Process and intermediates for the synthesis of (3-alkyl-5-piperidin-1-yl-3,3a-dihydro-pyrazolo[1,5-a]pyrimidin-7-yl)-amino derivatives and intermediates

Abstract

Disclosed is a process for the synthesis of compounds of Formula I by sequentially aminating, first with a primary amine and then with a secondary amine, an intermediate compound of the structure of Formula E1, wherein Ris a linear, branched, or cyclic alkyloxy functional group of the structure (—R—OH), Ris a linear, branched or cyclic alkyl group, Ris a linear, branched or cyclic alkyl group, and Ris an alkylene-heterocycle, said process comprising forming intermediate compound of Formula E1 by reacting, in a refluxing reaction solvent selected from alcohols having 5 or less carbon atoms and mixtures of two or more thereof, a methanol solution of a salt of a 4-alkyl-3-amino-pyrazole compound of Formula C1, with a diamidization reagent selected from dimethylmalonate, monomethylmalonyl-chloride, and malonyl dichloride in the presence of a Lewis base having sufficient proton affinity to abstract a proton from the 1-position nitrogen on the pyrazole ring.