title: Pteridines. I. Beta-keto sulfoxides and  -keto aldehyde hemithioacetals as pteridine precursors. A new selective synthesis of 6- and 7-substituted pteridines.
mesh_terms: D000080:Acetals; D000085:Acetates; D055598:Chemical Phenomena; D002621:Chemistry; D004987:Ethers; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy; D011621:Pteridines / Q000138:chemical synthesis*; D011743:Pyrimidines; D013454:Sulfoxides
chemical_list: D000080:Acetals; D000085:Acetates; D004987:Ethers; D011621:Pteridines; D011743:Pyrimidines; D013454:Sulfoxides