A series of differently substituted 3,5-diaryl-2,4,6-trimethylpyridines were prepared and characterized using the Suzuki-Miyaura coupling reaction with accordingly selected bromo-derivatives and arylboronic acids. The reaction conditions were carefully optimized allowing high yield of isolated products and also the construction of unsymmetricallysubstituted diarylpyridines, difficult to access by
申请人:EASTMAN KODAK COMPANY
(a New Jersey corporation)
公开号:EP0096641A2
公开(公告)日:1983-12-21
A process for selectively preparing isomers of polysubstituted pyrylium salts from isoolefins or isoolefin precursors comprises diacylating the isoolefin or isoolefin precursor with a carboxylic acid anhydride in the presence of an acid having a Hammett acidity function, when pure, between -10 and -5. This method is selective to obtain the most substituted isomer of pyrylium salt that can be obtained from the isoolefin or isoolefin precursor.
A new method is described for the regioselective synthesis of multisubstituted pyridine derivatives. Treatment of N-acetyl beta-enamino ketones with alkynes in the presence of the rhenium catalyst, Re-2(CO)(10), gives multisubstituted pyridines regioselectively. In this reaction, the N-acetyl moieties are important for the selective formation of the multisubstituted pyridines. This reaction proceeds via insertion of alkynes into a carbon carbon single bond of beta-enamino ketones, intramolecular nucleophilic cyclization, and elimination of acetic acid.
BOTA A.; BALABAN A. T.; CHIRALEU F., REV. ROUM. CHIM. <RRCH-AC>, 1976, 21, NO 1, 101-106