Stereoselective synthesis of the optical isomers of a new muscarinic receptor antagonist, HL-031120

摘要

We present here a practical stereoselective synthetic method to produce enantiopure isomers of a new muscarinic receptor antagonist, HL-031120 (3-quinuclidinyl-2'-cyclopentyl-2'-hydroxy-2'-phenylacetate, I). Four optical isomers were effectively by stereoselective synthesized using pivaldehyde as steric hindrance agent from the chiral starting material, (S) or (R)- mandelic acid. The isomers were obtained with 70-76% yields in 98-99% e. e.