5221-42-1Relevant articles and documents
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Wakselman,Guibe-Jampel
, p. 4715 (1970)
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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.
Visible Light-Induced Amide Bond Formation
Song, Wangze,Dong, Kun,Li, Ming
supporting information, p. 371 - 375 (2019/11/29)
A metal-, base-, and additive-free amide bond formation reaction was developed under an organic photoredox catalyst. This green approach showed excellent functional selectivity without affecting other functional groups such as alcohols, phenols, ethers, esters, halogens, or heterocycles. This method featured a broad substrate scope, good compatibility with water and air, and high yields (≤95%). The potential utilities were demonstrated by the synthesis of important drug molecules such as paracetamol, melatonin, moclobemide, and acetazolamide.
Catalyst-free, direct electrochemical synthesis of annulated medium-sized lactams through C-C bond cleavage
Ackermann, Lutz,Huang, Zhixing,Kuniyil, Rositha,Li, Yueheng,Ruan, Zhixiong,Xu, Zhongnan,Zhang, Chao
supporting information, p. 1099 - 1104 (2020/03/11)
A catalyst-free, direct electrochemical synthesis of synthetically challenging medium-sized lactams through C-C bond cleavage has been developed. In contrast to previous typical amidyl radical cyclization, this electrosynthetic approach enabled step-economical ring expansion through a unique remote amidyl migration under mild, metal- and external-oxidant-free conditions in a simple undivided cell. The strategy features unparalleled broad substrate scope with all ring sizes of (hetero)aryl-fused 8-11-membered rings and hetero atom-tethered rings, high yields, and good functional group tolerance. Our experimental and computational findings provided strong support for a SET-based reaction manifold.
