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


为了寻找具有改善生物活性的新型原卟啉原氧化酶（PPO，EC 1.3.3.4）抑制剂，设计并合成了一系列新型吡啶并[2,3- d ]嘧啶-2,4-二酮-苯并嗪酮杂化物9 – 13 。发现了几种具有改善烟草PPO ( mt PPO) 抑制作用和有前景的除草活性的化合物。其中，最有效的化合物是3-(7-氟-3-氧代-4-(prop-2-yn-1-yl)-3,4-二氢-2 H-苯并[ b ][1,4] ] 恶嗪-6-基)-1-甲基吡啶并[2,3- d ]嘧啶-2,4(1 H ,3 H )-二酮, 11q , K _i值为 0.0074 μM, 活性是其六倍氟米恶嗪 ( K _i = 0.046 μM) 对抗mt PPO。通过芽后和芽前施用，化合物11q在 37.5-150 g 活性成分 (ai)/ha 下表现出强而广的杂草控制谱，与氟啶嗪的效果相当。通过芽前施用， 11q在 150 g ai/ha 浓度下对玉米、大豆、花生和棉花是安全的，并且在 75 g ai/ha 浓度下对水稻和小麦有选择性，表明其在这些领域的潜在适用性。