Oxidation method of primary or secondary alcohol
View Patent ↗A method for preparing an aldehyde or ketone by oxidizing a primary or secondary alcohol in the presence of a nitroxyl radical compound and a co-oxidant in an organic solvent, which process is characterized in using an organic N-bromoamide compound or a combination of N-chlorosuccinimide and a compound having bromide ion as the co-oxidant.
1. A process for preparing an aldehyde or ketone by oxidizing a primary or secondary alcohol in the presence of a nitroxyl radical compound represented by the following formula (1),
wherein R 0 to R 4 are the same or different and straight or branched C 1-10 alkyl group, or two R 0 s may be combined together with the nitrogen atom to form a 5 to 7 membered hetero ring, and a co-oxidant in an organic solvent, which process comprises using an organic N-bromoamide compound or a combination of N-chlorosuccinimide and a compound having bromide ion as said co-oxidant.
2. The process of claim 1 wherein the nitroxyl radical compound is a compound of the following formula (1a),
wherein R 1 to R 4 are the same as defined above, R 5 and R 6 are both hydrogen atom or both C 1-6 alkoxy group, or one of R 5 and R 6 is hydrogen atom and the other is hydroxy group, C 1-6 alkoxy group, acyloxy group or acylamino group, or R 5 and R 6 taken together may form any one of ketal groups of the formulas (a) to (c),
wherein R 9 is C 1-6 alkyl, and R 10 and R 11 are both hydrogen atom or the same or different and are C 1-6 alkyl group.
3. The process of claim 2 wherein the nitroxyl radical compound is a compound of the formula (1a) wherein R 1 to R 4 are all methyl groups, and R 5 and R 6 are both hydrogen atom, or one of R 5 and R 6 is hydrogen atom and the other is hydroxy group, methoxy group, acetoxy group, benzoyloxy group or acetamide group.
4. The process of any one of claims 1 to 3 wherein the co-oxidant is an organic N-bromoamide compound.
5. The process of claim 4 wherein the organic N-bromoamide compound is N-bromosuccinimide or N-bromoacetamide.
6. The process of any one of claims 1 to 3 wherein the co-oxidant is a combination of N-chlorosuccinimide and a compound having bromide ion.
7. The process of claim 6 wherein the compound having bromide ion is an alkali metal bromide or a quaternary ammonium bromide.
8. The process of claim 6 wherein the compound having bromide ion is sodium bromide or potassium bromide.
9. The process of any one of claims 1 to 3 wherein the co-oxidant is N-bromoacetamide, N-bromosuccinimide, tribromoisocyanuric acid, dibromo dimethyl hydantoin, N-bromophthalimide or a combination of N-chlorosuccinimide and a compound having bromide ion.
10. The process according to claim 1 , which process consists essentially of using N-bromoacetamide, N-bromosuccinimide, tribromoisocyanuric acid, dibromo dimethyl hydantoin, N-bromophthalimide or a combination of N-chlorosuccinimide and a compound having bromide ion as said co-oxidant.
11. The process according to claim 9 , which process consists essentially of using N-bromoacetamide, N-bromosuccinimide, tribromoisocyanuric acid, dibromo dimethyl hydantoin, N-bromophthalimide or a combination of N-chlorosuccinimide and a compound having bromide ion as said co-oxidant.
12. The process according to claim 10 wherein the co-oxidant is N-bromosuccinimide or N-bromoacetamide.
13. The process according to claim 10 wherein the co-oxidant is a combination of N-chlorosuccinimide and a compound having bromide ion.
14. The process according to claim 11 wherein the co-oxidant is N-bromosuccinimide or N-bromoacetamide.
15. The process according to claim 11 wherein the co-oxidant is a combination of N-chlorosuccinimide and a compound having bromide ion.