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A simple, new and convenient metal free procedure for the synthesis of 5-substituted 1H-tetrazoles using various nitriles and sodium azide in the presence of urea and acetic acid with good to high yields is developed. The reaction plausibly proceeds through in situ formation of urea azide active complex without toxic and/or expensive metal catalysts.

A novel reaction involving in situ redox conversion of glyoxylate esters to glycine is described. Simple starting materials and mild conditions for the synthesis of glycine derivatives probably indicate a pathway towards prebiotic chemistry. This proceeds analogous to Cannizzaro reaction involving ammonia therefore it can be termed as intramolecular Aza-Cannizzaro type reaction. This reaction is examined in detail with an aid of computational analysis to corroborate the proposed mechanism.

We envisioned a facile construction of diversified pyrazinoindoles by using 1,1,1,3,3,3-Hexafluoroisopropanol (HFIP) as the solvent and catalyst, hence eliminating metal catalyzed routes for its development. The process is facilitated by HFIP that has emerged as a powerful tool for development of novel fused heterocycles. This cascade approach blends the asymmetric N-acylation with consecutive intramolecular cyclisation via Pictet-Spengler reaction as an efficient tool forming overall two stereogenic centers. Our approach deals with incorporation of l -amino acid on substituted indoles to provide the chiral N-acylated indole precursor followed by cyclisation to access pyrazinoindole derivatives in high enantiomeric excess up to >99% in good to excellent yields, which have great potential as molecular scaffolds in drug discovery. We have also described the mechanistic course of the reaction based on density functional theory.

An expeditious and practical method for the reduction of amides to amines is reported. The method consists of activation of amides with TMSCl followed by reduction with LiAlH 4 . Various amides/lactams including hindered amides and secondary amides gave the corresponding amines in good to excellent yields. This novel protocol has a wide substrate scope and shows good functional group tolerance with high stereoretention.

A novel synthesis of naproxen utilizing nitroaldol, 1,4-addition and Nef reaction is demonstrated where the desired S -enantiomer is achieved by resolution. Further to this first enantioselective 1,4-addition of Grignard reagent to nitroolefin is demonstrated to synthesize derivatives of naproxen.

Efficient methods have been developed for the synthesis of three active pharmaceutical ingredients (APIs) carbamazepine (Tegretol®) 1, oxcarbazepine (Trileptal®) 2, and eslicarbazepine acetate (Exalief®) 3 by employing enantioselective reduction and carboxamidation reaction.

Multiple sclerosis (MS) often results in chronic inflammatory and autoimmune disorders, and recent developments in understanding the disease pathogenesis has lead to newer therapeutic options for the treatment of the disease. The development of small molecule drugs with improved efficacy, better tolerability, and oral administration has received a new impetus with the discovery of newer classes of drugs. In this review, we have summarized the hitherto known synthetic strategies of fingolimod, laquinimod, cladribine, and teriflunomide reported in the literature which are the key small molecules and the first oral drug candidates for MS in various stages of clinical development or have been launched in the market.

The stereoselective total synthesis of (−)-achaetolide is described in a convergent manner. Grignard addition, Wittig homologation, acetate aldol and ring closing metathesis reactions were the key steps involved. The required olefinic alcohol fragments were synthesized from a single chiral pool material 2-deoxy- d -ribose and olefinic acid fragment was prepared from acetate aldol reaction. Both the olefinic acid and alcohols were prepared in a concise method.

Total synthesis of antidepressant drug, agomelatine is reported. Regio selective Friedel–Crafts acylation followed by Willgerodt–Kindler reactions is used as the key steps for the synthesis of agomelatine.

An expedient procedure for the acylation of alcohols, phenols, and thiophenols using catalytic amount of Zn(OTf)2 is described. This procedure is highly suitable for industrial application due to use of less toxic metal as a part of catalyst, short reaction time at ambient temperature, without any racemization of chiral alcohols.

Fluorescent molecules that emit in the near infrared are potentially useful as probes for biotechnology. A relatively under-explored design for probes of this type are the aza-BODIPY dyes; this study was performed to enhance our understanding of these materials and ways in which they may be used in dye cassette systems. Thus, the aza-BODIPY dyes 1aeg were prepared. An advanced intermediate toward an eighth compound in the series, 6h, was made but it could not be complexed with boron effectively to give 1h. Spectroscopic properties of these compounds were recorded, and correlations between substituent effects, UV absorbance, fluorescence emissions, and quantum yields were made. Compound 1a was coupled with a fluoresceinealkyne derivative to give the energy transfer cassettes 2 and 3. Both these compounds gave poor energy transfer and the possible reasons for this were discussed. ! 2008 Elsevier Ltd. All rights reserved.

An efficient and environmentally benign boric acid catalyzed protocol for the transesterification of ethyl acetoacetate with a variety of primary and secondary alcohols in good to excellent yields is described. The versatility of this transformation is demonstrated with problematic substrates such as propargyl alcohol and allyl alcohol, which are known to undergo Carroll rearrangement during transesterification.

A simple and convergent approach to enantiomerically pure 5-[[2-[1-[3,5-bis(trifluoromethyl)phenyl]ethoxy-3-(4-fluorophenyl)morpholin-4-yl]methyl]-1,2-dihydro-1,2,4-triazol-3-one 1, a potent orally active antagonist of the human neurokinin-1 (NK-1) receptor, is described. The synthetic procedure starts from p-fluorobenzaldehyde to access the racemic morpholinone 2 via a modified Strecker synthesis and utilizes a diastereomeric salt resolution technique to accomplish the synthesis of 1 in enantiomerically pure form and good yield.

Agomelatine was synthesized from 8-aminonaphthalen-2-ol by diazotization-iodination, formylation, C–C bond formation by nitroaldol and Pd/C hydrogenation of β-nitrovinylnaphthalene followed by N-acetylation. The route reported employs readily and commercially viable starting materials and reagents, and can potentially be utilized for process synthesis of agomelatine.

An efficient and convenient procedure for the reductive amination of aldehydes using NaBH4 in the presence of catalytic amount of Fe(OTf)3 is described.

The first stereoselective total synthesis of polyacetylene panaxjapyne C is described. The key reactions include regioselective opening of the epoxide and Cadiot–Chodkiewicz cross-coupling reactions. l -Ascorbic acid was used as a chiral pool material for the construction of the both terminal acetylenes.

A novel approach to the synthesis of Boc-core, a key starting material for ritonavir and lopinavir involving an unprecedented diastereoselective nitroaldol reaction on β-amino aldehyde is disclosed.

An alternative and scalable synthesis of dexlansoprazole ((R)-(+)-1); the (R)-enantiomer of Lansoprazole with an enantiomeric excess of >99.8% is presented.