Photochemische und chemische Synthesen biologisch aktiver 3‐Oxazoline

Photochemical and Chemical Syntheses of Biologically Active 3‐Oxazolines Using the photoreaction of 2H‐azirines with carbonyl compounds, the 2,2‐dimethyl‐3‐oxazolines 5a, 5b, and 6a have been obtained which bear a mono‐ or dichlorophenyl substituent at C(4) of the five‐membered heterocycle and pyridyl at C(5). These compounds exhibit interesting activities against phytopathogenic fungi. Because 6a had been selected for field testing, its photochemical preparation was supplemented by a chemical synthesis. However, the overall performance of 6a in the field was inferior to some of the recently introduced agricultural fungicides of the ergosterol biosynthesis inhibitor type. Although 16 additional 3‐oxazolines with varied substituents have been prepared, the fungicidal activity found with 6a could not be improved.