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

Temperature

50 °C

2-Pyrrol-1-yl-ethanamine 2b (2 g, 18 mmol) was dissolved in 40 mL of ethanol, followed by addition of formaldehyde solution (40%, 1.5 mL, 18 mmol) and a slow dropwise addition of 1 mL of trifluoroacetic acid. The reaction mixture was heated to 50° C. for 15 minutes, then cooled to room temperature and stirred for 12 hours. The reaction mixture was concentrated under reduced pressure, added with 50 mL of ethyl acetate, washed with saturated sodium bicarbonate solution (50 mL), dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated under reduced pressure to obtain 1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazine 2c (1.60 g, yield 72.7%) as a light yellow oil.

1. temperaturecooled to room temperature
2. concentrationThe reaction mixture was concentrated under reduced pressure
3. additionadded with 50 mL of ethyl acetate
4. washwashed with saturated sodium bicarbonate solution (50 mL)
5. dry with materialdried over anhydrous sodium sulfate
6. filtrationfiltered
7. concentrationThe filtrate was concentrated under reduced pressure

ORD record

ord-a7cfab18cce0455798ce856ca96380d8

Source dataset

uspto-grants-2016_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09273052B2