Pyridine → N-methoxy-N-methyl-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole-2-carboxamide

Temperatur

5.5 °C

To a cooled (5-6° C.), stirred suspension of crude potassium 5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole-2-carboxylate (0.82 g, 4.3 mmol) in dichloromethane (15 mL), containing N,N-dimethylformamide (0.1 mL, 1.3 mmol), is added, dropwise, oxalyl chloride (0.6 mL, 6.9 mmol). The reaction is exothermic with gas evolution. After the addition, the ice-bath is removed to allow the reaction mixture to stir at room temperature. After 3 hours, the solution is added to a stirred, cooled (10-12° C.) suspension of N,O-dimethylhydroxylamine hydrochloride (0.67 g, 6.9 mmol) in dichloromethane (7 mL) containing pyridine (1.7 mL, 21 mmol). After 40 minutes at room temperature, dichloromethane (35 mL) and water (25 mL) are added. The two layers are separated. The organic layer is extracted with water (2×25 mL), dried over anhydrous sodium sulfate, filtered and concentrated under diminished pressure to give 0.75 g (89% yield) of N-methoxy-N-methyl-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole-2-carboxamide as a brown solid.

1. additionis added
2. additionAfter the addition
3. customthe ice-bath is removed
4. stirringto stir at room temperature
5. additionthe solution is added to a stirred
6. temperaturecooled
7. waitAfter 40 minutes at room temperature
8. customThe two layers are separated
9. extractionThe organic layer is extracted with water (2×25 mL)
10. dry with materialdried over anhydrous sodium sulfate
11. filtrationfiltered
12. concentrationconcentrated under diminished pressure

ORD-Eintrag

ord-b463907f1b3f46de92c06a115f25fcbb

Quelldatensatz

uspto-grants-2007_10

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07276611B2