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Journal ArticleDOI

A Simple, Efficient and Green Procedure for the Knoevenagel Condensation of Aldehydes with N-Methylpiperazine at Room Temperature under Solvent-Free Conditions

18 Aug 2008-Synthetic Communications (Taylor & Francis Group)-Vol. 38, Iss: 13, pp 2103-2112
TL;DR: In this article, Knoevenagel condensation of aromatic, aliphatic, and heteroaromatic aldehydes with active methylene compounds such as ethylcyanoacetate, malononitrile, and cyanoacetamide proceed very smoothly at room temperature by simply mixing the ingredients together under solvent-free conditions.
About: This article is published in Synthetic Communications.The article was published on 2008-08-18. It has received 35 citations till now. The article focuses on the topics: Knoevenagel condensation & Malononitrile.
Citations
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Journal ArticleDOI
TL;DR: A mild, elegant, catalyst free, and waste free methodology has been developed for the clear-cut synthesis of a diverse range of nitriles, acrylates, and acrylamides in good to excellent yields using aqueous propan-1,2-diol, a green reaction medium, at ambient temperature as discussed by the authors.

3 citations

Journal ArticleDOI
TL;DR: In this paper, aryl methylene and 1-arylethylidenemalonodinitriles using 1,8-diazabicyclo[5.4.0] undec-7-ene (DBU) as a novel and highly efficient catalyst under conventional as well as microwave conditions.
Abstract: 3,5-disubstituted-2,6-dicyanoaniline derivatives have been synthesized via the reaction of aryl methylene- and 1-arylethylidenemalonodinitriles using 1,8-diazabicyclo[5.4.0] undec-7-ene (DBU) as a novel and highly efficient catalyst under conventional as well as microwave conditions. Use of non-hazardous, inexpensive and readily available base catalyst, convenient procedure, short reaction time and improved product yields are some added advantages of the present protocol.

3 citations


Cites methods from "A Simple, Efficient and Green Proce..."

  • ...with malononitrile as reported in the literature [20]....

    [...]

Journal ArticleDOI
TL;DR: The moisture and air stable ionic liquids 1-butyl-3-methylimidazonium tetrafluoroborate [bmim]BF4 and 1butyl 3methyloridazium hexafluorophosphate [BMim]PF6 were used as "green" recyclable alternatives to volatile organic solvents (VOCs) for ethylenediammonium diacetate (EDDA) catalyzed Knoevenagel condensation between aldehydes or ketones with active methylene compounds RE
Abstract: The moisture and air stable ionic liquids 1-butyl-3-methylimidazonium tetrafluoroborate [bmim]BF4 and 1-butyl-3-methylimidazonium hexafluorophosphate [bmim]PF6 were used as ‘green' recyclable alternatives to volatile organic solvents (VOCs) for ethylenediammonium diacetate (EDDA) catalyzed Knoevenagel condensation between aldehydes or ketones with active methylene compounds. Both aldehydes and ketones gave satisfactory results. The ionic liquids containing catalyst EDDA were recycled several times with no decreases in yields and reaction rates. In the case of 2-hydroxybenzaldehyde, the reactions led to the formation of 3-substituted coumarins under standard reaction conditions.

3 citations

Journal ArticleDOI
01 Mar 2016
TL;DR: In this article, a rapid and efficient synthesis of 3,5-diaryl-2,6-dicyanoanilines by cyclocondensation of arylidenemalonodinitriles with 1-arylethylidenem-alonodinstriles in the presence of KF/alumina as catalyst under solvent-free neat conditions using microwaves as an energy source is described.
Abstract: A rapid and efficient synthesis of 3,5-diaryl-2,6-dicyanoanilines by cyclocondensation of arylidenemalonodinitriles with 1-arylethylidenemalonodinitriles in the presence of KF/alumina as catalyst under solvent-free neat conditions using microwaves as an energy source is described.

2 citations


Cites methods from "A Simple, Efficient and Green Proce..."

  • ...The key intermediates arylidene- and 1-arylethylidenemalonodinitriles were prepared via Knoevenagel reaction of the corresponding aldehyde or ketone with malononitrile [43–45]....

    [...]

