CPC C07D 471/04 (2013.01) | 22 Claims |
1. A process for the preparation of a compound of formula (1) or a salt thereof,
the process comprising:
(a) reacting compound of formula (3) and compound of formula (4) to provide compound of formula (2),
in a solvent mixture comprising methanol and butanol;
(b) adding water;
(c) isolating solid crystalline form of compound of formula (2) characterized by XRPD pattern having 2θ values 5.5°, 7.5°, 9.7°, 10.1°, 14.5°, 15.9°, 18.1°, 20.2° and 21.5° degrees 2 theta (±0.2 degrees 2 theta); and
(d) transforming the compound of formula (2) into the compound of formula (1).
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