文摘
Two concise syntheses of the experimental rice herbicide 2,2-dimethyl-1-(4-methylthio-5-pyrimidinyl)indane are reported.The initial synthesis relies on a low-temperature addition of5-lithio-4-methylthiopyrimidine to 2,2-dimethyl-1-indanone toconstruct the pyrimidinylindane system. Process improvementsto this route are described and resulted in the preparation of90 kg of the title compound on pilot plant scale. Economicsdictated the need to identify a new synthetic route which utilizedinexpensive raw materials. Detailed herein is the initial discovery of a new route which features a novel combination ofdissolving metal reduction/formylation/cyclization to constructthe requisite pyrimidine ring. Process improvements to thischemistry have allowed us to deliver an appropriately substituted pyrimidinylindane in a minimal number of syntheticoperations.