2-胺基-5-異丙薁-1,3-雙酸二甲酯衍生物之溴化反應

Bromination of Derivatives of Dimethyl 2-Amino-5-lsopropyl -Azulene-1,3-Dicarboxylate

10.6623/chem.1992013

林雲山(Yun-Shan Lin)；蔡百豐(Pai-Feng Tsai)；陳發清(Fa-Chin Chen)；若林英嗣(Hidetsugu Wakabayashi)

化學

50卷2期（1992 / 06 / 01）

133 - 140

繁體中文

Dimethyl 2-acetamido-5-isopropylazulene-l,3-dicarboxylate在醋酸的質子溶劑中溴化反應時除了正常的七員環溴化產物外，還產生了在五員環有溴取代作用的異常溴化物，而其產率在整個產物中佔大多數。如改變溶劑為CHCI_3時五員環溴取代化合物幾乎是為整個產物的75%，其反應機構可由imine與enamine的tautomerism之機構來說明。

Bromination of dimethyl 2-acetamido-5-isopropylazulene-l,3-dicarboxylate in acetic acid (protic solvent) yields 8 brominated products. Among them, except the expected product from bromination at the 7-membered ring, 37% of products are unexpected bromine-substituted compounds in 5-membered ring. However, the bromination in chloroform (aprotic solvent) gives same brominated compounds in which 75% are 5-membered ring substituted compounds. Its mechanism could be explained by the tautomerism between imine and enamine existing in aprotic or protic solvent.