Microwave Irradiation Assisted Method for the Rapid Synthesis of fine Particles of alpha Al2O3 And alpha (Al1-XCrx)(2)O-3 And Their Coatings on Si(100)

Chromium substituted beta diketonate complexes of aluminium have been synthesized and employed as precursors for a novel soft chemistry process wherein microwave irradiation of a solution of the complex yields within minutes well crystallized needles of alpha (Al1 XCrx)(2)O-3 measuring 20 30 nm in diameter and 50 nm long By varying the microwave irradiation parameters and using a surfactant such as polyvinyl pyrrolidone the crystallite size and shape can be controlled and their agglomeration prevented These microstructural parameters as well as the polymorph of the Cr substituted Al2O3 formed may also be controlled by employing a different complex Samples of alpha (Al1 XCrx)(2)O-3 have been characterized by XRD FTIR and TEM The technique results in material of homogeneous metal composition, as shown by EDAX and can be adjusted as desired The technique has been extended to obtain coatings of alpha (Al1 XCrx)(2)O-3 on Si(100)

Radical Annulation Strategy to Chiral Pupukeanones: Total Synthesis of (+)-10-ex&l(- Naphthyl)pupukean-9-onea nd (+)-lO-exo-l(- Naphthyl)-5-epipupukean-9-ones1

Intramolecular alkylation reaction of the bromoenone 12, obtained from S-carvone in three steps, furnished the bicyclo[2.2.2]octenone 13. Contrary to the anticipated radical annulation reaction, the bicyclic bromides 14 and 15, obtained from the enone 13, generated exclusively the cyclopropane product 18 via a 3-exo-trig radical cyclization on reaction with nBu3SnH and AIBN, even in the presence of a large excess of a radicophile. On the other hand, bromoenone 24, synthesized from R-carvone via S-naphthylcarvone 21, underwent radical annulation reaction in the presence of radicophiles to furnish the isotwistanes 25-28 in a regio- and stereospecific manner. Hydrogenation of the olefin 34, obtained from the diketone 27 via a regiospecific Wittig reaction, furnished the naphthyl-5-epipupukean-9-one 33, whereas stereoselective hydrogenation of the enone 36, prepared from the keto ester 25 via a Grignard reaction and dehydration sequence, generated the naphthylpupukeanone 32.

Role of oestradiol-17β in the regulation of synthesis and secretion of human chorionic gonadotrophin by first trimester human placenta

Inhibition of aromatase, a key enzyme in the biosynthesis of oestradiol-17 beta, by the addition of 1,4,6-androstatrien-3,17-dione resulted in a significant increase in the levels of immunoreactive human chorionic gonadotrophin (hCG) in the medium and tissue. This increase was partially reversed by the simultaneous addition of oestradiol-17 beta. These effects on the levels of immunoreactive hCG were also reflected by the increased levels of mRNA specific for the alpha and beta subunits of hCG following the addition of the aromatase inhibitor. However, addition of tamoxifen resulted in a drastic decrease in the levels of both the messages. Based on these results, it is suggested that the synthesis of hCG is negatively modulated by oestradiol-17 beta in the human placenta.

Stabilization of α-nickel hydoxide in the presence of organic additives: chemical route to bulk synthesis

Organic molecules such as glucose or lactose mediate the synthesis and stabilize alpha-nickel hydroxide in a simple precipitation reaction, while, in the absence of these additives, beta-nickel hydroxide is formed. The additives are not incorporated in the product phase.

