- Electrophilically activated nitroalkanes in synthesis of 3,4-dihydroquinozalines
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Nitroalkanes activated with polyphosphoric acid serve as efficient electrophiles in reactions with various nucleophilic amines. Strategically placed second functionality allows for the design of annulation reactions enabling preparation of various heterocycles. This strategy was employed to develop an innovative synthetic approach towards 3,4-dihydroquinazolines from readily available 2-(aminomethyl)anilines.
- Aksenov, Alexander V.,Aksenov, Dmitrii A.,Aksenov, Nicolai A.,Grishin, Igor Yu.,Malyuga, Vladimir V.,Nobi, Mezvah A.,Rubin, Michael
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- CuCl2-catalyzed N[sbnd]O bond cleavage of oxime esters: Approach to imidazoheterocycles and furo[3,2-c]chromenyl fused imidazoles
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An articulate approach to a diverse set of imidazoheterocycles in good to high yields via a copper-catalyzed aza-annulation of several oxime esters with a group of 2-amino-azaarenes was developed. The above cyclization reaction probably proceeds via a single electron transfer process which embodies a new technique for creating two new C[sbnd]N bonds for imidazole ring synthesis. Gratifyingly, the implementation of this chemistry could be further stretched to the synthesis of a novel class of fused imidazoles bearing a furo[3,2-c]chromene moiety via a sequential C[sbnd]N bond formation, followed by C(sp2)-H functionalization/5-endo-dig-oxacyclization (C[sbnd]C and C[sbnd]O bonds) of in situ produced fused imidazoles with cyclic enynones in the presence of copper(II) as a π-electrophilic Lewis acid catalyst.
- Gudimella, Santosh K.,Kaur, Amanpreet,Kumar, Ram,Samanta, Sampak
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supporting information
(2020/07/08)
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- Preparation method of pyrimidine salicylate oxime ester compound and application of compound as herbicide
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The invention discloses a preparation method of a pyrimidine salicylate oxime ester compound and application of the compound as a herbicide, belongs to the technical field of herbicides, and relates to the application of the herbicide in selectively controlling gramineous weeds and broadleaf weeds for crops. The compound is a pyrithiobac oxime ester compound. The preparation method includes the following steps that acids of pyrithiobac are condensed with substituted acetophenoxime in the presence of an organic solvent and a condensation agent to prepare a (I) compound. At 45 g a.i./hm, thecompound can effectively control echinochloa crusgalli, eleusineindica, setaria viridis, amaranthus retroflexus, portulaca oleracea, chenopodium album and other grassy weeds and broadleaf weeds, can serve as a candidate herbicide in a cotton field and has potential industrial application. Meanwhile, the compound is environmentally friendly, low in toxicity and highly safe for crops such as cotton.The invention provides a preparation technology of the efficient and safe novel pyrimidine salicylate oxime ester compound with the herbicidal activity, the compound can be massively produced, the yield is high and the purity is high.
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Paragraph 0093; 0094
(2019/10/22)
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- SO2F2-Activated Efficient Beckmann Rearrangement of Ketoximes for Accessing Amides and Lactams
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A novel, mild and practical protocol for the efficient activation of the Beckmann rearrangement utilizing the readily available and economical sulfuryl fluoride (SO2F2 gas) has been developed. The substrate scope of the operationally simple methodology has been demonstrated by 37 examples with good to nearly quantitative isolated yields (over 90 % yield in most cases) in a short time, including B(OH)2, COOH, NH2, and OH substituted substrates. A tentative mechanism was proposed involving formation and elimination of key intermediate, sulfonyl ester.
- Zhang, Guofu,Zhao, Yiyong,Xuan, Lidi,Ding, Chengrong
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supporting information
p. 4911 - 4915
(2019/07/31)
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