Crystal structures and Hirshfeld surface analyses of a des-A-B-aromatic steroidal compound, and two of its derivatives, having a trans-2,3,4,5-tetrahydro-3a-methyl-7-methoxybenz[e]indane skeleton-structural comparisons with reported tetrahydrobenz[e]indene derivatives

The crystal structures and Hirshfeld surface analyses of the des-A-B-aromatic steroid derivative, (3a,9b)-1,2,3a,4,5,9b-hexahydro-7-methoxy-3a-methyl-3H-benz[e]-inden-3-one (or 5-methoxy-des-A-estra-5,7,9-triene-17-one) 1, its acetohydrazide derivative, 2, and its hydrazone derivative, 3, are reported. All three compounds crystallize in chiral space groups: compounds 1 and 2 in the orthorhombic space group P2₁2₁2₁ each with one molecule in the asymmetric unit, and compound 3 in the monoclinic space group P2₁ with two similar but independent molecules, Mol A and Mol B, in the asymmetric unit. Both the five-membered and six-membered non-aromatic rings in all three compounds have envelope or near envelope shapes. In compounds 2 and 3 the N=N units have (E)-arrangements. The intermolecular interactions in crystals of compound 1 are C-H · · · O hydrogen bonds and C-H · · · πinteractions, in compound 2 N-H · · · O and C-H · · · O hydrogen bonds and C-H · · · πinteractions are present, while in compound 3 there are just C-H · · · πinteractions. An important substructure in 1 is a sheet of molecules, composed of R66(44) rings, formed from C-H · · · O(methoxy) and C-H · · · O(carbonyl) hydrogen bonds, the molecules of which form columns linked via the B and D rings, i.e. in a head-to-tail fashion. Compound 2 is an acylhydrazonyl compound, in which the two independent molecules are linked into asymmetric dimers via strong classical N-H · · · O hydrogen bonds, with the formation of R22(8) rings. In both 1 and 2, further intermolecular interactions result in 3-dimensional structures, while compound 3 has a 1-dimensional structure arising from C-H · · · O interactions generating spiral chains. The results have been compared with existing data.