2-Methylthio-4,5,6,7-tetrahydro-1,2,4-triazolo[1,5-<Emphasis Type="Italic">a</Emphasis>]pyrimidin-5- and -7-Ones

The cyclocondensation of methylcinnamates and arylidene derivatives of Meldrums acid with 3-amino-5-methylthio-1,2,4-triazole in DMF gives 2-methylthio-4,5,6,7-tetrahydro-1,2,4-triazolo[1,5-a]-pyrimidin-5-ones. The reaction involving arylidene derivatives of Meldrums acid or its synthetic equivalents in ethyl acetate with a catalytic amount of pyridine gives a mixture of 2-methylthio-4,5,6,7-tetrahydro-1,2,4-triazolo[1,5-a]pyrimidin-5- and -7-ones.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 246–251, February, 2005.     

On triazoles XIX: The reaction of 5-amino-1,2,4-triazoles with functionalized acetoacetic esters

Summary Different functionalized alkyl 3-oxo-butyrates (2) were reacted with 5-amino-3-Q-1H-1,2,4-triazoles (1) to yield3 and4 type 1,2,4-triazolo[1,5-a]pyrimidinones. In case of2 (R ¹=methyl,R ²=1-ethoxycarbonylethyl,R ³=ethyl) beside the corresponding derivative4 the unexpected 5,6-dihydro-6,8-dimethyl-7-ethoxycarbonyl-3-methylthio-1,2,4-triazolo[4,3-a]-1,3-diazepin-5(9H)-one (7) was isolated, representing a novel ring system.

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Über Triazole, 19. Mitt.: Die Reaktion von 5-Amino-1,2,4-triazolen mit funktionalisierten Acetoessigestern

Zusammenfassung Verschiedene funktionalisierte 3-Oxo-buttersäurealkylester (2) wurden mit 5-Amino-3-Q-1H-1,2,4-triazolen (1) umgesetzt, wobei 1,2,4-Triazolo[1,5-a]pyrimidinone der Typen3 und4 erhalten wurden. Im Fall von2 (R ¹=Methyl,R ²=1-Ethoxycarbonylethyl,R ³=Ethyl) wurde neben dem erwarteten Derivat4 das unerwartete 5,6-Dihydro-6,8-dimethyl-7-ethoxycarbonyl-3-me-thylthio-1,2,4-triazolo[4,3-a]-1,3-diazepin-5(9H)-on (7) isoliert, welches ein neues Ringsystem darstellt.

     

Application of cyclic-1,3-diketones in domino and multicomponent reactions: facile route to highly functionalized chromeno[2,3-d]pyrimidinones and diazabenzo[b]fluorenones under solvent-free conditions

A facile and efficient protocol for the synthesis of chromeno[2,3-d]pyrimidinones and diazabenzo[b]fluorenones has been developed by one-pot three-component cyclocondensation of aldehydes, cyclic-1,3-diketones and 1,3-dimethylbarbituric acid in the presence of InCl₃ or P₂O₅ under solvent-free conditions.     

活性炭负载硫酸催化合成环戊并[d]嘧啶酮和六氢喹唑啉酮

制备了一种活性炭负载硫酸催化剂(H2SO4/AC),利用傅里叶变换红外光谱仪(FT-IR)和X射线衍射仪(XRD)表征了其形貌.在该催化剂作用下,以芳醛、尿素、环戊酮(环己酮)为原料,在无溶剂条件下经三组分一锅法反应合成了系列环戊并[d]嘧啶酮(六氢喹唑啉酮).该方法用于合成此两类化合物操作简单,对环境友好,具有良好的...     

Comparative reactivity of N′-(5-benzoyl/ethoxycarbonyl)thiazol-2-yl-N,N-dimethylformamidines with ketenes

The comparative account of the reactivities of N′-[(5-benzoyl and ethoxycarbonyl)thiazol-2-yl]-N,N-dimethylformamidines (1a and 1b), tremendously influenced by the electronic nature of the substituents on C-5 of the thiazolic ring with various monosubstituted and conjugated ketenes is reported herein. The DA cycloadditions of the dienyl pyrimidinone 3h with both symmetrical as well as unsymmetrical dienophiles leading to the formation of various thiazolic pyrimidinone derivatives are also reported.     

