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.     

1-Phenyl-6,7-disubstituted-aminopropyl)-1,2,3,4-tetrahydroisoquinolines as possible antituberculer agents

The Condensation of 3,4-disubstituted phenylethylamine and benzaldehyde furnished l-phenyl-6,7-disubstituted-1,2,3,4-tetrahydroisoquinolines l. which on reaction with 1,3-dibromopropane gave l-phenyl-6,7-disubstituted-2-(3-bromoprophyl)-1,2,3,4-tetrahydroisoquinolines 2. The reaction of 2 with different secondary amines resulted in the synthesis of 3. The compounds 3 were screened for their in vitro antituberculer activity against Mycobacterium smegmatis, and some of them have been found to be total inhibitors of M. Smegmatis     

Role of solvent in the compatibility of a vinylchloride–vinylacetate–maleic acid terpolymer and nitrocellulose blends

The compatibility of cast films of a vinylchloride–vinylacetate–maleic acid terpolymer (VMCH) and nitrocellulose (NC) blends is influenced by solvents. Transparent films of VMCH/NC blends are obtained when cast from solvents such as tetrahydrofuran or cyclohexanone, whereas hazy films are obtained when cast from solvents such as acetone or ethylacetate. Visible spectroscopy and phase morphology were used to analyse the compatibility–incompatibility of the blend. Differential scanning calorimetry (DSC) studies demonstrate that the transparent film is compatible, but the hazy film is incompatible. Fourier transform infra-red (FTIR) studies establish that a greater interaction is observed between the polymer pair in case of the compatible blend than in the case of the incompatible blend. A solvent dependency of blend compatibility is reflected in this study. The conformational state of the polymers in solution, which is responsible for the compatibility phenomena, may depend on the donor number and/or Taft-β value of the solvent. The greater the donor number and/or the Taft-β value, the higher may be the level of interaction between the solvent and the polymer molecules, which in turn may give a compatible blend after removal of the solvent.     

MoSe2 and WSe2 nanotubes and related structures

MoSe2 and WSe2 nanotubes are obtained by the reduction of the corresponding triselenides in hydrogen or by the decomposition of the ammonium selenometallates in a hydrogen atmosphere.     

Spectrophotometric studies on the zirconium complex of 2-(3,6-disulfo-8-hydroxynaphthylazo)-1,8-dihydroxynaphtualene-3, 6-disulfonic acid

Summary A chromotropic azo dye, DSNADNS, prepared from chromotropic acid and 1-amino-8-naphthol-3,6-disulfonic acid has been found to produce quantitative precipitation of zirconium in acid medium. The blue-violet complex formed is insoluble in all organic solvents commonly used for solvent extraction work, but is soluble in a number of liquid organic bases and solutions of ammonium salts in water showing pink to violet colouration. Spectrophotometric studies as to the nature of the complex in pyridine, triethanolamine ammonium acetate, oxalate and carbonate solutions and the analytical possibility of these solutions have been made. The complex appears to decompose in pyridine, ammonium acetate and ammonium oxalate solutions, but it is fairly stable in ammonium carbonate and triethanolamine solutions. The absorbance peaks of the dye in these solutions occur at 500 and 520 nm respectively, while the complex in triethanolamine and ammonium carbonate both shows absorbance maxima at 540 nm. The solution of the complex in these two solvents obeys Beer's law within a concentration range 4 to 25 mg of zirconium per litre. The molar absorbance coefficients of the complex in triethanolamine and ammonium carbonate are respectively 686 and 823, which indicate poor sensitivity. The solution of the complex in the former solvent is more stable than that in the latter and an analytical procedure for the spectrophotometric determination of zirconium, with little interference from foreign ions, may be developed with ease in the triethanolamine solution.

