One-Pot Synthesis of 4-Aminoquinazolines by Hexamethyldisilazane-Mediated Reaction of Quinazolin-4(3H)-ones with Amines

Hexamethyldisilazane-mediated reaction of quinazolin-4(3H)-ones with primary amines led to facile formation of 4-aminoquinazolines through tandem silylation and substitution in a single pot. Excellent yields of the products (83–97%) and environmental friendliness (avoiding the use of chlorination reagents) are the advantages of this method.      

Facile and Efficient Oxidation of Quinazolines into Quinazolin-4(3H)-ones by Peracetic Acid

A new approach to synthesize quinazoline-4(3H)-ones was achieved by oxidation of quinazolines using peracetic acid, which possesses some advantages of economic reagents, simplified operation, high efficiency, and environmental friendliness. Application of this method allowed us to synthesize a series of quinazolin-4(3H)-ones with different substituents at 6 and 7 positions in good to excellent yields, including the key intermediates of tyrosine kinase inhibitors such as PD153035, Erlotinib, and Gefitinib.

[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 and Antimicrobial Activity of Novel Quinoxaline Derivatives

In this study, certain 3‐substituted styrylquinoxalin‐2(1H)‐ones ( 2a‐d ) and their 2‐chloro ( 3a‐d ) and 2‐piperazinyl derivatives ( 4a‐g ) were synthesized from 3‐methylquinoxalin‐2(1H)‐one ( 1 ). In addition, a series of 1‐alkyl‐3‐substituted styrylquinoxalin‐2(1H)‐ones ( 5a‐d ) was also prepared. Moreover, 3‐(N²‐arylidenehydrazinocarbonyl)quinoxalin‐2(1H)‐ones ( 8a‐c ) as well as their cyclized oxadiazolinyl derivatives ( 9a‐c ) were prepared from 3‐hydrazinocarbonylquinoxalin‐2(1H)‐one ( 7 ). Furthermore, 3‐(5‐substituted thio‐1,3,4‐oxadiazol‐2‐yl)quinoxalin‐2(1H)‐ones ( 11a‐c ) and ( 12a‐c ) were obtained from the intermediate compound ( 10 ) ‐ previously obtained via cyclization of ( 7 ) with CS₂. Likewise, 3‐(5‐oxo‐4,5‐dihydro‐(1,3,4‐oxadiazol‐2‐yl)quinoxalin‐2(1H)‐one ( 13 ), 3‐[5‐(4‐nitrophenyl)‐1,3,4‐oxadiazol‐2‐yl]‐quinoxalin‐2(1H)‐one ( 14 ) and its 2‐chloro derivative ( 15 ) were prepared from 3‐hydrazinocarbonylquinoxalin‐2(1H)‐one ( 7 ). Some of these derivatives were evaluated for antimicrobial activity in vitro and some of the tested compounds showed antibacterial or antifungal activity.     

4(3H)-喹唑啉酮类Schiff碱的合成与抗烟草花叶病毒活性

采用邻氨基苯甲酸经醋酐酰化闭环得2-甲基苯并噁嗪-4-酮, 水合肼回流合成2-甲基-3-氨基-4(3H)-喹唑啉酮, 在无水乙醇中与芳醛反应得4(3H)-喹唑啉酮类Schiff碱. 经元素分析, IR, 1H NMR, 13C NMR对所合成的化合物进行了结构确认和表征. 初步生物活性测试表明, 化合物3t具有较高的抗烟草花叶病毒活性.     

Synthesis and Anti-HIV-1 Activity of 2-[2-(3,5-Dimethylphenoxy)ethylthio]pyrimidin-4(3H)-ones

New 2-[2-(3,5-dimethylphenoxy)ethyl]thio derivatives of pyrimidin-4(3H)-one containing various substituents at positions 5 and 6 of the pyrimidine ring were synthesized. It was shown that alkylation of 2-thiouracils with 1-bromo-2-(3,5-dimethylphenoxy)ethane in DMF takes place exclusively at the sulfur atom. The obtained 6-benzyl and 6-(2,6-difluorobenzyl) derivatives have clearly defined virus-inhibiting properties with respect to type 1 human immunodeficiency virus in vitro and suppress its reproduction by 50% at concentrations of 1.3 and 11.2 mM respectively.     

