نتایج جستجو برای: transannular interaction
تعداد نتایج: 565925 فیلتر نتایج به سال:
the ability of the present semiempirical quantum mechanics methods are surveyed for reproducing the transannular interaction in the bifunctional n-phenyl-5-azocanones. the am1 method is the best with the order of reliability being am1, pm3, mndo and mindo/3. am1 calculations were then carried out for quantification of transannular interaction. the n(o) ionization potential has been used for thi...
The ability of the present semiempirical quantum mechanics methods are surveyed for reproducing the transannular interaction in the bifunctional N-phenyl-5-azocanones. The AM1 method is the best with the order of reliability being Am1, PM3, MNDO and MINDO/3. AM1 calculations were then carried out for quantification of transannular interaction. The n(o) ionization potential has be...
conformational properties of n-aryl-1-azacyclooctan-5- ones with a p-methyl, m-methyl, and p-methoxy group as a substituent have been studied by 1h-nmr, 13c-nmr and ir spectroscopies. transannular interaction of the two functional groups have been examined from the ring inversion barriers and the carbonyl vibrational frequencies with reference to the corresponding data of the respective monofun...
The first transannular [4 + 2] cycloaddition reactions of macrocyclic dicobalt hexacarbonyl-dienyne complexes were demonstrated. Complexes were conveniently prepared through palladium(II)-catalyzed intramolecular oxidative cyclization of bis(vinylboronate esters) followed by complexation with dicobalt octacarbonyl. Transannular [4 + 2] cycloaddition reactions of the complexes occurred at lower ...
Tandem oxy-Cope and transannular vinylogous aldol reactions and/or vinylogous retro-aldol, conjugate addition, and transannular vinylogous aldol reactions transformed some tricyclic vinyl enones into fused tetracycles under basic conditions. Mesylates derived from similar tetracyclic products underwent efficient skeletal reorganization via transannular ring-opening but then different modes of t...
Conformational properties of N-aryl-1-azacyclooctan-5- ones with a p-methyl, m-methyl, and p-methoxy group as a substituent have been studied by 1H-NMR, 13C-NMR and IR spectroscopies. Transannular interaction of the two functional groups have been examined from the ring inversion barriers and the carbonyl vibrational frequencies with reference to the corresponding data...
BACKGROUND pulmonary insufficiency after transannular patch repair of tetralogy of Fallot is associated with a poorer outcome. OBJECTIVE to compare the results of 2 techniques of transannular patch repair. METHODS 93 patients with tetralogy of Fallot and hypoplasia of the right ventricular outflow tract underwent repair between 1990 and 2004 by 2 different techniques. Their ages ranged from...
BACKGROUND In tetralogy of Fallot, transannular patching is suspected to be responsible for late right ventricular dilatation. METHODS AND RESULTS In our institution, 191 patients survived a tetralogy of Fallot repair between 1964 and 1984. Transannular patching was used in 99 patients (52%), patch closure of a right ventriculotomy in 35, and direct closure of a right ventriculotomy in 55. Tw...
Phosphorescence in ethanol at 77 K. of the cyclophanes 1 1 4 has been investigated. It is shown that the phosphorescence characteristics are strongly determined by transannular interaction between the benzene rings. This interaction does not occur in cyclophanes 9 and 14. Phosphorescence quenching by silver Perchlorate of paracyclophanes and benzene derivatives 15-20 is due to the formation of ...
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