Patent ID: 8293912

Claim:
A process for preparing (1R-cis)-1-[(3,4-dimethoxyphenyl)methyl]-1,2,3,4-tetrahydro-6,7-dimethoxy-2-methyl-2-carboxyethyl-isoquinolinium salt of the formula VII: the process comprising: (a) reacting (R)-tetrahydropapaverine, compound IIA, or a salt thereof with an acrylic acid derivative of the formula CH 2 ═CHCOY (XI), in an organic solvent, to obtain compound (X) wherein Y of compound (X) is OR 1 or NR 2 R 3 , R 1 is alkyl, aryl or heteroaryl, and R 2 and R 3 are the same or different and each is independently selected from hydrogen, alkyl, aryl and heteroaryl; (b) reacting compound (X), or a salt thereof (IX), with a methylating agent to form compound (VIII); (c) optionally purifying compound (VIII); (d) converting compound (VIII) into compound (VII), and (e) optionally purifying compound (VII), wherein X 31 is an anion.