Patent ID: RE39251

Claim:
A crystalline polymorph of an epothilone analog represented by the formula comprising Form A characterized by: unit cell parameters approximately equal to the following: Cell dimensions a = 14.152(6) Å b = 30.72(2) Å c = 6.212(3) Å Volume = 2701(4) A 3 Space group P2 1 2 1 2 1 Orthorhombic Molecules/unit cell 4 Density (calculated) (g/cm 3 ) 1.247 Melting point 182-185° C. decomposition; and characteristic peaks in the powder x-ray diffraction pattern at values of two theta (CuKα λ=1.5406 Å at 22° C.): 5.69, 6.76, 8.38, 11.43, 12.74, 13.62, 14.35, 15.09, 15.66, 16.43, 17.16, 17.66, 18.31, 19.03, 19.54, 20.57, 21.06, 21.29, 22.31, 23.02, 23.66, 24.18, 14.98, 25.50, 26.23, 26.23, 26.46, 27.59, 28.89, 29.58, 30.32, 31.08 and 31.52.