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Synthesis of N^2-arylaminopyrimidine-5-carbonitrile derivatives via S_NAr amination reaction 被引量:1
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作者 Shahnaz Rostamizadeh Masoomeh Nojavan Reza Aryan 《Chinese Chemical Letters》 SCIE CAS CSCD 2015年第1期152-156,共5页
An efficient and high-yielding synthesis of N~2-arylaminopyrimidine-5-carbonitrile derivatives starting from arylamines and 2-methylthio-pyrimidine-5-carbonitriIe derivatives has been developed in the presence of cesi... An efficient and high-yielding synthesis of N~2-arylaminopyrimidine-5-carbonitrile derivatives starting from arylamines and 2-methylthio-pyrimidine-5-carbonitriIe derivatives has been developed in the presence of cesium carbonate as basic reagent.This new protocol showed high chemical tolerance for a range of functional groups,and only the methylthio substituent on C2 of the pyrimidine ring was replaced with arylamine derivatives under the reaction conditions. 展开更多
关键词 N^2-Arylaminopyrimidine-5-carbonitrilederivatives pyrimidine-5-ca rbonit rile derivatives C-N bond formation SNAr mechanism
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Synthesis and Crystal Structure of Ethyl 3-(4-Chlorophenyl)-3,4-dihydro-6-methyl-4-oxo-2-(pyrrolidin-1-yl)furo[2,3-d]pyrimidine-5-carboxylate 被引量:2
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作者 胡扬根 徐靖 丁明武 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2009年第6期689-692,共4页
The crystal structure of the title compound ethyl 3-(4-chlorophenyl)-3,4-dihydro-6- methyl-4-oxo-2-(pyrrolidin-1-yl)furo[2,3-d]pyrimidine-5-carboxylate (C20H20ClN3O4, Mr= 401.84) has been prepared and determined... The crystal structure of the title compound ethyl 3-(4-chlorophenyl)-3,4-dihydro-6- methyl-4-oxo-2-(pyrrolidin-1-yl)furo[2,3-d]pyrimidine-5-carboxylate (C20H20ClN3O4, Mr= 401.84) has been prepared and determined by single-crystal X-ray diffraction. The crystal is of monoclinic, space group P21/n with a = 20.6215(9), b = 8.5311(4), c = 21.6886(9) A^°, β = 91.607(1)°, V = 3814.0(3)A^°^3, Z = 8, Dc = 1.400 g/cm^3, F(000) = 1680, μ = 0.233 mm^-1, R = 0.0718 and wR = 0.1545 for 6717 observed reflections with I 〉 2σ(I). X-ray diffraction analysis reveals two crystallographically independent molecules in the asymmetric unit. 展开更多
关键词 crystal structure ethyl 3-(4-ehlorophenyl)-3 4-dihydro-6-methyl-4-oxo-2- (pyrrolidin-1-yl)furo[2 3-d]pyrimidine-5-earboxylate aza-Wittig reaction synthesis
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Design,Synthesis,and Biological Evaluation of 5H-Thiazolo[3,2-a]pyrimidine-6-carboxylic Acid Ethyl Ester Derivatives as a Novel Series of Acetylcholinesterase Inhibitors 被引量:1
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作者 ZHI Hui CHEN Lan-mei +4 位作者 ZHANG Lin-lin LIU Si-jie David Chi Cheong WAN LIN Huang-quan HU Chun 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2009年第3期332-337,共6页
Acetylcholinesterase inhibitors are the most frequently prescribed anti-Alzheimer's drugs. A series of 5H-thiazolo[3,2-a]pyrimidine-6-carboxylic acid ethyl ester derivatives as the novel acetylcholinesterase inhibito... Acetylcholinesterase inhibitors are the most frequently prescribed anti-Alzheimer's drugs. A series of 5H-thiazolo[3,2-a]pyrimidine-6-carboxylic acid ethyl ester derivatives as the novel acetylcholinesterase inhibitors was designed based on virtual screening methods. The target compounds were synthesized with Biginelli reaction and Hantzsch-type condensation of dihydropyrimidines with substituted phenacyl chlorides, and were characterized with elemental analysis, IR, MS, ^1H NMR, and ^13C NMR. The biological evaluation against human acetylcholinesterase in vitro indicated all the target compounds show more than 50% inhibition at 10μmol/L by means of the Ellman method. The results provide a starting point for the development of novel drugs to treat Alzheimer's disease and lay the foundation of searching for improved acetylcholinesterase inhibitors with the novel scaffolds. 展开更多
