A Heat and Light Mediated Synthetic Sequence Serendipitous Synthesis of Methyl Ester of Tris-Norpterosin-E

Synthesis of methyl ester of 3-oxo-indan-5-acetic acid (3), an analogue of the natura1 product pterosin-E (4), starting from cyclopentadiene (1) and p-benzoquinone (2) using a sequence of six ground and excited state reactions, is described.

Oestrogen-induced synthesis of thiamin-binding protein in immature chicks. Kinetics of induction, hormonal specificity and modulation

A specific radioimmunoassay procedure was developed to monitor the plasma concentrations of thiamin-binding protein, a minor yolk constituent of the chicken egg. By using this sensitive assay, the kinetics of oestrogen-induced elaboration of this specific protein in immature chicks was investigated. After a single injection of the steroid hormone, with an initial lag period of 4–5h the thiamin-binding protein rapidly accumulated in the plasma, attaining peak concentrations around 75h and declining thereafter. A 4-fold amplification of the response was noticed during the secondary stimulation, and this increased to 9-fold during the tertiary stimulation with the steroid hormone. The magnitude of the response was dependent on the hormone dose, and the initial latent period and the duration of the ascending phase of induction were unchanged for the hormonal doses tested during both the primary and secondary stimulations. The circulatory half-life of the protein was 6h as calculated from the measurement of the rate of disappearance of the exogenously administered 125I-labelled protein. Simultaneous administration of progesterone, dihydrotestosterone or corticosterone did not alter the pattern of induction. On the other hand, hyperthyroidism markedly decreased the oestrogenic response, whereas propylthiouracil-induced hypothyroidism had the opposite effect. The anti-oestrogen E- and Z-clomiphene citrates, administered 30min before oestrogen, effectively blocked the hormonal induction. a-Amanitin and cycloheximide administered along with or shortly after the sex steroid severely curtailed the protein elaboration. A comparison of the kinetics of induction of thiamin- and riboflavin-binding proteins by oestrogen revealed that, beneath an apparent similarity, a clear-cut difference exists between the two vitamin-binding proteins, particularly with regard to hormonal dose-dependent sensitivity of induction and the half-life in circulation. The steroid-mediated elaboration of the two yolk proteins thus appears to be not strictly co-ordinated, despite several common regulatory features underlying their induction.

A radical cyclisation based strategy to cuparenoids; synthesis of (±)-α-cuparenone, (±)-epilaurene and laurenes

Mercuric acetate catalysed one pot Claisen rearrangement of the cinnamyl alcohol Image , generated the pent-4-enal Image , which on homologation resulted the hex-5-enal Image . Radical cyclisation of the radical anion derived from Image , followed by oxidation provided the ketone mixture Image , a known precursor to the sesquiterpenes (Image )-α-cuparenone (Image ), (Image )-epilaurene (Image ) and laurene (Image )

A biomimetic total synthesis of allomicrophyllone: protective Diels-Alder reaction as a stratagem

A biomimetic total synthesis of bioactive tetracyclic natural product allomicrophyllone has been achieved in which a protective Diels-Alder reaction employing a disposable sacrificial 1,3-diene directs the regioselectivity of the subsequent Dials-Alder reaction. (C) 2010 Elsevier Ltd. All rights reserved.

A New Improved Procedure for the Synthesis of 4-Formylcarane - Precursor to Sandatrile, a Novel Perfumery Chemical

Stereospecific synthesis of 4-formylcarane (2) has been achieved through hydroboration-carbonylation of DELTA-3-carene. Both the reactions are optimised using sodium borohydride. The method is utilised for the synthesis of sandatrile (3), a novel perfumery chemical.

Benzyltriethylammon Tetrathiomolybdate: An Improved Sulfur Transfer Reagent for the Synthesis of Disulfides

Benzyltriethylammonium tetrathiomolybdate has been found to be a superior reagent for the conversion of alkyl halides to the corresponding disulfides in chloroform at room temperature.

