@article { ISI:000233214300008, title = {Facile direct conversion of aldehydes to esters and amides using acetone cyanohydrin}, journal = {Tetrahedron Letters}, volume = {46}, number = {48}, year = {2005}, month = {NOV}, pages = {8303-8306}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Aromatic aldehydes with electron-withdrawing groups undergo rapid reactions with a variety of alcohols and secondary amines to afford the corresponding esters and amides, respectively, in high yields, when treated with NaCN or acetone cyanohydrin and base under ambient reaction conditions. In case of alpha,beta-unsaturated aldehydes, simultaneous reduction of the C=C bond along with esterification occurred to produce the saturated esters in high yields. (c) 2005 Elsevier Ltd. All rights reserved.

}, keywords = {amidation, esteritication, reduction, sodium cyanide}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2005.09.173}, author = {Raj, I. V. P. and Sudalai, A.} } @article {48045, title = {Studies directed toward the total synthesis of nannocystin A}, journal = {ChemistrySelect}, volume = {7}, year = {2022}, month = {NOV}, pages = {e202203893}, type = {Article}, abstract = {

A full account of our efforts directed toward the stereoselective total synthesis of nannocystin A, a macrocyclic myxobacterial metabolite, is presented. In this endeavor, we have attempted two distinct synthetic routes to access polyketide fragment (C1-C11) of macrocyclic depsipeptide (21-membered) natural product from readily accessible building blocks 1,3-propanediol and benzaldehyde employing Evans aldol, CBS reduction, Heck cross-coupling, and Sharpless asymmetric epoxidation as key transformations. Ultimately, accomplished the synthesis of the complete skeleton (21-membered precursor for macrocyclic depsipeptide) of the nannocystin A possessing desired stereochemistry and functional groups.

}, keywords = {amidation, Depsipeptide, Evans aldol reaction, Macrocycle, Nannocystins}, issn = {2365-6549}, doi = {10.1002/slct.202203893}, author = {Nomula, Rajesh and Pratapure, Madhukar S. and Kontham, Ravindar} } @article {50103, title = {Liquid-assisted grinding mechanochemical approach for direct amidation of pyridone-carboxylic acid to synthesize an intermediate used in anti-viral API{\textquoteright}s bictegravir and cabotegravir}, journal = {ChemistrySelect}, volume = {11}, year = {2026}, month = {APR }, pages = {e05751}, type = {Article}, abstract = {

Mechanochemistry is viewed as an appealing alternative for the synthesis of various compounds, since it is regarded as an eco-friendly and economical method that can be performed under solvent-free reaction conditions. In this work, neat grinding and liquid-assisted grinding (LAG) methods for direct amidation of pyridone-carboxylic acid and 2,4,6-trifluorobenzylamine/2,4-difluorobenzylamine were studied using EDC.HCl as a coupling reagent to synthesize important intermediates used in the synthesis of anti-HIV drug molecules bictegravir, cabotegravir, and dolutegravir. The products were easy to separate as they easily precipitated out from water, and the purity of the products obtained was similar to 97\% for the intermediates, thus avoiding the need for their purification. This process eliminated the use of organic solvents for the reaction as well as for the work-up and product purification. The reaction was scaled up on a 15-g scale, giving good yields of the intermediates. The process was found to be practical, scalable, and reproducible on a gram scale.

}, keywords = {amidation, bictegravir, cabotegravir, mechanochemistry}, issn = {2365-6549}, doi = {10.1002/slct.202505751}, author = {Karche, Ranjit S. and Bankar, Shubham R. and Jadhav, Vrushali H.} }