New 2,3,4,6-tetra-substituted pyridines, useful as pharmaceuticals and plant-protection agents, prepared using an alkoxyallene as three-carbon synthon

摘要

2,3,4,6-tetra-substituted pyridines and their tautomeric pyridones are new. 2,3,4,6-tetra-substituted pyridines of formula (I), and their tautomeric pyridones when R3 = hydroxy, are new. [Image] R1alkyl, aryl or alkenyl, all optionally substituted; R2alkoxy or cycloalkoxy, preferably unsubstituted 1-12C alkoxy and especially methoxy, ethoxy, 1- or 2-propoxy, 1- or tert-butoxy; R3hydroxy, halo, trifluoromethanesulfonate, nonabromobutanesulfonate, p-toluenesulfonate, p-(bromo or nitro)benzenesulfonate, methanesulfonate, 2,2,2-trifluoroethanesulfonate, or, all optionally substituted, alkyl, alkenyl, ethynyl (substituted by R5), aryl, alkoxy, cycloalkoxy (especially optionally substituted 1-12C alkoxy), N-nucleophiles (especially ammonia, primary or secondary amines, azides) or sulfur-nucleophiles (especially thiols); R5hydrogen, aryl, alkyl, alkenyl, all optionally substituted; R4fluorinated alkyl, especially of formula -[(CFlHm)t-(CFnHo)u-(CFpHq)v]w-(CFrHs); each of l, n, p, m, o and q : 0-2, provided l+m, n+o and p+q = 2; each of r and s : 0-3, but must total 3, and l+n+p+r = at least 1; each t, u and v : 0-3; w : 0-10. Independent claims are also included for the following: (1) method for preparing (I) by sequential reaction of an alkoxyallene (II) with R1CN and R4COOH; and (2) use of (II) as 3-carbon building block in synthesis of pyridines, particularly (I).