Synthesis and fungicidal activity againstPyricularia oryzaeof 6-(1,2,4-triazol-4-yl) chromone and -1-thiochromone derivatives

Abstract

A series of novel 6‐(1,2,4‐triazol‐4‐yl) chromone and ‐1‐thiochromone (benzo[b]thiazin‐4‐one) derivatives was obtained by cyclisation via thiosemicarbazides which were prepared by reaction of hydrazines and the corresponding isothiocyanates. Their fungicidal activity was evaluated against the rice blast fungus Pyricularia oryzae. Of this series, 2,5,8‐trimethyl‐6‐(1‐propyl‐5‐thioxo‐3‐trifluoromethyl‐1,2,4‐triazol‐4‐yl) chromone, 6‐(1‐butyl‐5‐thioxo‐3‐trifluoromethyl‐1,2,4‐triazol‐4‐yl)‐2,5,8‐trimethylchromone, 6‐(1‐hexyl‐3‐methyl‐5‐thioxo‐1,2,4‐triazol‐4‐yl)‐2,5,8‐trimethylchromone and 6‐(1‐allyl‐5‐thioxo‐3‐trifluoromethyl‐1,2,4‐triazol‐4‐yl)‐2,5,8‐trimethylchromone were highly active (pEC50>6·0). Structure–activity relationship studies using the capacity factor k′ as a hydrophobicity index suggested that the log k′ optimum for 2,5,8‐trimethyl‐chromone and ‐1‐thiochromone derivatives was around 1·0, equivalent to a log Pow value of c. 4·4. © 1998 SCI

3-Ethyl-5-(4-oxochroman-3-ylmethylene)-1,3-imidazolidine-2,4-dione

“…The glitazones are a new class of antidiabetic drugs that act by improving sensitivity to insulin and are used in the treatment of type 2 diabetes (Bradley, 2002). Many natural and synthetic chromones have biological activities which make them of considerable pharmaceutical interest (Gotoda et al, 1998;Wang et al, 1999;Bozdag -Dü ndar et al, 2003;Yu et al, 2003;Bozdag -Dü ndar et al, 2005). The title compound, (I), is an isostere of 2,4-thiazolidinedione and it was synthesized for antidiabetic activity.…”

Direct difunctional carbonylation of terminal alkynes with sodium sulfinates to access olefin sulfonyl methyl esters under metal-free conditions

“…7 In addition, the difunctional carbonylation of alkynes is an ideal choice for the synthesis of six-membered benzo-fused heterocyclic ketones 8 such as flavones, 4-quinolones, thioflavones, benzosilinones and benzogerminones which have been extensively studied because of their broad biological activities (Scheme 1e). 9…”