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Zusammenfassung Ein Azofarbstoff der Chromotropsäure, DSNADNS, der aus Chromotropsäure und 1-Amino-8-naphthol-3,6-disulfonsäure dargestellt werden kann, ergibt mit Zirkonium in saurer Lösung eine quantitative Fällung. Der blauviolett gefärbte Komplex ist in allen üblichen organischen Lösungsmitteln unlöslich, löst sich jedoch in einigen flüssigen organischen Basen sowie wäßrigen Lösungen von Ammoniumsalzen mit rosa bis violetter Färbung. Die Lösungen des Komplexes in Pyridin, Triäthanolamin sowie in Ammoniumacetat, -oxalat und -carbonatlösungen und ihre analytische Verwendbarkeit werden spektrophotometrisch untersucht. In Pyridin sowie in Ammoniumacetat und -oxalatlösungen scheint sich der Komplex zu zersetzen, während er in Triäthanolamin und Ammoniumcarbonatlösungen ziemlich beständig ist. Das Absorptionsmaximum des Farbstoffs in diesen beiden Lösungsmitteln liegt bei 500 bzw. 520 nm, der Komplex weist in beiden Fällen ein Maximum bei 540 nm auf. Das Beersche Gesetz wird in beiden Lösungsmitteln von 4–25 mg Zr/l erfüllt. Der molare Absorptionskoeffizient beträgt 686 bzw. 823. Die Lösung des Komplexes in Triäthanolamin ist stabiler als in Ammoniumcarbonatlösung. Eine spektrophotometrische Bestimmung von Zirkonium, die nur wenig von Fremdionen gestört wird, könnte daher gut in Triäthanolaminlösung durchgeführt werden.

     

Rapid determination of molybdenum in ferromolybdenum and molybdenum additives, with oxine

A rapid method is presented for the gravimetric determination of molybdenum (as the oxinate) in ferromolybdenum and molybdenum additives. The sample is fused with a mixed flux of sodium peroxide and sodium carbonate in a zirconium crucible for complete decomposition. Leaching the cooled fusion cake with water provides instantaneous separation of molybdenum as sodium molybdate from iron(III) and other hydrous oxides. After filtration, the molybdenum is precipitated with oxine after addition of EDTA and oxalate to obviate interference from other metal oxinates, and determined gravimetrically. The precision and accuracy are comparable to those of referee methods.     

Electron impact induced fragmentation of some 1,2,4-triazole derivatives

The mass spectra of eight 1,2,4-triazole derivaties have been recorded and found tao reveal extensive hydrogen and skeletal migrations. The structures of the fragments have been confirmed by deuterium labelling and exact mass measurement. The compounds revealed striking differences in their spectra depending on the nature of the substituents.     

Self-assembled,wormlike-cylinder network of polystyrene-block-poly(ethylene oxide) micelles in solution

We report the formation of a highly entangled and interconnected, self-assembled, wormlike-cylinder network of polystyrene-block-poly(ethylene oxide) in N, N-dimethylformamide/water. In this system, N,N-dimethylformamide was a common solvent and water was a selective solvent for the poly(ethylene oxide) blocks. The degrees of polymerization of the polystyrene and poly(ethylene oxide) blocks were 962 and 227, respectively. The network was formed at copolymer concentrations higher than 0.4 wt % and consisted of self-assembled, wormlike cylinders that were interconnected by Y-shaped, T-shaped, and multiple junctions. The network morphology was visualized with transmission electron microscopy. Capillary viscometry measurements revealed an order-of-magnitude increase in the inherent viscosity of the colloidal system upon the formation of the network. A similar effort to obtain a wormlike-cylinder network in an N,N-dimethylformamide/acetonitrile system, in which acetonitrile was a selective solvent for the poly(ethylene oxide) blocks, was unsuccessful even at high copolymer concentrations; instead, the wormlike cylinders showed a tendency to align. The viscosity measurements also did not show a substantial increase in the inherent viscosity. Thus, the solvent played a critical role in determining the formation of the self-assembled, wormlike-cylinder network. This formation of the network resulted from an interplay between the end-capping energy, bending energy (curvature), and configurational entropy of the self-assembled, wormlike-cylinder micelles that minimized the free energy. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3605–3611, 2006