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以含不同取代基的杂环醛和乙酰丙酮为原料,经三步反应合成了一系列新型的4-甲基-3-乙酰基-2-杂环-2H,3H-苯并[f]-1,5-硫氮杂衍生物3a~3l,产物的结构经1H NMR,IR,MS和元素分析确证,且通过1H NMR测试,发现目标化合物存在着烯胺型和亚胺型结构的互变.测定了目标化合物的抑菌活性,抑菌结果为杂类化合物的结构与抑菌的关系提供了启示.同时,确定了目标化合物3h发生分解反应时主要副产物的结构,提出了其可能的生成机理. 相似文献
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以CuBr为催化剂,1,4,7-三氮杂环壬烷衍生物为配体,K2CO3为碱,110 ℃下通过取代的邻碘代酚和取代的环氧化物的串联反应制备了2,3-二氢-1,4-苯并二噁烷类化合物。各种芳香取代的环氧化物和脂肪取代的环氧化物均能顺利的与邻碘代酚反应,产物收率64%~83%。讨论了底物取代基与产物收率的关系,推测了反应机理。并用NMR和元素分析确定了产物结构。 相似文献
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我们已报道了1-对甲苯磺酰基-2-苯氧基-3-芳基-4-苯基-1,4,2-二氮磷酰杂环戊-5-酮的合成及除草活性[1],为了进一步探讨3-位取代基的变化对这类1,4,2-二氮磷酰杂环戊-5-酮的除草活性的影响,按如下方法合成了相应的3-位烷基取代的1-对甲苯磺酰基-4-苯基-1,4-二氮-2-磷酰杂环戊-5-酮(2),并对脂肪醛与1及亚磷酸酯的酸催化反应机理进行了初步探讨.用元素分析、NMR、MS证实了化合物2的结构.初步除草活性测定结果表明,2具有一定的除草活性;其除草活性比相应的3-位芳基取代类化合物的低[1].R:2a,H;2b,Me;2c,Et;2d,n-Pr… 相似文献
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3-苯基-4-氯-1,3,4-二氮磷杂环戊-2-硫酮的合成及其除草活性研究 总被引:1,自引:0,他引:1
报道了苯基硫脲与脂肪醛(酮)及三氯化磷进行的类Mannich反应,除生成预期产物3-苯基-4-氯-4-氧代-1,3,4-二氮磷杂环戊-2-硫酮(Ⅰ)外,还生成了少量3-苯基-4-氯-4-硫代-1,3,4-二氮磷杂环戊-2-硫酮(Ⅱ).当Ⅰ与Lawesson试剂在甲苯中反应时,可顺利地转化为Ⅱ.生物测定结果表明,Ⅱ具有较好的选择性除草活性.晶体结构测定表明,Ⅱ的五元磷杂环为平面结构. 相似文献
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Regioselective C3 Alkenylation of 4 H‐pyrido[1,2‐a]pyrimidin‐4‐ones via Palladium‐Catalyzed CH Activation 下载免费PDF全文
Dr. Wenjie Liu Dr. Shaohua Wang Qi Zhang Jingwen Yu Jiahe Li Zhiwei Xie Prof. Hua Cao 《化学:亚洲杂志》2014,9(9):2436-2439
A general and efficient palladium‐catalyzed direct C3 alkenylation of 4H‐pyrido[1,2‐a]pyrimidin‐4‐ones using AgOAc/O2 as the oxidant has been developed. A variety of 4H‐pyrido[1,2‐a]pyrimidin‐4‐ones were successfully coupled with acrylate esters, styrenes, methylvinylketone, and acrylamide in moderate to excellent yields. The reaction exhibited complete regio‐ and stereoselectivity. This transformation provides an attractive new approach to functionalize 4H‐pyrido[1,2‐a]pyrimidin‐4‐ones. 相似文献
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In the presence of N, N′‐dicyclohexylcarbodiimide, 2‐aminopyridine and its derivatives (2) condensed with 2, 2‐di‐hydropolyfluoroalkanoic adds (1) to give the corresponding amides. Subsequent intramolecular Micheal addition‐elimination reactions of the fluorine‐containing amides under basic conditions gave 4‐fluoroalkyl‐2H‐pyrido[1,2‐a]pyrimidin‐2‐ones (3) in good yields. 相似文献
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[DBU‐H]+ and H2o as effective catalyst form for 2,3‐dihydropyrido[2,3‐d]pyrimidin‐4(1H)‐ones: A DFT Study 下载免费PDF全文
DFT investigations are carried out to explore the effective catalyst forms of DBU and H2O and the mechanism for the formation of 2,3‐dihydropyrido[2,3‐d]‐pyrimidin‐4(1H)‐ones. Three main pathways are disclosed under unassisted, water‐catalyzed, DBU and water cocatalyzed conditions, which involves concerted nucleophilic addition and H‐transfer, concerted intramolecular cyclization and H‐transfer, and Dimroth rearrangement to form the product. The results indicated that the DBU and water cocatalyzed pathway is the most favored one as compared to the rest two pathways. The water donates one H to DBU and accepts H from 2‐amino‐nicotinonitrile ( 1 ), forming [DBU‐H]+‐H2O as effective catalyst form in the proton migration transition state rather than [DBU‐H]+‐OH?. The hydrogen bond between [DBU‐H]+···H2O··· 1 ? decreases the activation barrier of the rate‐determining step. Our calculated results open a new insight for the green catalyst model of DBU‐H2O. © 2015 Wiley Periodicals, Inc. 相似文献
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A series of new 2‐substituted 3‐(4‐chlorophenyl)‐5,8,9‐trimethylthieno[3′,2′: 5,6]pyrido[4,3‐d]pyrimidin‐4(3H)‐ones 8 were synthesized via an aza‐Wittig reaction. Phosphoranylideneamino derivatives 6a or 6b reacted with 4‐chlorophenyl isocyanate to give carbodiimide derivatives 7a or 7b , respectively, which were further treated with amines or phenols to give compounds 8 in the presence of a catalytic amount of EtONa or K2CO3. The structure of 2‐(4‐chlorophenoxy)‐3‐(4‐chlorophenyl)‐5,8,9‐trimethylthieno[3′,2′: 5,6]pyrido[4,3‐d]pyrimidin‐4(3H)‐one ( 8j ) was comfirmed by X‐ray analysis. 相似文献
