Crystal structure of cholesteryl ethyl carbonate

Cholesteryl ethyl carbonate, C30O3H50,M(r) = 458.7, monoclinic, P2(1), a = 18.681(2), b = 11.7697(10), c = 13.5656(10) Angstrom, beta = 105.37(2)degrees, V = 2876.0(4) Angstrom(3), Z = 4, D-c = 1.059 mgm(-3), mu = 0.506 mm(-1),F(000) = 1016, lambda (Cu K-alpha)=1.5418 Angstrom, final R and wR2 are 0.0727 and 0.2125 respectively

Theory of rotatory dispersion of cholesteric liquid crystals

A theory is developed of the circular dichroism and rotatory power of thin films of cholesteric liquid crystals. It is an extension of the treatment for infinitely thick specimens discussed in a previous paper. The therory predicts that the circular dichroism of a thin film plotted as a function of wave-length should exhibit a principal maximum accompanied by subsidiary maxima, and that the rotatory dispersin should be anomalous. Experimental circular dichroism and rotatory dispersion curves are presented for cholesteric cinnamate, cholesteryl-2-propyn-1-yl carbonate and spectratherm. The results are in qualitative agreement with the theory both inside and outside the region of reflexion. The rotatory dispersion curves are also in accord with the de Vries equation outside the region of reflexion

Addition of NOCl to cyclic vinylsilanes: An unexpected reversal of regiochemistry

NOCl adds to cyclic vinylsilanes in a syn manner with NO+ bonding to the β-carbon and Cl- to the α-carbon, which is a reversal of the regiochemistry expected from the β-silicon effect. The adducts dimerize to a single diastereomer containing enantiomeric pairs and/or give secondary products on further reaction. © 2001 Elsevier Science Ltd

1-(2-Chloro­acet­yl)-3-methyl-2,6-bis­(3,4,5-trimethoxy­phen­yl)piperidine-4-one

In the crystal structure of the title compound, C26H32ClNO8, the piperidine ring is in a twist-chair conformation, with puckering parameters Q = 0.655 (4) Å, θ = 93.1 (1) and ϕ = 254.4 (3)°. The ortho C atoms of the piperidine ring deviate from the plane defined by the remaining ring atoms by 0.380 (3) and −0.250 (3) Å

1-Benzhydryl-4-(4-chloro­phenyl­sulfonyl)piperazine

The title compound, C23H23ClN2O2S, was synthesized by the nucleophilic substitution of 1-benzhydrylpiperazine with 4-chloro­phenyl­sulfonyl chloride. The piperazine ring is in a chair conformation. The geometry around the S atom is that of a distorted tetra­hedron. There is a large range of bond angles around the piperazine N atoms. The dihedral angle between the least-squares plane (p1) defined by the four coplanar C atoms of the piperazine ring and the benzene ring is 81.6 (1)°. The dihedral angles between p1 and the phenyl rings are 76.2 (1) and 72.9 (2)°. The two phenyl rings make a dihedral angle of 65.9 (1)°. Intramolecular C—H⋯O hydrogen bonds are present

Synthesis and crystal structure of a novel substituted 1,4-dihydropyridine

The title compound, C15H16N2O3, was synthesized, characterized spectroscopically, and finally confirmed by X-ray diffraction studies. The compound crystallizes in the monoclinic space group P21/n with cell parameters a = 10.314(9) Å, b = 17.976(15) Å, c = 12.762(11) Å, β = 113.331(3)°, Z = 4, and V = 2173(3) Å3. The dihydropyridine ring in the structure is in a flattened-boat conformation. The 2-nitrophenyl ring is orthogonal to the 1,4-dihydropyridine ring. The structure exhibits an intermolecular hydrogen bond of the type C–H…O

1-Acryloyl-2,6-bis­(4-chloro­phen­yl)-3,5-dimethyl­piperidin-4-one

In the crystal structure of the title compound, C22H21Cl2NO2, the piperidinone ring is in a boat conformation

N-[4-Cyano-3-(trifluoro­meth­yl)phen­yl]-2-eth­oxy­benzamide

In the title compound, C17H13F3N2O2, the two aromatic rings are essentially coplanar, forming a dihedral angle of 2.78 (12)°. The non-H atoms of the eth­oxy group are coplanar with the attached ring [maximum deviation = 0.271 (3) Å]. An intra­molecular N—H⋯O hydrogen bond occurs. In the crystal structure, mol­ecules are linked by inter­molecular C—H⋯N and C—H⋯F hydrogen bonds

ChemInform Abstract: Addition of NOCl to Cyclic Vinylsilanes: An Unexpected Reversal of Regiochemistry.

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(Z)-3-(3,4-dimethoxyphenyl)-2-(4-methoxyphenyl)acrylonitrile

A new dipolarophile used in the construction of bioactive heterocycles, (\it Z)-3-(3,4-dimethoxy\-phen\-yl)-2-(4-methoxy\-phen\-yl)acrylonitrile, C\sb 18H\sb 17NO\sb 3, has been synthesized by base-catalysed reaction of 3,4-dimethoxy\-benzaldehyde with (4-methoxy\-phen\-yl)acetonitrile. The olefinic bond has \it Z geometry and the mol\-ecules are linked by C—-H⋅sO and C—-H⋅sN hydrogen bonds