@article {48681, title = {Organocatalysed one-pot three component synthesis of 3,3'-disubstituted oxindoles featuring an all-carbon quaternary center and [spiro 2H-pyran-3,4'-indoline]}, journal = {RSC Advances}, volume = {13}, year = {2023}, month = {APR}, pages = {13206-13212}, type = {Article}, abstract = {

A simple and efficient methodology for the one-pot synthesis of 3,3 {\textquoteleft}-disubstituted oxindoles featuring an all-carbon quaternary center has been demonstrated through l-proline catalysed three-component reaction based on sequential Knoevenagel condensation/Michael addition and also one-pot synthesis of spiro[2H-pyran-3,4 {\textquoteleft}-indoline] through consecutive Knoevenagel condensation/Michael addition/reduction/cyclization reactions from readily available isatin derivatives, malononitrile, and ketones. The present methodology presents several advantages, including simple reaction set-up, short reaction times, and easy to work-up. Also, this strategy offers broad substrate scope with excellent yields and high atom economy, under mild reaction conditions.

}, doi = {10.1039/d3ra00510k}, author = {Nichinde, Chandrakant B. and Patil, Baliram R. and Chaudhari, Suryakant S. and Mali, Bhupendra P. and Gonnade, Rajesh G. and Kinage, Anil K.} } @article {49053, title = {Base controlled rongalite-mediated reductive aldol/cyclization and dimerization of isatylidene malononitriles/cyanoacetates}, journal = {Organic and biomolecular chemistry}, volume = {22}, year = {2024}, month = {FEB}, pages = {1727-1732}, type = {Article}, abstract = {

In this study, we developed a novel methodology involving a base-controlled, rongalite-mediated reductive/aldol reaction, followed by cyclization of isatylidene malononitriles/cyanoacetates, resulting in the synthesis of spiro[2,3-dihydrofuran-3,3 {\textquoteleft}-oxindole]. Additionally, we have disclosed a rongalite-mediated dimerization process for isatylidene malononitriles, yielding dispiro[cyclopent-3 {\textquoteleft}-ene]bisoxindole. The utilization of rongalite in this reaction serves a dual purpose, acting both as a reducing agent and a C1 synthon. The developed approach has several advantages like a simple reaction setup, a wide substrate scope, requiring less time, using water as a green solvent, no metal or catalyst is required and products can be easily isolated via filtration with excellent yields under mild reaction conditions. A novel methodology was developed for the synthesis of spiro[2,3-dihydrofuran-3,3 {\textquoteleft}-oxindole] and dispiro[cyclopent-3 {\textquoteleft}-ene]bisoxindole under mild reaction conditions using inexpensive reagents.

}, issn = {1477-0520}, doi = {10.1039/d3ob01794j}, author = {Chaudhari, Suryakant S. and Nichinde, Chandrakant B. and Patil, Baliram R. and Girase, Amardipsing S. and Rama Krishna, Gamidi and Kinage, Anil K.} } @article {49643, title = {Organocatalyzed [4+2] cycloaddition of α,β-unsaturated ketones and isatylidene malononitrile: accessing spiro[3-arylcyclohexanone]oxindole derivatives}, journal = {RSC Advances}, volume = {14}, year = {2024}, month = {JAN}, pages = {2873-2877}, type = {Article}, abstract = {

Herein, we developed a series of compounds featuring spiro[3-arylcyclohexanone]oxindoles through Barbas [4 + 2] cycloaddition reactions between isatylidene malononitrile and alpha,beta-unsaturated ketones using l-proline as an organocatalyst. The reported methodology offers many advantages such as mild reaction conditions, diverse substrate scope with high yields, easy reaction setup, and use of easily synthesizable starting materials. An l-proline catalyzed-Barbas-[4 + 2]-cycloaddition reaction is reported for the synthesis of spiro[3-arylcyclohexanone]oxindole derivatives. The method can tolerate a diverse substrate scope with high yields.

