Absolute Configuration and Conformation of (-)-R-t-Butylphenylphosphinoamidate: Chiroptical Spectroscopy and X-ray Analysis.

The absolute configuration and conformations of (-)-tert-butylphenylphosphinoamidate were determined using three different chiroptical spectroscopic methods, namely vibrational circular dichroism (VCD), electronic circular dichroism (ECD), and optical rotatory dispersion (ORD). In each of the spectroscopic methods used, experimental data for the (-)-enantiomer of tert-butylphenylphosphinoamidate were measured in the solution phase. Using the concentration-dependent experimental infrared spectra, the existence of dimers in the solution was investigated, and the monomer-dimer equilibrium constant was determined. Concomitant quantum mechanical predictions of the VCD, ECD, and ORD for monomeric tert-butylphenylphosphinoamidate were carried out using density functional theory (DFT) calculations using the B3LYP functional and the 6-31G(d), 6-311G(2d,2p) and aug-cc-pVDZ basis sets. Similar predictions for dimeric tert-butylphenylphosphinoamidate were also obtained using the B3LYP/6-31G(d) method. A comparison of theoretically predicted data with the corresponding experimental data led to the elucidation of the absolute configuration as (-)-(R)-tert-butylphenylphosphinoamidate with one predominant conformation in the solution. This conclusion was independently supported by X-ray analysis of the complex with (+)-R-2,2'-dihydroxy-1,1'-binaphthol ((+)-R- BINOL).

A hybrid technique for ventriculoatrial shunt implantation--technical note.

PURPOSE: The aim of the article is to present the new hybrid technique for ventriculoatrial shunt implantation. METHODS: Two-and-a-half-year-old boy needed ventriculoatrial shunt implantation due to communicating hydrocephalus and impaired absorptive ability of the peritoneum. Because of a complete occlusion of the right internal jugular vein and critical stenosis of a distal part of the left internal jugular vein, the procedure was performed under fluoroscopy guidance in the catheterisation laboratory equipped with a 3-dimensional single plane angiography machine (Philips Allura--The Netherlands). At the level of critical stenosis of the left jugular vein, it was decided to perform a percutaneous venous balloon angioplasty. This procedure allowed inserting the ventriculoatrial shunt into the right atrium. RESULTS: The whole postoperative period was uneventful. Now, the child is free from symptoms of increased intracranial pressure. The boy has been followed for 9 months. In the control MRI examination, the ventricular system did not change as compared with the previous study. CONCLUSION: The disadvantage of the hemodynamic technique is a higher dose of X-ray irradiation in comparison to other techniques. The hybrid technique should be reserved only to very complicated cases.

Synthesis and phytotoxicity of new ionic liquids incorporating chiral cations and/or chiral anions.

The aim of this work was to synthesize chiral ionic liquids as chiral solvents for organic synthesis and to evaluate the phyto(eco)toxicity of the new products and starting N-alkylimidazoles and their potential environmental influence on soil and plants. Chiral ionic liquids containing anions such as Cl-, Br-, TsO-, PF6(-), NO3(-), CF3SO3(-), and (+)- and (-)-C6H5CH(OH)C(O)O- were synthesized using (-)-(1R)-6,6-dimethylbicyclo[3.1.1]hept-2-ene-2-ethyl [(-)-(1R)-nopyl] halides (X = Cl, Br) and tosylate in 62-100% yields. The chloride 7 and the nitrate 13 ionic liquids possessed a toxicity dependent on the applied concentration. The lowest concentration causing a distinct reduction in plant germination/growth was 100 mg/kg. Spring barley better tolerated the ionic liquids (200 mg/kg) than common radish (100 mg/kg). The nitrate liquid did not exhibit an inhibiting effect on the germination ability of seeds. The starting N-methylimidazole used in lower concentrations (1 and 10 mg/kg of soil dry weight) was not phytotoxic, in contrast to higher doses (>1000 mg/kg).

The long-term psychological effects of surgical treatment using neuroendoscopic techniques and Orbis Sigma shunt implantation in children suffering from hydrocephalus.

BACKGROUND: Hydrocephalus, which is the most common disease of the central nervous system in children, has a diverse etiology and clinical picture. Children suffering from hydrocephalus are often treated either by using a neuroendoscopic procedure or by Orbis Sigma shunt implantation. OBJECTIVES: To evaluate the long-term psychological effects of neuroendoscopic surgical treatment on the mental development and cognitive abilities of children suffering from hydrocephalus, in comparison with the results following Orbis Sigma shunt implantation, and to assess the impact of the kind of hydrocephalus on the outcome of the treatment. MATERIAL AND METHODS: The study involved 78 patients treated surgically for chronic noncommunicating hydrocephalus: 39 patients who had undergone neuroendoscopic surgery (average age: 12 years, SD +/- 7 years), and 39 who had undergone implantation of a ventriculo-peritoneal shunt (average age: 14 years +/- 5 years). The psychomotor development of the two groups was analyzed using psychomotor development tests including the Brunet-Lezine test, the Terman-Merrill test, Raven's Standard Progressive Matrices, Raven's Colored Progressive Matrices, the Benton Visual Retention Test, the Bender Visual Motor Gestalt Test, the Rey Fifteen-Item Memory Test, lateralization tests and a questionnaire. RESULTS: In the shunt group there were statistically significant prevalences hydrocephalus diagnosed perinatally and in the first year of life (p = 0.0291), epileptic seizures (p = 0.0181), intellectual disability (p = 0.0049) and gait disturbances (p = 0.006). There were statistically significant differences between two groups in the relative changes of linear measurements of the cerebral ventricle depending on the type of treatment: Relative Frontal Horn Index (RFHI): 0.93 following endoscopy and 0.64 following shunt implantation; Relative Evans' ratio (RER): 0.93 following endoscopy and 0.62 after shunt implantation; Relative Frontal and Occipital Horn Ratio (RFOHR): 0.89 after endoscopy and 0.69 after shunt implantation. The time treatment was undertaken and the incidence of mental retardation did not differ significantly between the two groups. CONCLUSIONS: The analysis of cerebral ventricle enlargement expressed in linear ventricular enlargement measurements revealed statistically important differences in the intellectual, cognitive and motor development between the groups treated with the two neurosurgical techniques.

Diastereomers of N-alpha-phenylethyl-t-butylsulfinamide: absolute configurations and predominant conformations.

N-alpha-Phenylethyl-t-butylsulfinamide is a complicated system for determining molecular stereochemistry because of numerous possibilities for assigning the absolute configuration and a predominant conformation. Two diastereomers of N-alpha-phenylethyl-t-butylsulfinamide derived from (-)-(S)-alpha-phenylethyl amine, a (+)-diastereomer and a (-)-diastereomer, have been synthesized and their experimental chiroptical spectroscopic properties have been measured. These properties include vibrational circular dichroism, electronic circular dichroism and optical rotatory dispersion. Using these experimental data, in conjunction with corresponding density functional theoretical predictions, the absolute configuration and predominant conformations of these two diastereomers have been determined. Also, the absolute configuration of (-)-diastereomer has been independently confirmed by determining its structure from X-ray diffraction data.