To search for new protoporphyrinogen oxidase (PPO, EC 1.3.3.4) inhibitors with improved bioactivity, a series of novel pyrido[2,3-d]pyrimidine-2,4-dione–benzoxazinone hybrids, 9–13, were designed and synthesized. Several compounds with improved tobacco PPO (mtPPO)-inhibiting and promising herbicidal activities were found. Among them, the most potent compound, 3-(7-fluoro-3-oxo-4-(prop-2-yn-1-yl)-3,4-dihydro-2H-benzo[b][1,4] oxazin-6-yl)-1-methylpyrido[2,3-d]pyrimidine-2,4(1H,3H)-dione, 11q, with a K_i value of 0.0074 μM, showed six times more activity than flumioxazin (K_i = 0.046 μM) against mtPPO. Compound 11q displayed a strong and broad spectrum of weed control at 37.5–150 g of active ingredient (ai)/ha by both post- and pre-emergence application, which was comparable to that of flumioxazin. 11q was safe to maize, soybean, peanut, and cotton at 150 g ai/ha, and selective to rice and wheat at 75 g ai/ha by pre-emergence application, indicating potential applicability in these fields.

中文翻译：

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作为原卟啉原氧化酶抑制剂的吡啶并[2,3 - d ]嘧啶-2,4-二酮-苯并恶嗪酮杂化物的合成及除草活性

要搜索新原卟啉原氧化酶（PPO，EC 1.3.3.4）具有改善的生物活性抑制剂，一系列新的吡啶并[2,3-的d ]嘧啶-2,4-二酮苯并恶嗪酮杂交种，9 - 13，设计并合成。发现了几种具有改善的烟草PPO（mt PPO）抑制作用和有希望的除草活性的化合物。其中，最有效的化合物3-（7-氟-3-氧代-4-（prop-2-yn-1-yl）-3,4-二氢-2 H-苯并[ b ] [1,4 ] oxazin-6-yl）-1-甲基吡啶[2,3- d ]嘧啶-2,4（1 H，3 H）-二酮，11q，带有一个K _i值为0.0074μM，显示对mt PPO的活性是氟米嗪（K _i = 0.046μM）的六倍。化合物11q在出苗后和出苗前均以37.5–150 g活性成分（ai）/ ha表现出强大而广泛的杂草控制效果，与氟米沙星相当。11q对150 g ai / ha的玉米，大豆，花生和棉花是安全的，并且通过出苗前施用对75 g ai / ha的水稻和小麦具有选择性，表明在这些领域中的潜在适用性。