Push-Pull Structures Based on 2-Aryl/thienyl Substituted Quinazolin-4(3H)-ones and 4-Cyanoquinazolines

Design and synthesis of 2-(aryl/thiophen-2-yl)quinazolin-4(3H)-ones and 4-cyano-2-arylquinazolines with Et₂N-, Ph₂N- or carbazol-9-yl- electron donating fragment are described. The key photophysical properties of these compounds have been studied by UV/Vis absorption and fluorescence spectroscopy in solvents of different polarity (toluene and MeCN). 2-(Aryl/thiophen-2-yl)quinazolin-4(3H)-ones show fluorescence in blue-green region in toluene solution with quantum yields up to 89% in the case of 2-(4’-N,N-diphenylamino[1,1’-biphenyl]-4-yl)-quinazolin-4(3H)-one. Moreover, triphenylamino derivative based on quinazolin-4(3H)-one with para-phenylene linker displays the highest quantum yield of 40% in powder. The fluorescence QY of Et₂N and Ph₂N derivatives decrease when going from toluene to MeCN solution, whereas carbazol-9-yl counterparts demonstrate strengthening of intensity that emphasizes the strong influence of donor fragment nature on photophysical properties. 4-Cyanoquinazolines are less emissive in both solvents, as well as, in solid state. The introduction of cyano group into position 4 leads to orange/red colored powder and dual emission bands. Some molecules demonstrate the increase in emission intensity upon addition of water to MeCN solution. According to frontier molecular orbitals (HOMO, LUMO) calculations, the energy gap of 4-cyanoquinazoline decreases by more than 1 eV compared to quinazolin-4-one, that is consistent with experimental data.     

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。     

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.     

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 Some Quinazoline‐2(1H),4(3H)‐dione Derivatives

Several quinazoline‐2(1H),4(3H)‐dione derivatives were synthesized from pyrimidine‐2(1H),4(3H)‐dione derivative.     

Synthesis of a Novel Series of 2,3‐Disubstituted Quinazolin‐4(3H)‐ones as a Product of a Nucleophilic Attack at C(2) of the Corresponding 4H‐3,1‐Benzoxazin‐4‐one

A new series of 2,3‐disubstituted quinazolin‐4(3H)‐one derivatives was synthesized by nucleophilic attack at C(2) of the corresponding key starting material 2‐propyl‐4H‐3,1‐benzoxazin‐4‐one (Scheme 2). The reaction proceeded via amidinium salt formation (Scheme 3) rather than via an N‐acylanthranilimide. The structure of the prepared compounds were elucidated by physical and spectral data like FT‐IR, ¹H‐NMR, and mass spectroscopy.     

Zirconyl(IV) Chloride Catalyzed Three Component One-pot Synthesis of Quinazolin-4(3H)-ones

Summary. An efficient one-pot method for synthesis of an array of quinazolin-4(3H)-ones from anthranilic acid, triethyl orthoformate, and amines using ZrOCl₂ is described. This method offers improvements for the synthesis of quinazolin-4(3H)-ones with regard to short reaction time, yield of products, and simplicity in operation.     

Synthesis and Antifungal Activity of Novel Quinazolin-4(3H)-one Derivatives

A novel group of 6-iodoquinazolin-4(3H)-one derivatives was prepared starting from 6-iodo-2-ethoxy-4H-3,1-benzoxazin-4-one (3) via action of various nitrogen nucleophiles such as primary and secondary amines, hydrazine hydrate, and its derivatives. The 3-amino-2-hydrazinyl-6-iodoquinazolin-4(3H)-one (15) was used as a key starting material to prepare new heterocyclic compounds. The structures of all synthesized compounds were inferred from the infrared, mass spectral, and ¹H NMR spectral data as well as elemental analysis. The fungicidal activities of the target compounds were preliminarily evaluated.     

超声辐射下水介质中一锅合成3-甲基-4-芳亚甲基-异噁唑-5(4H)-酮

报道了室温超声辐射下, 水相中通过乙酰乙酸甲酯、盐酸羟胺和芳香醛的三组分一锅反应, 合成了一系列3-甲基-4-芳亚甲基-异噁唑-5(4H)-酮衍生物. 在超声波辐射下, 参与反应的醛无论芳环上连有吸电子基或供电子基, 该一锅反应在室温下都能较好地进行; 对于α,β-不饱和醛、杂环芳醛以及二元芳醛与乙酰乙酸甲酯、盐酸羟胺的一锅反应也能在室温下顺利进行, 获得中等以上的收率. 产物的结构通过元素分析, IR, 1H NMR及单晶解析表征. 该方法具有操作简单和环境友好等优点.     

