• Korean Journal of Crystallography
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• v.11 no.2
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• pp.84-88
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• 2000

The crystal of cholesteryl crotylcarbonate was investigated by X-ray diffraction method. Crystallographic data for the title compound: P21, a=13.510(2)Å, b=11.843(2)Å, c=19.882(2)Å, β=106.88(1)°, Z=4. Reflections were collected with an Enraf-Nonius CAD-4 diffractometer equipped with a graphite monochromator. The structure was solved by direct methods and refined by least-squares analyses. The final R value was 0.125 for 2607 reflections. The cholesterol fragment of the title compound were in good agreement with those for related cholesterol derivatives. The molecules were stacked in clearly separated layers. At the center of the layers, there were cholesteryl-cholesteryl interactions between the symmetry-related B molecules and the cholesteryl-C(17) side chain of A molecules. There were also interactions between the C(17) side chain of B molecules and the crotylcarbonate chain in the interface region between layers. The crystal structure of the title compound turned out to be isostructural with those of cholesteryl ethylcarbonate and cholesteryl propylcarbonate.

• Journal of the Korean Chemical Society
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• v.25 no.3
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• pp.131-139
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• 1981

Cholesteryl hexanoate $(C_{33}H_{56}O_2)$, is monoclinic, space group $P2_1$, with a = 12.162(3), b = 9.314(3), c = 13.643(5) ${\AA}$, ${\beta}$ = $93. 55{\circ}(3)$ and two molecules per unit cell. The atomic coordinates from cholesteryl octanoate were used in an initial trial structure using X-ray intensities(Mo $K{\alpha}$ radiation) measured by a diffractometer at room temperature and $-75{\circ}C$. Structure refinement by block-diagonal least squares gave R = 0.129 and 0.105 for room and low temperature experiments respectively. The molecules are arranged in monolayers with their long axes antiparallel and severely tilted. There is a close packing of cholesteryl groups within the monolayers. The crystal structures is very similar to those of cholesteryl octanoate and cholesteryl oleate.

• Journal of the Korean Chemical Society
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• v.34 no.1
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• pp.29-36
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• 1990

Cholesteryl pentyl carbonate $(C_{33}H_{56}O_3)$ is monoclinic, space group P21, with a = 12.484(3), b = 9.043(3), c = 14.053(3)$\AA$, ${\beta} = 94.12(2)^{\circ}$ and z = 2. The intensity data were measured for the 2969 reflections within sin $\theta/\lambda = 0.52 {\AA}^{-1}$, using an automatic four--circle diffractometer and graphite monochromated Mo-K$\alpha$ radiation. The atomic coordinates from cholesteryl octanoate were used in an initial trial structure and the structure was refined by full-matrix least squares methods. The final R-factor was 0.12 for 1164 observed reflections. The pentyl group has shortened bond lengths due to the high thermal vibrations in this region. Adjacent molecules are related by $2_1$ screw axis so that they are arranged in an antiparallel array, corresponding to the Monolayer Type II packing mode. There are close packings of cholesteryl groups within the monolayers. This packing type is similar to those of cholesteryl hexanoate, octanoate, hexyl carbonate and oleate.

• Korean Journal of Materials Research
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• v.2 no.6
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• pp.398-407
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• 1992

Cholesteryl S-alkoxybenzene thiocarbonates was synthesized and their liquid crystal transition temperature were determined. Those compounds exhibit enantiotropic cholesteric mesophases. The cholestric-isotropic transition temperatures decrease gradually with increasing alkoxy chain length and mesophase transition were investigated by differential scanning calorimetry.

