6268-43-5Relevant articles and documents
Synthesis of unsymmetrical urea from aryl- or pyridyl carboxamides and aminopyridines using PhI(OAc)2via in situformation of aryl- or pyridyl isocyanates
Hunjan, Mandeep Kaur,Laha, Joydev K.,Singh, Neha
, p. 18815 - 18823 (2021/10/26)
A tandem synthesis of unsymmetrical ureas (N-aryl-N′-pyridylurea andN,N′-bipyridylurea) from aryl- or pyridyl carboxamides and aminopyridinesviaHofmann rearrangement has been reported. In particular, benzamides, picolinamide, nicotinamide, and isonicotinamide generate reactive intermediate isocyanates,in situ, in the presence of PhI(OAc)2, which upon further reaction with aminopyridines form urea derivatives. As the formation of pyridylisocyanates from their corresponding carboxamidesviaHofmann rearrangement remained unexplored previously, attempts have been made to trap the isocyanates. While the three pyridylisocyanates were trapped as their corresponding carbamates, 3-pyridylisocyanate was isolated and characterized. Unlike closely related previous methods reported for urea synthesis, the current method avoids direct use of isocyanates or eliminates the use of toxic phosgene for thein situgeneration of isocyanates.
Method for preparing symmetric urea compound
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Paragraph 0038-0043; 0175-0180, (2020/03/25)
The invention provides a novel reaction system for synthesizing a symmetric urea compound by taking CO2 as a carbonylation reagent, wherein Lewis base and hydrosilane are used as accelerators and efficiently enable an aromatic/aliphatic primary amine compound to react with normal-pressure CO2 to generate corresponding symmetric urea compounds containing different functional groups under mild conditions (100 DEG C, diglyme). According to the method, normal-pressure CO2 is used as an environmentally-friendly non-toxic carbonylation reagent, and cheap Lewis base and PMHS (industrial silicon waste) are used as accelerators, so that the use of toxic carbonylation reagents, isocyanate, high-pressure CO2, expensive dehydrating agents and precious metals is avoided, purification and separation ofintermediates are not needed, pure products can be obtained only through simple suction filtration and separation after the reaction is finished, and the method is an efficient and novel synthesis method and has high industrial application value.
Antischistosomal activity of N,N′-arylurea analogs against Schistosoma japonicum
Yao, Houzong,Liu, Fengyou,Chen, Jinglei,Li, Yan,Cui, Jinhao,Qiao, Chunhua
supporting information, p. 1386 - 1390 (2016/02/19)
Although the antischistosomal activities of N,N′-arylurea analogs were reported, systematic structure-activity relationships have not been conducted. In this Letter, we reported the design, synthesis and evaluation of 45 N,N′-arylurea analogs. Among these prepared compounds, 13 compounds were urea linker modified and 32 were N,N′-arylurea derivatives. The activity evaluation revealed 12 analogs exhibited IC50 values lower than 22.6 μM, and 7 of them had IC50 less than 10 μM against the juvenile Schistosoma japonicum in vitro. Their worm killing potency was even higher against adult worm. Unfortunately, low to moderate worm burden reduction of 0-33.4% was recorded after administration of a single oral dose of 200 mg/kg or 400 mg/kg to mice harboring S. japonicum.
