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Nucleophilic Substitution of Diethyl 2‐Chloroazulene‐1,3‐dicarboxylate with Alkyl Lithium
Author(s) -
Chen ArhHwang,
Yen HsiuHang,
Chen WenZhang,
Hong ZhiXi,
Yuan ShouBin,
Chen WenYi
Publication year - 2006
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.200600200
Subject(s) - chemistry , lithium (medication) , alkyl , nucleophilic substitution , carboxylate , medicinal chemistry , nucleophile , substitution reaction , organic chemistry , catalysis , medicine , endocrinology
Nucleophilic substitution reactions of diethyl 2‐chloroazulene‐1,3‐dicarboxylate with four alkyl lithiums (methyl lithium, ethyl lithium, n ‐propyl lithium and n ‐butyl lithium) afforded the major product of ethyl 2‐chloro‐4‐alkylazulene‐1‐carboxylate and some minor products of 2‐chloro‐4‐alkylazulene, 2,4‐dialkylazulene‐1‐carboxylic acid, ethyl 3,4‐dialkylazulene‐1‐carboxylate, diethyl 6‐alkylazulene‐1,3‐dicarboxylate and diethyl 2‐chloro‐5‐alkylazulene‐1,3‐dicarboxylate, respectively. The kinds and the yields of their products were significantly dependent on the kinds of alkyl lithiums, molar ratios of alkyl lithium/substrate and oxidation conditions at room temperature or under reflux. The major product of ethyl 2‐chloro‐4‐alkylazulene‐1‐carboxylate is proposed to be formed via an addition‐elimination mechanism.