Phosphoric Acid → HCID 67245645, compound

Temperature

-44 °C

A three neck flask fitted with an internal thermometer containing the material from Step iii (4.12 g, 30.5 mmol) was evacuated and then filled with nitrogen atmosphere, THF (50 mL) was added and the solution cooled to −44° C. (CH3CN/dry ice). n-Butyllithium (1.6M/hexane, 21 mL, 34 mmol) was added over 10 minutes, while maintaining the internal temperature at or below −35° C. The reaction was stirred at −33 to −45° C. for 75 minutes. Triisopropyl borate (8.4 mL, 36.6 mmol) was added and the cooling bath removed. The reaction was stirred for one hour then phosphoric acid (85% aqueous, 2.5 mL, 33.5 mmol) was added. The reaction was diluted with 10 mL water resulting in a precipitate. The reaction was stirred vigorously for 15 minutes. A yellow solid was collected by filtration, rinsing with EtOAc (about 50 mL) to provide a white powdery solid (9.57 g). Approximately half of the material was washed with 50 mL water to isolate 3.16 g of a pale pink solid. Both crops of material are the same as determined by spectral data. 1H NMR (400 MHz, METHANOL-d4) δ ppm 7.87 (1H, d, J=5.5 Hz), 7.95 (1H, s), 8.41 (1H, d, J=5.7 Hz), 9.11 (1H, s).

1. customA three neck flask fitted with an internal thermometer
2. customwas evacuated
3. additionfilled with nitrogen atmosphere, THF (50 mL)
4. additionwas added
5. temperaturewhile maintaining the internal temperature at or below −35° C
6. customthe cooling bath removed
7. stirringThe reaction was stirred for one hour
8. stirringThe reaction was stirred vigorously for 15 minutes
9. filtrationA yellow solid was collected by filtration
10. washrinsing with EtOAc (about 50 mL)

ORD record

ord-9bfeb279eb6541df962584c319d41794

Source dataset

uspto-grants-2015_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09090625B2