Synthetic and Theoretical Studies on the Reduction of Electron Withdrawing Group Conjugated Olefins Using the Hantzsch 1,4-Dihydropyridine Ester
摘要:
The Hantzsch 1,4-dihydropyridine ester (1) has been observed to be a useful selective reducing agent for the reduction of electron-withdrawing conjugated double bonds. The rate of this reaction was observed to be dependent upon the nature of the conjugated substituents and, consequently, the electronic nature of the unsaturated double bond. Theoretical calculations confirmed the importance of the HOMO-LUMO gap for this reaction and implicated a hydride transfer, agreeing with the experimentally observed reaction rate order. The calculations also revealed the importance of a boatlike structure of the 1,4-dihydropyridine nucleus as well as a trans arrangement of the ester groups to facilitate the hydride transfer.
materials toward more complex oxindole-based structures. These molecules can be prepared by the reduction of a 3-ylidene oxindole precursor by classical metal-catalysed chemical reductions of the olefin. In this work we present a biocatalytic approach for the reduction of oxindole-based olefins using baker'syeast. All the substrates were efficiently reduced in high yields. When an α,β-unsaturated ketone
A one-pot, three-component reaction of an isatin and kojic acid with an active methylene compound such as
ethyl cyanoacetate, methyl cyanoacetate and malononitrile in methanol using catalytic amount of DABCO to give 2'-
amino-6'-(hydroxymethyl)-8'H-spiro[indoline-3,4'-pyrano[3,2-b]pyran]-2,8'-diones in good to excellent yields under
reflux conditions, is described.
Synthesis of Novel Spiro Cyclic 2-Oxindole Derivatives of 6-Amino-4H-Pyridazine via [3+3] Atom Combination Utilizing Chitosan as a Catalyst
作者:Ismail Abdelhamid
DOI:10.1055/s-0028-1087558
日期:2009.3
Azaenamines were reacted with 3-cyanomethylidene-2-oxindoles using chitosan catalyst to yield spirocyclic 2-oxindole derivatives of 6-amino-4H-pyridazine and fused pyridazinoquinazolines.
DBU-Catalyzed, facile and efficient method for synthesis of spirocyclic 2-oxindole derivatives with incorporated 6-amino-4H-pyridazines and fused derivatives via [3+3] atom combination
作者:Ismail A. Abdelhamid、Mona H. Mohamed、Amr M. Abdelmoniem、Said A.S. Ghozlan
DOI:10.1016/j.tet.2009.09.081
日期:2009.11
3-Cyanomethylidene oxindole derivatives were prepared in excellent yields utilizing DBU-promoted Knoevenagelcondensation of isatin derivatives with active methylene reagents. The isolated products were then reacted with azaenamines via a DBU-promoted Michael addition to yield spirocyclic 2-oxindole derivatives with incorporated 6-amino-4H-pyridazines and their fused derivatives.
SYNTHESIS OF NEW FUSED AND SPIRO HETEROCYCLES DERIVED FROM 4-AMINO-5-MERCAPTO-3-TRIFLUOROMETHYL-1,2,4-TRIAZOLE
作者:A. M. El-sayed、A. Khodairy
DOI:10.1080/10426509808036972
日期:1998.1.1
Abstract Some new heterocyclic systems 2-9 were obtained through the reaction of 4-amino-5-mercapto-3-trifluoromethyl-1,2,4-triazole (1) with ylidenemalononitriles, 1,3-diketones, halonitriles, active nitriles, aromatic aldehydes or ketones. Also spiro systems 10-12 were achieved in one pot synthesis by addition of compound 1 to isatine, cycloalkanones or ylidenenitriles followed by cyclization. The