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HClO4‐SiO2, efficiently catalyzed the condensation of o‐aminophenols and 2‐bromo‐1‐aryl‐ethanones to yield 3‐aryl‐2H‐benzo[1,4]oxazines in good yields. 相似文献
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《Journal of mass spectrometry : JMS》2017,52(6):367-371
N‐methylimidazolidin‐4‐one organocatalysts were studied in the gas phase. Protonated and sodium‐cationized (sodiated) molecules are conveniently accessible by electrospray mass spectrometry. Protonation enables three different closed‐shell paths of ring cleavage leading to iminium ions. The fragmentation pattern is largely unaffected by exocyclic substituents and thus is valuable to characterize the substance type as N‐methylimidazolidin‐4‐ones. Sodiated species show a distinctly different fragmentation that is less useful for characterization purposes: apart from signal loss due to dissociation of Na+, the observation of benzyl radical loss is by far predominant. Only in absence of a benzyl substituent, an analogue of the third ring cleavage (loss of [C2H5NO]) is observed. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
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I. Forfar J. Guillon S. Massip J.‐M. Lger C. Jarry J.‐P. Fayet 《Journal of heterocyclic chemistry》2001,38(4):823-827
The isomeric 2‐substituted‐7(5)‐methyl‐2,3‐dihydro‐5(7)H‐oxazolo[3,2‐a]pyrimidin‐5‐ones 3a‐b and 7‐ones 2a‐b,7a were synthesized by cyclocondensation from the 5‐substituted‐2‐amino‐2‐oxazolines 1a‐b with biselectrophiles. In boiling ethanol, the reaction of 1a‐b with acetylenic esters led to a mixture of 2a‐b,7a with a small amount of (E)‐2‐N‐(2‐ethoxycarbonylethylene)‐5‐substituted‐2‐iminooxazolines 5a‐b . The ring annulation between 1a‐b and diketene gave the 2‐substituted‐7‐hydroxy‐7‐methyl‐2,3,6,7‐tetrahydro‐5H‐oxazolo[3,2‐ a ]pyrimidin‐5‐ones 4a‐b which can be easily dehydrated to provide the 2‐substituted‐7‐methyl‐2,3‐dihydro‐5H‐oxazolo[3,2‐a]pyrimidin‐5‐ones 3a‐b . 相似文献
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Tandem aza‐Wittig reaction of iminophosphorane with 1, 4‐phenylene diisocyanate followed by intramolecular heteroconjugate addition annulation after addition of a nucleophilic reagent (amine, phenol, and alcohol), in the presence of catalytic K2CO3 or NaOR, gives selectively the functionalized substituted 2, 2′‐di(alkylamino, aryloxy)‐3, 3′‐(1, 4‐phenylene)bis(thieno[3, 2‐d]pyrimidin‐4(3H)‐ones) and 2, 2′‐di(alkylamino or alkoxy)‐3, 3′‐(1, 4‐phenylene)bis(3, 5, 6, 7‐tetrahydro‐4H‐cyclopenta[4, 5]thieno[2, 3‐d]pyrimidin‐4‐ones). 相似文献
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2,3‐Dihydro‐4H‐thiopyrano[2,3‐b]pyridin‐4‐ones 4 were prepared by a three‐step sequence from commercially available 2‐chloropyridine ( 1 ). Thus, successive treatment of 1 with iPr2NLi (LDA) and α,β‐unsaturated aldehydes gave 1‐(2‐chloropyridin‐3‐yl)alk‐2‐en‐1‐ols 2 , which were oxidized with MnO2 to 1‐(2‐chloropyridin‐3‐yl)alk‐2‐en‐1‐ones 3 . The reactions of 3 with NaSH?n H2O proceeded smoothly at 0° in DMF to provide the desired thiopyranopyridinones. Similarly, 2,3‐dihydro‐4H‐thiopyrano[2,3‐c]pyridin‐4‐ones 8 and 2,3‐dihydro‐4H‐thiopyrano[3,2‐c]pyridin‐4‐ones 12 were obtained starting from 3‐chloropyridine ( 5 ) and 4‐chloropyridine ( 9 ), respectively. 相似文献
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The [3,3′(4H,4′H)‐bi‐2H‐1,3‐oxazine]‐4,4′‐diones 3a – 3i were obtained by [2+4] cycloaddition reactions of furan‐2,3‐diones 1a – 1c with aromatic aldazines 2a – 2d (Scheme 1). So, new derivatives of bi‐2H‐1,3‐oxazines and their hydrolysis products, 3,5‐diaryl‐1H‐pyrazoles 4a – 4c (Scheme 3), which are potential biologically active compounds, were synthesized for the first time. 相似文献