Synthesis of 4-Alkylidene-4<i>H</i>-3,1-benzoxazine Derivatives by Acid-Catalyzed Cyclization
of 2-Isocyanophenyl Ketones in the Presence of a Vinyl Ether
2-(1-Alkoxyalkyl)-4-alkylidene-4H-3,1-benzoxazines are conveniently prepared by the reaction of 1-(2-isocyanophenyl)ethanones or 1-(2-isocyanophenyl)propan-1-ones with a vinyl ether, such as 2-methoxypropene or ethyl vinyl ether, in the presence of a catalytic amount of (±)-camphor-10-sulfonic acid. 4H-3,1-benzoxazines - acid-catalyzed reaction - fused-ring system - isocyanides - vinyl ethers
2-(1-烷氧基烷基)-4-亚烷基-4 H -3,1-苯并恶嗪可通过1-(2-异氰基苯基)乙炔或1-(2-异氰基苯基)丙-1-酮与环己烯的反应方便地制备。乙烯基量,例如2-甲氧基丙烯或乙基乙烯基醚,在催化量的(±)-樟脑-10-磺酸的存在下。 4 H -3,1-苯并恶嗪-酸催化反应-稠环系统-异氰酸酯-乙烯基醚
Cyclization Reactions of 2-Isothiocyanatophenyl Ketones Giving 4-Hydroxyquinoline-2(1H)-thiones and 4-Alkylidene-1,4-dihydro-3,1-benzoxazine-2-thiones
methyl ketones, generated in situ by treatment of 2-isocyanophenyl methyl ketones with sulfur in the presence of a catalytic amount of selenium and excess triethylamine, underwent electrocyclicreaction (ECR) via their enolate forms to give 4-hydroxyquinoline-2(1H)-thiones. The reaction products from ethyl 2-isothiocyanatophenyl ketones generated in situfrom the correspondingisocyanides under similar
nucleophilic addition of a P-centered anion to isocyanides and cyclization reaction was developed for the efficient and practical synthesis of a wide range of 2-phosphinoyl indole and indol-3-ol derivatives. Unlike the well-documented synthesis of phosphorus-functionalized heterocycles via a P-centered radical, an anionic reactivityprofile of phosphine oxides is most likely involved in this domino transformation
开发了银催化的以 P 为中心的阴离子与异氰化物的化学选择性级联亲核加成和环化反应,用于有效且实用地合成各种 2-膦酰基吲哚和吲哚-3-醇衍生物。与通过P 中心自由基合成磷官能化杂环不同,氧化膦的阴离子反应性特征很可能参与这种多米诺骨牌转化。
Synthesis of 4-Alkylidene-2-(dimethylamino)methyl-4H-3,1-benzoxazines by the Reaction of Alkyl 2-Isocyanophenyl Ketones with Eschenmoser’s Salt
4-Alkylidene-2-(dimethylamino)methyl-4H-3,1-benzoxazines could be prepared in one-pot by simply treating alkyl 2-isocyanophenyl ketones with dimethyl(methylene)ammonium iodide (Eschenmoser's salt) in dichloromethane at 0 degrees C without any catalysts.