Current Organic Synthesis - Volume 10, Issue 2, 2013

Stereocontrolled formation of C-C bonds in polyfunctionalized carbohydrate derivatives, which are crucial synthetic intermediates, is sometimes very challenging. The application of low valent organometallic reagents for C-C bond formation in carbohydrate chemistry has recently attracted a great deal of attention, largely due to the mild reaction conditions required. We present here an overview of the application of different reductive C-C bond forming reactions in carbohydrate chemistry.

2'-Deoxy-methanocarba nucleosides are a class of compounds with important antiviral and antitumor activities. (N)-2'-deoxymethanocarbathymidine, (N)-MCT, is known as active and specific agent against herpes simplex viruses (HSV1 and 2) and Kaposi's sarcoma- associated herpes virus (KSHV). Some analogues such MRS2500 and MRS2279 have potent antithrombotic therapeutic effect due to their interactions with the purinergic P2Y1 receptors as antagonists, which have led to the new drug concepts. In the present review for the first time is provided a whole overview of the reported several synthetic approaches to the different analogues of 2'-deoxymethanocarba nucleosides as well as their biological activity.

Amide is the key functional group in organic and biological chemistry as it is present in many natural products of therapeutic importance, peptides and polymers. There is continuous exploration of methodologies that can facilitate the user to choose the method of its interest regarding the availability of substrates and high atom economy. In this review, the catalytic methods developed in the past decade mainly focusing on oxidative amidation of alcohols, aldehydes, ketones and esters, aminocarbonylation of aryl halides, alkanes, alkenes and alkynes using transition metals such as Ru, Rh, Fe, Cu, Co, Pd, Ag, Au, Ir and Zr based catalysts have been discussed to highlight the emerging methodologies and expansion of research. The methods developed for the conversion of nitriles and oximes to corresponding amides have also been discussed.

In this review article we have gathered relatively recent publications involving modern methodologies for iodination reactions of aromatic and heteroaromatic compounds using pure water or mixtures containing water as environmentally friendly media.

Tandem or sequential processes involving the Wittig reaction have been extensively used over the past decade in light of their potential in organic synthesis for the construction of complex molecules from simple precursor in a single process. This review is centered on the use of one-pot processes involving Wittig as the core reaction for the synthesis of highly functionalized and biologically important compounds and also for the total synthesis of natural products. The major exploits in this area of research for last decade are highlighted which demonstrate the enormous power of these processes in organic synthesis and underscores the ingenuity of synthetic chemists to achieve higher level of elegance and efficiency.

Novel, symmetrically distributed bisphenol A glycerolate dimethacrylate cross-linked polystyrene support (PS-BGD) for solid phase organic synthesis is presented here. PS-BGD support was synthesized in various mole densities of BGD by suspension copolymerization method. The swelling nature of PS-BGD in various polar/non-polar media was tested and used to compare with commercially available Merrifield, TentaGel and CLEAR supports. The formation of co-polymer was characterized using 13C NMR and FTIR techniques. The size, shape and morphological feature of beads were imaged using scanning electron microscopy. Functional modifications at different stages of reactions were qualitatively analyzed by FTIR and quantitatively analyzed by UV and volumetric methods. The physico-chemical stabilities in various synthetic reagent and solvent conditions were checked by recording FTIR and compared with initial spectrum. Efficiency of novel support was demonstrated by synthesizing classically difficult ACP peptide on PS-BGD and compared to SAT resin. Finally, biologically potent linear as well as single disulphide bonded peptides were synthesized and presented here. The purities of peptides were evaluated by HPLC and corresponding masses by MALDI-TOF analysis.

A simple and efficient synthesis of isoquinoline derivatives by the condensation of ortho-alkynyl aromatic aldehydes/ketones with urea in the presence of copper salts is developed.

Hydrochloric acid activated bentonite was used as a catalyst for hydroamination of cyclohexene with p-toluenesulfonamide under atmospheric pressure. The structure and surface acid property of the catalyst were studied by XRD and NH3-TPD. The effects of acid treatment condition and solvent on the yield of N-cyclohexyl-p-toluenesulfonamide were specifically studied. It was found that apolar aprotic solvents were the suitable solvents for this reaction. The bentonite activated by 2 mol/L hydrochloric acid showed the highest activity and the yield of N-cyclohexyl-p-toluenesulfonamide reached 83.7&percnt after 2 hours reflux using toluene as the solvent. The different substituted location and different substituted group on benzene ring of the anilines have important effects on the yields of products and the presence of the electron-withdrawing substituent is in favor of the reaction.