Patent ID: 8097723

Claim:
A process for the preparation of abacavir of formula (I), or a pharmaceutically acceptable salt thereof, comprising the step of: (a) ring closure of the compound of formula (IV) by first reacting said compound (IV) with anhydrous hydrochloric acid/(C 1 -C 6 )-alcohol, and then with tri(C 1 -C 4 )-alkyl orthoformate, in the absence of water, to yield compound of formula (III), wherein R 1 is a (C 1 -C 4 )-alkyl radical; (b) reacting the compound of formula (III) with cyclopropylamine to yield the compound of formula (II) wherein R 1 is a (C 1 -C 4 )-alkyl radical; and, (c) hydrolyzing the compound of formula (II) to yield abacavir (I) or a salt thereof.