Formaldehyde → 1,2,3,4-Tetrahydropyrrolo(1,2-a)pyrazine

Temperature

50 °C

To a ethanol solution (20 ml) of 1-(2-aminoethyl)pyrrole (9 mmol) and 37% formaldehyde (9 mmol) was added TFA (0.5 ml) and the resulting reaction mixture was stirred at 50° C. for 15 minutes. It was then cooled to come to 25° C. and stirred at this temperature for 4 hrs. Solvent was removed under reduced pressure, residue was dissolved in ethyl acetate, basified with aqueous sodium carbonate solution, organic layer was separated and dried over sodium sulfate. Evaporation of the organic layer gave the crude 1,2,3,4-Tetrahydro-pyrrolo[1,2-a]pyrazine which was dissolved in dichloromethane (90 ml) at to it DIPEA (12.15 mmol) and boc anhydride (8.9 mmol) were added at 0° C. The resulting reaction mixture was stirred for 16 hrs at 25° C. Organic layer was washed with sodium carbonate, water and brine and finally dried over sodium sulfate. Evaporation of the organic layer gave the crude product which was purified by column chromatography (1% ethyl acetate in dichloromethane). (10% ethyl acetate in hexane).

1. customthe resulting reaction mixture
2. temperatureIt was then cooled
3. customto come to 25° C.
4. stirringstirred at this temperature for 4 hrs
5. customSolvent was removed under reduced pressure, residue
6. dissolutionwas dissolved in ethyl acetate
7. customwas separated
8. dry with materialdried over sodium sulfate
9. customEvaporation of the organic layer

ORD record

ord-e92b5bb6099c469fb05833eb169534f9

Source dataset

uspto-grants-2012_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08178535B2