3-Oxoandrosta-4,6-dien-17β-yl 2-methyl-1H-imidazole-1-carboxylate and 3-oxo-5α-androst-17β-yl 2-methyl-1H-imidazole-1-carboxylate: C—H...π and π–π intermolecular interactions (original) (raw)
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Journal of Chemical Crystallography, 2010
Abstract The X-ray crystal structure of the bistetrazole steroid derivative: (25R)-3,12a-diaza-A,C-bishomo-5α-spirostano[3,4-d] [12a,12d] bistetrazole (HS-989) has been determined at room temperature. The crystals are orthorhombic, space group P212121 with a = 16.855(1) Å, b = 25.048(2) Å, c = 6.402(1) Å, V = 2702.7(5) Å3 Z = 4, Density (calculated) = 1.250 Mg/m3. The tetrazole-modified 7-membered rings A and C have similar modified uniaxial chair conformations, with pseudo-symmetry m through the extra C–N tetrazole bond; the 6-membered rings B and F are symmetrical chairs; of the 5-membered rings, D is in a half-chair and ring E an envelope conformation; tetrazole rings T1 and T2 are both planar and oriented towards the α-face. The spirostan moiety is β-oriented. Overall the modified steroid skeleton is reasonably flat, with a pseudo-torsion angle C(19)–C(10)···C(13)–C(18) of −6.2°. Conformational sampling, using high temperature SYBYL molecular dynamics was used to investigate different arrangements of the steroid skeleton. Predicted low energy conformations were found to compare favourably in some respects with both X-ray crystallographic and NMR observations but with important differences. Graphical Abstract Determination of the crystal structure and absolute configuration of the novel steroidal tetrazole derivative (25R)-3,12a-diaza-A, C-bishomo-5α-spirostano[3,4-d] [12a 12d] bistetrazole [HS-989] are reported. The report includes a detailed conformational analysis and comparative molecular dynamics study. HS-989 viewed along the bond C(10)–C(19): a sticks, b space filling (drawn with RASMOL 1994), c ESP (electrostatic potential) (drawn with ArgusLab http://www.planaria-software.com/feedback\_3\_0.htm)
Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry, 1982
The crystal structure of 17a-methyl-3fl-pyrrolidinyl-17a-aza-D-homo-5a-androstane (HS691), C24Ha2N2, comprising two independent molecules in space group P1, has been determined using direct methods, successive electron density syntheses and least-squares analysis. The structure was refined by block-diagonal least squares to R o = 0.054, R w = 0.062 tbr 2271 observed reflections and R o = 0.075, R w = 0.089 for a total of 3290 reflections measured on a four-circle diffractometer in the 09/20 scanning mode. The two independent molecules in P1, a = 7.228 (1), b = 10.276 (2), c = 15.095 (3),/L c~ = 98.377 (8), fl = 84.690 (9), y = 99.409 (12) °, are related by a pseudo twofold axis. The two molecules have very similar geometry, the major differences being in the puckering of the pyrrolidine rings and their orientations with respect to the modified steroid skeleton. The methyl carbon atom C(20) on N(17a) is equatorial in both molecules.
CrystEngComm, 2014
A structural and conformational study of 3β-acetoxy-17-chloro-16-formyl-5α-androstan-16-ene has been carried out by using X-ray analysis and M06-2X density functional calculations. The compound crystallizes with three independent molecules in the asymmetric unit. Natural Bond Order and Atoms in Molecules methods were used for a better understanding of the key factors that determine the stability of this steroidal molecule, particularly the role of C-H⋯Cl intramolecular interactions. A detailed investigation of C-H⋯Cl and C-H⋯O intermolecular interactions, in addition to the most important van der Waals contribution, are presented by means of Hirshfeld surface analysis. The crystal packing exhibits an unusual intra-and intermolecular hydrogen bond pattern, and shows the importance of non-classical interactions in the construction of the supramolecular assembly. Excellent agreement between the theoretical and experimental data is found.
