2-{1-[(6R,S)-3,5,5,6,8,8-Hexamethyl-5,6,7,8-tetra­hydro­naphthalen-2-yl]ethyl­idene}-N-methyl­hydrazinecarbo­thioamide

Abstract

The synthesis, crystal structure and Hirshfeld analysis of (R,S)-fixolide 4-methyl­thio­semicarbazone is reported. The compound is disordered over the fixolide fragment and in the crystal, the mol­ecules are linked by H⋯S inter­actions with graph-set motif C(4), forming mono-periodic hydrogen-bonded ribbons along [100].

The reaction between a racemic mixture of (R,S)-fixolide and 4-methyl­thio­semicarbazide in ethanol with a 1:1 stoichiometric ratio and catalysed with HCl, yielded the title compound, C₂₀H₃₁N₃S [common name: (R,S)-fixolide 4-methyl­thio­semicarbazone]. There is one crystallographically independent mol­ecule in the asymmetric unit, which is disordered over the aliphatic ring [site-occupancy ratio = 0.667 (13):0.333 (13)]. The disorder includes the chiral C atom, the neighbouring methyl­ene group and the methyl H atoms of the methyl group bonded to the chiral C atom. The maximum deviations from the mean plane through the disordered aliphatic ring amount to 0.328 (6) and −0.334 (6) Å [r.m.s.d. = 0.2061 Å], and −0.3677 (12) and 0.3380 (12) Å [r.m.s.d. = 0.2198 Å] for the two different sites. Both fragments show a half-chair conformation. Additionally, the N—N—C(=S)—N entity is approximately planar, with the maximum deviation from the mean plane through the selected atoms being 0.0135 (18) Å [r.m.s.d. = 0.0100 Å]. The mol­ecule is not planar due to the dihedral angle between the thio­semicarbazone entity and the aromatic ring, which amounts to 51.8 (1)°, and due to the sp ³-hybridized carbon atoms of the fixolide fragment. In the crystal, the mol­ecules are connected by H⋯S inter­actions with graph-set motif C(4), forming a mono-periodic hydrogen-bonded ribbon along [100]. The Hirshfeld surface analysis suggests that the major contributions for the crystal cohesion are [(R,S)-isomers considered separately] H⋯H (75.7%), H⋯S/S⋯H (11.6%), H⋯C/C⋯H (8.3% and H⋯N/N⋯H (4.4% for both of them).

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