新型2-氨基-呋喃并[2,3-d]嘧啶-4(3H)-酮衍生物的合成及抗肿瘤活性

报道应用aza-Wittig反应,采用易得的原料,在温和的条件下,以78%～90%的产率有效的合成了新型2-氨基-呋喃并[3,2-d]嘧啶-4(3H)-酮衍生物5,其结构经IR,1H NMR,MS和元素分析确认.为进一步得到结构确认,化合物5c经X射线衍射分析证实.运用噻唑蓝(MTT)标准法对化合物5进行了体外抗肿瘤活性的测定,其中5f对肺癌细胞A459的IC50值为18.4μmol/L,显示出潜在良好的抗肿瘤活性.     

4-(N-乙酰氨基)-3-(4-芳基噻唑-2-氨基)苯甲酸乙酯的合成与生物活性

以3-氨基-4-乙酰氨基苯甲酸乙酯为原料设计合成了18种4-(N-乙酰氨基)-3-(4-芳基噻唑-2-基)-苯甲酸乙酯新化合物.化合物结构经质谱,元素分析,1H NMR和13C NMR确证.生物活性实验结果表明,化合物3d,3h,3p(40μg/mL)对神经氨酸酶(NA)的抑制率分别为36.02%,33.40%,42.05%;化合物3g,3h(500mg/L)对纹枯病菌的抑制率为50%.     

3-苯基喹唑啉-4(3H)-酮的合成及晶体结构

标题化合物C14H10ON2是由邻硝基苯甲酰苯胺与原甲酸三乙酯在低价钛试剂作用下反应而得。结构通过单晶X-射线衍射分析确定, 其晶体属于单斜晶系, 空间群P21/c, a = 12.080(2), b = 7.793(1), c = 11.599(1) ? b = 97.56(1), Mr = 222.24, V = 1082.4(2) ?, Dc = 1.364 g/cm3, Z = 4, m(MoKa) = 0.88 mm-1, F(000) = 464, R = 0.0385, wR = 0.0851。X-衍射分析表明: 平面I (C(1)~C(6))与平面II (C(9)~C(14))之间的夹角为124.38; 平面I与平面III (ON(1)?N(2)C(7)C(8)C(9)C(14))之间的两面角为125.47; 平面II与平面III之间的两面角为2.76。     

Synthesis and anti-inflammatory activity of 2,3-diaryl-4(3H)-quinazolinones

2,3-Diaryl-4(3H)-quinazolinones containing various substituents on diaryl rings have been synthesized and evaluated for their cyclooxygenase-2 inhibitory activity by the colorimetric COX (ovine) inhibitor screening assay and anti-inflammatory activity by the carrageenan-induced rat paw edema assay. 2-(4-Nitrophenyl)-3-(4-tolyl)-4(3H)-quinazolinone showed a maximum COX-2 inhibition of 27.72% at 22 μM concentration in the present series and exhibited a mild anti-inflammatory activity at a dose of 50 mg/kg in carrageenan-induced rat paw edema assay. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1198–1205, August, 2006.     

Synthesis and Antimicrobial Studies of Novel Billogical Heterocycles

The synthetic route of sildenafil promoted us to synthesize new object molecules. New analogues containing a 4-thiazolidinone ring bonded to the phenyl moiety at the 2-position, 7-(substituted anilino)-6-fluoro-2-(p-meth- oxy-m-{[2-(p-hydroxyphenyl)-4-oxo-1,3-thiazolidin-3-yl]aminocarbonyl}phenylsulfonamido)benzothiazoles (4a—4l) have been synthesized by cyclization with thioglycollic acid of Schiff bases 3a—3l from corresponding 7-(substituted anilino)-6-fluoro-2-(p-methoxy-m-hydrazinocarbonyl phenylsulfonamido)benzothiazoles (2a—2l). Compounds 2a—2l in turn were prepared by dehydroxyhalogenation followed by condensation with hydrazine hydrates of acids 1a—1l. Compounds 1a—1l in turn were prepared by chlorosulfonation of o-methoxy benzoic acid followed by condensation with 6-fluoro-7-(substituted anilino)-2-aminobenzothiazoles. Final compounds have been characterized by their elemental analysis, IR, NMR and mass spectra. All the synthesized compounds have been screened for their antimicrobial activities. Some of them showed good activities.