Synthesis and Herbicidal Activity of 2-(7-Fluoro-3-oxo- 3,4-dihydro-2H-benzo[b][1,4]oxazin-6-yl)isoindoline-1,3-diones

Abstract

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-yl)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.

Design and Synthesis of Novel Triazolyl Benzoxazine Derivatives and Evaluation of Their Antiproliferative and Antibacterial Activity

“…A series of triazolyl benzoxazine derivatives were synthesized by reacting 6-chloro-4-(prop-2-yn-1-yl)-2H-benzo[b] [1,4]oxazin-3(4H)-one (11) and (12) with various aromatic and aliphatic azides (13)(14)(15)(16) via copper(I)-catalyzed 1,3-dipolar cycloaddition (Scheme 1). The key propargyl benzoxazine intermediate was prepared from 2-amino-4-chlorophenol (5) and 2-amino-5-nitrophenol (6).…”

“…Recently, a compound cappamensin A (4) isolated from the roots of Capparis sikkimensis displayed significant in vitro antitumor activity in various human cell lines [7]. Moreover, benzoxazine derivatives are also known to exhibit other activities such as anti-inflammatory [8], antiulcer [9], antipyretic [10], antihypertensive [11], antifungal [12], potassium channel modulators [13], antirheumatic agents [14], and plant resistance factors against microbial diseases and insects [15].…”

A Convenient and Efficient Method for the Synthesis of a Novel Series of N‑Butyl‑1,4-oxazino[2’,3’:4,5]pyrano[3,2-c]quinolinones

“…[1][2][3][4][5] Oxazines heterocycles are special arresting group of compounds known to show effective biological and medicinal properties. 6 The 1,4-oxazine scaffold is a structural subunit of many naturally occurring and synthetic bioactive compounds and have many biological activities such as anti-inflammatory, 7 antiulcer, 8 antipyretic, 9 antihypertensive, 10 antifungal, 11 antirheumatic agents. 12 Pyrano[3,2-c]quinolinones skeletons, including both quinolone ring and pyran moiety, have received much attention due to their various biological properties.…”

Microwave-assisted synthesis of optically active N-substituted 2-methyl-2H-benzo[b][1,4]oxazin-3(4H)-ones and -thiazin-3(4H)-ones via Smiles rearrangement

“…14 Moreover, certain kinds of benzo [1,4]oxazin-3(4H)-ones are of interest as photochromic compounds, 15,16 and some possess herbicidal properties. 17 Benzo[b] [1,4]thiazin-3(4H)-ones exhibit different pharmacological activities: bacteriostatic, 18 antimicrobial, 19 antifungal, 20,21 Na + /H + exchange-system inhibitor, 22 and calcium antagonist. [23][24][25] For example, levosemotiadil (Figure 1), an S-enantiomer of semotiadil, is an antiarrhythmic drug that blocks sodium and calcium channels.…”