关键词 Acetylcholinesterase inhibitor Docking screening HETEROCYCLE Biological activity 5H-Thiazolo[3 2-a] pyrimidine-6-carboxylic acid ethyl ester derivative
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晶习改变剂对α-CaSO_4·0.5H_2O晶体形貌的作用机理 被引量:5
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作者 唐明亮 沈晓冬 黄金龙 《建筑材料学报》 EI CAS CSCD 北大核心 2014年第2期280-283,308,共5页
在水热法制备α-CaSO4·0.5H2O工艺中,需要加入晶习改变剂来调控α-CaSO4·0.5H2O晶体形貌.根据晶习改变剂对α-CaSO4·0.5H2O晶体端面构造以及晶面结构的影响,探讨了不同晶习改变剂调控α-CaSO4·0.5H2O晶体形貌的作... 在水热法制备α-CaSO4·0.5H2O工艺中,需要加入晶习改变剂来调控α-CaSO4·0.5H2O晶体形貌.根据晶习改变剂对α-CaSO4·0.5H2O晶体端面构造以及晶面结构的影响,探讨了不同晶习改变剂调控α-CaSO4·0.5H2O晶体形貌的作用机理.结果表明:Al 3+和有机酸都能改变α-CaSO4·0.5H2O晶体的生长习性,但是作用方式不同.Al 3+主要作用于α-CaSO4·0.5H2O晶体的{001}面族;有机酸单独存在时其酸根离子则主要吸附于α-CaSO4·0.5H2O晶体的锥面面族;有机酸根离子和Al 3+共同存在时,会形成络合离子,结合在α-CaSO4·0.5H2O晶体的{001}面族. 展开更多
关键词 α-caS04·0 5H20 晶习改变剂 晶体形貌
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基于YOLOv5-CA算法的野生动物目标检测研究 被引量:6
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作者 朱高兴 于瓅 《信息技术与信息化》 2022年第6期32-35,共4页
在YOLOv5s模型的基础上,增加多尺度特征检测层,引入协调注意力机制,采用大目标检测的预训练权重文件,对野生动物的识别检测进行了研究,提出了基于YOLOv5-CA的野生动物目标检测算法。实验结果表明:在自制野生动物数据集上对改进前后的网... 在YOLOv5s模型的基础上,增加多尺度特征检测层,引入协调注意力机制,采用大目标检测的预训练权重文件,对野生动物的识别检测进行了研究,提出了基于YOLOv5-CA的野生动物目标检测算法。实验结果表明:在自制野生动物数据集上对改进前后的网络模型训练对比,YOLOv5s的mAP为91.2%,YOLOv5-CA的mAP为96.8%,优化后的模型YOLOv5-CA的mAP比YOLOv5s提高了5.6%,查准率P、召回率R都有明显提高。由此可见,YOLOv5-CA能够更加精准和有效的对野生动物进行检测,较好的提高了野生动物检测性能。 展开更多
关键词 目标检测 深度学习 野生动物 YOLOv5-ca 协调注意力
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Facile and efficient synthesis of 5,7-disubstituted thiazolo[5,4-d] pyrimidine-4,6(5H,7H)-diones
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作者 Liang Chen Zhan Mei Li +2 位作者 Jie Zhou Hong Rui Song Bai Ling Xu 《Chinese Chemical Letters》 SCIE CAS CSCD 2012年第6期695-698,共4页
A facile and efficient approach was developed to access 5, 7-disubstitued thiazolo[5,4-d]pyrimidine-4, 6(5H, 7H)-diones through condensation of N-substituted 5-amino-4-carbethoxythiazole with structurally diverse is... A facile and efficient approach was developed to access 5, 7-disubstitued thiazolo[5,4-d]pyrimidine-4, 6(5H, 7H)-diones through condensation of N-substituted 5-amino-4-carbethoxythiazole with structurally diverse isocyanates in the presence of sodium hydride. The easy availability of substrates and tolerance of structural diversity in this reaction make it attractive to be used for construction of libraries in drug discovery process. 展开更多
关键词 Thiazolo[5 4-d]pyrimidine-4 6(5H 7H)-dione ISOCYANATE ISOTHIOCYANATE Sodium hydride
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Improved microwave-assisted catalyst-free synthesis of9-aryl-5,9-dihydropyrimido[4,5-d][1,2,4]triazolo[1,5-a]pyrimidine-6,8(4H,7H)-dione derivatives
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作者 Mahnaz Farahi Bahador Karami Zohreh Banaki 《Chinese Chemical Letters》 SCIE CAS CSCD 2015年第9期1065-1067,共3页
Agreen regioselective synthesis of some new and known 9-aryl-5,9-dihydropyrimido[4,5-d][l,2,4]triazolo[1,5-a]pyrimidine-6,8(4H,7H)-diones has been described via the microwave-assisted one-pot reaction of 3-amino-1H-... Agreen regioselective synthesis of some new and known 9-aryl-5,9-dihydropyrimido[4,5-d][l,2,4]triazolo[1,5-a]pyrimidine-6,8(4H,7H)-diones has been described via the microwave-assisted one-pot reaction of 3-amino-1H-1,2,4-triazoles,aromatic aldehydes and barbituric acids under solvent- and catalyst-free conditions.This operationally simple procedure is less laborious and provides a better scope than previously reported procedures. 展开更多
关键词 9-Aryl-5 9-dihydropyrimido[4 5-d] [ 1 2 4]triazolo[1 5-a]pyrimidine- 6 8(4H 7H)-diones Barbituric acids 3-Amino- 1 H- 1 2 4-triazoles Aryl aldehydes Microwave-assisted synthesis
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A novel and efficient synthesis of pyrazolo[3,4-d]pyrimidine derivatives and the study of their anti-bacterial activity 被引量:7
