Process for preparing 2-amino-5-cyanobenzoic acid derivatives
View Patent ↗Disclosed is a method for preparing a compound of Formula 1 comprising (1) contacting a compound of Formula 2, with (2) at least one alkali metal cyanide and (3) at least one compound of Formula 4 wherein R 1 is NHR 3 or OR 4 ; R 2 is CH 3 or Cl; R 3 is H, C 1 -C 4 alkyl, cyclopropyl, cyclopropylcyclopropyl, cyclopropylmethyl or methylcyclopropyl; R 4 is H or C 1 -C 4 alkyl; and X is Br, Cl or I. Also disclosed is a method for preparing a compound of Formula 4 comprising contacting a mixture of (i) at least one compound of Formula 9 and (ii) at least one metal reducing agent with (iii) dichlorobis(triphenylphosphine)nickel, and further disclosed is a method for removing nickel impurities from a mixture thereof with compounds of Formula 1 comprising contacting the mixture with oxygen in the presence of an aqueous cyanide solution, and additionally disclosed is a method for preparing a compound of Formula 5 wherein R 5 , R 6 , R 7 and Z are as defined in the disclosure, using a compound of Formula 1, characterized by preparing the compound of Formula 1 by the method disclosed above.
1. A method for preparing a compound of Formula 1
wherein
R 1 is NHR 3 or OR 4 ;
R 2 is CH 3 or Cl;
R 3 is H, C 1 -C 4 alkyl, cyclopropyl, cyclopropylcyclopropyl, cyclopropylmethyl or methylcyclopropyl; and
R 4 is H or C 1 -C 4 alkyl;
comprising contacting (1) a compound of Formula 2
wherein X is Br, Cl or I;
with (2) at least one compound of Formula 3
M 1 CN 3
wherein M 1 is an alkali metal;
and (3) at least one compound of Formula 4
provided that when X is Cl, then R 2 is methyl.
2. The method of claim 1 wherein R 1 is NHR 3 .
3. The method of claim 2 wherein R 3 is CH 3 , R 2 is CH 3 , and X is Br or Cl.
4. The method of claim 1 wherein M 1 is selected from the group consisting of sodium and potassium.
5. The method of claim 1 wherein the at least one compound of Formula 4 contains at least about 80 percent chloro-1-naphthalenylbis(triphenylphosphine)-nickel.
6. The method of claim 5 wherein the at least one compound Formula 4 contains at least about 90 percent chloro-1-naphthalenylbis(triphenylphosphine)nickel.
7. The method of claim 1 wherein the compound of Formula 2, the compound or compounds of Formula 3 and the compound or compounds of Formula 4 are contacted in the presence of a suitable organic solvent.
8. The method of claim 7 wherein the compound of Formula 2 and the compound or compounds of Formula 3 are contacted with the suitable organic solvent to form a mixture, and then a slurry of the compound or compounds of Formula 4 in the suitable organic solvent is added to the mixture.
9. The method of claim 7 wherein the suitable organic solvent comprises one or more solvents selected from ethanol, xylenes, toluene and N,N′-dimethylformamide.
10. The method of claim 7 wherein the suitable organic solvent contains at least 50% by weight ethanol, and M 1 is potassium.
11. The method of claim 1 further comprising preparing the at least one compound of Formula 4 by contacting a mixture of (i) at least one compound of Formula 9
and (ii) at least one metal reducing agent with (iii) dichlorobis(triphenylphosphine)nickel.
12. The method of claim 1 further comprising a method for removing nickel impurities from a mixture thereof with compounds of Formula 1 comprising contacting the mixture with oxygen in the presence of an aqueous cyanide solution.
13. The method of claim 12 wherein the aqueous cyanide solution comprises sodium cyanide, potassium cyanide, or mixtures thereof.