Stereospecific construction of multiple contiguous quaternary carbons. Total synthesis of (±)-cis,anti,cis-1,8,12,12-tetramethyl-4-oxatricyclo[6.4.0.02,6]dodecan-3-ol, a thapsane isolated from Thapsia villosa var minor

The details of the first total synthesis of a natural thapsane lg containing three contiguous quaternary carbon atoms, starting from cyclogeraniol (9) '5 described. The Claisen rearrangement of 9 with methoxypropene in the presence of a catalytic amount of propionic acid produced ketone 10. Rhodium acetate-catalyzed intramolecular cyclopropanation of a-diazo-&keto ester 12, obtained from 10 via 8-keto ester 8, furnished cyclopropyl keto ester 7. Lithium in liquid ammonia reductive cleavage of cyclopropyl compound 7 gave a 1:l mixture of hydrindanone 6 and keto1 13. Wittig methylenation of 6 furnished ester 21. Epoxidation of 21, followed by BF3-OEt2-catalyzed rearrangement of epoxide 23 afforded hemiacetal 25. Treatment of hemiacetal 25 with triethylsilane in trifluoroacetic acid furnished lactone 22, a degradation product of various thapsanes. Finally, DIBAH reduction of lactone 22 generated the thapsane

Synthesis of substituted 8-aminoquinolines and phenanthrolines through a Povarov approach

The synthesis of 8-aminoquinolines and 1,10-phenanthrolines with substituents in alpha of the nitrogen has been performed through an inverse-demanding aza-Diels-Alder (Povarov reaction) in the fluoroalcohols TFE or HFIP. This path involves simple starting materials: 1,2-phenylenediamines, enol ethers and aldehydes.

Synthesis and Isolation of 5,6-Dihydro-4H-1,3-Oxazine Hydrobromides by Autocyclization of N-(3-Bromopropyl)amides

5,6-Dihydro-4H-1,3-oxazine hydrobromides have been synthesized by the nucleophilic autocyclo-O-alkylation of N-(3-bromopropyl)amides under neutral conditions in chloroform. It is found that electron-donating amide alpha-substituents influence the autocyclization efficiency.

Synthesis of Functionalized Dihydrothiophenes from Doubly Activated Cyclopropanes Using Tetrathiomolybdate as the Sulfur Transfer Reagent

A number of doubly activated cyclopropanes were synthesized starting from various substituted bromosulfonium bromides in good yield. Regioselective ring-opening of cyclopropanes with tetrathiomolybdate as the sulfur transfer reagent gave dihydrothiophenes in excellent yield.

A new Fuzzy-LOGIC based Model for Chlorophyll-a in Pulicat Lagoon, India

Coastal lagoons are complex ecosystems exhibiting a high degree of non-linearity in the distribution and exchange of nutrients dissolved in the water column due to their spatio-temporal characteristics. This factor has a direct influence on the concentrations of chlorophyll-a, an indicator of the primary productivity in the water bodies as lakes and lagoons. Moreover the seasonal variability in the characteristics of large-scale basins further contributes to the uncertainties in the data on the physico-chemical and biological characteristics of the lagoons. Considering the above, modelling the distributions of the nutrients with respect to the chlorophyll-concentrations, hence requires an effective approach which will appropriately account for the non-linearity of the ecosystem as well as the uncertainties in the available data. In the present investigation, fuzzy logic was used to develop a new model of the primary production for Pulicat lagoon, Southeast coast of India. Multiple regression analysis revealed that the concentrations of chlorophyll-a in the lagoon was highly influenced by the dissolved concentrations of nitrate, nitrites and phosphorous to different extents over different seasons and years. A high degree of agreement was obtained between the actual field values and those predicted by the new fuzzy model (d = 0.881 to 0.788) for the years 2005 and 2006, illustrating the efficiency of the model in predicting the values of chlorophyll-a in the lagoon.

Adaptive Keeper Design for Dynamic Logic Circuits Using Rate Sensing Technique

The increasing variability in device leakage has made the design of keepers for wide OR structures a challenging task. The conventional feedback keepers (CONV) can no longer improve the performance of wide dynamic gates for the future technologies. In this paper, we propose an adaptive keeper technique called rate sensing keeper (RSK) that enables faster switching and tracks the variation across different process corners. It can switch upto 1.9x faster (for 20 legs) than CONV and can scale upto 32 legs as against 20 legs for CONV in a 130-nm 1.2-V process. The delay tracking is within 8% across the different process corners. We demonstrate the circuit operation of RSK using a 32 x 8 register file implemented in an industrial 130-nm 1.2-V CMOS process. The performance of individual dynamic logic gates are also evaluated on chip for various keeper techniques. We show that the RSK technique gives superior performance compared to the other alternatives such as Conditional Keeper (CKP) and current mirror-based keeper (LCR).

