Tri-filial presentation of familial tuberous sclerosis with renal tumors.

Tuberous sclerosis is a rare neuro-cutaneous syndrome with autosomal dominant penetrance. Only some organs are involved, e.g., skin (earthy skin thickenings, ash leaf patches), cerebral cortex (hamartomatous nodules) and kidneys, (angiolipoma, adenocarcinoma). These hamar-tomatous swellings resemble potatoes and hence, referred to as tubers. We herein report on three patients (all familial), father, son and granddaughter, with this rare involvement, from the eastern part of India. The father and son had involvement of only the skin (i.e. nose) and kidneys while the disease penetrated further in the subsequent filial generations with son and granddaughter having skin, brain and bilateral kidney involvement. This kind of tri-filial progression has not till date, been reported from this region, making it an interesting case presentation.

Infrared spectroscopy and elastic properties of nanocrystalline Mg-Mn ferrites prepared by co-precipitation technique.

Nanoparticles having particle size in the range 25-40 nm for compositions x = 0.0, 0.2, 0.4 and 0.5 of Mg(x)Mn(1-x)Fe2O4 spinel ferrite system have been prepared by chemical co-precipitation route. The microstructure, infrared spectral and elastic properties have been studied by means of energy dispersive analysis of X-rays (EDAX), transmission electron microscopy (TEM), X-ray diffraction (XRD) and infrared spectroscopic (IR) measurements, before (W) and after high temperature annealing A(w). The force constants for tetrahedral and octahedral sites determined by infrared spectral analysis, lattice constant and X-ray density values by X-ray diffraction pattern analysis; have been used to calculate elastic constants. The magnitude of force constant and elastic moduli for nanocrystalline W-samples are found to be larger as compared to coarse grained A(w)-samples. The results have been explained in the light of redistribution of cations and as a result change in mean ionic charge for such cationic sites, elastic energy and grain size reduction effect of Nanoparticles.

Synthesis of a triply phosphorylated pentapeptide from human tau-protein.

Two different strategies for the synthesis of a triply phosphorylated pentapeptide are described. In both cases a monophosphorylated selectively N-deprotected tripeptide is employed as C-terminal fragment. Coupling of this building block with a C-terminally unmasked bis-phosphorylated seryl-dipeptide unexpectedly failed due to decomposition of this peptide upon activation with different coupling reagents. Instead stepwise N-terminal elongation of the peptide chain with serine derivatives and subsequent O-phosphorylation of the serine OH-groups was successful. These results indicate that assembly of multiply phosphorylated peptides from preformed multiply phosphorylated phosphopeptide building blocks in general may be problematic and that a stepwise elongation of the amino acid chain may be preferable.

Comparison of the two anomers of methyl 2-(N-benzylamino)-2, 3-dideoxy-4,6-O-phenylmethylene-3-C-phenylsulfonyl-D-glucopyranoside

The title compounds, the alpha and beta anomers of methyl 2-(N-benzylamino)-2,3-dideoxy-4, 6-O-phenylmethylene-3-C-phenylsulfonyl-D-glucopyranoside, C(27)H(29)NO(6)S, belong to the class of deoxyamino-sugars prepared by the addition of amines at C2. The endocyclic bond lengths of the pyranose ring in the alpha anomer are shorter than the corresponding bonds in the beta anomer. The pyranose ring is in the chair form in the former, while it is in the boat form in the latter. These observed differences could be attributed to the C2 substitution of a bulky group. The phenylsulfonyl and benzylamino groups are in equatorial positions in the alpha anomer, while the benzylamino group is axial in the beta anomer.

Diastereoselective addition of amines to vinyl sulfone modified carbohydrates: a highly flexible methodology for the synthesis of new classes of deoxyaminosugars

Methyl 2,3-dideoxy-4,6-O-(phenylmethylene)-3-C-phenylsulfonyl-alpha- D-erythro-hex-2-enopyranoside (5 alpha) and methyl 2,3-dideoxy-4,6-O-(phenylmethylene)-3-C-phenylsulfonyl- beta-D-erythro-hex-2-enopyranoside (5 beta) have been subjected to Michael addition reaction with various amines to develop a new methodology for the synthesis of new classes of aminosugars. Compound 5 alpha reacted with primary amines to generate gluco- derivatives, but secondary amines produced both gluco- (major) and manno- (minor) isomers. Compound 5 beta, on the other hand, produced only gluco- isomers with both primary and secondary amines. The stereochemical course of addition of some of the amines to 5 alpha and 5 beta are significantly different from that of the addition of amines to 3-nitroenopyranoses. The present route to the syntheses of various aminosugars with gluco- configurations from 5 alpha and 5 beta constitutes a novel method for the introduction of N-monoalkylated and N,N-dialkylated amines to the C-2 carbon of pyranoses in equatorial configurations.

Enzymes and protecting group chemistry.

Enzymatic protecting group techniques are increasingly finding their use in almost all areas of synthetic organic chemistry. Some of the recent papers have dealt with the use of such protecting groups in combination with classical methods. The modification of known protecting groups to increase the efficiency and selectivity of deprotection is on the rise. The methodology needs to be explored more intensively and systematically to realise its full potential.

Regiospecific synthesis of deuterium-labelled 2'-deoxyribonucleosides.

Regiospecific chemical methodologies have been developed for the incorporation of deuterium regio and stereospecifically in all four naturally occurring 2'-deoxynucleosides.