Herbicidal quaternised triazolo-pyridine derivs. - esp. useful for selective control of monocotyledonous weeds in dicotyledonous crops e.g. peas, beans and cotton

摘要

Triazolopyridines of formula (I) and triazolopyridinium salts of formula (Ia) are new In the formulae, R1-4 are H, halogen, opt. substd. alkyl, aryl or aralkyl, NO2 or CN, R5 is a C-bonded quaternised N-contg. heterocyclic gp. X is 1 equiv. of an anion, R7 is opt. substd. alkyl or a C-bonded opt. substd. and opt. satd. heterocyclic gp. (quaternised if N-contg.), R6 is alkyl or, when R7 is a heterocyclic gp. contg. a quaternised N atom ortho to the bonding posn. R6 can form a CH2, CH2CH2, CH2CH2CH2 or CH=CR gp. bonded to the quaternised N atom, R is alkyl. A typical cpd. is 1-methyl-2-(1-methylpyridinium-4-yl) -s-triazolo(1,5-a pyridinium bis(methyl sulphate). In an example, this is prepd. from 1-aminopyridinium chloride and 4-cyanopyridine.