Triethylamine → 2,3-Diphenyl-5,6,7,8-tetrahydropyrido[3,2-b]pyrazine

A suspension of 2,3-diphenylpyrido[3,2-b]pyrazine (Intermediate D) (49.1 g, 143 mmol), triethylamine (20 ml, 143 mmol) and 10% palladium on carbon (19.5 g) in dry THF (410 ml) was placed under an atmosphere of hydrogen (100 mbar) at room temperature for 61 h. After 24 h and 48 h additional palladium catalyst was added (2×4.9 g). The reaction mixture was filtered and the catalyst was washed with THF. The filtrate was concentrated in vacuo and the crude product was dissolved in warm EtOAc (1500 ml) and washed with sat. Na2CO3 solution (400 ml). The aqueous portion was extracted with EtOAc (200 ml) and the combined organic extracts were washed with water (150 ml), brine (300 ml), dried over sodium sulfate and concentrated in vacuo. This crude product was purified by chromatography on silica eluting with neat DCM followed by DCM (1% MeOH) to afford the title product;

1. waitAfter 24 h
2. filtrationThe reaction mixture was filtered
3. washthe catalyst was washed with THF
4. concentrationThe filtrate was concentrated in vacuo
5. dissolutionthe crude product was dissolved in warm EtOAc (1500 ml)
6. washwashed with sat. Na2CO3 solution (400 ml)
7. extractionThe aqueous portion was extracted with EtOAc (200 ml)
8. washthe combined organic extracts were washed with water (150 ml), brine (300 ml)
9. dry with materialdried over sodium sulfate
10. concentrationconcentrated in vacuo
11. customThis crude product was purified by chromatography on silica eluting with neat DCM

ORD record

ord-6152673d056a44cfb5847afd6b239b04

Source dataset

uspto-grants-2014_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08754085B2