Synthesis, Spectroscopy and Crystal Structure Analysis of N.sup.1,N.sup.3-dicyclohexyl-N.sup.1-urea

• Published in: Journal of chemical crystallography Vol. 52; no. 2; p. 260
• Main Authors: Vachlioti, Eleanna, Kalantzi, Stefania, Papaioannou, Dionissios, Nastopoulos, Vassilios
• Format: Journal Article
• Language: English
• Published: Springer 01.06.2022
• Subjects: Crystals; Diffraction; Nuclear magnetic resonance spectroscopy; Structure; Tretinoin; Urea; X-rays
• ISSN: 1074-1542; 1572-8854
• DOI: 10.1007/s10870-021-00917-x

The title compound, C.sub.33H.sub.50N.sub.2O.sub.2, is a side product in the reaction of all-trans-retinoic acid (atRA) with N-hydroxysuccinimide, in the presence of the coupling agent N,N'-dicyclohexylcarbodiimide, which produces the 'active' ester succinimidyl all-trans-retinoate as the product. It crystallizes in the orthorhombic Pbca space group. The compound was characterized by .sup.1H-NMR, .sup.13C-NMR, ESI-MS and IR spectroscopy and its structure was determined by single-crystal X-ray diffraction. For example in the .sup.13C-NMR spectrum, diagnostic peaks are those of the two amide carbonyl C atoms at [delta] 169.5 and 154.2 ppm, the ten olefinic C atoms of the unsaturated chain of atRA moiety at [delta] 149.0, 139.3, 137.7, 137.3, 134.9, 130.2, 130.0, 129.4, 128.5 and 121.5 ppm and the two methine C atoms of the N,N'-dicyclohexylurea moiety at [delta] 57.9 and 49.5 ppm. Detailed analysis of its molecular and supramolecular structure showed that close-packing principles (elongated shape/large hydrophobic region of the molecule) together with chemical factors (N-H[midline horizontal ellipsis]O and C-H[midline horizontal ellipsis]O intermolecular interactions) direct the 3D self-assembly process in the crystalline state. Hirshfeld surface analysis was employed, a powerful approach to quickly and easily gain insight into molecular environments in the crystalline state. Graphical The synthesis and X-ray structure of 1-((2E, 4E, 6E, 8E)-3,7-dimethyl-9-(2,6,6-trimethylcyclohex-1-enyl)nona-2,4,6,8-tetraenoyl)-1,3-dicyclohexylurea, a side product in the synthesis of succinimidyl all-trans-retinoate, is reported; Hirshfeld surface analysis was employed to identify intermolecular interactions.