• Korean Journal of Crystallography
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• v.13 no.1
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• pp.21-24
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• 2002

The crystal structure of cholesteryl crotonate was investigated by X-ray diffraction. Crystallo-graphic data for the title compound: P2₁, a = 13.446(4) , b = 11.802(3) , c = 18.782(5) , β = 103.99(2)°, Z = 4. Reflections were collected with an Enraf-Nonius CAD-4 diffractometer equipped with a graphite monochromator. The structure was solved by direct methods and refined by least-squares analyses. The final R value was 0.092 for 1604 reflections. The cholesterol fragment of the title compound were in good agreement with those for related cholesterol derivatives. The molecules were stacked in clearly separated layers. At the center of the layers, there were cholesterol-cholesteryl interactions between the symmetry-related A molecules and the cholesteryl-C(17) side chain of B molecules. There were also interactions between the C(17) side chain of A molecules and the crotonate chains off and B molecules in the interface region between layers. The crystal structure of the title compound turned out to be isostructural with those of cholesteryl ethylcarbonate, cholesteryl propylcarbonate, and cholesterol crotylcarbonate. The crystals show the liquid crystalline state having the cholesteric phase.

• Journal of the Korean Chemical Society
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• v.49 no.3
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• pp.334-338
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• 2005

• Korean Journal of Crystallography
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• v.15 no.1
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• pp.29-34
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• 2004

The crystal structure of cholesteryl hemisuccinate ($C_{31}H_{50}O_4$) was investigated by X-ray diffraction method. The cholesterol fragment of the title compound were in good agreement with those for related cholesterol derivatives. The unit cell contains four cholesteryl hemisuccinate molecules that are not related by crystal symmetry and have their tetracyclic system almost parellel to each other. There are two pairs of hydrogen-bonded dimer between A and D molecules and B and C molecules. These two hydrogen-bonded dimers are parallel to the c-axis, and are closely packed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.7
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• pp.625-629
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• 2000

We synthesized a new copoly (PM4Ch-ChMA) copoly(poly(4-methacryloyloxy) chalcone-cholesteryl methacrylate) having chalconyl and cholesteryl moiety for homeotropic liquid crystal(LC) alignment. Pretilt angles of nematic(N) LC generated by linearly polarized UV exposure on the copolymer surfaces were investigated. Good thermal stabilities of the synthesized copolymer were obtained by TGA (Thermogravimetric Analysis) measurement. Pretilt angles of the NLC decreased with increasing UV exposure time on the copolymer surfaces. We consider that the pretilt angle of the NLC is attributed to increased chalcone by increased UV exposure time. High pretilt angle of the NLC is attributed to increased chalcone by increased UV exposure time. High pretilt angle of 81$^{\circ}$was observed after the UV exposure for 3 min.

• Bulletin of the Korean Chemical Society
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• v.10 no.2
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• pp.177-184
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• 1989

The structure of cholesteryl isobutyrate, $(CH_3)_2CHCOOC_{27}H_{45}$, was determined by single crystal X-ray diffraction methods. Cholesteryl isobutyrate crystallized monoclinic space group $P2_1$, with a = 15.115 (8)${\AA}$, b = 9.636 (5)${\AA}$, c = 20.224 (9)${\AA}$, ${\beta}$ = 93.15 (5)$^{\circ}$, z = 4, $D_c = 1.03 g/cm^3 $and Dm= 1.04 g/$cm^3$. The intensity data were measured for the 3417 reflections, within $sin{\theta}/{\lambda} = 0.59{\AA}^{-1}$, using an automatic four-circle diffractometer and graphite monochromated Mo-$K_{\alpha}$ radiation. The structure was solved by fragment search Patterson methods and direct methods and refined by full-matrix least-squares methods. The final R factor was 0.129 for 2984 observed reflections. The two symmetry-independent molecules (A) and (B) are almost fully extended. The molecules are in antiparallel array forming monolayers with thickness $d_{100}$ = 15.2${\AA}$, and molecular long axes are nearly parallel to the [$\bar{1}$01] directions. The two distinct molecules form separate stacks with almost the same orientations, but with differing degrees of steroid overlap. Thers is a close packing of cholesteryl groups within the monolayers. The packing type is similar to those of cholesteryl hexanoate and cholesteryl oleate.

• Bulletin of the Korean Chemical Society
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• v.26 no.12
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• pp.2072-2074
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• 2005