Ruthenium catalysed N,N′-diarylurea synthesis from N-aryl substituted formamides and aminoarenes

Abstract

Mesitylene refluxN-Aryl substituted formamides react smoothly with aminoarenes in the presence of a catalytic amount of dichlorotris(tripheny1phosphine)ruthenium to afford various N,N'-diarylureas in good yields.

Modified zirconia solid acid catalysts for organic synthesis and transformations

“…The conventional method for the synthesis of diphenylureas is based on phosgene, carbonates, carbamates or carboxylicacid derivatives [34,35]. However, phosgene and isocynates are highly toxic and expensive to handle.…”

A Convenient Synthesis of Unsymmetrically Substituted Ureas via Carbamoyl Azides of α‐N‐Protected Amino Acids

“…Alternative syntheses of ureas involve the reaction of amines with NCO equivalent compounds like carbamates,3a,3c,13 or formamides (in the presence of a Ru catalyst) 14. All these methods require the initial preparation of the reagents, long reaction times, and the final isolation of the reactive intermediate from the excess amount of the reagent 13b.…”

Iron-catalyzed urea synthesis: dehydrogenative coupling of methanol and amines

“… 17 – 21 Metal-catalyzed dehydrogenative coupling approaches for urea synthesis avoid concerns about high pressures and have the advantage of producing dihydrogen (H 2 ) as the only byproduct. Unfortunately, the few examples of dehydrogenative coupling of formamides and amines 22 – 25 and amide cross-coupling 26 , 27 require high catalyst loadings (2–5 mol%) and most also need a stoichiometric peroxide additive. In addition, the preparation of the formamide starting materials is often tedious and typically employs harsh formylating reagents.…”