The mode of action of 2-(7-fluoro-3-oxo-3,4-dihydro-2H-benzo[b][1,4]oxazin-6-yl)-4,5,6,7-tetrahydro-2H- isoindoline-1,3-diones, including the commercial herbicide flumioxazin, had been identified as inhibition of protoporphyrinogen oxidase (protox). As part of continuous efforts to search for new herbicides with high efficacy, broad-spectrum activity, and safety to crops, flumioxazin and its iodo analogue (B2055) were used as lead compounds for further optimization. Series of novel compounds were prepared by multistep synthetic procedures starting from 5-fluoro-2-nitrophenol. All of the test compounds were structurally confirmed by 1H NMR, IR, mass spectroscopy, and elemental analysis. Preliminary bioassay data showed that some of them possess commercial levels of herbicidal activity comparable to those of other protox-inhibiting herbicides. One of the best compounds, 5-fluoro-2-(7-fluoro-3-oxo-4-(prop-2-ynyl)-3,4-dihydro-2H-benzo[b][1,4]oxazin-6-y l)isoindoline-1,3-dione (8e), has IC50 values for velvetleaf (Abutilon theophrasti Medic) and crabgrass (Digitaria sanguinalis) comparable to thos of B2055. With respect to crop selectivity, compound 8e is similar to flumioxazin. Compound 8e is safe to cotton and maize at a rate of 150 g of active ingredient (ai)/ha or less when applied at pre-emergent stage, and it has the best safety to wheat among the tested crops, showing no injury after post-emergent application at 7.5-30 g of ai/ha.

中文翻译：

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2-（7-氟-3-氧代-3,4-二氢-2H-苯并[b] [1,4]恶嗪-6-基）异吲哚啉-1,3-二酮的合成及除草活性。

2-（7-氟-3-氧代-3,4-二氢-2H-苯并[b] [1,4]恶嗪-6-基）-4,5,6,7-四氢-的作用方式包括市售除草剂氟米沙星在内的2H-异吲哚啉-1,3-二酮已被鉴定为对原卟啉原氧化酶（protox）的抑制作用。为了不断寻求新的高效，广谱活性和对农作物安全的除草剂，氟米沙星及其碘类似物（B2055）被用作进一步优化的先导化合物。通过从5-氟-2-硝基苯酚开始的多步合成程序制备了一系列新型化合物。通过1 H NMR，IR，质谱和元素分析在结构上确认所有测试化合物。初步的生物测定数据表明，其中一些具有与其他抑制protox的除草剂相当的商业除草活性。最好的化合物之一，5-氟-2-（7-氟-3-氧代-4-（丙-2-炔基）-3,4-二氢-2H-苯并[b] [1,4]恶嗪- 6-基）异吲哚啉-1,3-二酮（8e）具有与B2055相当的绒毛（Abutilon theophrasti Medic）和马尾草（Digitaria sanguinalis）的IC50值。关于作物选择性，化合物8e类似于氟米嗪。在出苗前施用时，化合物8e对棉花和玉米的安全性为有效成分（ai）/公顷为150 g或更少，并且对受试作物中小麦的安全性最高，在出苗后对作物无伤害7.5-30 g ai / ha的紧急应用。具有与B2055相似的天鹅绒（Abutilon theophrasti Medic）和马鞭草（Digitaria sanguinalis）的IC50值。关于作物选择性，化合物8e类似于氟米嗪。在出苗前施用时，化合物8e对棉花和玉米的安全性为有效成分（ai）/公顷为150 g或更少，并且对受试作物中小麦的安全性最高，在出苗后对作物无伤害7.5-30 g ai / ha的紧急应用。具有与B2055相似的天鹅绒（Abutilon theophrasti Medic）和马鞭草（Digitaria sanguinalis）的IC50值。关于作物选择性，化合物8e类似于氟米嗪。在出苗前施用时，化合物8e对棉花和玉米的安全性为有效成分（ai）/公顷为150 g或更少，并且对受试作物中小麦的安全性最高，在出苗后对作物无伤害7.5-30 g ai / ha的紧急应用。