反应详情

温度

85 °C

In a 100 ml flask, 6-methyl-quinoxaline (1.25 g, 8.68 mmol) was dissolved with N-bromosuccinimide (2.32, 13.0 mmol) and benzoyl peroxide (0.15 g, 0.62 mml) in 31 g of chlorobenzene. The mixture was heated up to 85° C. to give a pale yellow solution that turned reddish with time. The solution was maintained at 85° C. for two hours and it was then cooled to −10° C. and filtered. The solution was vacuum dried to give an orange solid residue. The orange solid was then mixed with an alkaline solution prepared by dissolving 2.6 g of sodium hydroxide pellets in 50 ml of water. The mixture was gently heated to 85-95° C. to give a solution of 6-hydroxymethyl-quinoxaline that was mixed with the catalyst (5% Pt/C, 0.2 g) and maintained at that temperature with air sparging. The reaction was monitored by GCMS showing the consumption of 6-hydroxymethyl-quinoxaline and the formation of 6-quinoxalinecarboxaldehyde. After 10 hours, both compounds were completely consumed indicating the end of the reaction. The aqueous solution was cooled to room temperature and filtered. The yellow solution obtained was neutralized with 3.18 g of 96% sulfuric acid dissolved in 5 ml of water. A yellow precipitated was formed during the addition of acid. The yellow solid was filtered and air dried to give 0.67 g of dry product (45% yield). The lower yield in this experiment is attributed to a loss of bromomethyl-quinoxaline that was not recovered with from the succinimides precipitate by washings with pentane as explained in Examples 1 and 2.

1. customto give a pale yellow solution that
2. temperatureThe solution was maintained at 85° C. for two hours
3. temperatureit was then cooled to −10° C.
4. filtrationfiltered
5. customdried
6. customto give an orange solid residue
7. additionThe orange solid was then mixed with an alkaline solution
8. customprepared
9. temperatureThe mixture was gently heated to 85-95° C.