Crystal Structure and Synthesis of Three New Steroidal Derivatives as Antiandrogens
Journal of Chemical Crystallography, 2010
The structures of 3b-cyclobutyl carbonyloxy-5androsten-17-one (C 24 H 34 O 3 ), compound 1; 3b-cyclopentyl carbonyloxy-5-androsten-17-one (C 25 H 36 O 3 ), compound 2; and 3b-cyclohexyl carbonyloxy-5-androsten-17-one (C 26 H 38 O 3 ) compound 3 were established by spectral and X-ray diffraction studies. Steroidal derivatives 1-3 exhibited a high antiandrogenic effect and could be considered as potential drugs for the treatment of prostate cancer. Compound 1 crystallizes in the orthorhombic space group P2 1 2 1 2 1 with unit cell parameters a = 6.618(2), b = 14.167(3), c = 22.329(5) Å , Z = 4. Compound 2 crystallizes in the orthorhombic space group P2 1 2 1 2 1 with unit cell parameters a = 6.631(2), b = 13.865(4), c = 23.952(7) Å , Z = 4. Compound 3 crystallizes in the orthorhombic space group P2 1 2 1 2 1 with unit cell parameters a = 6.6100(9), b = 13.896(2), c = 24.491(3) Å , Z = 4. All three structures (1-3) were solved by direct methods and refined to R = 0.0708, 0.0750 and 0.0496, respectively. For compound 2, there is positional disorder of the side chain at C3. All the rings of both steroid skeletons are trans connected. For structures 1-3, the six-membered rings A, B and C have a deformed chair, half chair and deformed chair conformations. The five-membered rings D adopt an intermediate envelope and half-chair conformations. For structure 2, the five-membered rings E and EA have a deformed envelope and an intermediate envelope and half-chair conformations, respectively. For structure 3, the sixmembered ring E adopts a deformed chair conformation. Cohesion of the crystals can be attributed to van der Waals and weak C-H_O interactions.
Steroids, 1995
one has been determined. The proton-proton distances in the solid state from previous crystallographic studies are compared with the corresponding distances from novel and previous solution NMR as well as from novel in vacuo modeling studies.
New steroid-fused P-heterocycles
Steroids, 2007
s t e r o i d s 7 2 ( 2 0 0 7 ) 446-458 a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m j o u r n a l h o m e p a g e : Dedicated to Professor Gyula Schneider on the occasion of his 75th birthday. Epimers Conformational study a b s t r a c t 16-Aminomethyl-17-hydroxyestrone 3-methyl ether 6 and its N-propyl (17), N-benzyl (18) and N-arylmethyl derivatives (19-22) were subjected to ring closure reactions with phenylphosphonic dichloride in order to synthetize P-epimeric oxazaphosphorinanes 23a, 24-29 in which the hetero ring is condensed to ring D of the sterane skeleton. The stereostructures of the products were evaluated by 1 H, 13 C and 31 P NMR spectroscopy. The geometry was optimized by utilizing the B3LYP DFT method. The NMR spectral data and the results of the ab initio calculations demonstrated that the stereostructure of the hetero ring was strongly affected by the rigid sterane framework condensed to it, and the phosphoramidate ring proved to adopt predominantly a distorted-boat conformation, regardless of the P-configuration. In the general procedure, 4-fluorobenzaldehyde (9, 0.22 mL) was used. Imine 14 (590 mg, 70%) was obtained. Mp 161-163 • C; 1 H NMR (400 MHz, DMSO-d 6 , ı [ppm]): 