Naveenkumar Kolla

New Synthesis of Donepezil Through Palladium‐Catalyzed Hydrogenation Approach

Abstract A new, economical, and efficient process has been developed for large‐scale synthesis of donepezil 1, an anti‐Alzheimers drug. The process involves palladium‐catalyzed hydrogenation of (2E)‐5,6‐dimethoxy‐2‐(pyridin‐4‐ylmethylene)indan‐1‐one 6 to provide 5,6‐dimethoxy‐2‐(piperidin‐4‐ylmethyl)indan‐1‐one 8 as a key step. DRL‐IPD Communication No. 006.

Efficient Synthesis of (1R)‐[3,5‐Bis(trifluoromethyl)phenyl] Ethanol, a Key Intermediate for Aprepitant, an NK‐1 Receptor Antagonist

Abstract Enzyme‐catalyzed efficient synthesis of (1R)‐[3,5‐bis (trifluoromethyl) phenyl] ethanol (R)‐(3), a key intermediate for aprepitant, via enantioselective transesterification of racemic 1‐[3,5‐bis (trifluoromethyl) phenyl] ethanol (RS)‐3 using vinyl acetate as the acyl donor in the presence of Candida antarctica lipase‐B (CAL‐B) in an overall yield of 84% with >99% ee is described.

(R)-(+)-2-{[(3-Methyl-4-nitro-pyridin-2-yl)meth-yl]sulfin-yl}-1H-benzimidazole.

The title compound, C14H12N4O3S, is an intermediate of Dexlansoprazole, a proton pump inhibitor (PPI) mainly developed for anti-ulcer activity. The absolute configuration of the title compound was determined as R. The crystal structure reveals that the molecules form chains along the b axis through N—H⋯N and C—H⋯O hydrogen-bonded dimers. These chains are connected via weak C—H⋯O hydrogen bonds.