Synthesis of N-substituted piperazinyl carbamoyl and acetyl derivatives of tetrahydropapaverine: potent antispasmodic agents

The synthesis and structure-activity-relationship (SAR) for a series of N-substituted piperazinyl carbamoyl 7-15 and piperazinyl acetyl 18-26 derivatives of tetrahydropapaverine have been carried out. The general synthetic methods of carbamoyl tetrahydropapaverine analogues involve N-substituted piperazines and carbamoyl imidazole tetrahydropapaverine as starting materials. Another route for synthesizing these compounds, involving the formation of carbamoyl imidazole piperazine has also been explored. Acylation of tetrahydropapaverine followed by substitution with various piperazinyl moities afforded the acetyl tetrahydropapaverine derivatives. Variously substituted piperazines have been used to monitor the effect of electron releasing and electron withdrawing substituents upon the antispasmodic activity of the molecules. Effect of varying electron densities on the antispasmodic activity, by altering the position of these groups on the benzene ring has also been monitored. Pharmacological methods involve the in vitro antispasmodic activity studies on a freshly removed guinea pig ileum using a force displacement transducer amplifier connected to a physiograph. Among the analogues synthesized in the present study, a promising compound 7, a potent muscle relaxant as compared to papaverine has been obtained.     

In vitro and in silico study of Aloe vera leaf extract against human breast cancer

Abstract

Aloe vera leaf contains some bioactive compounds that have a strong binding affinity toward estrogen receptor as compared to standard drug tamoxifen. In this study, we have found that the IC₅₀ of Aloe vera leaf extract against breast cancer cell line (MCF-7) is 23?µg/mL which is much lower than the IC₅₀ (332?µg/mL) of Aloe vera leaf extract against non-cancerous cell line (NIH-3T3). We have also calculated the total concentration of phenolic acid (385.662?µg/mL), flavonoids (160.402?µg/mL) and alkaloids (276.754?µg/mL) in Aloe vera leaf extract. The free radical scavenging activity of Aloe vera leaf extract is 67% to 89% (at 50 to 300?µg/ml). Our virtual molecular docking study suggests that bioactive compounds like Aloe-emodin (?8.8?Kcal/mol), 7-hydroxy-2,5 dimethylchromone (?7.5?Kcal/mol), Beta-sitosterol (?7.3?Kcal/mol) etc. have a greater binding affinity toward estrogen alpha receptor as compared to standard drug Tamoxifen (?6.4?Kcal/mol).

     

Spectral studies, cyclic voltammetry and synthesis of cobalt(II) and ruthenium(III) complexes with symmetric and asymmetric ring containing membered N2S2, N4, and N5 donor macrocyclic ligands

Reaction of divalent cobalt(II) and trivalent ruthenium(III) salts (NO3, SCN and SO4) with macrocyclic ligands L1, L2 and L3 having N2S2, N4 and N5 core, have been designed and carry out. All these three macrocyclic ligands and their complexes were obtained in pure form. Their structures were investigated by using microanalytical analyses, IR, mass, magnetic moments, electronic and EPR spectral studies. The redox properties of the complexes were also examined by cyclic voltammetry. An interesting feature of complexes is that the relatively large rings of macrocyclic ligands prevent the macrocyclic rings from approaching the metal center as closely as they would, if they were not constrained. So the Ru-N distances are longer than expected due to ring size. Electrochemical studies show that the macrocyclic ligand L1 is more effective electron donors to ruthenium than of L2 and L3. Electronic spectral properties also show that the sulphur donor atom of L1 weakens the ligand field with respect to ligand-to-metal charge-transfer band. However it is expected that second-row transition metal-ligand bonds tend to be weaker than third-row transition metal-ligand bonds. There are well-established examples of reactions in which decreased of reactivity down a triad of transition metals is not observed. These novelties are usually attributed to pi-bonding effects for ligands such as carbon monoxide, solvent effects, or a change in mechanism.     

Quantitative estimations of ferric iron by phosphoric acid in aqueous-alcoholic medium

Summary The only method recommended for the direct estimation of ferric iron in presence of HCl is to reduce the ferric iron to ferrous iron and then to titrate against KMnO₄ solution by adding Reinhardt-Zimmermann reagent (MnSO₄ + H₂SO₄ + H₃PO₄). The solubility of the phosphato complexes of ferric chloride and phosphoric acid is much reduced by adding a nonaqueous solvent, ethyl alcohol or acetone. This property has been availed of to find out a method of estimating ferric iron directly against standard solution of phosphoric acid in aqueous-nonaqueous medium using K₄Fe(CN)₆ or cupferron as external indicators. A slight discrepancy at the end point, however, exists in the direct titration but it can be removed by applying a correction factor determined from the estimated results.     

Substituent dependent regioselective synthesis of pyranopyrandiones and 1,2-teraryls from 2H-pyran-2-ones

The one-pot substituent-directed regioselective synthesis of 1,7-diaryl-2-methyl-4H,5H-pyrano[3,4-c]pyran-4,5-diones 3 as the major and 3,4-diaryl-2-methyl-6-methylsulfanylbenzonitriles 4 as the minor products has been delineated through ring transformation of suitably functionalized 2H-pyran-2-ones 1 with aryl acetones 2. Under similar reaction conditions, 6-aryl-4-sec-amino-2H-pyran-2-ones 5 led, regioselectively, to 3,4-diaryl-2-methyl-6-sec-aminobenzonitriles 6.     

Über triterpene—XXIX : Zur struktur des avenacins

From the roots of oat (Avena sativa) a second antibiotic active glycoside, avenacine B, was isolated in addition to the main glycoside avenacine A. In the aglycone of A the double bond could not be established contrary to the statement in the literature but an aldehyde group in addition to the keto group was identified and therefore the proposed structure has to be revised. In the aglycone of B the —CH₂OH-group of A has been substituted by CH₃. The structures of the sugar chains in both glycosides have been determined, in avenacine A as [β-d-gluco-pyranosyl(1 → 4)-[β-d-glucopyranosyl (1 → 2)]-α-l-arabinosyl (1)- and in B as [β-d-glucopyranosyl (1 → 4)]-β-d-glucopyranosyl (1)-.     

Photometric determination of trivalent gallium,indium and thallium with Xylenol orange

Summary Xylenol orange reacts very sensitively with gallium(III), indium (III) and thallium(III) to form reddish violet colored chelates having _max 560 nm in case of Ga and In and _max 590 nm in case of Ti at P_H 4.0. The molar ratio for all the chelates is 1 1 (metal reagent). Optimum conditions including the range for adherence to Beer's law, effect of P_H on the color intensity, effect of excess reagent, and sensitivity are reported for the photometric determination of these metal ions using Xylenol orange.

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Zusammenfassung Xylenolorange reagiert sehr empfindlich mit Gallium(III), Indium(III) und Thallium(III) unter Bildung rötlich-violetter Chelate mit einem Absorptionsmaximum bei 560 nm im Falle von Ga und In bzw. 590 nm für Tl bei p_H 4,0. Das Molverhältnis ist in jedem Fall 11. Die besten Arbeitsbedingungen, der Gültigkeitsbereich des Beerschen Gesetzes, der Einfluß des P_H auf die Farbintensität und des Reagensüberschusses sowie die Empfindlichkeit werden für die photometrische Bestimmung der genannten Ionen angegeben.