Voacalgines A–E,new indole alkaloids from Voacanga grandifolia

Five new indole alkaloids, voacalgines A–E (1–5) consisting of a C-mavacurine type of skeleton with 2,3-dihydroxybenzoate moiety, a macroline-type of skeleton, or a macroline-type of skeleton with C₆ unit, were isolated from the bark of Voacanga grandifolia. Their relative structures were determined by means of NMR data. Voacalgine A showed moderate cell growth inhibitory activities against HL-60 and HCT116 cells.     

New Secondary Metabolites from Allium victorialis

Allumines A and B ( 1 and 2 , resp.), two new steroidal alkaloids, and a new cyclopentene derivative, 3 , were isolated from the CHCl₃‐soluble fraction of the whole plant of Allium victorialis. Their structures were elucidated by spectroscopic techniques, including 1D‐ and 2D‐NMR spectroscopy.     

Concise and Simple Synthesis of M1 Allosteric Agonist TBPB

A concise and simple synthesis of M₁ allosteric agonist 1-(1′-(2-methylbenzyl)-1,4′-bipiperidin-4-yl)-1H-benzo[d]imidazol-2(3H)-one (TBPB) using economical and commercially available orthophenylenediamine (O-PDA) and Boc piperidone has been described. The disclosed scheme allows synthesizing more analogs that were otherwise difficult to prepare with the original method.

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Efficient Preparation of Biologically Important 1,2-Amino Alcohols

An efficient three-step methodology developed for the preparation of 1,2-amino alcohols. In the first step a rapid coupling between bromoketones and potassium phthalimide in ionic liquid produced α-phthalimido ketones in quantitative yields, which is followed by a facile reduction using NaCNBH₃ in acetic acid to give corresponding phthalimido alcohols and finally effecting hydrazinolysis in water at 60 °C to yield biologically important 1,2-amino alcohols.     

Microwave-Assisted Synthesis of 2-Long Alkenyl Chain Benzoxazoles and Naphtho[2,3-d]oxazoles and Their Antimicrobial Evaluation

A microwave-assisted combinatorial synthesis of 2-long alkenyl chain benzoxazoles and naphtho[2,3-d]oxazoles with a catalytic amount of phosphorus pentasulphide at ambient pressure has been developed. This procedure constitutes a simple, practical, and green synthetic method for benzoxazoles and their structural analogs. All the compounds [2(a–d) through 6(a–d)] have been screened for antibacterial and antifungal activity. The compounds have showed good activity against Gram-positive and Gram-negative bacteria. All the compounds have also showed good results against almost all fungal strains. The structures of the synthesized compounds are elucidated by IR, ¹H NMR, ¹³C NMR, MS data, and elemental analysis.     

Synthesis and Characterization of Cyclotriphosphazenes Bearing Chalcones Derivatives

A series of new cyclotriphosphazenes bearing chalcones derivatives, N₃P₃Cl₅[OC₆H₄ CH=CHC(O)C₆H₄OC_nH_2n+1] and N₃P₃[OC₆H₄CH=CHC(O)—C₆H₄OC_nH_2n+1]₆, has been synthesized. A convenient synthetic method was performed from the reaction of hexachlorocyclotriphosphazenes with one and six equivalents of (E)-3-(4-(alkyloxy)phenyl)-1-(4-hydroxyphenyl)prop-2-en-1-one (2a–c). The compounds differ in the length of alkyl groups, C_nH_2n+1, where n = 10, 12, and 14, respectively. All the products were obtained in high yields. The structures of the synthesized compounds were defined by elemental analysis, IR, ¹H, ¹³C, and ³¹P NMR.     

Giant dielectric constant and low loss tangent in polypyrrole doped with dodecylbenzene sulfonic acid

Soluble in organic solvent polypyrrole was prepared using dodecylbenzene sulfonic acid as a functional dopant. The dielectric constant was measured as high as 1.6 × 10⁴ at 100 Hz and 450 K with very low dissipation factor. This thermally activated relaxation process plays a dominant role for the low frequency dielectric response. It is suggested that this dipolar polarization may mainly originate from the hopping of charge carriers between localized sites over the potential barriers.     

New Dithiocarbamate Compounds from Organotin(IV)

Abstract

A series of new organotin(IV) dithiocarbamate compounds of type R_nSn (S₂CNR′R″)_4-n (n = 2, 3; R = dimethyl, dibutyl, diphenyl, triphenyl and tert-butyl; R′ = methyl, ethyl, benzyl; R″ = isopropyl, ethyl, ethanol) have been successfully synthesized. Elemental analysis showed that the percentage of the elements conformed to the general formula of these compounds. The important peaks of the infrared spectra for the stretching mode ν(C?N), ν(C?S), and v(Sn-S) for the compounds were observed in the area of 1440–1480 cm^?1, 940–1000 cm^?1, and 340–90 cm^?1, respectively. The ¹³C NMR spectra showed the most important peak for N¹³CS₂ chemical shifts were observed in the range 190–210 ppm. X-ray single crystal studies for several structures of these compounds showed that the chelating mode of the dithiocarbamate groups to the central tin atoms were either bidentate or anisobidentate.

GRAPHICAL ABSTRACT     

Mixed micellization of gemini surfactant with nonionic surfactant in aqueous media: a fluorometric study

Herein we report on the study of the interactions between alkanediyl-α,ω-type cationic dimeric (gemini) surfactant and the nonionic Triton X-100 in aqueous medium. The critical micelle concentrations of binary mixtures were determined by fluorometric study. Using the regular solution theory for the analysis of the experimental data, the attractive nature of interactions and synergistic behavior of gemini surfactant and Triton X-100 mixture were demonstrated. The micelle aggregation number was measured using steady state fluorescence quenching method. The micropolarity, binding constant and dielectric constant of mixed systems were determined from the ratio of peak’s intensity (I ₁/I ₃) in the pyrene fluorescence emission spectrum.