Syntheses, crystal structures and Hirshfeld surface analyses of N-arylsulfonyl derivatives of cytisine

Abstract

By arylsulfonylation of cytisine in the presence of triethylamine, three new compounds have been obtained in good yields: (7R,9R)-N-[(4-ethylphenyl)sulfonyl]cytisine, C19H22N2O3S (I) {systematic name: (1R,5R)-3-[(4-ethylphenyl)sulfonyl]-1,2,3,4,5,6-hexahydro-8H-1,5-methanopyrido[1,2-a][1,5]diazocin-8-one}, (7R,9R)-N-[(4-chlorophenyl)sulfonyl]cytisine, C17H17ClN2O3S (II) {systematic name: (1R,5R)-3-[(4-chlorophenyl)sulfonyl]-1,2,3,4,5,6-hexahydro-8H-1,5-methanopyrido[1,2-a][1,5]diazocin-8-one} and (7R,9R)-N-[(3-nitrophenyl)sulfonyl]cytisine, C17H17N3O5S (III) {systematic name: (1R,5R)-3-[(3-nitrophenyl)sulfonyl]-1,2,3,4,5,6-hexahydro-8H-1,5-methanopyrido[1,2-a][1,5]diazocin-8-one}. The crystal structures of the compounds were determined on the basis of single-crystal X-ray diffraction data. The crystal structures of (I)–(III) are distinguished by the arrangement of two fragments of the molecule around the sulfonyl site. For all structures, weak C—H...O hydrogen bonds are developed. Hirshfeld surface analysis shows that H...H (for I and II) and H...O/O...H (for III) interactions make the most important contribution to the crystal packing.