Patent ID: 8143423

Claim:
A process for preparing a hydroxamic acid represented by the formula (I): wherein: R 1 is a hydrogen atom, a C 1-6 alkyl group which may be substituted with one or more sub stituents which are the same or different, a C 2-6 alkenyl group which may be substituted with one or more substituents which are the same or different, a C 2-6 alkynyl group which may be substituted with one or more substituents which are the same or different, a C 3-8 cycloalkyl group which may be substituted with one or more sub stituents which are the same or different, a C 3-8 cycloalkenyl group which may be substituted with one or more substituents which are the same or different, a C 6-14 aryl group which may be substituted with one or more substituents which are the same or different, a C 6-14 aryl-C 1-6 alkyl group which may be substituted with one or more substituents which are the same or different, a C 6-14 aryl-C 2-6 alkenyl group which may be substituted with one or more substituents which are the same or different, a C 6-14 aryl-C 2-6 alkynyl group which may be substituted with one or more substituents which may be the same or different, a 4- to 10-membered non-aromatic heterocyclic group containing one or more heteroatoms which are independently nitrogen, sulfur or oxygen and which group may be substituted with one or more substituents which are the same or different, or a 5- to 14-membered aromatic heterocyclic group containing one or more heteroatoms which are independently nitrogen, sulfur or oxygen and which group may be substituted with one or more substituents which are the same or different; and R 2 is a C 6-14 aryl group which may be substituted with one or more substituents which are the same or different, which process comprises reacting an aldehyde represented by the formula (II): wherein R 1 is as defined above, with a nitroso compound represented by the formula (III): wherein R 2 is as defined above, in the presence of a N-heterocyclic carbene (NHC) catalyst, the NHC catalyst being derived from a triazolium salt represented by the formula wherein R 9 is phenyl (Ph) which may be substituted, i-propyl ( i Pr), mesityl (Mes) or 2,6-diisopropylphenyl (2,6- i Pr-Ph); and X − is Br − , BF 4 − or CF − .