Combustion Synthesis of Metal Chromite Powders

Fine-particle metal chromites (MCr2O4, where M = Mg, Ca, Mn, Fe, Co, Ni, Cu, and Zn) have been prepared by the combustion of aqueous solutions containing the respective metal nitrate, chromium(III) nitrate, and urea in stoichiometric amounts. The mixtures, when rapidly heated to 350°C, ignite and yield voluminous chromites with surface areas ranging from 5 to 25 m2/g. MgCr2O4, sintered in air at 1500°C for 5 h, has a density of 4.0 g/cm3.

Combustion synthesis of rare earth cuprates

Rare earth cuprates, La2CuO4 Nd2CuO4, La1.8M0.2CuO4 (M=Ca.Sr) and Nd1.85Ce0.15CuO4 have been prepared by the combustion of redox mixtures containing corresponding metal nitrates and maleic hydrazide, C4H4N2O2, at 350°C. The solid combustion products are submicron size amorphous powders which on heat treatment (700°C, 30 minutes) yield crystalline single phase cuprates. Strontium doped lanthanum cuprate, La1.8Sr0.2CuO4, shows an onset of superconductivity at 36K.

A Convenient High-Yield Room-Temerature Synthesis of Mixed Tri(Amino) Silanes by Transmination of Tris(Dicyclohexylamino) Silane And-Their Characterization

Tris(dicyclohexylamino)silane. (DCA)3SiH. is prepared by the reaction of trichlorosilane with dicyclohexylamine. This is found to undergo transamination reactions with other secondary amines (R2NH). such as pyrrolidine, piperidine, hexamethyleneimine. morpholine. N-methylpiperazine and diethylamine to yield mixed tri(amino)silanes of the formula (DCA)(R2N)2SiH in quantitative yields. These new derivatives are found to be moisture sensitive and hydrolyze to yield their respective amines, hydrogen and silica. They are found to be stable in an inert atmosphere. They have been characterized by IR, NMR (H-1, Si-29), mass spectroscopy and CHN analysis. N-15 NMR for one of the compounds has been done.

Bridging the Ruddlesden–Popper and the Dion–Jacobson series of layered perovskites: synthesis of layered oxides, A2–xLa2Ti3–xNbxO10(A = K, Rb), exhibiting ion exchange

Solid solutions of the formula, A2–xLa2Ti3–xNbxO10(A = K, Rb), exist for the range 0[less-than-or-eq]x[less-than-or-eq]1.0, bridging n= 3 members of the Ruddlesden–Popper series (A2La2Ti3O10) and the Dion–Jacobson series (ALa2Ti2NbO10). For 0[less-than-or-eq]x[less-than-or-eq]0.75, the phases possess body-centred structures characteristic of the Ruddlesden–Popper phases, while the x= 1 members are isostructural with KCa2Nb3O10(A = K) and CsCa2Nb3O10(A = Rb). Protonated derivatives, H2–xLa2Ti3–xNbxO10, which are prepared by ion exchange, retain the structural difference of the parent phases. A difference in the Brønsted acidity of the protonated derivatives revealed by intercalation experiments with organic bases seems to be related to this structural difference.

One pot synthesis of polycyclic oxygen aromatics. Part IV reaction of THP ether of 2-bromomethyl phenols

Reaction of 2-bromomethyl-1-(2′-tetrahydropyranyloxy) benzene 3a with tetrachlorocatechol(TCC) in acetone in presence of anhydrous K2CO3 resulted in the formation of diastereomeric products to which cis- & trans- 6-chloro-8-hydroxy-8-(2-oxopropyl)spiro[9H-benzo[a]xanthen- 9,2′(1′H) benzofuran]-7(8H)-one (7a & 8a) structures were assigned, along with tetrachlorocatechol ethers (5a & 6a). Similar reaction of 3a with tetrabromocatechol(TBC) gave the expected monobromo compounds 7d & 8d along with the ethers 5d & 6d. When the reaction was repeated with substrates 3b–c with TCC/TBC in ketonic solvents(acetone/methyl ethyl ketone), the corresponding compounds 5b–c to 8b–c, 5e–f to 6e–f, 7e–g & 8e–h were obtained. A suitable explanation has been given for the formation of acetonyl compound 6 in this reaction.