Electroorganic synthesis of benzathine

Benzathine is prepared in good yields from cyanobenzene by a combination of electrochemical hydrogenation and Kolbe electrolysis using nickel and platinum electrodes in the presence of methanolic sodium methoxide in an undivided cell.     

Synthesis of thiadiazoles,triazoles and oxadiazoles from sulfonyl acetic acids via a common route

A new class of five membered heterocycles, thiadiazoles, triazoles and oxadiazoles were prepared from sulfonyl acetic acids via acid hydrazides.     

Spectrophotometric determination of dopamine in pharmaceutical formulations

A new spectrophotometric method was developed for the estimation of dopamine. The method is based on the bromination of the dopamine with a solution of excess brominating mixture. After bromination, the excess brominating mixture is treated with potassium iodide to produce a yellow solution. The absorbance of yellow solution was measured at 350 nm on a Spectronic 1001 spectrophotometer against distilled water as a blank.From Zhurnal Analiticheskoi Khimii, Vol. 60, No. 3, 2005, pp. 2842285.Original English Text Copyright © 2005 by Rami Reddy, Sreedevi, Prabhavathi, Chakravarthy.This article was submitted by the authors in English.     

The first example of a liquid crystalline side-chain polymer with bent-core mesogenic units: ferroelectric switching and spontaneous achiral symmetry breaking in an achiral polymer

A dimethylsiloxane diluted polysiloxane side chain co-polymer with non-chiral banana-shaped mesogenic units shows an optically isotropic ferroelectric switching polar smectic C phase (SmCPF) consisting of a conglomerate of homogeneously chiral domains with opposite handedness.     

Enzymatic kinetic resolution of racemic 4-tetrahydropyranols by Candida rugosa lipase

Enzymatic kinetic resolution of (±)-hydroxytetrahydropyrans has been achieved for the first time by means of lipase-mediated transesterification to afford optically active (2S,4R)-tetrahydropyranyl acetates and (2R,4S)-tetrahydropyranols in excellent yields with high enantioselectivity. Absolute configurations of the tetrahydropyranyl acetates were assigned as (S) by chemical correlation.     

A mild, rapid and highly regioselective ring-opening of epoxides and aziridines with acetic anhydride under solvent-free conditions using ammonium-12-molybdophosphate

A highly regioselective ring opening of epoxides and aziridines can be carried out efficiently with acetic anhydride to form the acetates of the corresponding 1,2-diols and 2-amino-alcohols, respectively, using ammonium-12-molybdophosphate (AMP) as a heterogeneous catalyst, at room temperature, in the absence of solvent.     

Sensitive and selective spectrophotometric method for the determination of trace amounts of osmium with 1,2,3-indanetrione monothiosemicarbazone

Summary Sensitive and Selective Spectrophotometric Method for the Determination of Trace Amounts of Osmium with 1,2,3-Indanetrione Monothiosemicarbazone A simple, sensitive and selective spectrophotometric method has been developed for the determination of osmium using 1,2,3-indane-trione monothiosemicarbazone (ITMT). The method is based on the colour reaction between ITMT and osmium(VIII) in hydrochloric acid (0.32–0.60 M) medium. The calibration graph for measurement at 440 nm is linear in the range 1.4–33.6g of osmium per 25ml, with a molar absorptivity of 6.43×10⁴l·mole^–1·cm^–1. The effect of interferences has been studied and the method applied to the determination of osmium in synthetic samples whose composition correspond to osmiridium or syserkite, with good results.     

Effect of sodium metasilicate on natural flotability of coal

The effect of the quantity of sodium metasilicate and conditioning time in one set of experiments, and the effect of the solution concentration of sodium metasilicate, added at the same dosage and conditioning time to coal slurry, on flotability of a typical Indian coal in another set of experiments are studied. Two sets of 3² full factorial experiments are carried out to assess the effects of the aforementioned variables. The generated data are analyzed quantitatively and explained qualitatively. At 0.1% (w/v) solution concentration of solution added (0.02 g/kg) and 8 min conditioning time, sodium metasilicate acted as activator for kaolinite, whereas at 1.0% (w/v) solution concentration (0.2 g/kg), it acted as dispersant. The best observed condition of depressant is obtained at an added concentration of 10.0% (w/v, 0.2 g/kg) and 8 min conditioning time. The desired effect of the sodium metasilicate can be achieved by controlling its quantity, solution concentration added, and conditioning time.     

Neutral and ionic aluminum,gallium, and indium compounds carrying two or three terminal ethynyl groups

The syntheses of the ionic compounds [Li(+).2 dioxane (2,6-iPr(2)C(6)H(3)N(SiMe(3))Al(C triplebond CSiMe(3))(3))(-)].0.75 dioxane (1), [(Li(+))(2).(dioxane)(7)](0.5) [2,6-iPr(2)C(6)H(3)N(SiMe(3))Ga(C triplebond CSiMe(3))(3)(-)].1.5 dioxane (2), and [(Li(+))(2).(dioxane)(7)](0.5) [2,6-iPr(2)C(6)H(3)N(SiMe(3))In(C triplebond CSiMe(3))(3)(-)].1.5 dioxane (3) by the reaction of the corresponding organo metal chloride with LiC triplebond CSiMe(3) are reported. The neutral ethynyl compounds Br-Al(C triplebond CtBu)(2).2 THF (4), Cl-Ga(C triplebond CtBu)(2).THF (5), Cl-In(C triplebond CtBu)(2).2 THF (6), Al(C triplebond CtBu)(3).C[N(Me)CMe](2) (7), Ga(C triplebond CtBu)(3).dioxane (8), and In(C triplebond CtBu)(3).NEt(3) (9) have been obtained in good yields from the reaction of AlBr(3), GaCl(3), and InCl(3) with LiC triplebond CtBu in the presence of a Lewis base. Compound 7 is the first heterocyclic carbene substituted ethynyl derivative. Aluminum and gallium compounds with three terminal ethynyl groups Al(C triplebond CPh)(3).NMe(3) (10) and Ga(C triplebond CPh)(3).NMe(3) (11) have been prepared by the reaction of AlH(3).NMe(3) or GaH(3).NMe(3) with three equivalents of phenylethyne. All the above-mentioned compounds have been structurally studied. In compound 1 the lithium ion is coordinated to the three terminal ethynyl groups, whereas in compounds 2 and 3 the lithium is coordinated to the solvent (dioxane). Compound 8 crystallizes as a coordination polymer with dioxane molecules bridging the individual gallium units.