Synthesis and characterization of single-crystalline alpha-MoO3 nanofibers for enhanced Li-ion intercalation applications

High quality, single-crystalline alpha-MoO3 nanofibers are synthesized by rapid hydrothermal method using a polymeric nitrosyl-complex of molybdenum(II) as molybdenum source without employing catalysts, surfactants, or templates. The possible reaction pathway is decomposition and oxidation of the complex to the polymolybdate and then surface condensation on the energetically favorable 001] direction in the initially formed nuclei of solid alpha-MoO3 under hydrothermal conditions. Highly crystalline alpha-MoO3 nanofibers have grown along 001] with lengths up to several micrometres and widths ranging between 280 and 320 nm. The alpha-MoO3 nanofibers exhibit desirable electrochemical properties such as high capacity reversibility as a cathode material of a Li-ion battery.

Synthesis Based on Cyclohexadienes .11. A A new total synthesis of (±)-norprezizanone

Acid catalyzed rearrangement of endo 1-methoxytricyclo[6.2.2.0(3,8)]dodec-2-en-10-ol 8c afforded the ketone 9 which has been transformed into (+/-)-norprezizanone 19 thus completing a formal synthesis of (+/-)-zizaene. A key step in this strategy is a stereospecific 1,4-addition of a methyl group

Synthesis, characterization, and thermal degradation studies on group VIA derived weak-link polymers

Polymers containing group VIA derived weak links, viz. poly(styrene disulfide) (PSD), poly- (styrene tetrasulfide) (PST), and poly(styrene diselenide) (PSDSE), have been synthesized. The polymers PSD and PST were characterized by NMR, IR, UV, TGA, and fast atom bombardment m w spectrometric (FABMS) techniques. The presence of different configurational sequences in PSD and PST were identified by *3C NMR spectroscopy. PSDSE, being insoluble in common organic solvents, was characterized using solid-state lac NMR (CP-MAS) spectroscopy. Thermal degradation of polymers under direct pyrolysis-mass spectrometric (DP-MS) conditions revealed that all the polymers undergo degradation through the weaklink scission. A comparative study of the pyrolysis products of these polymers with that of poly(styrene peroxide) (PSP) revealed a smooth transformation down the group with no monomer (styrene or oxygen) formation in PSP to only styrene and selenium metal in PSDSE. This trend of group VIA is explained from the energetics of the C-X bond (X = 0, S, and Se) which also seems to be important in addition to the weak X-X bond cleavage. In PSP and PSD, the behavior is also explained from the energetics of the alkoxy and thiyl radicals. The unique exothermic degradation in PSP compared to endothermic degradation in PSD and PSDSE is explained from the nature of the producta of degradation.

Synthesis of A1PO4, LaPO4 and KTiOPO4 by flash combustion

Fine particle AlPO4, LaPO4 and KTiOPO4 have been prepared by the flash combustion of aqueous solutions containing metal nitrate, ammonium hydrogen phosphate, ammonium nitrate or ammonium perchlorate and carbohydrazide or tetraformal trisazine. When rapidly heated at 400 °C, the solution containing the redox mixtures ignites to undergo self-propagating, gas-producing, exothermic reactions. Formation of crystalline phosphates was confirmed by powder X-ray diffraction patterns and IR spectra. The metal phosphates formed are fine and have 20�78 m2 g?1 surface area.

Synthesis of Isoquinolines from Indanones-Total Synthesis of Illudinine

Schmidt reaction of 5-methoxy or 7-methoxyindan-1-ones or their derivatives results exclusively in isocarbostyrils which are converted into 6-methoxy or 8-methoxyisoquinolines in good yields. This strategy has been extended to the total synthesis of illudinine methyl ester (1b) starting from methyl 8-methoxy-2,2-dimethyl-7-oxo-1,2,3,5,6,7-hexahydro-s-indacene-4-carboxylate (4).