Iranian Journal of Chemistry and Chemical Engineering
Volume:14 Issue: 1, May-Jun 1995

A simple, rapid and sensitive method has been developed for determination of traces of tellurium (VI) (0.096-1.250 mg/mL) based on its catalytic effect on the reduction reaction of toluidine blue by sulfide ion at pH 4. The reaction is monitored spectrophotometrically by measuring the decrease in absorbance of the dyestuff at 628 nm by the fixed time method. The detection limit is 80 ng/mL and the relative standard deviation for 1mg/mL tellurium is 2.2%.

2-(Methylamino) pyridine (HMAP) reacts with MeLi in THF and generates the lithium salt (LiMAP). Further reaction of [Cu(TMEDA)2][CuCl2] (TMEDA=tetramethylethylenediamine) with one equivalent of this ligand in THF leads to the formation of a yellow dimerci Cu(I) complex, [Cu(MAP)]2. Analytical data, molecular weight, and magnetic susceptibility measurements, confirm the formula [Cu(MAP)]2.

Lead, copper, cobalt, nickel, iron and zinc ions form monocitrate complexes (negative charge) in citrate solution which is absorbed on the citrate form of anion-exchange resins (citrate as counter ion) by exchange of citrate ion with citrate complexes. These are subsequently recovered from the resin by 0.5M ammonium citrate eluent at pH 2.0. Under optimized conditions, quantitative recovery was achieved simultaneously for lead, cobalt, copper, nickel, iron and zinc (preconcentration factor 20). Each element could be determined by atomic absorption spectroscopy (AAS) with high precision.

Five new 1-hydroxy-2-(1-alkyloxymethyl)-9, 10-anthraquinones (9a-e) have been prepared. Selective nitration of 2-methyl-9, 10-anthraquinone, reduction to the corresponding amine, diazotization and treatment by sulfuric acid solution afforded the 1-hydroxy-2-methyl-9, 10-anthraquinone in good yield as the key intermediate. Reaction with dimethylsulphate/K2CO3 and subsequent monobromination with NBS/CCl4 produced 1-methoxy-2-(bromomethyl)-9, 10-anthraquinone A mixture of HBr/AcOH was used for demethylation. Treatment of hydroxybromo derivatives with different alcohols affordedcorresponding ethers in high yields.

The synthesis of 1,5-dihydroxy-9, 10-anthraquinone (17); (1,5-DHA) was accomplished during, attempts towards the synthesis one of its derivatives called anthralin (1,8-dihydroxy-9-anthrone) which is known as an antipsoriasis drug since 1916 [1]. This work is a new reigiospecilic preparation of 1,5-DHA based on Friedel – Crafts reaction starting from 1,4-dimethoxybenzene. This synthetic route, in addition to being successful, produced interesting by-products, in terms of biological activities. The advantage of this work over other attempts is the use of inexpensive materials and mild reaction conditions.

Functional trimethylsilylacetylenes 2(a-I) with different functional groups were synthesized from their corresponding acyl chloride (1) in good yields.

The equilibrium constant of adduct formation between some triorganotin chloride of the type R3SnCl(R=C6H5, p-CH3C6H4, n-CH3(CH2)3, C6H5-CH2) and Lewis bases Clˉ, Brˉ, and Iˉ, were average equilibrium constant values for the systems studied shows the following acceptor trend of tin (IV) in the triorganotin chlorides: p-tolyl > n-butyl > phenyl > benzyl The influence of the organic moieties on the acceptor property of tin (IV) is discussed.

6-Methyl-2-phenyl-7H-oxazolo [3,2-b][1,2,4] triazine (1) underwent ring transformation on treatment with ammonia and primary amines to afford the corresponding imidazo [1,2-b][1,2,4] triazine (2). Treatment of (1) with hydrazine hydrate gave the corresponding 3-aryl-4H-1, 2,4-triazino [4,3-b][1,2,4] trazin-8 (1H)-one (3).

The 1H and natural –abundance 13C-NMR spectra of 1-thiacyclooctan-3- one (1) have been measured from 25 to - 100°C. Coalescence is observed in the 1H-NMR spectra of (1) at about - 80° C, and attributed to ring inversion in a boat – chair conformation, which is the predominant conformation of (1). The free energy of activation (ΔG¹) for this process is 9.2±0.2 kcal/mol. The 13C-NMR spectra of (1) is temperature independent.