| Abstract
| - Synthesis of some new substituted [3-(3-chloro-4-fluorophenyl)-2-oxo-3,4-dihydro-2H-2λ5-benzo[e][1,3,2]oxazaphosphinin-2-yl]-(aryl/alkyl)methanols (7a−k) based on the Pudovick reaction wasaccomplished in the presence of niobium pentoxide (Nb2O5) without using an external chiral ligand.Nb2O5 appears to form the metal complex intermediate catalyst system (6) by reacting with 3-(3-chloro-4-fluoro-phenyl)-3,4-dihydrobenzo[e][1,3,2]oxazaphosphinine-2-oxide (4), which not only directsthe Pudovick addition reactions of aldehyde but also increases the yields and purity of the products.These compounds exhibited a lethal effect on whip smut of sugarcane and were degraded in theenvironment in the presence of bacteria and fungi to nontoxic phosphate residues that act as possibleplant nutrients. Thus, a new class of benzooxazaphosphininyl methanol derivatives that act in synergyboth as antipathogens and as plant nutrients in the environment have been discovered. Keywords: Pudovick reaction; benzooxazaphosphinyl methanols; niobium pentoxide; whip smut.
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