Crystal Structure Analysis of Synthetic Cholestrol Compounds-Vitamin D3-Analogues

The title compound 1 ( 24-(S)-Hydroxycholesta-1,4-dien-3-one ) crystallises in orthorhombic space group $P2_12_12_1$ with z =4.The unit cell dimensions are a=7.5882(9)A, b=10.0745(14)A, c = 31.2553(23)A, $V =2389.4(5)A^3$, $D_{cal} =1.108Mg/m^3$. The title compound 2 ( 24-(R)-Hydroxycholesta-1,4-dien-3-one ) crystallises in monoclinic space group C2 with two molecules per assymetric unit and with Z=8. The Unit cell dimensions are a=16.752(4)A, b=12.578(4)A ,c=23.160(5)A, \beta =96.43(2)°, $V=4849.0(2)A^3$, $D_{cal}=1.092Mg/m^3$ . In compound 1 and in both the molecules of compound 2 the ring A deviates from planarity,the rings B & C are in chair conformation and the five membered ring D is in envelope conformation. The priority sequence attached to the chiral carbon C24 has 'S'designation in compound 1 and 'R'designation in compound 2. The structures are stabilized by O-H - O hydrogen bonds.