Synthesis of New Fused and Spiro 1,5‐Benzodiazepines

[1,3‐Dihydro‐4‐phenyl(1,5)benzodiazepin‐2‐ylidene]malononitrile 1_a was treated with formaline and some different primary amines to give the corresponding pyrimido(1,5)benzodiazepines 2_a–d . Treatment of compound 1_a with halo reagents yielded the corresponding pyrrolobenzodiazepines 3_a,b . The reaction of compound 1_a with active methylenes, bidentates, S,S‐ and N,S‐acetals afforded the corresponding spiro(1,5)‐benzodiazepines 4_a‐c–8_a,b , respectively.     

Use of quercetin in an improved method for molybdenum determination in waste water,silicate rocks and diverse alloys

A simple and highly sensitive spectrophotometric method for molybdenum (VI) determination has been developed. The method is based on solubilizing the binary molybdenum-quercetin complex and sensitizing the color reaction with cetyltrimethylammonium bromide (CTAB). The optimal conditions for the quantitative determination of molybdenum are studied. In KCl-HCl buffered medium of pH 2.3, the molar absorptivity of the 122 (Moquercetin-CTAB) ternary complex is 2.03 × 10⁵ 1 · mol^–1 · cm^–1 at 420 nm. The system obeys Beer's law up to 0.30 g/ml of molybdenum and the sensitivity index is 0.47 ng · cm^–2. The method is free of interference of most of the common metal ions and anions. The developed procedure has been successfully applied to molybdenum determination in waste water, silicate rocks and diverse alloys.     

On the Electrochemical Behaviour of Some 2,3-Dihydrothiazolo[3,2-a]Benzimidazol-3-One and 1-Ethylmercapto-3(4H)-Isoquinolones Derivatives

The electrochemical behaviour of several derivatives containing the sequence S-C-CO-N in their structure presented as such or in masked form in both aqueous and non-aqueous media are reported. The results of electrooxidation indicated that when the S atom is present as hetero atom in the structure of the molecule the main product will be the sulphone derivative, on the other hand when present in the form C=S the preferential product is the dimer. The overall redox study indicated that the azo group at C-2 is very active in both aqueous and non aqueous media. On the other hand derivatives substituted at C-2 the preferential electrochemical step is the attack of the hetero ring itself.     

A13C nuclear magnetic resonance study of some linear alkynyl gold(I) and silver(I) complexes

Summary Phenylacetylide gold(I) and silver(I) compounds of the type [n-Bu₄N][M(C=CPh)₂], (1) and [n-Bu₄N][XMC=CPh], (2) have been studied by¹³C n.m.r. spectroscopy and their chemical shifts are reported for the first time. The shielding of the alkynyl carbon linked directly to the metal in (2) isca. 10–15 ppm less than the analogous carbon in (1) (M=Au), andca. 6–11 ppm less in the silver complexes (M=Ag). The variation in chemical shift depends on the nature of X(X=Cl, Br, I, C₂Ph and Ph₃P) and indicates greatly different degrees of polarization of the Au-C= (or Ag-C=) bonds in (1) and (2). I.r. spectra of the title compounds are reported and confirm the weakness of ML back-bonding. Comparison is also made with¹³C and i.r. data for platinum, and mercury complexes.     

Omega chrome black blue G as a colorimetric reagent for the microdetermination of various cations

Summary Omega Chrome Black Blue G has been found to be a suitable colorimetric reagent for the detection of cobalt and for the determination of copper, cobalt, cadmium, lead and magnesium. The effects of time, p_H, temperature, and foreign ions on the absorbancy are investigated. The reagent is practically suitable for the determination of microgram amounts of cobalt in presence of nickel and other ions which evoke a red colour.The reagent is not suitable for the determination of nickel, calcium, strontium, and zinc.     

