Patent ID: 6399828
Filing Date: 2002-06-04
Classification: C07C

Abstract:
A process for making compound of formula I from a phenylpropanolamine salt of formula II through the intermediate compound of formula III wherein:R1 is hydrogen or a lower alkyl group; each R2 is independently a hydrogen, halogen, lower alkyl group, lower alkoxy groups, lower alkyl group substituted with 1 to 5 halogens, lower alkoxy groups substituted with 1 to 5 halogens, or both R2 together when on adjacent carbons constitute a â€”O(CH2)xOâ€” where x is 1 to 4, thereby forming a ring structure fused with the phenyl group; R3 is a C1-C8-alkyl group, a C1-C12-aralkyl group, C1-C12-alkaryl group, or a phenyl group, each optionally substituted by 1 to 5 substituents selected from halogen, hydroxy, or C1-C6-alkyl; and HX is an equivalent of an organic or inorganic acid, the process comprising:(a) acylating the phenylpropanolamine salt of formula II with an acylating agent in a solvent at elevated temperature to make a reaction mixture containing an O-acylated phenylpropanolamine salt of formula III which can be isolated by the addition of a crystallization solvent, or optionally this mixture can be used in the next step; and (b) hydrogenating the O-acylated phenylpropanolamine salt to make the compound of formula I in the presence of a catalyst.