Palladium-catalyzed reaction of aryl halides with ureas

Palladium‐Catalyzed CN and CO Coupling–A Practical Guide from an Industrial Vantage Point†

“…[26] These findings are backed both by crystallographic data and by 31 P NMR data. The former restriction of the methodology to electron-rich aryl halides could be removed by using Pd 2 (dba) 3 as precatalyst instead of Pd(II)acetate.…”

“…Figure 5) that show especially high activity for coupling of aryl halides with amides, [26 -28] hydrazines, [29] oxazolidinones [30] and ureas. [31] These bisphosphines interestingly can act in a trans-chelating mode. [26] Whereas the above-mentioned ligands constitute the most versatile choice with respect to performance and reliability, new lines of ligand design have led to other classes as well.…”

“…Mild bases like potassium phosphate [48,66] now represent a cheap alternative to the rather expensive cesium carbonate. [31] The fine tuning of the stronger bases also led to a protocol that allows the use of sodium methoxide [47,64] or even more interesting, sodium hydroxide [16,65] as base. In those cases it was understood that next to the catalyst the right combination of base and solvent plays a very important role in the catalytic activity.…”

Palladium‐Catalyzed Aromatic Carbon‐Nitrogen Bond Formation

“…Beletskaya found that coupling reactions between electron-deficient aryl halides and ureas could be accomplished with XantPhos, 4, as the supporting ligand with Pd 2 (dba) 3 [114]. When N-phenylurea was used as a substrate, N-aryl-Nlphenylureas were isolated as the major products.…”

In vitro inhibition of polyphenol oxidase by some new diarylureas

“…N,N′-diarylureas are valuable starting material used in organic synthesis. They have numerous applications such as drugs, pesticides, herbicides, antioxidants and anion-binding receptors 17 . Many urea derivatives are very important compounds because of their biological activities.…”