1. (1R*,2S*,4S*,5R*)-Cyclo-hexane-1,2:4,5-tetra-carb-oxy-lic dianhydride
Akira Uchida, Masatoshi Hasegawa, Eiichiro Takezawa, Shinya Yamaguchi, Atsushi Ishikawa, Takashi Kagayama Acta Crystallogr Sect E Struct Rep Online. 2012 Mar 1;68(Pt 3):o579. doi: 10.1107/S1600536812003571. Epub 2012 Feb 4.
The title compound, C(10)H(8)O(6), a promising raw material to obtain colorless polyimides which are applied to microelectronic and optoelectronic devices, adopts a folded conformation in which the dihedral angle between the two anhydro rings is 55.15 (8)°. The central six-membered ring assumes a conformation inter-mediate between boat and twist-boat. In the crystal, mol-ecules are linked by weak C-H⋯O inter-actions, forming a layer parallel to the bc plane.
2. (2S,4S)-2-[(S,E)-2-Bromo-1-nitro-methyl-3-phenyl-all-yl]-4-methyl-cyclo-hexa-none
Long Zhao, Chao Wu, Wen-Zeng Weng, Chu-Xia Yan, Ai-Bao Xia Acta Crystallogr Sect E Struct Rep Online. 2012 Apr 1;68(Pt 4):o1253. doi: 10.1107/S1600536812013098. Epub 2012 Mar 31.
The crystal structure of the title compoud, C(17)H(20)BrNO(3), contains three chiral centers, which all exhibit an S configuration. The C=C double bond has an E conformation. The cyclo-hexane ring is in a chair conformation. In the crystal, mol-ecules are linked by weak N-O⋯Br inter-actions [O⋯Br = 3.136 (4) Å].
3. (2S,4S)-3-Acryloyl-6-oxo-2-phenyl-perhydro-pyrimidine-4-carboxylic acid
Sandip K Kundu, Mathew P D Mahindaratne, Brian Quinõnes, George R Negrete, Edward R T Tiekink Acta Crystallogr Sect E Struct Rep Online. 2009 Dec 4;66(Pt 1):o3. doi: 10.1107/S1600536809050892.
In the title compound, C(14)H(14)N(2)O(4), the central six-membered ring adopts a twisted boat conformation with the phenyl substituent occupying an orthogonal position [dihedral angle = 86.88 (11)°]. In the crystal, mol-ecules are linked by carboxylic acid-carbonyl O-H⋯O and amide-carbonyl N-H⋯O hydrogen bonds, forming a three-dimensional network.
