Synthesis and Evaluation of New Ethyl 2,3- Dihydro-3-oxoisothiazolo[5,4- b ]pyridine- 2-alkanoate Derivatives as Potential Herbicides

✍ Scribed by Gil, Maria J.; Zabalza, José M.; Navarro, Javier; Mañú, Maria A.; González, Alberto; Merino, Víctor Martínez; Canal, Arantxa; Royuela, Mercedes; Aparicio-Tejo, Pedro M.

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 285 KB
• Volume: 49
• Category: Article
• ISSN: 1526-498X
• DOI: 10.1002/(sici)1096-9063(199702)49:2<148::aid-ps515>3.0.co;2-u

✦ Synopsis

Several ethyl 2,

pyridine-2-alkanoate derivatives were synthesized as herbicides. Only 5-methyl derivatives inhibited both hypocotyl and root growth in the lettuce (L actuca sativa L.) seedling test at 100 mg litre~1. Only ethyl propionate and valerate derivatives showed signiÐcant inhibition at 0É1 mg litre~1, whereas ethyl acetate or butyrate derivatives were inactive. Contrary to unoxidized derivatives, the inhibitory e †ect of 1-oxide and 1,1-dioxide derivatives was strongly dependent on concentration ; ethyl 2,3-dihydro-5-methyl-3-oxoisothiazolo[5,4-b]pyridine-2-propionate 1,1-dioxide inhibited 100% of germination at 100 mg litre~1 and 45% of lettuce seedling growth at 0É1 mg litre~1. Quantitative structureÈinhibition of growth relationship analysis carried out by adaptive least-squares (ALS) method gave a good correlation with small and hydrophobic 5-substituents as well as with odd carbon-chain ethyl alkanoates in position 2. Active compounds did not show auxin-like activity from 0É1 to 100 mg litre~1.