Silver-catalyzed synthesis of amides from amines and aldehydes
The invention provides a method for producing amides via the reaction of aldehydes and amines with oxygen adsorbed on a metallic silver or silver alloy catalyst. An exemplary reaction is shown in Scheme 1: (I), (II), (III).
1. A method for preparing an amide comprising reacting an aldehyde and a primary or secondary amine with oxygen adsorbed on a catalyst comprising silver metal or an alloy thereof to produce the amide.
2. The method of claim 1 , wherein the amide is of formula III, the aldehyde is of formula I and the primary or secondary amine is of formula II:
wherein R 1 is selected from the group consisting of H, C 1 -C 6 straight chain alkyl, C 3 -C 6 branched alkyl, and C 3 -C 8 cycloalkyl; and
wherein R 2 and R 3 are independently selected from the group consisting of H, C 1 -C 6 straight chain alkyl, C 3 -C 6 branched alkyl, and C 3 -C 8 cycloalkyl, or R 2 and R 3 , together with the nitrogen to which they are attached, form a 3- to 6-membered heterocyclic ring; or R 1 and R 2 together are C 1 -C 6 alkylene.
3. The method of claim 2 , wherein R 1 is selected from the group consisting of H, C 1 -C 4 straight chain alkyl, C 3 -C 4 branched alkyl, and C 3 -C 4 cycloalkyl; and
wherein R 2 and R 3 are independently selected from the group consisting of H, C 1 -C 4 straight chain alkyl, C 3 -C 4 branched alkyl, and C 3 -C 4 cycloalkyl, or R 2 and R 3 , together with the nitrogen to which they are attached, form a 3- to 6-membered heterocyclic ring.
4. The method of claim 2 , wherein R 2 and R 3 are methyl.
5. The method of claim 1 , wherein the aldehyde is formaldehyde.
6. The method of claim 1 , wherein the silver alloy is an alloy of silver and gold.
7. The method of claim 1 , wherein the source of the adsorbed oxygen is oxygen gas.
8. The method of claim 1 , wherein the amine is a primary amine.
9. The method of claim 1 , wherein the amine is a secondary amine.
10. The method of claim 1 , wherein the catalyst is promoted by a material selected from the group consisting of metal halides, carbonates, sulfites, sulfates, nitrites, and nitrates, transition metal oxoanions, lanthanides, and alkali and alkaline earth metals.
11. The method of claim 1 , wherein the temperatures is from 270 to 1000 K.
12. The method of claim 1 , wherein the pressure is from 0.1 atm to 5 atmospheres.
13. The method of claim 1 , wherein the catalyst is carried on an inert supporting material.