Ammonia → Lamotrigine

A solution of 2,3-dichlorobenzoyl cyanide (32 g, 0.16M) in dimethylsulphoxide (80 ml) was added dropwise to a stirred suspension of aminoguanidine bicarbonate (81.67 g. 0.6M) which had been treated with 8N aqueous nitric acid (400 ml) at a temperature of ca 25° C. The mixture was stirred for 3 hours, then left to stand at room temperature for 7 days. The cooled mixture was stirred and basified with 0.880 aqueous ammonia (400 ml) at 20° C., then stirred with ice cooling for 30 minutes. The resulting solid was separated by filtration, washed thoroughly with water and finally dried in vacuo. The above solid was added to a 10% w/v solution of potassium hydroxide pellets in methanol (400 ml) and the solution heated to reflux for 11/2 hours. When cool the solution was evaporated down in vacuo, treated with ice water (800 ml) then stirred for 30 minutes and filtered. The residue was dried and recrystallised from isopropanol to give 3,5-diamino-(2,3-dichlorophenyl)-1,2,4-triazine Yield 6.8 g (15.6%), m.p. 216°-218° C. (uncorrected).

1. waitleft
2. waitto stand at room temperature for 7 days
3. stirringThe cooled mixture was stirred
4. stirringstirred with ice cooling for 30 minutes
5. customThe resulting solid was separated by filtration
6. washwashed thoroughly with water
7. customfinally dried in vacuo
8. additionThe above solid was added to a 10% w/v solution of potassium hydroxide pellets in methanol (400 ml)
9. temperaturethe solution heated
10. temperatureto reflux for 11/2 hours
11. temperatureWhen cool the solution
12. customwas evaporated down in vacuo
13. additiontreated with ice water (800 ml)
14. stirringthen stirred for 30 minutes
15. filtrationfiltered
16. customThe residue was dried
17. customrecrystallised from isopropanol

ORD record

ord-20177862e6074aadb5ad220f1104bd0e

Source dataset

uspto-grants-1987_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04649139