Lithium borohydride → HCID 22347523, Verbindung

Temperatur

0 °C

To a solution of tert-butyl 6-(2-ethoxy-2-oxoethyl)-1-methyl-2,3-dihydropyrido[2,3-b]pyrazine-4(1H)-carboxylate 1.05 g, 3.13 mmol)) in dry THF (15 mL) at room temperature was added a solution of LiBH4 (2.0 M in THF, 1.88 mL), and the resulting mixture was heated to reflux. After 16 hours the mixture was cooled to 0° C. and carefully quenched with water (20 mL). After 10 minutes, the mixture was extracted three times with ethyl acetate. The combined organic extracts were dried over MgSO4, filtered, and concentrated under reduced pressure. This residue was dissolved in CH2Cl2 (3 mL), and to this solution was added 4 M HCl in dioxane (6 mL) all at once at room temp. After 4 hours, the mixture was concentrated under reduced pressure to get the crude product, which was chromatographed on silica gel (eluent: 98/2/0.5 dichloromethane/methanol/-ammonium hydroxide) to afford the desired product as a gray solid. (390 mg) H NMR (400 MHz, CDCl3) δ 2.73 (t, 2H), 2.72 (s, 3H), 3.20 (t, 2H), 3.58(m, 2H), 3.89 (t, 2H), 6.36 (d, 1H), 6.58(d, 2H).

1. temperaturethe resulting mixture was heated to reflux
2. customcarefully quenched with water (20 mL)
3. extractionthe mixture was extracted three times with ethyl acetate
4. dry with materialThe combined organic extracts were dried over MgSO4
5. filtrationfiltered
6. concentrationconcentrated under reduced pressure
7. dissolutionThis residue was dissolved in CH2Cl2 (3 mL)
8. additionto this solution was added 4 M HCl in dioxane (6 mL) all at once at room temp
9. waitAfter 4 hours
10. concentrationthe mixture was concentrated under reduced pressure
11. customto get the crude product, which
12. customwas chromatographed on silica gel (eluent: 98/2/0.5 dichloromethane/methanol/-ammonium hydroxide)

ORD-Eintrag

ord-8f37e5f5dd9445f2a01ee84934349e33

Quelldatensatz

uspto-grants-2005_07

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US06921767B2