Indole- and carbazole-substituted pyridinium iodide salts: a rare case of conformational isomerism in crystals.

A series of indole- and carbazole-substituted pyridinium iodide salts has been synthesized and characterized. X-ray analysis revealed that the iodide salt of the indole-substituted cation (E)-4-(1H-indol-3-ylvinyl)-N-methylpyridinium (IMPE(+)), C(16)H(15)N(2)(+) x I(-), (I), has two polymorphic modifications, (Ia) and (Ib), and a hemihydrate structure, C(16)H(15)N(2)(+) x I(-) x 0.5H(2)O, (II). Until now, only one crystal modification has been identified for the (E)-4-(9-ethyl-9H-carbazol-3-ylvinyl)-N-methylpyridinium (ECMPE(+)) iodide salt, C(22)H(21)N(2)(+) x I(-), (III). Crystals of (Ia) and (Ib) comprise stacks of antiparallel cations with iodide anions located in the channels between the stacks. Due to the presence of the water molecules, the packing in (II) is quite different to that found in (Ia) and (Ib), and positional disorder involving a statistical superposition of two rotamers of IMPE(+), with different orientations of the indole fragment, was found. Crystals of (III) contain two independent ECMPE(+) rotamers with different orientations of their carbazole substituents. The cations are packed in stacks, with the iodide anions located in the channels between the stacks. In (III), the iodide was found to be disordered over two sites, with occupancies of 0.83 and 0.17.

trans-1-Cyano-2-(2-methoxyphenyl)-1-nitroethylene.

The title compound, C(10)H(8)N(2)O(3), has been prepared by condensation of 2-methoxybenzaldehyde and nitroacetonitrile in ethanol at room temperature. Its investigation has been undertaken as a part of search for new nonlinear optical compounds. The pi-conjugated molecule is almost planar. Molecules in the crystal are packed in stacks with antiparallel molecular orientation and slightly alternating distances between mean molecular planes.

Molecular mechanics calculations of 10-vertex boron cage compounds.

The model proposed earlier for molecular mechanics calculations of 7- and 12-vertex boranes, carboranes, and metallocarboranes has been extended to the case of 10-vertex borane cage compounds. To use the MM3 program with the standard connectivity file, and to avoid program alterations, the 10-vertex cages of the molecules were presented as a superposition of four formally independent fragments. Interactions between the fragments were described with a Hill-like potential, with the parameters adjusted for valence interactions. Standard values for the bond lengths and bond angles in the 10-vertex boron cage have been found by statistical analysis of X-ray data on borane cage compounds stored in the Cambridge Structural Database. Several substituted neutral molecules and anions have been considered, and good agreement of the calculated and experimental data has been obtained. Using the approach developed, the unknown structure of the [mu-B20H16O(CH2)4O(CH2)2CH(CH3)2]3- ion has been calculated.

[The diagnosis of lesions of the venous collectors of the brain]. / Diagnostika porazhenii venoznykh kollektorov golovnogo mozga.

Comparative data of transcranial ultrasonic dopplerography (170 patients) and radionuclide antroscintigraphy (124), received during diagnostics of defeats of venous collectors of brain are analyzed. Five variants of defeats of venous collectors (cross, sigmoid, internal of jugular vein), but also unpaired sine (direct, confluent) are described. Received results permit to reveal interrelation of infringements of venous outflow and increase of intracranial pressure.

[The cerebrospinal fluid pathways in infantile cerebral palsy]. / Likvornye puti golovnogo i spinnogo mozga pri detskom tserebral'nom paraliche.

Liquor routes of the brain and spine were examined in 16 children aged 2 to 12 with infantile cerebral paralysis by radioisotope cistern-myelography with Tc99m-DTPK. Simultaneous imaging of liquor tract pathology in the brain and spine helped distinguish three variants of liquorodynamic abnormalities in infantile cerebral paralysis characterized by various combinations of disorders, in CSF circulation, resorption, and formation of routes for additional CSF discharge. The role of CSF routes involvement in the brain and spine in the formation of a pathologic pattern in infantile cerebral paralysis is analyzed.

[Evaluation of the effectiveness of polychemotherapy of glial tumors of the brain]. / Otsenka éffektivnosti polikhimioterapii glial'nykh opukholei golovnogo mozga.

A total of 85 courses of polychemotherapy were conducted in 23 patients after surgical treatment of malignant glial tumors. The efficacy of the treatment was checked by means of neurological, neuropsychological, and electroencephalographic methods of examination and radionuclide-gamma-tomography. The aggregate of these tests is necessary for detecting early signs of irresponsiveness of the tumor to chemotherapy and changing the treatment schedule.

[Possibilities of quantitative criteria of the effectiveness of treatment of glial brain tumors]. / Vozmozhnosti kolichestvennykh kriteriev otsenki lecheniia glial'nykh opukholei golovnogo mozga.

The authors suggest a quantitative criterion for evaluating the efficacy of radiotherapy in patients with glial tumors of the brain. Three types of course followed by the disease are distinguished: regressive, progressive, and undulating. The use of the quantitative criterion made it possible to detect patients with individual increased sensitivity to macrofractional radiotherapy and to come to the decision on the expediency of conducting the next series of irradiation in each concrete case.

The X-ray investigation of 16 alpha,17 alpha-thiazolidine derivatives of delta 4- and delta 5-pregnanes and conformational analysis of their oxathiolane analog.

An X-ray study of 3,20-dioxo-4-pregnene-[16 alpha,17 alpha-d]--2',2'-dimethylthiazolidine (I) and 3 beta-hydroxy-20-oxo-5--pregnene-[16 alpha,17 alpha-d]-2',2'- dimethylthiazolidine (II) has been carried out. Two independent molecules in crystal II have significantly different conformations of the D and E rings, although according to the atom-atom potential calculations the energy of interaction of these molecules with their neighbors in crystal is the same. The calculation of conformational energy of 3,20-dioxo-4-pregnene-[17 alpha,16 alpha-d]-2',2'--dimethyloxathiolane (III) by the molecular mechanics method (MMM) indicates a possibility of existence of two similar conformers also for this molecule. The MMM calculation shows also that the conformation of molecule III (as well as progesterone) with the 17 beta-acetyl group torsion angle C(16)C(17)C(20)0(20) close to -120 degrees is possible.