Vilsmeier Reaction of 3-Aminopropenamides: One-Pot Synthesis of Pyrimidin-4(3H)-ones
摘要:
A facile one-pot synthesis of pyrimidin-4(3H)-ones was developed via reactions of a series of readily available 3-aminopropenamides with varied Vilsmeier reagents, and a mechanism involving sequential halogenation, formylation, and intramolecular nucleophilic cyclization is proposed.
Tf<sub>2</sub>O-Mediated Cyclization of α-Acyl-β-(2-aminopyridinyl)acrylamides: Access to N-Substituted 4<i>H</i>-Pyrido[1,2-<i>a</i>]pyrimidin-4-imines
N-substituted 4H-pyrido[1,2-a]pyrimidin-4-imines is developed from α-acyl-β-(2-aminopyridinyl)acrylamides mediated by triflic anhydride (Tf2O) in the presence of 2-chloropyridine. This amide activation protocol features mild reaction conditions, simple execution, excellent yields, and high chemoselectivity, and is also applied to the synthesis of substituted 4H-pyrido[1,2-a]pyrimidin-4-ones via a practical
由三氟甲磺酸酐(Tf 2 O)介导的α-酰基-β-(2-氨基吡啶基)丙烯酰胺开发了一种N-取代的4 H-吡啶并[1,2 - a ]嘧啶-4-亚胺的简便有效的直接合成方法在2-氯吡啶存在下。该酰胺活化方案具有反应条件温和,操作简单,产率高和化学选择性高的特点,并且还可以通过实用的一锅法应用于取代的4 H-吡啶并[1,2- a ]嘧啶-4-酮的合成。程序。
A Facile One-Pot Synthesis of Substituted Thieno[2,3-b]pyridines from Enaminones
A facile and efficient one-pot synthesis of substitutedthieno[2,3-b]pyridines has been developed. Treatment of enaminones, such as 2-acetyl-3-(dimethylamino)propenamides and -propenoates, with 2-cyanothioacetamide in the presence of potassium carbonate in N,N-dimethylformamide at 80 ˚C followed by addition of methylene-active bromides at room temperature provided, via intramolecular cyclization,
已经开发了一种简便,高效的一锅法合成取代的噻吩并[2,3- b ]吡啶。在80°C下于N,N-二甲基甲酰胺中的碳酸钾存在下,用2-氰基硫代乙酰胺处理2-氨基-3-(二甲基氨基)丙烯酰胺和-丙烯酸酯等烯胺酮,然后在室温下添加亚甲基活性溴化物通过分子内环化提供2,3,5,6-四取代的噻吩并[2,3- b ]吡啶的温度为78-90%。该方案结合了噻吩并[2,3- b ]吡啶环的构建和修饰,增加了最终材料的结构多样性,这些最终产品来自易于获得的材料。 烯胺酮-环化-杂环-吡啶-2(1 H)-硫酮-噻吩并[2,3- b ]吡啶
PIFA-Mediated Oxidative Cyclization Reactions of α-Acyl Acrylamides: A Synthetic Route to Substituted Isoxazol-3(2H)-ones
substituted isoxazol-3(2H)-ones from readily available α-acyl acrylamides. An intramolecular cyclization of various α-acyl β-amino acrylamides in the presence of PIFA and TFA is described. This transformation features mild reaction conditions, simple execution, high chemoselectivity, and metal catalyst-free oxidation, and thereby, provides not only an alternative protocol for the construction of N–O bond, but
Cyclization of a variety of beta-aminoacrylamides in the presence of iodosobenzene (PhIO) is described. This process features mild reaction conditions, simple execution, and high chemoselectivity and thereby provides an efficient protocol for the divergent synthesis of substituted isoxazoles and 2H-azirines via switchable N-O and N-C bond formation controlled by simply varying the beta-substituent R-3 of the readily available substrates.