Trifluoroacetic anhydride → 3-bromo-5H,6H,7H-cyclopenta(b)pyridin-7-ol

3-Bromo-6,7-dihydro-5H-[1]pyrindine 1-oxide (6.97 g, 32.6 mmol) was dissolved in CH2Cl2 (150 ml); then, trifluoroacetic anhydride (20.5 g, 13.6 ml, 97.7 mmol) was added drop by drop below 25° C. with intense stirring and stirring was continued for 6 hours at RT. The mixture was then quenched with aqueous 1M NaOH solution. The aqueous mixture was stirred for two hours and extracted three times with CH2Cl2/2-propanol 4:1. The organic layers were dried over MgSO4, filtered and concentrated in vacuo to give a crude product (6.279 g) which was purified by flash chromatography (silica gel, 50 g, 20% to 100% EtOAc in heptane) to yield the title compound (5.38 g, 77%) as light brown solid. MS: 214.0 (MH+, 1Br).

1. stirringstirring
2. customThe mixture was then quenched with aqueous 1M NaOH solution
3. stirringThe aqueous mixture was stirred for two hours
4. extractionextracted three times with CH2Cl2/2-propanol 4:1
5. dry with materialThe organic layers were dried over MgSO4
6. filtrationfiltered
7. concentrationconcentrated in vacuo
8. customto give a crude product (6.279 g) which
9. customwas purified by flash chromatography (silica gel, 50 g, 20% to 100% EtOAc in heptane)

ORD-Eintrag

ord-3933d0f045224212b7d3377fe045a55a

Quelldatensatz

uspto-grants-2013_11

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08592426B2