0.74 (s, 3H, 18-H 3 ), 2.74 (m, 2H, 6-H 2 ), 3.30 (m, 1H, one of 16a-H 2 ), 3.68 (s, 3H, 3-OMe), 3.74 (dd, 1H, J = 10.0 Hz, J = 4.8 Hz, 17-H), 3.95 (dd, 1H, J = 11.4 Hz, J = 4.0 Hz, the other 16a-H 2 ), 4.68 (d, 1H, J = 4.8 Hz, OH), 6.58 (d, 1H, J = 2.5Hz, 4-H), 6.66 (dd, 1H, J = 8.5 Hz, J = 2.5 Hz, 2-H), 7.16 (d, 1H, J = 8.5 Hz, 1-H), 7.26 (d, 2H, J = 8.6. Hz, 3 -H and 5 -H), 7.78 (dd, 2H, J = 8.6 Hz, J = 5.8 Hz, 2 -H and 6 -H), 8.34 (s, 1H, imine-H); EI-MS (70 eV) m/z (%): 421 (86) [M + ], 393
Journal of Chemical Crystallography
The single crystal X-ray structure of the novel steroid derivative, 6E-hydroximino-androst-4-ene-3,17-dione (C 19 H 25 NO 3) (code name RB-499), possessing antiproliferative activity against various cell lines is presented. The analysis produced the following results: chemical formula C 19 H 25 NO 3; Mr = 315.40; crystals are orthorhombic space group P2 1 2 1 2 1 with Z = 4 molecules per unit cell with a = 6.2609(2), b = 12.5711(4), c = 20.0517(4) Å,Vc = 1578.18(7) Å 3 , crystal density Dc = 1.327 g/cm³. Structure determination was performed by direct methods, Fourier and full-matrix least-squares refinement. Hydrogens were located in the electron density and refined in position with isotropic thermal parameters. The final R-index was 0.0324 for 3140 reflections with I > 2σ and 308 parameters. The Absolute Structure Parameter − 0.07(5) confirms the correct allocation of the absolute configuration. The presence of the double bond C=O at position 3 in Ring A has caused a distortion from the usual chair conformation and created an unusual distorted sofa conformation folded across an approximate m-plane through C(1)-C(4). Ring B is a distorted chair, its conformation being influenced by the presence of the C(6)=N(6)-O(6)H group in position 6. Ring C is a symmetrical chair. Ring D exhibits both a distorted mirror symmetry conformation [influenced by the C(17)=O(17) group] and a distorted twofold conformation. DFT calculations indicated some degree of flexibility in rings A, C and D with ring A showing the greatest variation in torsion angles. The crystal packing is governed by H-bonds involving O(3), O(6) and O(17). DFT calculations of bond distances and angles, optimized at the B3LYP/6-31++G(d,p) level, were in good agreement with the X-ray structure.
2021
Aim. Definition of the structure of 1-ethoxy-3a,8a-dihydroxy-3-(1-naphthyl)methyl-1,3,3a,8a-tetrahydroindeno[1,2d]imidazole-2,8-dione. Methods. XRD study of the structure, mass spectrometry, 1H and 13C NMR spectroscopy. Results. It has been found that ninhydrin reacts with N-ethoxy-N’-(1-naphthyl)methylurea yielding only one of the possible diastereomers of 1-ethoxy-3a,8a-dihydroxy-3-(1-naphthyl)methyl-1,3,3a,8a-tetrahydroindeno[1,2d]imidazole-2,8-dione such as the diastereomer. The structure of 1-ethoxy-3aS,8aR-dihydroxy-3-(1naphthyl)methyl-1,3,3a,8a-tetrahydroindeno[1,2-d]imidazole-2,8-dione has been analyzed by XRD study. The formation of alternative trans-3a(HO),8a(HO)-diastereomer has not been observed. Conclusions. In 1-ethoxy3aS,8aR-dihydroxy-3-(1-naphthyl)methyl-1,3,3a,8a-tetrahydroindeno[1,2-d]imidazole-2,8-dione the 3aand 8ahydroxyl groups are cis-oriented to each other. There are two independent molecules of the compound 15 (15A and 15B) in the asymmetric part of the unit...