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Journal ArticleDOI

Solvent‐free synthesis of 5‐methyl‐7‐aryl‐4,7‐dihydrotetrazolo[1,5‐a]pyrimidine‐6‐carboxylic esters catalyzed by sulfamic acid

01 Nov 2008-Journal of Heterocyclic Chemistry (Wiley)-Vol. 45, Iss: 6, pp 1609-1613
TL;DR: In this article, the solvent-free synthesis of 5-methyl-7-aryl-4,7-dihydrotetrazolo[1,5-a]pyrimidine-6-carboxylic esters was performed and effectively catalyzed by sulfamic acid.
About: This article is published in Journal of Heterocyclic Chemistry.The article was published on 2008-11-01. It has received 38 citations till now. The article focuses on the topics: Sulfamic acid & Aryl.
Citations
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Journal ArticleDOI
TL;DR: Most of the published methods for the synthesis of 1,5-DSTs include the use of nitriles, amides, thioamides, imidoyl chlorides, heterocumulenes, isocyanate, isothiocyanates, carbodiimides, ketenimines, ketones, amines, and alkenes as the starting materials.
Abstract: This report provides a brief overview of the various representative literature procedures for the synthesis of 1,5-disubstituted tetrazoles (1,5-DSTs) and fused 1,5-disubstituted tetrazoles with more than 120 references. Most of the published methods for the synthesis of 1,5-DSTs include the use of nitriles, amides, thioamides, imidoyl chlorides, heterocumulenes, isocyanates, isothiocyanates, carbodiimides, ketenimines, ketones, amines, and alkenes as the starting materials. The transformation of 1- and 5-substituted tetrazoles into 1,5-DSTs is also covered in this report.

102 citations

Journal ArticleDOI
TL;DR: Versatile and novel reactions of 5-aminotetrazole with structurally diverse aryl aldehydes and building blocks with active methylene catalyzed by iodine were investigated in a multicomponent one-pot protocol.
Abstract: Versatile and novel reactions of 5-aminotetrazole with structurally diverse aryl aldehydes and building blocks with active methylene catalyzed by iodine were investigated in a multicomponent one-pot protocol. A series of 5,7-diaryl-4,7-dihydrotetrazolo[1,5-a]pyrimidines C and 5-methyl-7-aryl-4,7-dihydrotetrazolo[1,5-a]pyrimidine-6-carboxylates D were obtained in moderate to good yields. Further exploration rapidly afforded various E in good to excellent yields; in addition, compound F was also obtained under the same condition. The structures of products were characterized by LC-MS, 1H NMR, 13C NMR, and elemental analysis.

87 citations

Journal ArticleDOI
TL;DR: This is the first design, preparation, characterization and application of the present nanomaterial and also the first ultrasound irradiated synthesis of the biologically and pharmaceutically important heterocyclic compounds in water as a green solvent.

79 citations

Book ChapterDOI
01 Jan 2010
TL;DR: An overview of known multicomponent heterocyclizations using aminoazoles as a key reagent and their rich synthetic potential for obtaining five-, six-, and seven-membered heterocycles is presented in this article.
Abstract: Because of the significant role in biological processes in living cells and the diverse types of physiological activities, heterocyclic compounds are in focus of intense investigations by academic and applied-oriented chemists. Considerably, a scientific renaissance of heterocycles during the last decades is closely related to the development of multicomponent approaches to their synthesis. Multicomponent methodology fundamentally different from two-component or sequential processes together with other innovative synthetic methods like microwave- and ultrasonic- assisted reactions offer some new possibilities in constructing heterocyclic systems with high level of molecular diversity and complexity. An overview of known multicomponent heterocyclizations using aminoazoles as a key reagent and their rich synthetic potential for obtaining five-, six-, and seven-membered heterocycles is presented. A special attention is paid to the tuning of chemo- and regio- and positional selectivity of some reactions as well as to the application of nonclassical activation methods based on microwave and ultrasonic irradiation.

70 citations

Journal ArticleDOI
TL;DR: In this paper, a novel application of highly stable Fe(OTf)3 as an efficient catalyst for carbon-carbon bond formation via the activation of a terminal alkyne C-H bond under solvent-free conditions is described.
Abstract: A novel application of highly stable Fe(OTf)3 as an efficient catalyst for carbon–carbon bond formation via the activation of a terminal alkyne C–H bond under solvent-free conditions is described. Notably, this protocol of green synthesis, which produced quinolines from the reaction of amines, aldehydes and terminal aryl alkynes, shows attractive characteristics including concise one-pot conditions, high atom economy, very limited energy consumption, and the sequential catalytic process requires only a catalytic (5 mol%) amount of Fe(OTf)3 with short reaction periods (3 h). Meanwhile, the catalyst was easily recovered from the reaction system and reused smoothly with only a little loss of activity.

62 citations

References
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Journal ArticleDOI

1,104 citations

Journal ArticleDOI
Kappe Co1
TL;DR: This Account highlights recent developments in the Biginelli reaction in areas such as solid-phase synthesis, combinatorial chemistry, and natural product synthesis.
Abstract: In 1893, P. Biginelli reported the synthesis of functionalized 3, 4-dihydropyrimidin-2(1H)-ones (DHPMs) via three-component condensation reaction of an aromatic aldehyde, urea, and ethyl acetoacetate. In the past decade, this long-neglected multicomponent reaction has experienced a remarkable revival, mainly due to the interesting pharmacological properties associated with this dihydropyrimidine scaffold. In this Account, we highlight recent developments in the Biginelli reaction in areas such as solid-phase synthesis, combinatorial chemistry, and natural product synthesis.

971 citations

Journal ArticleDOI
TL;DR: Crambines A (7) (eight steps, 22%). B (45d) (8 steps, 19%), C1 (98) (seven steps, 21%), and C2 (9a) (7 steps, 27%) have been synthesized expediently and stereospecifically by a biomimetic route from methyl acetoacetate as mentioned in this paper.
Abstract: Crambines A (7) (eight steps, 22%). B (45d) (eight steps, 19%), C1 (98) (seven steps, 21%), and C2 (9a) (seven steps, 27%) have been synthesized expediently and stereospecifically by a biomimetic route from methyl acetoacetate. Aminodihydropyrimidines 39 and 40 are formed efficiently from enone ester 36 by a two-step procedure involving addition of O-methylisourea to give methoxydihydropyrimidine 37 followed by displacement of the methoxy group of 37 with ammonia. Hydrogenolysis of 40a and 40d afford crambines C2 and C1, respectively. Mesylation of the alcohol of 39a or 40a followed by Et 3 N-catalyzed cyclization and hydrogenolysis affords crambine A (7)

210 citations

Journal ArticleDOI
TL;DR: It is proposed that S-monastrol binding to Eg5 induces a stable conformational change in the motor domain that favors ATP re-synthesis after ATP hydrolysis, thereby yielding a nonproductive Mt·Eg5 complex that cannot establish or maintain the bipolar spindle.

154 citations