Synthesis and Herbicidal Evaluation of Triketone-Containing Quinazoline-2,4-diones

Abstract

Exploring novel 4-hydroxyphenylpyruvate dioxygenase (EC 1.13.11.27, HPPD) inhibitors is one of the most promising research directions in herbicide discovery. To discover new triketone herbicides with broad-spectrum weed control as well as excellent crop selectivity, a series of (total 52) novel triketone-containing quinazoline-2,4-dione derivatives were synthesized and further bioevaluated. The greenhouse testing indicated that many of the newly synthesized compounds showed better or excellent herbicidal activity against broadleaf and monocotyledonous weeds at the dosages of 37.5-150 g of active ingredient (ai)/ha. The structure and activity relationship in this study indicated that the triketone-containing quinazoline-2,4-dione motif has possessed great impact on herbicide activity and may be used for further optimization. Among the new compounds, III-b and VI-a-VI-d displayed a broader spectrum of weed control than mesotrione. In addition, the compound III-b also demonstrated comparatively superior crop selectivity to mesotrione, thus possessing great potential for weed control in the field.

Novel HPPD inhibitors: triketone 2H‐benzo[b][1,4]oxazin‐3(4H)‐one analogs

“…(The crystal structures have been deposited at the Cambridge Crystallographic Data Centre and allocated the deposition numbers CCDC 1450978 and CCDC 1450980.) To synthesize the enol ester ( J ), the acid ( I ) is generally transformed into the corresponding acid chloride using SOCl 2 or ClCOCOCl . The limitation of this method is that it can only be utilized to prepare acid chlorides that are stable and not sensitive to SOCl 2 , ClCOCOCl or heat.…”

“…All related work was conducted using the methods reported previously. 8,16,17,[23][24][25][26] The IC 50 values are summarized in Table 1.…”

“…Modification of the benzene ring of existing triketone HPPD herbicides has been an effective method of obtaining new HPPD inhibitors. Modified benzene rings of these novel HPPD herbicides include: benzo[ d ]oxazol‐2(3 H )‐one, 2,3‐dihydrobenzo[ b ]thiophene‐1,1‐dioxide, 4 H ‐thiochromene, quinoline, aryloxymethylene and quinazoline‐2,4(1 H ,3 H )‐dione …”

“…Modified benzene rings of these novel HPPD herbicides include: benzo[d]oxazol-2(3H)-one, 12 2,3-dihydrobenzo[b]thiophene-1,1-dioxide, 13 4H-thiochromene, 14 quinoline, 8 aryloxymethylene 15 and quinazoline-2,4(1H,3H)dione. 16,17 In our previous work, a series of 2H-1,4-benzoxazin-3-(4H)-one herbicides were designed and synthesized as PPO herbicides. Most of these exhibited excellent herbicidal activity.…”

Synthesis and herbicidal activity of novel pyrazole aromatic ketone analogs as HPPD inhibitor

“…Among them, triketone HPPD herbicides with triketone and aromatic moieties are the most widely studied . For example, many studies have reported that the modification of the aromatic part of triketone derivatives is an effective way to obtain new inhibitors with improved potency. All the modified triketone derivatives mainly focused on aromatic component, which is replaced by heterocycles, aliphatic side chains, fused heterocycles and fused aromatics …”