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作者 Shahnaz Rostamizadeh Masoomeh Nojavan +2 位作者 Reza Aryan Hamid Sadeghian Mahdieh Davoodnejad 《Chinese Chemical Letters》 SCIE CAS CSCD 2013年第7期629-632,共4页
In this work 4-amino-6-aryl-2-phenyl pyrimidine-5-carbonitrile derivatives were synthesized through a one-pot, three-component reaction of an aldehyde, malononitrile and benzamidine hydrochloride, in the presence of m... In this work 4-amino-6-aryl-2-phenyl pyrimidine-5-carbonitrile derivatives were synthesized through a one-pot, three-component reaction of an aldehyde, malononitrile and benzamidine hydrochloride, in the presence of magnetic nano Fe304 particles as a catalyst under solvent-free conditions. 3-Amino-6-aryl- 2-phenylpyrazolo[3,4-d]pyrimidine derivatives were prepared through an efficient and environmentally friendly reaction between 4-amino-6-aryl-2-phenylpyrimidine-5-carbonitrile derivatives and hydra- zine hvdrate and their antibacterial activity has been evaluated 展开更多
关键词 Pyrrazolo[3 4-d]pyrimidine derivatives pyrimidine-5-carbonitrile derivatives Antibacterial activity Staphylococcus aureus Enterococcus raffinosus
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Brφnsted acidic ionic liquid catalyzed highly efficient synthesis of chromeno pyrimidinone derivatives and their antimicrobial activity 被引量:3
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作者 Janardhan Banothu Rajitha Bavanthula 《Chinese Chemical Letters》 SCIE CAS CSCD 2012年第9期1015-1018,共4页
A series of 8,9-dihydro-2-(2-oxo-2H-chromen-3-yl)-5-aryl-3H-chromeno[2,3-d]pyrimidine-4,6(5H^7H)-diones (Sa-j)have been synthesized by the reaction of 2-amino-5,6,7,8-tetrahydro-5-oxo-4-aryl-4H-chromene-3-carbon... A series of 8,9-dihydro-2-(2-oxo-2H-chromen-3-yl)-5-aryl-3H-chromeno[2,3-d]pyrimidine-4,6(5H^7H)-diones (Sa-j)have been synthesized by the reaction of 2-amino-5,6,7,8-tetrahydro-5-oxo-4-aryl-4H-chromene-3-carbonitrile (4a-j) with couma- rin-3-catboxylic acid under neat conditions employing Brnsted acidic ionic liquid (4-sulfobutyl)tris(4-sulfophenyl)phosphonium hydrogen sulfate as catalyst. Structures of all the compounds were established on the basis of analytical and spectroscopic data. All the compounds were evaluated for their in vitro antimicrobial activity against different bacterial and fungal strains. 展开更多
关键词 Antimicrobial activity Ionic liquid Neat conditions 8 9-Dihydro-2-(2-oxo-2H-chromen-3-yl)-5-aryl-3H-chromeno[2 3-d]pyrimidine- 4 6(5H 7H)-dione
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An efficient synthesis of novel pyridothieno-fused thiazolo[3,2-α]pyrimidinones via Pictet–Spengler reaction 被引量:2
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作者 Dao-Lin Wang Dong Wang +2 位作者 Liang Yan Guang-Yu Pan Jian-Nan Yang 《Chinese Chemical Letters》 SCIE CAS CSCD 2016年第6期953-956,共4页
An efficient method for the synthesis of novel pyrido[3'',2'':4',5']thieno[3',2':2,3]pyrido [4,5:d][1,3]thiazolo[3,2-a]pyrimidine-4-one derivatives(5) has been developed using a Pictet–Spengler reaction ... An efficient method for the synthesis of novel pyrido[3'',2'':4',5']thieno[3',2':2,3]pyrido [4,5:d][1,3]thiazolo[3,2-a]pyrimidine-4-one derivatives(5) has been developed using a Pictet–Spengler reaction between 2-(3-aminothieno[2,3-b]pyridin-2-yl)thiazolo[3,2-a] pyrimidin-5-one(3), which could be obtained from the condensation of 7-(chloromethyl)-5H-thiazolo[3,2-a]pyrimidin-5-one(1) with3-cyanopyridine-2-thione(2) via Thorpe–Ziegler isomerization, and aromatic aldehydes under NH2SO3 H as catalysis in good yields. 展开更多
关键词 7-Chloromethyl-5H-thiazolo[3 2-α]pyrimidin-5-one 3-Cyanopyridine-2-thione Pyrido[3'' 2'' 4' 5']thieno[3' 2' 2 3]pyrido [4 5:d] [1 3]Thiazolo[3 2-a]pyrimidine-4 one Thorpe–Ziegler reaction Pictet–Spengler reaction
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