Synthesis and fungicidal activity against Pyricularia oryzae of 6-(1,2,4-triazol-4-yl) chromone and -1-thiochromone derivatives

✍ Scribed by Gotoda, Satoshi; Takahashi, Nobuyoshi; Nakagawa, Hirofumi; Murakami, Mitsuyuki; Takechi, Tomoko; Komura, Tomozo; Uchida, Toshiro; Takagi, Yasushi

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 387 KB
• Volume: 52
• Category: Article
• ISSN: 1526-498X
• DOI: 10.1002/(sici)1096-9063(199804)52:4<309::aid-ps727>3.0.co;2-j

✦ Synopsis

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-triÑuoromethyl-1,2,4-triazol-4-yl) chromone, 6-(1-butyl-5-thioxo-3-triÑuoromethyl-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-triÑuoromethyl-1,2,4-triazol-4-yl)-2,5,8-trimethylchromone were highly active (pEC 50 [ StructureÈactivity relationship studies using the capacity factor k@ as a 6É0). hydrophobicity index suggested that the log k@ optimum for 2,5,8-trimethylchromone and -1-thiochromone derivatives was around 1É0, equivalent to a log value of c. 4É4.