Carbene-Catalyzed [4 + 2] Annulation of 2H-Azirine-2-carboxaldehydes with Ketones via Azolium Aza-Dienolate Intermediate
摘要:
A new carbene-catalyzed [4 + 2] annulation of 2H-azirine-2-carbaldehydes with ketones was developed, thus providing the 2,3-dihydro-6H-1,3-oxazin-6-one core structures with broad scope and good to excellent yields. Notably, the azolium aza-dienolates generated from the addition of NHCs to 2H-azirines are first uncovered.
Design, synthesis, and antifungal activity of inhibitors of brassilexin detoxification in the plant pathogenic fungus Leptosphaeria maculans
摘要:
Potential inhibitors of Leptosphaeria maculans mediated detoxification of the phytoalexin brassilexin were designed and synthesized based on the planar heteroaromatic structure of isothiazolo[5,4-b]indole. Screening of these compounds for inhibition of brassilexin detoxification in cultures of L. maculans indicated that 4-(2-chlorophenyl)isothiazole had the largest effect on the rate of brassilexin detoxification. However, the most antifungal compound among the potential inhibitors, isothiazolo[5,4-b]quinoline, did not appear to affect the metabolism of brassilexin noticeably, suggesting that growth inhibition is not sufficient to slow down the rate of brassilexin detoxification. Furthermore, it was determined that 4-arylisothiazoles as well as isothiazolo[5,4-b]thianaphthene displayed antifungal activity against L. maculans. (c) 2005 Elsevier Ltd. All rights reserved.