Patent ID: 7741492

Claim:
Method for obtaining a pharmaceutically active compound, Irbesartan polymorph A, or a pharmaceutically acceptable salt thereof, which comprises: (a) a coupling reaction of the compound of formula (II) with the 2-(1H-tetrazol-5-yl)phenylboronic acid of formula (III): in a solvent medium selected from an organic polar or aqueous solvent, or a mixture of water and water-miscible solvent or a biphasic system, in the presence of an organic or inorganic base, capable of forming a salt with the tetrazole ring of the compound of formula (III), at a temperature between 25 and 150° C., with a palladium catalyst and, if required, a phosphine ligand, to obtain Irbesartan (1): in the form of an aqueous solution of one its organic- or inorganic-base salts; (b) the preceding aqueous alkaline solution is acidified to pH 4.8 to 5.2 and the precipitate so obtained is filtered; and (c) the product of stage (b) is recrystallised in the presence of an organic solvent or a mixture thereof with water to give Irbesartan polymorph A with the following X-ray diffraction spectrum: Pos.[°2Th.] d-spacing [Å] Rel. Int.[%] 4.76 18.561 100 8.20 10.783 2.71 9.43 9.377 2.8 10.54 8.396 1.72 12.50 7.080 35.21 13.32 6.646 4.4 14.13 6.268 1.8 16.37 5.415 1.61 17.03 5.207 8.25 17.67 5.021 3.06 18.90 4.696 3.76 19.44 4.567 13.86 20.06 4.426 8.16 20.59 4.314 6.94 21.13 4.204 7.03 21.69 4.097 6.4 22.67 3.923 5.66 23.19 3.835 11.07 23.68 3.758 7.84 26.42 3.374 1.27 26.83 3.324 2.05 27.70 3.220 3.22 28.52 3.130 2.57 31.96 2.800 1.52 33.06 2.710 1.82.