Efficient Use of 1,2-Dihaloazine Synthons in Transition-Metal-Free Preparation of Diverse Heterocycle-Fused 1,4-Oxazepines

Gold-catalyzed formation of aryl-fused pyrazolooxazepines via intramolecular regioselective 7-exo-dig cyclization

An efficient gold-catalyzed method was developed for the formation of aryl-fused pyrazolooxazepines from ortho-O-propargyl aryl pyrazoles via 7-exo-dig cyclization in good yields.

Design, synthesis, crystal structure and fungicidal activity of (E)-5-(methoxyimino)-3,5-dihydrobenzo[e][1,2]oxazepin-4(1H)-one analogues

A practical method of four-step synthesis towards novel (E)-5-(methoxyimino)-3,5-dihydrobenzo[e][1,2]oxazepin-4(1H)-one antifungals is presented, where a commercially available pesticide and pharmacology intermediate, (E)-methyl 2-(2-(bromomethyl)phenyl)-2-(methoxyimino)acetate (1), was used as starting material. These compounds were confirmed by ¹H NMR, ¹³C NMR, high-resolution mass spectroscopy and X-ray crystal structure. Via in vitro fungicidal evaluation, the moderate to high activities of several compounds against eight phytopathogenic fungi were demonstrated. Especially, the fungicidal activities of compounds 5-03 and 5-09 were comparable to those of the controls azoxystrobin and trifloxystrobin in precise virulence measurements for four fungi. These results suggested that dihydrobenzo[e][1,2]oxazepin-4(1H)-one analogues could be considered as potential fungicidal candidates for crop protection.

Structurally diverse arene-fused ten-membered lactams accessed via hydrolytic imidazoline ring expansion

A facile approach to hitherto unknown ten-membered ring systems via a hydrolytic imidazoline ring expansion (HIRE) is described. Medium-sized rings are scarce in the contemporary medicinal chemistry toolbox. The new HIRE strategy broadens the arsenal of synthetic methods to obtain such scaffolds.