TITLE:
A Facile Synthesis of 9,10-Dimethoxybenzo[6,7]- ox-epino[3,4-b]quinolin-13(6H)-one and Its Derivatives
AUTHORS:
Dingqiao Yang, Xiuli Liang, Xiongjun Zuo, Yuhua Long
KEYWORDS:
The Intramolecular Friedel-Crafts Acylation Reaction: 9, 10-Dimethoxybenzo; [6, 7]oxepino[3, 4-b]quinolin-13(6H)-one and Its Derivatives; 6, 7-Dimethoxy-2-(phenoxymethyl)quinoline-3-carboxylic Acid: Ethyl; 6, 7-dimethoxy-2-(phenoxymethyl)quinoline-3-carboxylate: PPA
JOURNAL NAME:
International Journal of Organic Chemistry,
Vol.3 No.2,
June
13,
2013
ABSTRACT: A concise
and efficient method for the synthesis of novel 9,10-imethoxybenzo[6,7]oxepino[3,4-b]quinolin13(6H)-one and
its derivatives 7a-p has been developed via the
intramolecular Friedel-Crafts acylation reactions of 6,7-dimethoxy-2-(phenoxymethyl)quinoline-3-carboxylic
acids 6a-p with polyphosphoric
acid (PPA) as catalyst and solvent under mild conditions. The key intermediates
6a-p were prepared through the in situ formation of ethyl 6,7-dimethoxy-2-(phenoxymethyl)quinoline-3-carboxylates
5a-p followed by hydrolysis
with aqueous ethanolic sodium hydroxide
solution. The novel synthetic method has the advantages of good yields, easy
work-up, and environmentally friendly character, which may provide a novel
highly efficient process for making quinoline and related azaheterocycle
libraries.