Dehydration of N-unsubstituted-N-(2-ureidobenzoyl)-anthranilic acids 1 and 2 furnishes derivatives (10 and b), 4H-3,1-benzoxazin-4-one. The latter may subsequently be isomerized into quinazolin-2-on 16 and 19, respectively. The former may be further dehydrated to yield the quinazolino-[4.3-b]quinazoline-6,8-dione (17).
N-未取代的-N-(2-脲基苯甲酰基)-邻氨基苯甲酸1和2的脱水提供衍生物(10和b),4 H -3,1-苯并恶嗪-4-酮。后者随后可以分别异构化为喹唑啉-2-on 16和19。前者可以进一步脱水以产生喹唑啉基-[4.3-b]喹唑啉-6,8-二酮(17)。
4H-3,1-Benzoxazinone-(4), 3.Mitt.: �ber die K�nigsche ?N,N?-Diphenyl-guanidin-o,o?-dicarbons�ure?. Eine Richtigstellung
作者:G�bor Doleschall、K�roly Lempert
DOI:10.1007/bf00904699
日期:——
Oxidative Ring Expansion of Spirocyclic Oxindole Derivatives
作者:Jan Bergman、Carl-Johan Arewång、Per H. Svensson
DOI:10.1021/jo501269f
日期:2014.10.3
3H)dione 8, which was also identified as an intermediate in the oxidation of isamicacid. Mild hydrolysis of 7 gave the 10-membered molecule 22. Isamicacid could easily be converted to N-nitrosoisamic acid, which when heated in ethanol underwent a ring expansion to a hydroximino derivative, 38, of compound 6. The structure of 38 was confirmed by X-ray crystallography.