Phototransformation of metoxuron [3‐(3‐chloro‐4‐methoxyphenyl)‐1,1‐dimethylurea] in aqueous solution

UV irradiation of metoxuron in aerated aqueous solution at 254 nm or between 300 and 450 nm led initially to an almost specific photohydrolysis of the C–Cl bond, resulting in the formation of 3‐(3‐hydroxy‐4‐methoxyphenyl)‐1,1‐dimethylurea (MX3) and hydrogen chloride. The quantum yield was determined to be 0.020 (±0.005) in solutions irradiated at 254 nm. Five minor photoproducts were also identified, in particular the dihydroxydimethoxybiphenyl derivatives resulting from the phototransformation of MX3. Irradiation increased the toxicity of an aqueous solution of metoxuron to the marine bacterium Vibrio fischeri. © 2001 Society of Chemical Industry     

Activity of the botanical aphicides 1,5‐diphenyl‐1‐pentanone and 1,5‐diphenyl‐2‐penten‐1‐one on two species of Aphididnae

1,5‐Diphenyl‐1‐pentanone (A) and 1,5‐diphenyl‐2‐penten‐1‐one (B) are natural products extracted for the first time from Stellera chamaejasme. Laboratory bioassay showed that the two products have strong contact activity and very good anti‐feedant activity against Aphis gossypii and Schizaphis graminum. Both products showed dose‐dependent relationships for both forms of activity against the two aphids, the contact activity of B being about twice that of A. Both products were inferior to methomyl in contact activity but superior in anti‐feedant activity against the two aphids. This is the first report of aphicidal activity in these two compounds, which may represent a new class of aphicide. © 2001 Society of Chemical Industry     

Synthesis and antifungal activity of 2‐azetidinonyl‐5‐(2‐benzoylphenoxy)methyl‐1,3,4‐oxadiazoles against seed‐borne pathogens of Eleusine coracana (L.) Gaertn

BACKGROUND: Finger millet is a major food crop as well as feed and fodder for livestock, especially in regions of southern India. A sturdy crop to fluctuating environmental conditions, it can be cultivated in all seasons of the year. Leaf, neck and finger blast caused by Pyricularia grisea Sacc. and Bipolaris setariae (Saw.) Shoem, as well as leaf spot disease, Bipolaris nodulosa (Berk & M.A.Curtis) Shoem, are major production constraints in southern India. Apart from environmental conditions, the use of harvested seeds by farmers is a major reason for disease prevalence. Benzophenone analogues have been investigated for controlling phytopathogenic fungi. In addition, the most important applications of azetidin‐2‐ones are as antibiotics. Based on this information, the present study was conducted to explore the antifungal activity of integrated 2‐azetidinonyl and 1,3,4‐oxadiazoles moieties into a benzophenone framework. RESULTS: A simple high‐yielding method for the integration of heterocyclic rings, namely 2‐azetidinonyl, at the benzophenone nucleus has been achieved, starting from substituted 2‐hydroxybenzophenones under mild conditions on a wet solid surface using microwave irradiation. In the present study, an array of newly synthesised compounds, 2‐azetidinonyl‐5‐(2‐benzoylphenoxy)methyl‐1,3,4‐oxadiazoles, were screened for their antifungal property against blast and leaf spot causing fungi associated with the seeds of finger millet, cv. Indof‐9. CONCLUSION: Two of the newly synthesised compounds showed promising effects in depleting the incidence of seed‐borne pathogenic fungi of finger millet. The suppression of Pyricularia grisea and Bipolaris setariae resulted in enhanced seed germination and seedling growth. Copyright © 2009 Society of Chemical Industry