Process for the preparation of nitrooxyderivatives of paracetamol
The present invention relates to a new process for the preparation of a compound of the following formula (I):
1. A process for preparing a compound of the following formula (I):
wherein X is a straight or branched C 1 -C 20 -alkylene chain, said process comprising reacting a compound of the following formula (II):
wherein M is a hydrogen atom or a cation of an alkaline or alkaline earth metal, an onium cation with a compound of the following formula (III):
O 2 NO—X—COY (III)
wherein Y is OH, Cl, OCOOR, —OCO—X—ONO 2 wherein R is a C 1 -C 6 alkyl and X is as defined above.
2. The process according to claim 1 wherein X is a straight or branched C 1 -C 6 alkyl chain.
3. The process according to claim 1 wherein X is a propylene chain.
4. The process according to claim 1 wherein Y is OH and M a hydrogen atom.
5. The process according to claim 4 wherein the reaction is carried out in aprotic dipolar solvents, in the presence of a dehydrating agent selected from: dicyclohexylcarbodiimide (DCC); or DCC and an aminopyridine; Amberlyst-15; diethyl azodicarboxylate and triphenylphosphine.
6. The process according to claim 1 wherein M is Na or K and Y is Cl.
7. The process according to claim 6 wherein the reaction is carried out in dipolar aprotic solvents selected from tetrahydrofuran, dioxane, tert-butyl methyl ether.
8. The process according to claims 1 wherein M is an onium cation and Y is Cl.
9. The process according to claim 8 wherein the onium cation is selected from tetraalkylammonium or tetraalkylphosphonium and the reaction is carried out in aprotic solvents selected from toluene, chlorobenzene, tetrahydrofuran, tert-butyl methyl ether.