Method for the production of 2-amino-5-cyano-N,3-dimethylbenzamide
View Patent ↗The present invention relates to a process for preparing 2-amino-5-cyano-N,3-dimethylbenzamide of formula (I) by reacting 2-amino-5-cyano-3-methylbenzoic esters or diesters with methylamine.
1. A process for preparing 2-amino-5-cyano-N,3-dimethylbenzamide of formula (I)
comprising reacting
(A) 2-amino-5-cyano-3-methylbenzoic esters of formula (II)
where
R 1 represents pentyl, hexyl, 2-ethylhexyl, methoxyethyl or benzyl,
or
(B) 2-amino-5-cyano-3-methylbenzoic diesters of formula (III)
where
A represents alkylene or alkyloxyalkylene,
with MeNH 2 .
2. The process according to claim 1 , wherein a 2-amino-5-cyano-3-methylbenzoic ester of formula (II) and/or a 2-amino-5-cyano-3-methylbenzoic diester of formula (III) is reacted with MeNH 2 by using at least one base.
3. The process according to claim 1 , wherein a compound of formula (I) is obtained by reacting a 2-amino-5-cyano-3-methylbenzoic ester of formula (II).
4. The process according to claim 1 , wherein a compound of formula (I) is obtained by reacting a 2-amino-5-cyano-3-methylbenzoic diester of formula (III).
5. The process according to claim 2 , wherein the base is selected from the group consisting of sodium amide, sodium hydride, sodium hydroxide, sodium cyanide, potassium cyanide, potassium carbonate, sodium carbonate, caesium carbonate, sodium methoxide and triethylamine.
6. The process according to claim 1 , wherein a 2-amino-5-cyano-3-methylbenzoic ester of formula (II) is obtained by reacting a compound of formula (IV)
with CuCN, where X represents Br or I,
and said compound of formula (IV) is obtained by reacting a compound of formula (VI)
with a mixture of HBr/H 2 O 2 .
7. The process according to claim 1 , wherein a 2-amino-5-cyano-3-methylbenzoic diester of formula (III) is obtained by reacting a compound of formula (V)
with CuCN, where X represents Br or I,
and said compound of formula (V) is obtained by reacting a compound of formula (VII)
with a mixture of HBr/H 2 O 2 .
8. The process according to claim 6 , wherein from 0.8 mol to 1.4 mol of copper(I) cyanide is used per 1 mol of compound of formula (IV).
9. The process according to claim 6 , wherein copper(I) cyanide is used in N,N-dimethylformamide, N,N-dimethylacetamide, N-methylformanilide, N-methylpyrrolidone, hexamethylphosphoramide or dimethyl sulphoxide as solvent.
10. The process according to claim 2 , wherein a compound of formula (I) is obtained by reacting a 2-amino-5-cyano-3-methylbenzoic diester of formula (III).
11. The process according to claim 5 , wherein a compound of formula (I) is obtained by reacting a 2-amino-5-cyano-3-methylbenzoic diester of formula (III).
12. The process according to claim 7 , wherein from 0.8 mol to 1.4 mol of copper(I) cyanide is used per 1 mol of compound of formula (V).
13. The process according to claim 7 , wherein copper(I) cyanide is used in N,N-dimethylformamide, N,N-dimethylacetamide, N-methylformanilide, N-methylpyrrolidone, hexamethylphosphoramide or dimethyl sulphoxide as solvent.
14. The process according to claim 4 , wherein A represents ethylene or hexylene.
15. The process according to claim 3 , wherein R1 is benzyl.
16. The process according to claim 3 , wherein R1 is methoxy ethyl.
17. The process according to claim 3 , wherein R1 is pentyl, hexyl, or 2-ethylhexyl.