Synthesis,Antibacterial, and Antifungal Activities of Imidazo[2,1-c][1,2,4]triazoles and 1,2,4-Triazolo[4,3-a]pyrimidinones

A straightforward method has been developed for the synthesis of 1-phenyl-imidazo [2,1-c][1,2,4]triazole derivatives 5a–j and 1-phenyl-[1,2,4]triazolo[4,3-a]pyrimidinones derivatives 6a–g starting from 5-amino-1-phenyl[1,2,4]triazole and p-toluenesulfonic acid (PTSA). This methodology affords a number of 1-phenyl-imidazo [2,1-c][1,2,4]triazoles 5a–j and 1-phenyl-[1,2,4]triazolo[4,3-a]pyrimidinones 6a–g in reasonable yields and short reaction times. The structures of all new compounds were elucidated using infrared, ¹H and ¹³C NMR, and high-resolution mass spectrometry. Some of the newly synthesized compounds were screened for their antimicrobial activity.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications ^® for the following free supplemental resource(s): Full experimental and spectral details.]     

Synthesis of Tetrahydro‐2(1H)quinazolinones,Cyclopenta[d]‐2(1H)pyrimidinones,and Their Thioxo Analogs from 2‐Trifluoroacetyl‐1‐methoxycycloalkenes

A series of six (8)‐alkyl‐4‐trifluoromethyl‐5,6,7,8‐tetrahydro‐2(1H)quinazolinones, 4‐trifluoromethyl‐cyclopenta[d]‐2(1H)pyrimidinones, and their thioxo analogs from the reaction of five β‐alkoxyvinyl trifluoromethyl ketones, derived from alkylated cyclohexanones and cyclopentanone with urea and thiourea, is reported. The reactions were carried out in a single step in propan‐2‐ol as solvent and boron trifluoride diethyl etherate as catalyst in 18–65% yield.     

Cyclizations of Alkenyl(Alkynyl)-Functionalized Quinazolinones and their Heteroanalogues: A Powerful Strategy for the Construction of Polyheterocyclic Structures

Quinazolin-4-one, its heteroanalogues, and derivatives represent an outstandingly important class of compounds in modern organic, medicinal, and pharmaceutical chemistry, as these molecular structures are noted for their wide synthetic and pharmacological potential. In the last years, ever-increasing research attention has been paid to quinazolinone derivatives bearing alkenyl and alkynyl substituents on the pyrimidinone nucleus. The original structural combination of synthetically powerful endocyclic amidine (or amidine-related) and exocyclic unsaturated moieties provides a driving force for cyclizations, which offer an efficient toolkit to construct a variety of fused pyrimidine systems with saturated N- and N,S-heterocycles. In this connection, the present review article is mainly aimed at systematic coverage of the progress in using alkenyl(alkynyl)quinazolinones and their heteroanalogues as convenient bifunctional substrates for regioselective annulation of small- and medium-sized heterocyclic nuclei. Much attention is paid to elucidating the structural and electronic effects of reagents on the regio- and stereoselectivity of the cyclizations as well as to clarifying the relevant reaction mechanisms.     

Rapid and mild synthesis of quinazolinones and chromeno[d]pyrimidinones using nanocrystalline copper(I) iodide under solvent-free conditions

This paper describes a very simple, efficient synthesis of quinazolinones and chromeno[d]pyrimidinones from the reaction of aryl aldehydes, urea/thiourea and active methylene compounds(dimedone/4-hydroxycoumarin) using nano-sized CuI particles under solvent-free conditions. The highlights of this new method are based on using an effective and recyclable catalyst, affording high yields of products, mild reaction conditions, facile work-up and purification.     

Acetylenic chemistry,part 20: Ring opening of 3-azaisatoic anhydride with acetylenic amines: Synthesis of pyrido[2,3-d]pyrimidinones

Summary Ring opening of 3-azaisatoic anhydride with acetylenic amine gave the nicotinamides3 a–c. The reaction of triphosgene with the nicotinamides3 a–c yielded the pyrido[2,3-d]pyrimidinones4a,5b,5c, and7b.

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Acetylenchemie, 20. Mitt.: Ringöffnung von 3-Azaisatosäureanhydrid mit Acetylenaminen: Synthese von Pyrido[2,3-d]pyrimidinonen

Zusammenfassung Bei Ringöffnung von 3-Azaisatosäureanhydrid mit Acetylenaminen entstehen die Nicotinamide3 a–c. Die Reaktion von Triphosgen mit den Nicotinamiden3 a–c führt zu den Pyrido[2,3-d]pyrimidinonen4a,5b,5c und7b.