Synthesis 2003(13): 2005-2010
DOI: 10.1055/s-2003-41043
PAPER
© Georg Thieme Verlag Stuttgart · New York

Chemoselectivity in the Reactions Between Ethyl 4,4,4-Trifluoro-3-oxobutanoate and Anilines: Improved Synthesis of 2-Trifluoromethyl-4- and 4-Tri­fluoromethyl-2-quinolinones

Dmitrii O. Berbasov, Vadim A. Soloshonok*
Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73019, USA
Fax: +1(405)3256111; e-Mail: vadim@ou.edu ;
Further Information

Publication History

Received 21 April 2003
Publication Date:
28 August 2003 (online)

Abstract

Chemoselectivity in the reactions between ethyl 4,4,4-trifluoroacetoacetate (ethyl 4,4,4-trifluoro-3-oxobutanoate) and various anilines was systematically studied as a function of the reaction conditions used (solvent/temperature, catalyst). The results obtained allowed chemoselective (>90%) synthesis of the corresponding ethyl 3-arylamino-4,4,4-trifluorobut-2-enoates and N-aryl-4,4,4-trifluoro-3-oxobutyramides, which were cyclized to afford 2-trifluoromethyl-4-quinolinones and 4-trifluoromethyl-2-quinolinones, respectively.

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Ohkura, H.; Berbasov, D. O.; Soloshonok, V. A. Tetrahedron 2003, in press.

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In the reported procedure (see Ref. [2] )the starting keto ester 3 and anilines 4 were used in a ratio of 2:1; accordingly, the corresponding yields of the products 2 are calculated based on 4. Despite the fact that keto ester 3 is a cheap technical bulkware, it is still more expensive than most of the anilines 4, therefore, we believe that the chemical yields, as one of the criteria of synthetic efficiency, should be calculated on 3 to make an economical sense.