Total synthesis of carbazole alkaloids

A Suzuki-Miyaura cross coupling, followed by triphenylphosphine mediated Cadogan reductive cyclization sequence provided efficient access to a series of carbazole alkaloids.In the present work, this approach was applied to the total synthesis of mukonine, clauszoline K, koenoline, murrayanine, murrayafoline A, mukoeic acid, glycoborine, glycozolicine, mukolidine, mukoline, glycozoline, 3-methoxy-9H-carbazole-1-carboxylic acid methyl ester, (3-methoxy-9H-carbazol-1-yl)-methanol, 3-methoxy-9H-carbazole-1-carbaldehyde, 3-methoxy-9H-carbazole-1-carboxylic acid, 2-methyl-9H-carbazole and nonsteroidal anti-inflammatory drug (NSAID) carprofen and its derivatives.     

An algebraic multigrid solver for transonic flow problems

This article presents the latest developments of an algebraic multigrid (AMG) based on full potential equation (FPE) solver for transonic flow problems with emphasis on advanced applications. The mathematical difficulties of the problem are associated with the fact that the governing equation changes its type from elliptic (subsonic flow) to hyperbolic (supersonic flow). The flow solver is capable of dealing with flows from subsonic to transonic and supersonic conditions and is based on structured body-fitted grids approach for treating complex geometries. The computational method was demonstrated on a variety of problems to be capable of predicting the shock formation and achieving residual reduction of roughly an order of magnitude per cycle both for elliptic and hyperbolic problems, through the entire range of flow regimes, independent of the problem size (resolution).     

A simple procedure for the preparation of 2‐cyano‐4‐chloropyridines

4‐Nitro‐pyridine‐N‐oxides are reacted with ethylchloroformate and trimethylsilyl cyanide to give 4‐chloro‐2‐cyanopyridine. J. Heterocyclic Chem., (2011).     

Asymmetric Synthesis of Unnatural Amino Acids and Tamsulosin Chiral Intermediate

An efficient and enantioselective hydrogenation of N-acetylamino phenyl acrylic acids was successfully developed by using ruthenium catalyst. This methodology is important in the field of pharmaceuticals and provides a new process for the preparation of unnatural amino acids and tamsulosin chiral intermediate.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource: Full experimental and spectral details.]     

An improved process for the synthesis of nintedanib esylate

Nintedanib esylate is synthesized via novel intermediates of (Z)-methyl 3-(acetoxy-phenyl)methylene)-1-acetyl-2-oxoindoline-6-carboxylate and N-(4-aminophenyl)-2-chloro-N-methylacetamide in good yields.     

A High-Performance Catalytic and Recyclability of Phyto-Synthesized Silver Nanoparticles Embedded in Natural Polymer

The present work deals with phytogenic synthesis of Ag NPs in the natural polymer alginate as support material using Aglaia elaeagnoidea leaf extract as a reducing, capping, and stabilizing agent. Ag nanoparticles embedded in alginate were characterized using UV–Vis absorption spectroscopy, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, transmission electron microscopy techniques and selected area electron diffraction techniques. The formation of AgNPs embedded in the polymer was in spherical shape with an average size of 12 nm range has been noticed. The prepared embedded nanoparticles in polymer were evaluated as a solid heterogeneous catalyst for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) and methylene blue to leuco methylene blue in the liquid phase using sodium borohydride (NaBH₄) as reducing agent. The silver nanoparticles embedded polymer exhibited extraordinary catalytic efficacy in reduction of 4-NP to 4-AP and the rate constant is 0.5054 min^?1 at ambient conditions. The catalyst was recycled and reused up to 10 cycles without significant loss of catalytic activity. The preparation of Ag–CA composite was facile, stable, efficient, eco-friendly, easy to recycle, non-toxic, and cost effective for commercial application.     

Regioselective Synthesis of 1‐Substituted Indazole‐3‐carboxylic Acids

In this article, we study the synthesis of 1‐substituted indazole‐3‐carboxylic acids from 2‐halobenzoic acids.     

Total Syntheses of AF-2785 and Gamendazole—Experimental Male Oral Contraceptives

Both AF-2785 and gamendazole are experimental male oral contraceptives. The total syntheses of these two compounds are achieved in good yields.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

Synthesis of Entacapone by Pd-Catalyzed Heck Coupling Reaction

Synthesis of entacapone from 4-iodo-2-methoxy-phenol with 2-cyano-N,N-diethylacrylamide by palladium-catalyzed Heck reaction, as a key step, is described.