13256-75-2

Upstream product

• 4013-71-2 pyridine-2-carbonyl azide 
• 106-49-0 p-toluidine 
• 504-29-0 2-aminopyridine 
• 622-58-2 p-Tolylisocyanate 
• 201230-82-2 carbon monoxide 
• 619-55-6 para-methylbenzamide 

Relevant academic research and scientific papers

Synthesis of unsymmetrical urea from aryl- or pyridyl carboxamides and aminopyridines using PhI(OAc)2via in situformation of aryl- or pyridyl isocyanates

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.

Metal-free synthesis of pyridin-2-yl ureas from 2-aminopyridinium salts

An unprecedented base promoted domino approach has been developed for the synthesis of pyridin-2-yl urea derivatives via the reaction of 2-aminopyridinium salts and arylamines. The developed strategy tolerated a wide range of functional groups and afforded pyridin-2-yl ureas in moderate to good yields. The reaction was postulated to involve tandem cyclization, intermolecular nucleophilic addition, ring opening, and demethylation.

Synthesis of unsymmetrical 2-pyridyl ureas via selenium-catalyzed oxidative carbonylation of 2-aminopyridine with aromatic amines

A simple, one-pot, phosgene-free approach to a series of unsymmetrical 2-pyridyl ureas starting from 2-aminopyridine and various aromatic amines is reported for the first time. The procedure employs inexpensive selenium as the catalyst, and carbon monoxide (instead of phosgene) as the carbonyl reagent. The products are obtained in moderate to good yields via selenium-catalyzed oxidative cross-carbonylation of the substrate amines in the presence of oxygen. The selenium functions as a phase-transfer catalyst and can be recovered easily and reused without any significant degradation of its catalytic activity.

Corrosion-protective properties of 1-phenacylmethyl-2- arylcarbamido(arylthiocarbamido)pyridinium bromides

Inhibiting effect of 1-phenacylmethylpyridinium bromides containing urea or thiourea substituents in the pyridinium ring on steel and zinc corrosion in sulfuric acid solutions was studied.

Heteroacyl Azides as Acylating Agents for Aromatic or Heteroatomic Amines (1)

The possibility of formation of substituted heterocyclic amides from heteroacyl azides and aromatic or heteroatomic amines was investigated.Although acylation proceeded in some cases under mild reaction conditions, formation of N,N'-disubstituted ureas was the main process at elevated temperatures.