Ionic Liquid Promoted Eco-friendly and Efficient Synthesis of 2,3-Dihydroquinazolin-4(1<Emphasis Type="Italic">H</Emphasis>)-ones

Summary. 2,3-Dihydroquinazolin-4(1H)-ones were efficiently synthesised by the reaction of isatoic anhydride, a primary amine or ammonium acetate, and different aromatic aldehydes in 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF₄) without using any acidic catalyst. Also a bis-derivative of the title compound as a polyheterocyclic system was synthesised successfully in high yield.     

One-pot, Simple, and Convenient Synthesis of 2-Thioxo-2,3-dihydroquinazolin-4(1 H )-ones

A simple and convenient method for the synthesis of diverse 2-thioxo-2,3-dihydroquinazolin-4(1H)-ones was developed as one-pot reaction of anthranilic acid esters, primary amines, and bis(benzotriazolyl)methanethione in presence of the amidine base DBU.     

低价钛促进的1,2-二氢喹唑啉-4(3H)-酮的合成

喹唑啉-4(3H)-酮是一类生物碱,取代喹唑啉-4(3H)-酮具有广泛的药理学活性．因而对其合成方法和合成新型喹唑啉-4(3H)-酮的衍生物的研究已成为热点．低价钛试剂是一种还原偶联试剂,它能引起醛酮的还原偶联生成烯烃,还能引起其它官能团的还原偶联反应,该反应已应用于天然产物和一些碳环化合物的合成,而用于杂环化合物的合成研究报道较少．本文报道低价钛试剂(TiCl4-Zn体系)促进的1,2-二氢喹唑啉-4(3H)-酮的合成。     

One-step Synthesis of 3,4-Dihydrobenzimidazo[2,1- b ]quinazolin-1(2 H )-ones in an Ionic Liquid

A novel class of 3,4-dihydrobenzimidazo[2,1-b]quinazolin-1(2H)-ones was synthesized in very short reaction times with good yields in the presence of 3-butyl-1-methyl imidazolium bromide as a room temperature ionic liquid at 120°C. The ionic liquid can be recycled for subsequent reactions without any loss of efficiency.     

Ionic liquid promoted synthesis of 3-(2′-benzothiazolo)-2,3-dihydroquinazolin-4(1H)-ones

3-(2′-Benzothiazolo)-2,3-dihydroquinazolin-4(1H)-ones have been synthesized in high yields in the presence of 1-butyl-3-methylimidazolium bromide [bmim]Br as an ionic liquid; the reaction work-up is simple and the ionic liquid can be easily separated from the product and reused.     

Zeolite-Catalyzed Method for the Preparation of 2,3-Dihydroquinazolin-4(1H)-ones

The reaction of isatoic anhydride, amines, and aldehydes in the presence of a microporous zeolite gave 2,3-dihydroquinazolin-4(1H)-one derivatives with good to excellent yield. The yield depends on the structure of the aldehyde and/or amine compound.     

Urea/Thiourea as Ammonia Surrogate: A Catalyst-Free Synthesis of 2-Substituted 2,3-Dihydroquinazolin-4(1H)-ones/Quinazoline-4(3H)-ones

Urea/thiourea have been identified as an effective ammonia surrogate in the construction of quinazolin-4(3H)-one ring. This strategy afforded a simple and catalyst-free synthesis of 2-substituted 2,3-dihydroquinazolin-4(1H)-ones and quinazolin-4(3H)-ones via the reaction of isatoic anhydride and aryl aldehydes in the presence of urea or thiourea in ethanol. The reaction proceeded well to afford the quinazolin-4(3H)-one or its dihydro derivative, depending on the nature of carbonyl compounds employed.     

Synthesis of 2,3-dihydroquinazolin-4(1H)-ones catalyzed by zirconium (IV) chloride as a mild and efficient catalyst

2, 3-Dihydroquinazolin-4 (1H)-ones have been synthesized in the high to excellent yields via condensation of 2-aminobenzamide with aldehydes and ketones in the presence of catalytic amount of ZrCl₄ in EtOH at room temperature. Mild reaction conditions, clean reaction media, simple workup and easy purification are advantages of this methodology.     

Carboxamides of Dihydropyridin-2(1 H)-ones

3-Carboxamides and 3-carboxanilides of 6-alkyl and 6-aryldihydropyridin-2(1H)-ones have been prepared via different reaction pathways. All synthesized amides show hydrogen bonds in their NMR spectra. The 4-hydroxy compounds were obtained as a mixture of tautomers. Their configurations were elucidated by NMR experiments.     

Synthesis of 2,3-Dihydroquinazoline-4(1H)-ones

An efficient, inexpensive, and heterogeneous catalyst, [Al(H₂PO₄)₃], was applied in a three-component, one-pot cyclocondensation reaction of isatoic anhydride with primary amines (or ammonium salts) and aldehydes to afford the corresponding quinazolinone derivatives in excellent yields. Reactions occurred under thermal solvent-free conditions. It was found that this solid acidic catalyst could be easily recovered and reused for at least three cycles without any loss of activity.     

Ionic Liquid Promoted Efficient Three-Component Synthesis of 2-Thioxo-2H-Thiopyrans

Abstract

An efficient one-pot three-component method for the synthesis of a variety of 2-thioxo-2H-thiopyrans has been described. Fairly good yields are obtained by cyclization reactions of arylidenemalononitriles, derived in situ from ketones and malononitrile, with carbon disulfide in the presence of a base in the ionic liquid 1-butyl-3-methylimidazolium bromide as reaction medium.

[Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental resource: Selected Data.]

GRAPHICAL ABSTRACT      

高温水中2,3-二氢喹唑啉-4(1H)-酮衍生物的合成反应研究

为发展绿色化学,减少化学反应中有毒害溶剂的使用,本文以高温水为溶剂,在未使用任何有机溶剂及催化剂的条件下,以2-氨基苯甲酰胺与醛为底物,成功合成了2,3-二氢喹唑啉-4(1H)-酮衍生物。研究了反应温度、反应时间及芳环上取代基对反应的影响。在摩尔比1∶1、温度为130℃、反应时间1h的优化条件下,收率为32. 4%～85. 7%。     

2-芳基-2,3-二氢4(1H)-喹唑啉酮类化合物的合成

在NaHSO4催化下,以苯甲醛和邻氨基苯甲酰胺为底物,在室温下合成了一系列2-芳基-2,3-二氢-4(1H)-喹唑啉酮类化合物,该反应产率高、操作简单、并且避免使用有毒的金属催化剂.     

Convenient and Scalable Synthesis of 2,3-Dihydroquinazolin-4(1H)-one Derivatives and Their Anticancer Activities

An efficient and mild InBr₃-catalyzed approach to synthesize 2,3-dihydroquinazolin-4(1H)-one derivatives (3a–3aa) has been developed. Notably, all the products were isolated by recrystallization and the reaction is accessible on a gram scale. Moreover, the reactions only require 10–60 min. All the synthesized compounds were evaluated for their in vitro anticancer activity against four human cancer cell lines.     

Efficient one-pot synthesis of 2,3-dihydroquinazolin-4(1H)-ones from aromatic aldehydes and their one-pot oxidation to quinazolin-4(3H)-ones catalyzed by Bi(NO3)3·5H2O: Investigating the role of the catalyst

An efficient and novel synthesis of 2,3-disubstituted 2,3-dihydroquinazolin-4(1H)-ones via one-pot, three-component reaction of isatoic anhydride, primary amines and aromatic aldehydes catalyzed by Bi(NO₃)₃·5H₂O under solvent-free conditions is described. Oxidation of these 2,3-dihydroquinazolin-4(1H)-ones to their quinazolin-4(3H)-ones was also successfully performed in the presence of Bi(NO₃)₃·5H₂O. This new method has the advantages of convenient manipulation, short reaction times, excellent yields, very easy work-up, and the use of commercially available, low cost and relatively non-toxic catalyst. The role of Bi(NO₃)₃·5H₂O was also investigated in these transformations.     

Synthesis and structure of 2-aryl-4 H -acenaphth[5,6- bc ]oxepin-4-ones

Oxidation of 2-aryl-7,8-dihydro-4H-acenaphth[5,6-bc]oxepin-4-ones with chloranil led to the formation of 2-aryl-4H-acenaphth[5,6-bc]oxepin-4-ones. Their spectral characteristics were analyzed, and a calculation of the molecular structure of model and real compounds was carried out. Original Russian Text ? R.V. Tyurin, A.A. Milov, A.N. Bezuglov, A.N. Antonov, L.G. Minyaeva, V.V. Mezheritskii, 2007, published in Zhurnal Organicheskoi Khimii, 2007, Vol. 43, No. 10, pp. 1474–1478.     

Visible-light-induced three-component reaction of quinoxalin-2(1H)-ones,alkenes and CF3SO2Na leading to 3-trifluoroalkylated quinoxalin-2(1H)-ones

A facile and metal-free visible-light-enabled three-component reaction of quinoxalin-2(1 H)-ones,alkenes and CF₃SO₂Na has been developed under air at room temperature.This photocatalytic tandem reaction using 4 CzIPN as the photocatalyst and air as the green oxidant,provides a mild and environmentally friendly approach to access a series of 3-trifluoroalkylated quinoxalin-2(1 H)-ones.     

Synthesis of 2,3-dihydroquinazolin-4(1H)-ones catalyzed by a-chymotrypsin

We discovered that a-chymotrypsin has a promiscuous ability to catalyze the cyclocondensation of aromatic and aliphatic aldehydes with 2-aminobenzamides to afford the corresponding 2,3-dihydroquinazolin-4(1H)-ones successfully in high yields(90%–98%) under alcohol solvent. The catalytic activity of a-chymotrypsin was evaluated through investigating the temperature, the enzyme loading and the ratio of substrates in the enzyme-catalyzed reactions. The present method proves to be efficient and environmentally friendly in terms of short reaction time, high yield, green catalyst and the clean products obtained without further purification processes.     

2-氨基噻吩并[2,3-d]嘧啶-4(3H)-酮衍生物的合成

丁醛(1)、氰乙酸乙酯、硫磺在三乙胺作用下制得2-氨基-4-乙基噻吩-3-羧酸乙酯(2), 2再与三苯基膦、六氯乙烷及三乙胺反应, 以84%的产率得到膦亚胺3. 应用膦亚胺3与芳基异氰酸酯的氮杂Wittig反应, 生成的碳二亚胺4, 再与仲胺作用得到中间体5, 而后在醇钠的催化下关环制得2-二烷氨基噻吩并[2,3-d]嘧啶-4(3H)-酮衍生物6, 产率为58%～82%.