69022-76-0Relevant academic research and scientific papers
Furopyridines. VII. Preparation and Hydrolysis of 2-Cyano and 3-Cyano Derivatives of Furo-, Furo-, and Furopyridine
Morita, Hiroyuki,Shiotani, Shunsaku
, p. 373 - 376 (2007/10/02)
This paper describes the preparation and hydrolysis of 2-cyano and 3-cyano derivatives of furo-, furo-, and furopyridine.Treatment of furopyridines 1a, 1b and 1c with n-butyllithium in hexane-tetrahydrofuran at -70 deg C and subsequent addition of N,N-dimethylformamide yielded 2-formyl derivatives 2a, 2b and 2c.Dehydration of the oximes 4a, 4b and 4c of 2a, 2b and 2c gave 2-cyano compounds 5a, 5b and 5c, which were hydrolyzed to give 2-carboxylic acids, 6a, 6b and 6c, respectively.Reaction of 3-bromo compounds 7a, 7b and 7c with copper(I) cyanide in N,N-dimethylformamide afforded 3-cyano derivatives 8a, 8b and 8c.Alkaline hydrolysis of 8a, 8b and 8c gave compounds formed by fission of the 1-2 bond of furopyridines 9a, 9b and 9c, while acidic hydrolysis gave the corresponding carboxamides, 10a, 10b and 10c.
Furopyridines. V. A Simple Synthesis of Furopyridine and Its 2- and 3-Methyl Derivatives
Morita, Hiroyuki,Shiotani, Shunsaku
, p. 549 - 552 (2007/10/02)
A simple synthesis of furopyridine and its 2- and 3-methyl derivatives from ethyl 3-hydroxyisonicotinate (2) is described.The hydroxy ester 2 was O-alkylated with ethyl bromoacetate or ethyl 2-bromopropionate to give the diester 3a or 3b.Cyclization of compound 3a afforded ethyl 3-hydroxyfuropyridine-2-carboxylate (4) which was hydrolyzed and decarboxylated to give furopyridin-3(2H)-one (5a).Cyclization of 3b gave the 2-methyl derivative 5b.Reduction of 5a and 5b with sodium borohydride yielded the corresponding hydroxy derivative 6a and 6b, respectively, which were dehydrated with phosphoric acid to give furopyridine (7a) and its 2-methyl derivative 7b. 4-Acetylpyridin-3-ol (8) was O-alkylated with ethyl bromoacetate to give ethyl 2-(4-acetyl-3-pyridyloxy)acetate (9).Saponification of compound 9, and the subsequent intramolecular Perkin reaction gave 3-methylfuropyridine (10).Cyclization of 9 with sodium ethoxide gave 3-methylfuropyridine-2-carboxylic acid, which in turn was decarboxylated to give compound 10.
