Synthesis of carbamate or urea compounds

A method for preparing an N,N-diaryl substituted urea derivative for nitrocellulose stabilization, said method comprising a first step of preparing a carbamate according to formula I, comprising reacting an amine according to formula II and a compound according to formula III, in the presence of a catalyst that comprises an N,N-dialkylimidazolium ionic liquid or a non-nucleophilic base

• wherein
• Ar1 is an aryl that is optionally substituted with one or more of halide, alkoxy, alkyl, nitro, sulfonate, ester, amide and/or carboxylate;
• Ar2 is Ar1 or an aryl that is optionally substituted with one or more of halide, alkoxy, alkyl, nitro, sulfonate, ester, amide and/or carboxylate;
• X is an alkoxy, or an aryloxy and is optionally substituted with one or more of halide, alkoxy, alkyl, nitro, sulfonate, ester, amide and/or carboxylate;
• and
• LG is an alkoxy, an aryloxy, an amine that is optionally substituted with one or two C1-C4 alkyl groups, an amide, a sulfonate, a halide, a nitrate, a phosphate or a carboxylate;
• wherein the catalyst is present in less than 50 mol % with respect to the amine according to formula II;
• and
• followed by a second step wherein the carbamate according to formula I is reacted with an amine to form said N,N-diaryl substituted urea derivative for nitrocellulose stabilization.