Studies on synthesis and plant growth retardant activity of cyclic bis-quaternary salts of ammonia from phthalic acid using conventional and microwave methods

Phthalilc acid 1 has been converted to bis (oxiran-2-ylmethyl) phthalate 2 followed by ring opening to di-tertiary amines viz: bis (3-[diethylamino)-2-hydroxypropyl] phthalate 3 and bis [2-hydroxy-3-[piperidin-1-yl) propyl] phthalate 3 and bis carried through conventional as well as non-conventional methods (microwave irradiation on solid support). Di-tertiary amines 3 and 4 have been quaternized to give cyclic bis-quarternary ammonium salts 3a-c and 4a,b which in turn are tested for their efficacy as plant growth regulators on rice (Oryza sativa). All the tested compounds are found to be good plant growth retardants. Compounds 4c is found to be the best plant growth retardant among the six newly synthesized compounds.