}, doi = {10.1039/d3ra07652k}, author = {Patil, Baliram R. and Nichinde, Chandrakant B. and Chaudhari, Suryakant S. and Krishna, Gamidi Rama and Kinage, Anil K.} } @article {49688, title = {Conjugate addition/cyclization of propanal with isatylidene malononitriles: an efficient one-pot organocatalytic approach for the synthesis of 3'-methyl spiro[2H-pyran-3,4'-indoline]}, journal = {Organic \& Biomolecular Chemistry}, volume = {23}, year = {2025}, month = {JUN}, pages = {6214-6219}, type = {Article}, abstract = {

The organocatalyzed one-pot Michael addition reaction of propanal to isatylidene malononitriles remains largely unexplored due to challenges in controlling the reaction and preventing side processes such as aldol condensation, self-aldolization, and 1,3-dipolar cycloaddition. In this study, we introduce a one-pot methodology for the synthesis of 3 {\textquoteleft}-alkyl spiro[2H-pyran-3,4 {\textquoteleft}-indoline] via an organocatalyzed Michael addition of simple propanal to isatylidene malononitrile derivatives, which are generated in situ from isatin derivatives and malononitrile. Subsequent reduction of the Michael adduct with NaBH4 leads to the target product with high efficiency under mild conditions. This strategy offers several advantages, including environmental sustainability, high to excellent yields, shorter reaction times, cost-effectiveness, and ease of implementation.

}, issn = {1477-0520}, doi = {10.1039/d5ob00553a}, author = {Patil, Baliram R. and Nichinde, Chandrakant B. and Girase, Amardipsing S. and Chaudhari, Suryakant S. and Kinage, Anil K.} } @article {49505, title = {Efficient synthesis of 3,3'-Spirooxindole γ-Butyrolactone via Rongalite-mediated domino reductive aldol and spiro-lactonization reactions}, journal = {ChemistrySelect}, volume = {10}, year = {2025}, month = {FEB}, pages = {e202405996}, type = {Article}, abstract = {

In this study, we develop a novel methodology involving rongalite-mediated domino reductive/aldol reaction, followed by spiro-lactonization of 2-oxoindolin-3-ylidene acetates/malonates in presence of base to synthesis of 3,3 {\textquoteleft}-spirooxindole gamma-butyrolactone. The detail study, such as effect of solvent, effect of different base and substrate has been carried out. Scale up of this methodology is also done. Sodium hydroxymethanesulfinate dihydrate (rongalite) concurrently has a dual role in this context; it acts as a reducing agent as well as C1 synthon. This approach offers several advantages, such as being metal- and catalyst-free, involving a simple reaction protocol, having a wide substrate scope, using water as a green solvent, and providing good to excellent yields of the products under mild reaction conditions.

}, keywords = {(+/-) Coixspirolactam A \& [3, 3 {\textquoteleft}-spirooxindole gamma-butyrolactone], Domino reductive/aldol/spiro-lactonization, Good step economy, Rongalite as reductant \& C1 synthon, Water as a green solvent}, issn = {2365-6549}, doi = {10.1002/slct.202405996}, author = {Chaudhari, Suryakant S. and Nichinde, Chandrakant B. and Patil, Baliram R. and Girase, Amardipsing S. and Kinage, Anil K.} } @article {49536, title = {Sequential nitro-michael addition and reductive cyclization cascade reaction for diastereoselective synthesis of multifunctionalized 3,3'-pyrrolidinyl-spirooxindoles}, journal = {European Journal of Organic Chemistry}, volume = {28}, year = {2025}, month = {FEB}, type = {Article}, abstract = {

In this investigation, we elucidated, one-pot two stage efficient synthesis of multifuctionalized spiro[oxindole -3,3 {\textquoteleft}-pyrrolidine]. The methodology proceeds via organocatalyzed nitro-Michael addition reaction between indolylidenecyanoesters and nitroalkanes to formed nitro-Michael adduct which transformed into multifunctionalized 3,3 {\textquoteleft}-pyrrolidinyl-spirooxindoles by metal catalyzed reductive cyclization cascade. DFT investigations were conducted to elucidate the mechanism underlying the preferential reduction of the nitro group, with subsequent attack on the nitrile and ester groups remain inert throughout the reaction process. The approach is operationally simple, easily scalable, exhibits compatibility with readily accessible starting material and catalysts, thereby emphasizing cost-effectiveness.

}, keywords = {3 {\textquoteleft}-pyrrolidinyl spirooxindoles, DFT study for regioselective cyclization, Diastereoselective 3, organocatalysis, Pd/C catalysed partial reductive spirocyclization}, issn = {1434-193X}, doi = {10.1002/ejoc.202401121}, author = {Nichinde, Chandrakant B. and Bhati, Meema and Girase, Amardipsing S. and Patil, Baliram R. and Chaudhari, Suryakant S. and Gamidi, Rama Krishna and Joshi, Kavita and Kinage, Anil K.} }