Patent ID: 8519197

Claim:
A method of producing a compound of formula (I) wherein R represents H, alkyl, a substituted or unsubstituted phenyl; or a pharmaceutically or orally acceptable salt thereof, comprising: (a) reacting a compound of formula (II); with bromine in an organic solvent to obtain a compound of formula (III); (b) reacting the compound of formula III with MOM-Cl in an organic solvent in the presence of an organic base to obtain a compound of formula (IV); (c) reacting the compound of formula IV with R—CH═CH—CH 2 —Br, wherein R is defined as above, in an organic solvent with magnesium and ethyl bromide to obtain a compound of formula V; (d) converting the compound of formula V with a suitable deprotecting agent in an organic solvent to obtain a compound of formula I; and (e) optionally, converting the compound of formula I to its pharmaceutically or orally acceptable salts.