Infrared study of the effect of some solvents on the structural properties of soybean proteins

The effect of three groups of solvents classified according to their water miscibility on soybean proteins at 80°C and 100°C was investigated by following the changes in their infrared spectra. The results showed that, for immiscible solvents, the values of the absorbances ratios

Phytochemical,antimicrobial and antiquorum-sensing studies of pulicaria undulata L.: a revision on the structure of 1β,2α,3β,19α,23-pentahydroxy-urs-12-en-28-oic acid

Abstract

Phytochemical study of the aerial part of Pulicaria undulata L. led to the isolation of nine compounds. The structure of 1β,2α,3β,19α,23-pentahydroxy-urs-12-en-28-oic acid (4) was revised and confirmation of the stereochemical configuration of the hydroxyl groups was established using NOESY and selective decoupling experiments. The other compounds were identified as 1,2-dehydro-1,10α-dihydropseudoivalin (1), axillarin (2), grandifloric acid-15-β-glucoside (3), myrianthic acid (5), caffeic acid (6), quercetin (7), paniculoside IV (8) and caffeic anhydride (9). The structures were characterized by 1?D, 2?D NMR spectroscopy and confirmed with HRMS. Antimicrobial and antiquorum-sensing activities of the different extracts and isolated compounds of the plant were investigated. Generally, the phenolic rather than the terpenoidal compounds exhibited remarkable antimicrobial and antiquorum-sensing activity.

     

Surface activity—thermodynamic properties and light scattering studies for some novel aliphatic polyester surfactants

The preparation of 12 new polyester surfactants based on aliphatic amines and different ethylene oxide content is described. These surfactants were characterized by determining their molecular weights and polydispersity by gel permeation chromatography (GPC) and nitrogen content. Drop volume tensiometry (DVT) was used to measure the surface tension at 25, 35, 45 and 55°C. The surface tension isotherms were used to determine critical micelle concentration (CMC), maximum Gibb's adsorption (Γ_max), minimum area per molecule (A_min), the effectiveness of surface tension reduction (π_cmc) and the efficiency (pC₂₀). The thermodynamic parameters of micellization (ΔG_mic, ΔH_mic, ΔS_mic) and of adsorption (ΔG_ad, ΔH_ad, ΔS_ad) were calculated and the data showed that these surfactants favor micellization to adsorption. The static scattered light intensity measurements provide the calculation of the molecular weight of micelle and the aggregation number (N°), while the dynamic light scattering provide the hydrodynamic radius of micelle (R_H) and the diffusion coefficient at different surfactant concentrations. The hydrodynamic radius of micelle (R_H) at different surfactant concentrations could be used also to determine the CMC giving results that are comparable to those obtained by surface tension measurements. All the data are discussed regarding the chemical structure of the polymeric surfactants. Copyright © 2004 John Wiley & Sons, Ltd.     

The electroreduction of pyrazolone glyoxalic ester derivatives in aqueous buffered media

Summary The polarographic reduction of two series of pyrazolone derivatives in alcoholic buffered media indicated that these molecules predominate in the hydrazone form and are reduced via a 4e^– irreversible process. The main eletrolysis products, 3,6-bis(pyrazoline-5-on-3yl)piperazine-2,5-dione (3), and 3,6-bis(1-phenyl-pyrazoline-5-on-3yl)piperazine-2,5-dione (4) were isolated and identified. A mechanism has been suggested and discussed.

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Die Elektroreduktion von Pyrazolon-Glyoxalester-Derivaten in wäßrigem, gepuffertem Medium

Zusammenfassung Die polarographische Reduktion zweier Serien von Pyrazolon-Derivaten in alkoholisch-wäßrigem, gepuffertem Medium zeigt, daß diese Moleküle bevorzugt in der Hydrazono-Form vorliegen und über einen irreversiblen 4e^–-Prozeß reduziert werden. Die Hauptprodukte der Elektrolyse, 3,6-bis(pyrazolin-5-on-3-yl)piperazin-2,5-dion (3) und 3,6-bis(phenylpyrazolin-5-on-3-yl)piperazin-2,5-dion (4) wurden isoliert und identifiziert. Ein Mechanismus wird vorgeschlagen und diskutiert.

     

Synthesis and Reactions of Novel Pyrimido[4,5-<Emphasis Type="Italic">c</Emphasis>]pyridazine and <Emphasis Type="Italic">s</Emphasis>-Triazolo[3′,4′:2,3]pyrimido[4,5-<Emphasis Type="Italic">c</Emphasis>]pyridazine Derivatives

Summary. The reaction of 3-chloro-5,6-diphenylpyridazine-4-carbonitrile with potassium thiocyanate gave the corresponding isothiocyanate derivative. This was reacted with aromatic amines in ethanol to afford pyrimido[4,5-c]pyridazine derivatives. The reaction of the latter compounds with hydrazine hydrate led to the formation of 6-hydrazino derivatives. One hydrazino compound was reacted with a variety of reagents to produce other new pyrimidopyridazines as well as a number of s-triazolo derivatives.