@article { ISI:000365952200050, title = {Ammonium persulfate activated DMSO as a one-carbon synthon for the synthesis of methylenebisamides and other applications}, journal = {RSC Advances}, volume = {5}, number = {123}, year = {2015}, month = {NOV}, pages = {101641-101646}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Activation of DMSO to work as an economical and environmentally benign one-carbon synthon has been achieved by using a bench-top reagent ammonium persulfate for general and efficient access to symmetrical methylenebisamides from primary amides. This methodology was used to achieve a three-component Mannich reaction using acetophenone, saccharin and DMSO to furnish a beta-amino ketone. It also provided a metal-free synthesis of thiadiazole and bis(phenyl)methane. Effectively, this method uses DMSO as a safer surrogate to formaldehyde. A mechanism for methylenebisamide formation involving radical intermediates has been proposed based on mechanistic studies.

}, issn = {2046-2069}, doi = {10.1039/c5ra21801b}, author = {Mahajan, Pankaj S. and Tanpure, Subhash D. and More, Namita A. and Gajbhiye, Jayant M. and Mhaske, Santosh B.} } @article {45709, title = {Achmatowicz reaction: A versatile tool in bioactive natural products synthesis}, journal = {Current Organic Chemistry}, volume = {21}, year = {2017}, month = {APR}, pages = {503-545}, type = {Article}, abstract = {

Achmatowicz reaction has emerged as an efficient tool in organic synthesis since its discovery in 1971 by Achmatowicz Jr. The original protocol went through several advantageous variations. Biocatalytic and metal catalyzed versions of this reaction are some of the significant achievements, which further enhanced its effectiveness. The pyranone product of the Achmatowicz reaction is a versatile building block for the synthesis of bioactive scaffolds, drugs and natural products. The present review covers the application of the Achmatowicz reaction in the synthesis of natural products and bioactive molecules reported from 1971 to date. It has been divided into seven sections on the basis of the core structures of the natural products synthesized utilizing the Achmatowicz reaction. We believe that this comprehensive review will attract many more organic chemists to explore its utility in organic synthesis, especially in the synthesis of bioactive natural products as well as drugs in their efficient and atom economical synthesis.

}, keywords = {Achmatowicz reaction, carbohydrates, Furanols, Natural products, pyranones, Total synthesis}, issn = {1385-2728}, doi = {10.2174/1385272821666161208154754}, author = {Mahajan, Pankaj S. and Humne, Vivek T. and Mhaske, Santosh B.} } @article {44191, title = {Application of sulfur ylides in 1,2-difunctionalization of arynes via insertion into a C-S sigma-bond}, journal = {Organic Letters}, volume = {20}, year = {2018}, month = {FEB }, pages = {848-851}, type = {Article}, abstract = {

A novel reactivity of sulfur ylides has been demonstrated in a transition-metal-free protocol to access ortho-substituted thioanisole derivatives by insertion of arynes into a C-S sigma-bond in moderate to good yields. The reaction involves the formation of C-C and C-S bonds and consecutive breaking of two C-S bonds under operationally mild reaction conditions.

}, issn = {1523-7060}, doi = {10.1021/acs.orglett.7b04003}, author = {Ahire, Milind M. and Thoke, Mahesh B. and Mhaske, Santosh B.} } @article {47651, title = {Annulation of enals with carbamoylpropiolates via NHC-catalyzed enolate pathway: access to functionalized maleimides/iso-maleimides and synthesis of aspergillus FH-X-213}, journal = {Journal of Organic Chemistry}, volume = {86}, year = {2021}, month = {JUL }, pages = {9466-9477}, type = {Article}, abstract = {Herein we report the N-heterocyclic carbene (NHC)-catalyzed [3 + 2] annulation of alpha,beta-unsaturated aldehydes with carbamoylpropiolates via an unusual enolate pathway leading to the construction of highly functionalized maleimides or isomaleimides. The electronic effect imposed by the alkyl/aryl group present on the amide nitrogen of carbamoylpropiolates plays a crucial role in the selective formation of these important five-membered heterocyclic building blocks. The developed protocol is mild and tolerates a wide range of substituents on both substrates. The application of this protocol in the synthesis of the antibacterial natural product Aspergillus FH-X-213 has also been demonstrated.}, issn = {0022-3263}, doi = {10.1021/acs.joc.1c00782}, author = {Viveki, Amol B. and Pol, Mahesh D. and Halder, Priyanka and Sonavane, Sameer R. and Mhaske, Santosh B.} } @article {49818, title = {Atom-economical and scalable asymmetric synthesis of daridorexant key starting material (S)-2-methylproline via the memory of chirality}, journal = {Organic Process Research \& Development}, volume = {29}, year = {2025}, month = {DEC}, pages = {3223-3228}, type = {Article}, abstract = {

alpha-Methylproline is a key starting material (KSM) for important drugs, such as Daridorexant, Veliparib, Trofinetide, Enlicitide chloride, and Usnoflast. A practical and scalable asymmetric synthesis of (S)-2-methylproline and its derivatives has been disclosed here using a diketopiperazine intermediate-based strategy that leverages the memory of chirality. Commencing from an inexpensive starting material, l-proline, it proceeds through dimerization and alkylation, followed by hydrolysis under mild conditions, avoiding column chromatography to furnish enantiomerically pure (S)-2-methylproline.HCl, which was also converted to (S)-Boc-2-methylproline and (S)-2-methylproline methyl ester.HCl. In contrast to prior multistep approaches, which rely on expensive chiral auxiliaries and hazardous reagents, this concise three-step route offers operational simplicity, scalability, and superior stereochemical control, making it an attractive method for the synthesis of proline-derived building blocks for peptidomimetics and pharmaceutical applications.

}, keywords = {alpha-methylproline, atom economy, memoryof chirality, Stereoselective}, issn = {1083-6160}, doi = {10.1021/acs.oprd.5c00366}, author = {Bhatt, Gaurang J. and Kumar, Shubham and Mhaske, Santosh B.} }