N-bromobutanimide → Methyl 3-Amino-6-bromopyrazine-2-carboxylate

3-Aminopyrazine-2-carboxylic acid methyl ester (1 kg), N-bromosuccinimide (1.162 kg and acetonitrile (8 L) were charged into reactor. The mixture was stirred at room temperature for 10 min, heated to 75-80° C. and held for 2-3 hours under slightly refluxing conditions. The mixture was cooled to 25° C. and evaporated to dryness on a rotary evaporator. The resulting dark solids were redissolved in dichloromethane (20 L) and activated carbon (100 g) was charged. The resulting suspension was stirred at 25° C. for 30-60 minutes before filtering to remove insolubles. The filtrate was subsequently washed with saturated Na2SO3 (3×5 L) aqueous solution and water (5 L). The Organic layers were collected after phase separation. Dichloromethane was removed on rotary evaporator and Methyl 3-amino-6-bromopyrazine-2-carboxylate was obtained as a brown solid which was used in the next step without further purification (wet product 1090 g).

1. temperatureheated to 75-80° C.
2. waitheld for 2-3 hours under slightly refluxing conditions
3. temperatureThe mixture was cooled to 25° C.
4. customevaporated to dryness on a rotary evaporator
5. dissolutionThe resulting dark solids were redissolved in dichloromethane (20 L)
6. additionactivated carbon (100 g) was charged
7. stirringThe resulting suspension was stirred at 25° C. for 30-60 minutes
8. filtrationbefore filtering
9. customto remove insolubles
10. washThe filtrate was subsequently washed with saturated Na2SO3 (3×5 L) aqueous solution and water (5 L)
11. customThe Organic layers were collected
12. customafter phase separation
13. customDichloromethane was removed on rotary evaporator

ORD record

ord-88d86351c5914cd6b13e99ed85788468

Source dataset

uspto-grants-2012_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08198285B2