The structure of tetrazole steroid analogues. I. The structure of 17β-(5-methyltetrazol-1-yl)-7a-aza-B-homoandrost-5-eno[7a,7-d]tetrazol-3β-yl acetate (HS-665)

Abstract

The crystal structure of the novel synthetic molecule 17fl-(5 -methyltetrazol-1 -yl)-7a-aza-B-homoandrost-5-eno[ 7a,7-dltetrazol-3fl-yl acetate (HS-665), C23H32NsO2, has been determined by X-ray diffraction using direct methods. Crystals are monoclinic, P2, with a = 6.414 (1), b = 23.668 (3), c = 7.779 (1) A, fl = 100.08 (1) °, Z = 2, and the structure was refined by least-squares analysis to R o = 0.039 for 1790 reflections measured on a four-circle diffractometer. Rings A (chair) and D (envelope) are in their usual steroid conformations while ring C, which is usually chair, is a strained chair/sofa having lost most of its pseudosymmetry, and the heterocyclic seven-membered ring B-homo has a distorted sofa or 'butterfly-like' conformation with two predominantly planar 'wings' of four atoms each. Both tetrazole rings are planar. The molecule is slightly curled with two shallow convex surfaces: one, convex towards the a face, formed by rings A, B-homo and the fused tetrazole ring T~; the other, convex towards the fl face, formed by rings B-homo, C and D. The curvature of the molecule results in a short C(18)...C(19) distance of 3.887 A compared with the normal value of around 4.6 A.

Synthesis, characterization, X-ray diffraction, antimicrobial and in vitro cytotoxicity studies of 7a-Aza-B-homostigmast-5-eno [7a,7-d] tetrazole

“…An ORTEP drawing with the atomic numbering scheme is shown in Fig. 1 and the crystallographic data, selected bond lengths and bond angles are listed in Tables 5 and 6 the additional bond in ring B [26]. The bond distances and bond angles of the compound show a fair amount of agreement with those of some analogous steroids [27][28][29][30].…”

Absolute structure of (3aS,5S,7aS,7bS,9aR,10R,12aR,12bS)-7b-hydroxy-4,4,7a,9a,12a-pentamethyl-10-[(2′R)-6-methylheptan-2-yl]-2,8,9-trioxooctadecahydrobenzo[d]indeno[4,5-b]azepin-5-yl acetate from 62-year-old crystals

“…type) with an N atom in the seven-membered ring. Three pentacyclic compounds with a tetrazole ring at N1-C2 have been reported [LEXVOB (Alam et al, 2013), TZANDT (Husain et al, 1981) and VEVLAK (Rajnikant et al, 2006)], the former and latter showing very similar molecular conformation and interactions that lead to very similar unit-cell dimensions ($35Â6Â12 Å ). There is only one entry with the same six-, seven-, six-and five-membered ring combination containing O instead of N (HIXSAI; Morales et al, 1999) but the configuration of C5 is inverted and therefore the dihedral angle between mean planes of the six-and seven-membered rings differ significantly and thus also the molecular conformation.…”

Steroids and related studies. LIV. The structure of 17a-methyl-3β-pyrrolidinyl-17a-aza-D-homo-5α-androstane (HS691)

“…In the range 0 _< 65 ° a total of 5435 reflections were measured which resulted in a unique data set of 3555 reflections after scaling and merging equivalents, of which 2271 with I o > 30(lo) were classified as observed. The usual Lp factors were applied and semi-empirical absorption corrections were made using a modification of the North, Phillips & Mathews (1968) method (Kopfmann & Huber, 1968;Tickle, 1979;Husain, Palmer, Singh, Bhardwaj & Paul, 1981). p(Cu Ka) = 0.400 mm -~ and lur = 0.15-0.30 for the crystal used for collection of intensities.…”