A practical synthesis of an orally potent renin inhibitor, isopropyl (2R,3S)-4-cyclohexyl-2-hydroxy-3-{N-[(2R)-2-morpholinocarbonylmethyl-3-(1-naphthyl)propionyl]-L-histidyl}aminobutyrate

Abstract

The practical synthesis of an orally potent human renin inhibitor, isopropyl (2R,3S)-4-cyclohexyl-2-hydroxy-3-{N-[(2R)-2-morpholinocarbonylmethyl-3-(1-naphthyl)propionyl]-L-histidyl}-aminobutyrate, is presented. Optically pure cyclohexylnorstatine isopropyl ester (P₁–P₁′ moiety) was diastereoselectively and simply prepared from L-phenylalanine methyl ester. In a one-pot reaction, N-[(2R)-2-morpholinocarbonylmethyl-3-(1-naphthyl)propionyl]-L-histidine methyl ester (P₄–P₂moiety) was conveniently hydrolysed, protected with a Boc group attached to the side-chain imidazole function, and coupled with the cyclohexylnorstatine ester to give the optically pure target renin inhibitor.