- Diethylamine: A smart organocatalyst in eco-safe and diastereoselective synthesis of medicinally privileged 2-amino-4H-chromenes at ambient temperature
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Diethylamine has been demonstrated to be an efficient organocatalyst in the diastereoselective synthesis of Bcl-2 protein antagonist (HA-14-1) and of its structural analogues by one-pot condensation between salicylaldehyde and three different C-H acids, viz. ethyl cyanoacetate, phenylsulfonyl acetonitrile, and malononitrile. Easy commercial availability of the catalyst at extremely low cost and avoidance of conventional work-up as well as purification procedures qualifies this scalable protocol for a "near-ideal synthesis".
- Kulkarni, Makarand A.,Pandit, Kapil S.,Desai, Uday V.,Lad, Uday P.,Wadgaonkar, Prakash P.
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- An efficient condensation of substituted salicylaldehyde and malononitrile catalyzed by lipase under microwave irradiation
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The present work illustrates the condensation of substituted salicylaldehyde and malononitrile catalyzed by lipase under microwave irradiation. The reaction obtains two different products by a delicate control of the substrate molar ratio and reaction time. This protocol has the advantages of high yield, short reaction time and environmental friendliness.
- Yang, Fengjuan,Wang, Zhi,Wang, Haoran,Wang, Chunyu,Wang, Lei
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- Visible light induced, catalyst free, convenient synthesis of chromene nucleus and its derivatives using water-ethanol mixture as a solvent
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A highly efficient, green, eco-friendly, one pot protocol has been demonstrated for the synthesis of 2-imino-2H-chromene-3-carbonitrile (3), 2-aminochromene (4) and chromeno(2,3-b)pyridines (5). The synthesis of the chromene nucleus has been carried out under visible light irradiation in a water-ethanol mixture at room temperature using salicylaldehyde and malononitrile in different proportions. The adopted method shows significant advantages such as mild and clean reaction conditions, eco-friendly procedures, absence of catalysts and a short reaction time. This protocol involves the use of CFL as the visible light source and shows high selectivity in the presence of a mixture of ethanol and water. The reaction proceeds with good to excellent yield.
- Yadav, Snehlata,Srivastava, Madhulika,Rai, Pratibha,Singh, Jaya,Tiwari, Kamla Prasad,Singh, Jagdamba
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- Synthesis of 4H-chromene-isoxazole hybrids via ortho-hydroxy directing cyclization of isoxazole-styrenes and Michael addition of imino-chromenes in aqueous medium
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A green, efficient, and one-pot method synthesis of functionalized 4H-chromene-isoxazole hybrids is reported via o-hydroxy group directing cyclization of isoxazole-styrenes and Michael addition of 3,5-dimethyl-4-nitroisoxazole on 2-imino-2H-chromene-3-carbonitrile (independent methods). The developed methodology was further extended for nitromethane, malononitrile, and alkylcyanoacetates as Michael donors.
- Nagaraju, Sakkani,Sathish, Kota,Kashinath, Dhurke
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supporting information
p. 1252 - 1258
(2021/03/06)
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- Catalyst-free cascade synthesis of densely functionalized chromenes in water
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An expeditious and environmental friendly, general protocol has been developed for the synthesis of 2-amino-3-cyano-4H-chromenes via cascade Knoevenagel-Michael-intramolecular cyclization in water. Pure solid products were obtained by simple filtration technique. The aqueous catalyst-free reactions lead to high product yield at room temperature.
- Bhat, Subrahmanya Ishwar
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p. 2532 - 2536
(2019/10/02)
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- Aegle marmelos in heterocyclization: Greener, highly efficient, one-pot three-component protocol for the synthesis of highly functionalized 4 H -benzochromenes and 4 H -chromenes
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A facile, one-pot three-component protocol for the synthesis of 2-amino-4H-chromene derivatives has been demonstrated using Bael Fruit Extract (BFE) as a natural catalyst in a green reaction medium. This method offers a mild, efficient and highly economic
- Shinde, Sachin,Damate, Shashikant,Morbale, Smita,Patil, Megha,Patil, Suresh S.
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p. 7315 - 7328
(2017/02/05)
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- Synthesis of 2-amino-3-cyano-4H-chromen-4-ylphosphonates and 2-amino-4H-chromenes catalyzed by tetramethylguanidine
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Synthesis of 2-amino-4H-chromen-4-ylphosphonates and 2-amino-4H-chromenes has been accomplished by the reaction of salicylaldehyde, malononitrile, dialkyl/diphenylphosphites catalyzed by 1,1,3,3-tetramethylguanidine (TMG) under neat conditions at room tem
- Kalla, Reddi Mohan Naidu,Byeon, Seong Jin,Heo, Min Seon,Kim, Il
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p. 10544 - 10551
(2013/11/19)
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- Solvent-free cascade assembling of salicylic aldehydes and malononitrile: Rapid and efficient approach to 2-amino-4H-chromene scaffold
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Solvent-free NaOAc- or KF-catalyzed assembling of salicylic aldehydes with two molecules of malononitrile affords (2-amino-3-cyano- 4H-chromen-4-yl) malononitriles in 94-99% yields within 10 min.
- Elinson, Michail N.,Medvedev, Michael G.,Ilovaisky, Alexey I.,Merkulova, Valentina M.,Zaimovskaya, Tatiana A.,Nikishin, Gennady I.
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- One-pot synthesis of 4H-chromene and dihydropyrano[3, 2-c]chromene derivatives in hydroalcoholic media
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4ff-Chromenes and dihydropyrano[3, 2-c]chromenes are obtained in good to excellent yields by a simple, mild and efficient procedure using poly(N, N'-dibromo-N-ethyl-benzene-1, 3-disulfonamide) [PBBS] and N, N, N, N,-tetrabromobenzene-1, 3-disulfonamide [T
- Ghorbani-Vaghei, Ramin,Toghraei-Semiromi, Zahra,Karimi-Nami, Rahman
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experimental part
p. 905 - 909
(2012/01/06)
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