Biological activity predictions, crystallographic comparison and hydrogen bonding analysis of cholane derivatives

458-469A total of eighteen molecules of cholane derivatives (I-XVIII) (a series of steroids) have been included to predict their pharmacological effects, specific mechanisms of action, known toxicities, drug-likeness, etc, by using the statistics of multilevel neighbourhoods of atoms (MNA) descriptors for active and inactive fragments. The biological activity spectra for substances have been correlated on SAR base (structure-activity relationships data and knowledge base), which provides the different Pa (possibility of activity) and Pi (possibility of inactivity). Most of the probable activities have been characterized by Pa and Pi values, which depict that all the molecules have high value of teratogen activity. The Lipinski’s thumb rule predicts that all the cholane derivatives have stronger preponderance for “cancer-like-drug” molecules and some of their related analogous have entered in the ANCI (American National Cancer Institute) database. Some selected bond distances and bond angles of interest have been taken into account and deviation of bond distances/bond angles, vis-a-vis the substitutional group and X–H…A intra/intermolecular hydrogen bonds has been discussed in detail. X–H…A intra and intermolecular hydrogen bonds in the molecules have been described with the standard distance and angle cut-off criteria. D–θ and d–θ scatter plots for intra- and intermolecular interactions are presented for better understanding of packing interactions existing among these derivatives. There exists only one C–H…O intramolecular bifurcated hydrogen bond, while high tendency of intermolecular bifurcated hydrogen bonds based on a defined O–H…O has been observed, in which O atom acts as a prototype donor as well as acceptor. The frequency of occurrence of C–H…O hydrogen bonds is predominant (i.e. 85.7%) in intramolecular interactions, whereas in intermolecular interactions, frequency of occurrence for O–H…O interactions is 62.9%. Solvent-solute/solute-solvent interactions have also been investigated to understand more complicated processes that occur for biomolecules in aqueous solutions. The number of hydrogen donors in each derivative is less than 5, except for molecule XVIII and which has 91.3% of drug-likeness, instead of observed range of 96.5-99.3%

Crystallographic analysis of 1H, 4H-tetrahydro-8-methyl-quinolizino-(9,9a,1gh)coumarin

524-527The crystal structure of 1H,4H-tetrahydro-8-methyl-quinolizino-(9,9a,1gh)coumarin (C16H17NO2) has been determined by X-ray crystallographic techniques. The compound crystallizes in monoclinic space group P21/n with unit cell parameters: a = 8.657(5) Å, b = 10.251(5) Å, c = 14.508(5) Å, = 96.61(1)°, Z = 4, V = 1278.91(11) Å3. The structure has been solved by direct methods and refined upto reliability index of 4.8%. The fused benzene and pyrone rings are planar. Both the piperidine rings exist in distorted sofa conformation. The crystal structure is stabilized by C-H...O hydrogen bonds

Synthesis, crystal structure and study of X-H…A interactions in<b style=""> </b>N,N′-bis-(4-methoxy-benzylidine)-hydrazine

602-605Synthesis and crystal structure of N,N′-bis-(4-methoxy-benzylidine)-hydrazine have been reported in this paper. The title compound crystallizes in the monoclinic space group C2/c with unit cell parameters a = 17.416(3), b = 10.711(3) and c =8.428(3)Å, =113.64(2)o, V = 1440.2(8)Å3 and Z = 4. The structure has been refined to a R-value of 0.038 for 937 observed reflections. The molecules adopt columnar packing in the unit cell and the crystal structure is stabilized by two intra- and five intermolecular hydrogen bonded interactions

A comparative crystallographic analysis of the X-ray structure of three cholest-based steroidal molecules

1855-1859The molecular and crystal structures of (+)-4-cholesten-3-one 1 cholesteryl chloroformate 2 and cholesteryl-caprylate 3 have been determined by using X-ray crystallographic and computational techniques. All the three compounds crystallize in the monoclinic space group P2₁ with unit cell parameters: a=10.683(5)Å, b=7.861(2), c=14.616(2), β=105.8(2)º for [1], a=12.294(2)Å, b=9.399(8), c=12.787(2), β=113.3(1)º for [2] and a = 12.778(9), b = 9.201(4), c = 14.063(6) Å, β = 93.85(4)º for [3]. The number of molecules per unit cell in case of each structure is 2. The final R-factor for [1] is 0.054, [2] 0.077 and [3] 0.068. Besides some interesting geometrical and structural features, all the three molecules exhibit C-H…O hydrogen bonding. A comparative crystallographic analysis of all the three molecules has been reported in this paper