Titanium Reagents for the Synthesis of 2-Substituted Benzo[b]thiophenes on the Solid Phase

The first observation on polymerization of 1,3-benzothiazines: synthesis of mono- and bis-thiazine monomers and thermal properties of their polymers

Mono and difunctional 1,3-benzothiazines (PH-a-BZT, PH-ddm-BZT) have been synthesized by a method different from the one reported in the literature.

Metal and Non-Metal Catalysts in the Synthesis of Five-Membered S-Heterocycles

BACKGROUND

A wide variety of biological activities are exhibited by N, O and S containing heterocycles and recently, many reports appeared for the synthesis of these heterocycles. The synthesis of heterocycles with the help of metal and non-metal catalyst has become a highly rewarding and important method in organic synthesis. This review article concentrated on the synthesis of S-heterocylces in the presence of metal and non-metal catalyst. The synthesis of five-membered S-heterocycles is described here.

OBJECTIVE

There is a need for the development of rapid, efficient and versatile strategy for the synthesis of heterocyclic rings. Metal, non-metal and organocatalysis involving methods have gained prominence because traditional conditions have disadvantages such as long reaction times, harsh conditions and limited substrate scope.

CONCLUSION

The metal-, non-metal-, and organocatalyst assisted organic synthesis is a highly dynamic research field. For ßthe chemoselective and efficient synthesis of heterocyclic molecules, this protocol has emerged as a powerful route. Various methodologies in the past few years have been pointed out to pursue more sustainable, efficient and environmentally benign procedures and products. Among these processes, the development of new protocols (catalysis), which avoided the use of toxic reagents, are the focus of intense research.

Traceless Solid-Phase Organic Synthesis

Traceless solid-phase synthesis represents an ultimate sophisticated synthetic strategy on insoluble supports. Compounds synthesized on solid supports can be released without a trace of the linker that was used to tether the intermediates during the synthesis. Thus, the target products are composed only of the components (atoms, functional groups) inherent to the target core structure. A wide variety of synthetic strategies have been developed to prepare products in a traceless manner, and this review is dedicated to all aspects of traceless solid-phase organic synthesis. Importantly, the synthesis does not need to be carried out on a linker designed for traceless synthesis; most of the synthetic approaches described herein were developed using standard, commercially available linkers (originally devised for solid-phase peptide synthesis). The type of structure prepared in a traceless fashion is not restricted. The individual synthetic approaches are divided into eight sections, each devoted to a different methodology for traceless synthesis. Each section consists of a brief outline of the synthetic strategy followed by a description of individual reported syntheses.

A potent free fatty acid receptor 1 agonist with a glucose-dependent antihyperglycemic effect

PAFA is a promising free fatty acid receptor 1 agonist with a glucose-dependent antihyperglycemic effect, allowing for treating type-2 diabetes.

Direct synthesis of 3-acylbenzothiophenes via the radical cyclization of 2-alkynylthioanisoles with α-oxocarboxylic acids

A radical cascade cyclization strategy has been developed to provide a direct route to access 3-acylbenzothiophenes from simple chemical feedstocks.

Three-component 2-aryl substituted benzothiophene formation under transition-metal free conditions

A base-mediated efficient entry for 2-aryl substituted benzothiophene from 2-bromobenzene aldehydes, benzylic esters and elemental sulfur.

Crystal structure of 2-(p-tolyl)-6-(trifluoromethyl)benzo[b]thiophene-3-carbonitrile

In the title compound, C₁₇H₁₀F₃NS, the dihedral angle between the fused benzo­thio­phene ring system (r.m.s. deviation = 0.042 Å) and the benzene ring is 29.78 (11)°. The crystal structure features C—H⋯F and very weak C—H⋯N hydrogen bonds, which generate (001) sheets.

One-pot synthesis of 2,3-substituted benzo[b]thiophenes via Cu(i) catalysed intramolecular cyclisation from dithioesters

The novel route involves CuI catalyzed C–S bond formation using dithioesters. This approach is valuable for synthesis of rolaxifene analogues.

Enhanced stereoselectivity of a Cu(II) complex chiral auxiliary in the synthesis of Fmoc-L-γ-carboxyglutamic acid

L-γ-Carboxyglutamic acid (Gla) is an uncommon amino acid that binds avidly to mineral surfaces and metal ions. Herein, we report the synthesis of N-α-Fmoc-L-γ-carboxyglutamic acid γ,γ'-tert-butyl ester (Fmoc-Gla(O(t)Bu)(2)-OH), a suitably protected analogue for Fmoc-based solid-phase peptide synthesis. The residue was synthesized using a novel chiral Cu(II) complex, whose structure-based design was inspired by the blue copper protein rusticyanin. The five-coordinate complex is formed by Shiff base formation between glycine and the novel ligand (S)-2-(N-(2-methylthio)benzylprolyl)aminobenzophenone in the presence of copper. Michael addition of di-tert-butyl methylenemalonate to the α-carbon of the glycine portion of the complex occurs in a diastereoselective fashion. The resulting (S,S)-complex diastereomer can be easily purified by chromatography. Metal complex decomposition followed by Fmoc protection affords the enantiomerically pure amino acid. With the use of this novel chiral complex, the asymmetric synthesis of Fmoc-Gla(O(t)Bu)(2)-OH was completed in nine steps from thiosalicylic acid in 14.5% overall yield.