Controlling diastereoselectivity in the reactions of enantiomerically pure alpha-bromoacyl-imidazolidinones with nitrogen nucleophiles: substitution reactions with retention or inversion of configuration.

Diastereoselective substitution reactions of [small alpha]-bromoacyl-imidazolidinones with nitrogen nucleophiles can be promoted with either retention or inversion of configuration by carrying out reactions under epimerising or non-epimerising conditions.

Novel rearrangements of sesquiterpenoid panasinsane derivatives under acidic conditions.

The sesquiterpenoid panasinsane derivatives 11 and 14-16 have been prepared from caryophyllene oxide (7). The novel rearrangement reactions of compounds 11 and 14 under TCNE-catalyzed solvolysis conditions and the reactions of compounds 15 and 16 under superacid conditions (HSO3F/Et2O, -63 degrees C) have been investigated. The ginsenol derivative 17 is obtained from compounds 11 and 14 under TCNE-catalyzed conditions. The rearrangement of compounds 15 and 16 under superacid conditions leads to the novel sesquiterpene derivatives (1S,4S,7S,10S,11S)-3,3,10,11-tetramethyltricyclo[5.3.1.0(4,10)]undecan-1,11-yl sulfate (19) and (1S,4S,5S,8S)-2,2,4,8-tetramethyl tricyclo[3.3.2.1(4,8)]undecan-11-one (20). The influence of the secondary hydroxyl group at C-5 of the panasinsane derivatives on the course of these rearrangements is discussed.

Cerium masquerading as a group 4 element: synthesis, structure and computational characterisation of [CeCl(N(SiMe3)2)3].

Oxidation of the three-coordinate cerium amide [Ce(N-(SiMe3)2)3] with TeCl4 in toluene solution yields purple, diamagnetic [CeCl(N(SiMe3)2)3], whose structure has been examined by X-ray crystallographic and computational methods.

The Remarkable Stable Emerald Green C60 F15 [CBr(CO2 Et)2 ]3 : The First [60]Fullerene That Is also the First [18]Trannulene.

It is both an [18]trannulene and a [60]fullerene. It is aromatic and a hexa-substituted benzene. It is formed by the first proven example of an SN 2' reaction in a fullerene. It is intensely colored and stable. It is C60 F15 [CBr(CO2 Et)2 ]3 , the first example of a new class of fullerene derivatives (see Schlegel diagram).

Thermally Stable Heterobinuclear Bivalent Group 14 Metal Complexes Ar2 M-Sn[1,8-(NR)2 C10 H6 ] (M=Ge, Sn; Ar=2,6-(Me2 N)2 C6 H3 ; R=CH2 tBu).

The first thermally robust Ge(II) -Sn(II) compound 1 and the structurally characterized Sn(II) -Sn(II) analogue 2, which maintain their structural integrity in solution, were obtained by treating MAr2 (M=Ge, Sn; Ar=2,6-(Me2 N)2 C6 H3 ) with Sn[1,8-(NR2 )2 C10 H6 ] (R=CH2 tBu). On the basis of structural and spectroscopic data, the M-Sn bond is regarded as the interaction of a MAr2 donor with an Sn[1,8-(NR2 )2 C10 H6 ] acceptor.

The bio-transformation of ent-19-hydroxykaur-16-en-15-one by Cephalosporium aphidicola.

ent-19-Hydroxykaur-16-en-15-one is transformed to ent-3 beta,16 beta,19-trihydroxykauran-15-one by Cephalosporium aphidicola. The structure of this metabolite was established by X-ray crystallography.

Interpretation of bodily symptoms in hypochondriasis.

Although it has been suggested that hypochondriasis is caused by the misinterpretation of innocuous bodily sensations, support for this hypothesis rests largely upon uncontrolled self-report. We investigated the interpretation of ambiguous bodily sensations in three experiments using separate samples of non-clinical subjects differing in level of hypochondriacal concern. Results confirmed that subjects with high hypochondriacal concern endorse more thoughts about illness interpretations of bodily sensations, but reported thought content resembled 'catastrophic' rather than the 'non-emergency' thoughts suggested by Warwick and Salkovskis (Hypochondriasis. Behavior Research and Therapy, 28, 105-117, 1990). Presence of an interpretive bias was further supported in a study of recognition bias for disambiguated versions of ambiguously threatening sentences, although this applied as much to social as to illness threats. A final experiment failed to support the hypothesis of an automatic inference bias, but did show that subjects with high hypochondriacal concern were quicker to correctly identify previously exposed illness words. Thus, reported thoughts are consistent with catastrophic interpretations of common bodily sensations, but interpretive bias may not be limited to illness threat. However, high hypochondriacal subjects do show a more specific enhanced perceptual sensitivity to illness cues, which may play a role in maintaining their concern with bodily symptoms.

Stress and social support as predictors of dietary compliance in hemodialysis patients.

This study examined the effects of minor stress on variations in biochemical indices of dietary compliance in hemodialysis patients. Subjects completed the Schedule of Recent Events, the Weekly Stress Inventory, and the Social Support Questionnaire. In addition, two biochemical measures of dietary compliance were obtained from the patients' medical charts. Multiple regression analysis, with baseline levels of compliance and the relatively stable influence of major life events and social support controlled for, revealed that minor stress was significantly predictive of changes in dietary compliance. The results suggest that minor stress may affect health status in the chronically ill by reducing compliance behaviors.

Structural chemistry of 1,2 dilauroyl-DL-phosphatidylethanolamine: molecular conformation and intermolecular packing of phospholipids.

Crystals of 1,2 dilauroyl-DL-phosphatidyl-ethanolamine:acetic acid are monoclinic with a = 46.2, b = 7.77, c = 9.95 A, beta = 92.0 degrees ; space group P2(1)/c. The structural analysis, based on the visual estimates of 1467 reflection intensities, was achieved by direct methods, and least squares analysis convergence was to R(1) = 0.28. There are marked differences between the observed molecular conformation and those that have been predicted theoretically. The mean planes containing the lipid chains are essentially parallel to one another; the phosphodiester moiety has a double gauche conformation, while intermolecular hydrogen bonding modifies the conformation that could be anticipated for an isolated phosphatidylethanolamine molecule. The intermolecular packing produces the classical lipid bilayer structure, adjacent lipid bilayers being separated by acetic acid molecules of crystallization. The hydrocarbon chain packing can be considered either as a quasi-hexagonal type or as a complex orthorhombic subcell arrangement. One-dimensional electron density profiles across the lipid bilayer at increasing resolution clearly demonstrate the origin of features present on the low resolution profiles of both model and natural membranes.