Water → 5-Methylpyrazine-2-carboxaldehyde

In methanol (15 ml), 5-methylpyrazine-2-carboxylic acid (manufactured by Tokyo Kasei Kogyo Co., Ltd.) (1.25 g) was dissolved. Then, the solution was added with WSCI hydrochloride (2.59 g) and N,N-dimethylaminopyridine (1.65 g) in this order, followed by stirring at room temperature for 3 hours. The reaction solution was added with water and then extracted with chloroform. The organic layer was washed with saturated saline solution and then dried with anhydrous sodium sulfate. The solvent was distilled off and the resulting crude product was then purified through silica gel column chromatography (chloroform/methanol). The purified product was dissolved in ethanol (15 ml) and THF (8 ml) and added with calcium chloride (1.11 g). After that, the reaction solution was cooled to 0° C. and then gradually added with sodium borohydride (757 mg), followed by stirring at room temperature for 19 hours. The reaction solution was added with a 1 mol/l citric acid solution (40 ml), followed by extraction with ethyl acetate. The organic layer was washed with saturated saline solution and then dried with anhydrous sodium sulfate, followed by distilling the solvent off. The residue was dissolved in chloroform (10 ml) and then added with manganese dioxide (chemically processed product) (2.2 g), followed by stirring at room temperature for 1 hour. After completion of the reaction, the catalyst was filtrated out through Celite and the solvent was then distilled off. The crude product obtained was purified through silica gel column chromatography (chloroform/methanol), thereby obtaining the subject compound (35.9 mg) as a colorless oily substance.

1. extractionextracted with chloroform
2. washThe organic layer was washed with saturated saline solution
3. dry with materialdried with anhydrous sodium sulfate
4. distillationThe solvent was distilled off
5. customthe resulting crude product was then purified through silica gel column chromatography (chloroform/methanol)
6. dissolutionThe purified product was dissolved in ethanol (15 ml)
7. additionTHF (8 ml) and added with calcium chloride (1.11 g)
8. temperatureAfter that, the reaction solution was cooled to 0° C.
9. additiongradually added with sodium borohydride (757 mg)
10. stirringby stirring at room temperature for 19 hours
11. additionThe reaction solution was added with a 1 mol/l citric acid solution (40 ml)
12. extractionfollowed by extraction with ethyl acetate
13. washThe organic layer was washed with saturated saline solution
14. dry with materialdried with anhydrous sodium sulfate
15. distillationby distilling the solvent off
16. dissolutionThe residue was dissolved in chloroform (10 ml)
17. additionadded with manganese dioxide (chemically processed product) (2.2 g)
18. stirringby stirring at room temperature for 1 hour
19. customAfter completion of the reaction
20. filtrationthe catalyst was filtrated out through Celite
21. distillationthe solvent was then distilled off
22. customThe crude product obtained
23. customwas purified through silica gel column chromatography (chloroform/methanol)

ORD record

ord-949c981be40d4c2d857479dc75980ef4

Source dataset

uspto-grants-2007_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07176227B2