Naproanilide is a rice herbicide. Itself it has no herbicidal activity however its major metabolite 2-(2-naphthoxy)propionic acid does. It is only slightly toxic. Photodegradation appears to be the main degradation pathway in paddy fields. Little is known about the toxicity of this substance to wildlife.
Pure product is white crystal, odorless. m.p.128°C, relative density 1.256 (25°C), vapor pressure 66.66Pa (110°C). solubility at 27°C: acetone 171g/L, benzene 36g/L, toluene 42g/L, ethanol 17g/L, water 0.74mg/L. Stable in neutral and weakly acidic solution, unstable in alkaline or hot strongly acidic solution. The The original drug is stable to, but the drug solution is not stable after water. Half-life in soil is 2-7d, disappear in 1 month.
Naproanilide is used as a herbicide.
ChEBI: Naproanilide is a member of naphthalenes.
Naproanilide is synthesised through a three-step process starting from 2-chloropropanoic acid, aniline, and 2-naphthol. First, 2-chloropropanoic acid undergoes a nucleophilic substitution with aniline, where the amine group replaces the chlorine atom, forming an amide intermediate. In the second step, this intermediate reacts with 2-naphthol in the presence of a base, such as sodium hydroxide, which activates the phenolic oxygen to act as a nucleophile. This leads to the formation of a naphthyl ether linkage, completing the structure of naproanilide.
Stimulates RNA synthesis. Absorbed through stems and roots. No herbicidal activity itself but is rapidly hydrolysed to an active metabolite
In the rice paddy ecosystem, naproanilide is
biodegraded by the rice plant and organisms in the
paddy field and by soil organisms and is mainly
hydrolyzed to 2-(2-naphthoxy)propionic acid (NOP)
and its methyl ester (NOPM). In rice plants (Oryza
sativa L.) and Sagittaria pygmaea MIQ, naproanilide is
metabolized to phytotoxic NOP. In rice plants, NOP
subsequently undergoes hydroxylation and rapid
conjugation with glucose. Phytotoxic NOP is produced
only in a small amount. In S. pygmaea, the amounts
of NOP and NOPM are significantly greater than those
in rice plants. The difference in metabolites of
naproanilide shows a possible mechanism of their
herbicidal selectivity. Naproanilide and NOP in
aqueous solution are rapidly degraded under sunlight and UV light. The disappearance of naproanilide in the
paddy field is largely attributed to photochemical
degradation in the surface water.
