such ability to lower blood sugar are useful in the treatment of type II diabetes and/or obesity with associated insulin resistance. Processes for the preparation of such compounds and compositions containing such compounds as the active ingredient thereof are also disclosed.

Abstract: A glycoprotein phosphotyrosyl protein phosphatase is isolated from human tissues, such as human placental membrane. Upon membrane solubilization and extraction of the enzyme it was subjected to chromatographic purification and isolation. The analytical and biological responses of the enzyme demonstrate that it is novel and readily distinguished from other enzymes previously isolated from similar tissues. The enzyme is a dephosphorylation enzyme of membrane phosphoprotein kinases, and as such has utility as an antidiabetic agent, an antiatherosclerosis agent or an antitumor agent since certain membrane receptor kinases involved in each such biological function involve a phosphorylation mechanism for cell transformation, metabolism and growth and which, when blocked by the instant enzyme, results in a suppression or alteration of the biological function.