| abstract |
FIELD: organic synthesis. SUBSTANCE: trans-6- [substituted pyrrol-1-yl)alkyl]pyran-2-on derivatives having general formula I: (I), wherein R 1 is phenyl optionally substituted by fluorine, bromine, or chlorine; R 2 and R 3 are hydrogen, alkyl, phenyl or radical -CONR 5 R 6 , in which R 5 and R 6 are hydrogen, alkyl, or phenyl optionally substituted by fluorine, chlorine, or bromine; and R 4 is C 1-6 - alkyl, are prepared with compound of formula II ( ) with compound of formula III ( ) followed by interaction of resulting intermediate having formula IV (NC-CH 2 CH-CH 2 -CO-CH 2 -CONR 8 R 9 ) with R 10 2 BOCH 3 or R 10 2 B and then with borane in solvent. Resulting compound NC-CH 2 CH-CH 2 -CO-CH 2 -CONR 8 R 9 is brought into reaction with reagent R 11 R 12 C(OCH 3 ) 2 or R 11 R 12 CO under acid conditions. Resulting ketal having formula V ( ) is hydrogenated and brought into reaction with compound R 1 COCHR 2 CHR 3 COR 4 to give intermediate VI ( ), which is treated with acid in solvent and hydrolyzed with base to give intermediate that, after neutralization with acid and dissolution in solvent with simultaneous removal of water, is converted into final product. EFFECT: increased yield and reduced expenses on reagents. 14 cl, 2 dwg, 6 ex |