D,L‐Proline‐Catalyzed One‐Pot Synthesis of Pyrans and Pyrano[2,3‐c]pyrazole Derivatives by a Grinding Method under Solvent‐Free Conditions

Abstract D,L‐Proline was found to efficiently catalyze the one‐pot condensation of aromatic aldehydes, malononitrile, and dimedone (1,3‐cyclohexanedione or 3‐methyl‐1‐phenyl‐2‐pyrazolin‐5‐one) 2‐Amino‐3‐cycano‐4‐aryl‐7,7‐dimethyl‐5,6,7,8‐tetrahydrobenzo[b]pyrans and 6‐amino‐5‐cyano‐4‐aryl‐1,4‐dihydropyrano[2,3‐c]pyrazoles were synthesized by a grinding method under solvent‐free conditions. The reaction proceeded cleanly at room temperature to afford the products in good yields.

[1]  L. Gong,et al.  l-Proline amide-catalyzed direct asymmetric aldol reaction of aldehydes with chloroacetone , 2006 .

[2]  V. Choudhary,et al.  A green process for chlorine-free benzaldehyde from the solvent-free oxidation of benzyl alcohol with molecular oxygen over a supported nano-size gold catalyst , 2005 .

[3]  M. Potdar,et al.  An ionic liquid influenced l-proline catalysed asymmetric Michael addition of ketones to nitrostyrene , 2005 .

[4]  J. Yadav,et al.  A d,l-proline catalyzed diastereoselective trimolecular condensation: an approach to the one-pot synthesis of perhydrofuro[3,2-b]pyran-5-ones , 2005 .

[5]  P. Bhuyan,et al.  Sodium Bromide Catalyzed One-Pot Synthesis of Tetrahydrobenzo[b]pyrans via a Three-Component Cyclocondensation under Microwave Irradiation and Solvent-Free Conditions. , 2005 .

[6]  Tong‐Shuang Li,et al.  A Clean and Simple Synthesis of 6‐Amino‐4‐Aryl‐5‐Cyano‐3‐Methyl‐1‐Phenyl‐1,4‐Dihydropyrano[2,3‐c]Pyrazole in Water , 2005 .

[7]  Wenzhi Yang,et al.  Solvent‐Free Synthesis of Ethyl α‐Cyanocinnamates Catalyzed by K2O–Al2O3 Using Grinding Method , 2004 .

[8]  D. Shi,et al.  One-pot synthesis of 2-amino-4-aryl-5-oxo-5,6,7,8-tetrahydro-4H-1-benzopyran-3-carbonitriles in aqueous media , 2004 .

[9]  P. Bhuyan,et al.  Sodium bromide catalysed one-pot synthesis of tetrahydrobenzo[b]pyrans via a three-component cyclocondensation under microwave irradiation and solvent free conditions , 2004 .

[10]  Tong‐Shuang Li,et al.  A Clean One-pot Synthesis of Tetrahydrobenzo(b)pyran Derivatives Catalyzed by Hexadecyltrimethyl Ammonium Bromide in Aqueous Media , 2004 .

[11]  D. Shi,et al.  Three‐Component One‐Pot Synthesis of 1,4‐Dihydropyrano[2,3‐c]pyrazole Derivatives in Aqueous Media , 2004 .

[12]  Ji-tai Li,et al.  One‐Pot Synthesis of 2‐Amino‐4‐aryl‐3‐carbalkoxy‐7,7‐dimethyl‐5,6,7,8‐tetrahydrobenzo[b]pyran Derivatives Catalyzed by KF/Basic Al2O3 Under Ultrasound Irradiation , 2004 .

[13]  Ji-tai Li,et al.  Synthesis of α,α,-Bis(Substitutedbenzylidene) Cycloalkanones by a Grinding Method † , 2003 .

[14]  G. Kaupp,et al.  Solvent-free Knoevenagel condensations and Michael additions in the solid state and in the melt with quantitative yield , 2003 .

[15]  D. Shi,et al.  A Convenient Synthesis of 5-Oxo-5,6,7,8-tetrahydro-4 H -benzo-[b]-pyran Derivatives Catalyzed by KF-Alumina , 2003 .

[16]  B. List.  Proline-catalyzed asymmetric reactions , 2002 .

[17]  S. Tu,et al.  A FACILE ONE POT SYNTHESIS OF PYRANO[2,3-c]PYRAZOLE DERIVATIVES UNDER MICROWAVE IRRADIATION , 2002 .

[18]  D. Shi,et al.  A CONVENIENT SYNTHESIS OF 2-AMINO-5,6,7,8-TETRAHYDRO-5-OXO- 4-ARYL-7,7-DIMETHYL-4H-BENZO-[b]-PYRAN-3-CARBONITRILE UNDER MICROWAVE IRRADIATION , 2002 .

[19]  N. Deka,et al.  Microwave mediated solvent-free acetylation of deactivated and hindered phenols , 2001 .

[20]  S. Srinivasula,et al.  Structure-based discovery of an organic compound that binds Bcl-2 protein and induces apoptosis of tumor cells. , 2000, Proceedings of the National Academy of Sciences of the United States of America.

[21]  K. Tanaka,et al.  Solvent-free organic synthesis. , 2000, Chemical reviews.

[22]  Kamaljit Singh,et al.  A synthetic entry into fused pyran derivatives through carbon transfer reactions of 1,3-oxazinanes and oxazolidines with carbon nucleophiles , 1996 .

[23]  R. Sheldon.  Selective catalytic synthesis of fine chemicals: opportunities and trends , 1996 .

[24]  N. Martín,et al.  Development of methods for the synthesis of chiral, highly functionalized 2-amino-4-aryl-4H-pyrans , 1994 .

[25]  N. Martín,et al.  Michael Addition of Malononitrile to α‐Acetylcinnamamides , 1993 .

[26]  S. Agathos,et al.  Enhancement of cyclosporin production in a Tolypocladium inflatum strain after epichlorohydrin treatment. , 1990, Journal of biotechnology.

[27]  N. Martín,et al.  Synthesis of cyclobutenes by the novel photochemical ring contraction of 4-substituted 2-amino-3,5-dicyano-6-phenyl-4H-pyrans , 1989 .

[28]  S. Hatakeyama,et al.  A new route to substituted 3-methoxycarbonyldihydropyrans; enantioselective synthesis of (–)-methyl elenolate , 1988 .