Evaluation of Electrophilic Heteroaromatic Substitution: Synthesis of Heteroaromatic-Fused Pyrimidine Derivatives via Sequential Three-Component Heterocyclization
作者:Fung Fuh Wong、Yu-Ying Huang、Chun-Hsi Chang
DOI:10.1021/jo301463m
日期:2012.10.5
A new sequentialthree-componentheterocyclization was developed by reacting aromatic and heterocyclic substrates, including aminobenzenes, 1-aminonaphthalene, 2-aminopyrazines, 5-aminopyrazoles, 3-aminopyridine, 5-aminopyrimidine, 5-aminoquinoline, and 8-aminoquinoline, with formamide in the presence of PBr3. The reaction gave the corresponding pyrazolo[3,4-d]pyrimidines in good yields (59–96%), except
通过使芳香族和杂环底物(包括氨基苯,1-氨基萘,2-氨基吡嗪,5-氨基吡唑,3-氨基吡啶,5-氨基嘧啶,5-氨基喹啉和8-氨基喹啉)与甲酰胺反应,开发了一种新的顺序三组分杂环化方法在PBr 3存在下。除氨基苯和3-氨基吡啶外,该反应以较高的收率(59-96%)得到了相应的吡唑并[3,4- d ]嘧啶。提出了包括三步酰胺化,亲电取代亚胺化和氧化环化的合理反应机理,以解决杂环化问题。发现反应的反应性与芳族或杂环底物的亲电子性成比例。
One-Flask Synthesis of Pyrazolo[3,4-d]pyrimidines from 5-Aminopyrazoles and Mechanistic Study
作者:Wan-Ping Yen、Shuo-En Tsai、Naoto Uramaru、Hiroyuki Takayama、Fung Wong
DOI:10.3390/molecules22050820
日期:——
converted into pyrazolo[3,4-d]pyrimidines. The experiments demonstrated that the reaction intermediates were the chemical equivalents of 4-(iminomethyl)-1,3-diphenyl-1H-pyrazol-5-yl)formamidines. The rate of the reaction could be described as being proportional to the reactivity of amine reactants during intermolecular heterocyclization, especially when hexamethyldisilazane was used.
An efficient one-pot methodology for the synthesis of pyrazolo[3,4-d]pyrimidines was developed by using 5-aminopyrazoles with formamide in presence of PBr3 as the coupling agent. Among the examples presented in this work, compounds 41 and 54-56 with phenyl or 2-quinolinyl groups at N-1 and p-Me-Ph, p-Cl-Ph, or p-OMe-Ph group at C-3 position in the pyrazole ring possessed better potency against NCl-H226 and NPC-TW01 cancer cells with GI(50) values between 18 mu M and 39 mu M. (c) 2012 Elsevier Ltd. All rights reserved.
Efficient acid catalytic synthesis of pyrazolopyrimidines from 1H-pyrazol-5-yl-N,N-dimethylformamidines with cyanamide
The efficient acid catalytic synthesis of pyrazolo [3,4-d]pyrimidine was developed by treating 1H-pyrazol-5-yl-N,N-dimethylformamidine with various aminating agents including N,O-bis(trimethylsilyl)hydroxylamine (NHSiMe3(OSiMe3)), cyanamide (NH2CN), hydroxylamine (NH2OH), methoxyamine (NH2OMe), hydrazine (NH2NH2), and urea (NH2C(O)NH2) in acidic solution at reflux. Based on the experimental result