Dissertation
06 Feb 2015
TL;DR: This thesis describes two major approaches that have been investigated to synthesize ICL DNA and describes approaches to prepare a 7-deaza-2’-deoxyguanosine cross-linked dimer where the C7 atoms are attached by an alkylene linker.
Abstract: Cellular DNA is susceptible to damage by chemical agents that causes modifications which includes interstrand cross-links (ICL). ICLs covalently attach the complementary DNA strands, and interfere with replication and transcription by preventing strand separation. The deliberate formation of ICL in DNA by bi-functional alkylating chemotherapeutic agents leads to the death of cancer cells. Development of tumors resistant to these agents is a factor in the lack of response in some patients, with removal of ICL believed to play a role in resistance. In mammalian cells, the precise role of excision repair in eliminating ICL is not completely understood. For better understanding of the repair pathways involved in removing ICL damage, ICL DNA duplexes containing well-defined modified moieties are required to mimic the lesions induced by chemotherapeutic agents. This thesis describes two major approaches that have been investigated to synthesize ICL DNA. The first describes a method to prepare DNA duplexes containing cross-linked N3-butylene-N3 thymidines that enables the preparation of asymmetric nucleotide sequences around cross-linked sites. Protective groups for the 3’- and 5’-hydroxyl moieties were screened for compatibility of subsequent extensions from a cross-linked thymidine dimer incorporated in a support bound oligonucleotide by automated DNA synthesis. Two cross-linked dimer phosphoramidites were prepared, one with dimethoxytrityl (DMT) and allyloxycarbonyl (Alloc) protective groups at 5’-O positions and a 3’-O-t-butyldimethylsilyl (TBS) group which enabled the production of completely asymmetric ICL DNA duplexes in good yields. After coupling of the cross-linked phosphoramidite to a linear strand assembled on the solid support, the DMT group was cleaved on the synthesizer to allow for the synthesis of the second arm of the duplex. The Alloc group was then removed via an off-column strategy to expose the 5'-hydroxyl group to complete assembly of one strand of the duplex to form a "Y-shaped" intermediate. Final removal of a 3'-O-TBS group off column followed by coupling with deoxynucleoside 5'-phosphoramidites yielded ICL DNA duplexes containing completely asymmetric nucleotide composition around the cross-link site. The identity and composition of the ICL duplexes were confirmed by mass spectrometry (ESI-TOF) and enzymatic digestion. The synthesized ICL duplexes displayed characteristic features of a B-form duplex and had stabilities that were higher than those of the unmodified controls assessed by circular dichroism (CD) spectroscopy and UV thermal denaturation experiments. The second major project describes approaches to prepare a 7-deaza-2’-deoxyguanosine cross-linked dimer where the C7 atoms are attached by an alkylene linker. The chemical instability of alkylated N7 2’-deoxyguanosine (dG) represents a major challenge for preparing ICL DNA containing an alkylene linkage between the N7 atoms. The incorporation of a C7-alkylene cross-linked dimer of 7-deaza-2’-deoxyguanosine in DNA would allow for the preparation of a chemically stable ICL which mimic lesions formed by bifunctional alkylating agents (i.e. mechlorethamine and hepsulfam). Two synthetic methods were explored to prepare 7-deazaguanine (and other 7-deazapurines). These involved two cyclization strategies to prepare these molecules starting from a pyrimidine or a pyrrole to produce the purine. In both synthetic methods it was challenging to purify some of the intermediates. All intermediates in the synthetic method starting from the pyrimidine precursors to produce the 7-deazapurines were more stable while the production of the 7-deazapuines from the pyrroles resulted in higher yields. An attempt to produce a C7 cross-linked dimer of 7-deaza-2’-deoxyguanosine containing a heptamethylene linker is described. Starting from 7-deazaguanine, 7-iodo-7-deaza-2’-deoxyguanosine was prepared in good yield. This nucleoside was converted to 5’-O-DMT-7-iodo-7-deaza-2’-deoxyguanosine and the Sonogashira reaction used with 1,6-heptadiyne to introduce the heptamethylene linker. Unfortunately, multiple challenges were encountered with the dimerization and hydrogenation reactions which did not allow for the synthesis of the desired dimer for solid-phase synthesis of the ICL DNA.

2 citations


Cites methods from "A Simple, Efficient and Green Proce..."

  • ...for 16 h.[555-566] The product was extracted with EtOAc from aqueous solution, and then concentrated under high vacuum....

    [...]

References
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Journal ArticleDOI
TL;DR: This paper presents a new approach to solvent-free organic synthesis called “Solvent-free synthesis with real-time stoichiometry” that combines high-performance liquid chromatography and high-tech electronics.
Abstract: Solvent-free organic synthesis , Solvent-free organic synthesis , کتابخانه دیجیتال جندی شاپور اهواز

1,004 citations

Book
01 Jan 2003
TL;DR: In this paper, the authors proposed a Solvent Free Organic Synthesis (SOS) method for organic synthesis, which is a state-of-the-art method for solvent-free organic synthesis.
Abstract: Solvent-free organic synthesis , Solvent-free organic synthesis , کتابخانه دیجیتال جندی شاپور اهواز

828 citations

Journal ArticleDOI
TL;DR: In this article, the knoevenagel condensation of carbonyl substrates with acidic methylene reagents proceeds smoothly in presence of zinc chloride, without the need for solvent, to produce products of good purity in high yield.

268 citations

Journal Article
TL;DR: In this article, the authors proposed a methodology for condensation of aliphatic aldehyde with diethyl malonate, which is not very easy to achieve by conventional reagents, and was not addressed adequately in literature.
Abstract: The basic ionic liquid 1-butyl-3-methylimidazolium hydroxide, [bmIm]OH, efficiently catalyzes Knoevenagel condensation without requirement of any organic solvent. A wide range of aliphatic and aromatic aldehydes and ketones easily undergo condensations with diethyl malonate, malononitrile, ethyl cyanoacetate, malonic acid and ethyl acetoacetate. The reactions proceed at room temperature and are very fast (10-30 min). However, the most significant feature of this methodology is the condensation of aliphatic aldehyde with diethyl malonate, which is not very easy to achieve by conventional reagents, and was not addressed adequately in literature providing a general and convenient procedure.

204 citations