Benzene → 1,3,4-Trihydroxy-6-oxabicyclo[3.2.1]octan-7-one

In a 200 ml round-bottom flask fitted with a stirring bar, reflux condenser, Dean-Stark trap, and argon inlet, 5 g of quinic acid (1, 26 mmol) was placed and 10 mL of dry DMF was added via syringe and the slurry stirred at room temperature. Next, benzene 60 mL and p-toluenesulfonic acid 0.5 g were added, and the slurry was heated to reflux for 26 h. TLC was used confirm the completion of reaction. A 1:1 mixture of EtOAc and 16eptanes (100 mL) was added to the cooled reaction mixture. The mixture was stirred for 1 h at room temperature and filtered. The collected solid was again stirred with a 1:1 mixture of EtOAc and 17eptanes (100 mL) for 1 hr at room temperature and filtered. Tituration was repeated one more time with a 1:1 mixture of EtOAc and 17eptanes (100 mL) and the precipitate collected to give 3.5 g of Lactone 2 (78% yield). Mp: 192-193° C., Rf 0.25 (EtOAc); MS: [M-H]−: 171; 1H NMR (300 MHz, DMSO) δ 1.72 (t, J=1.6 Hz, 1H), 1.82-1.88 (m, 1H), 2.07-2.13 (m, 1H), 2.25 (d, J=1.1 Hz, 1H), 3.49 (ddd, J=11.4, 6.3, 5.7 Hz, 1H), 3.82 (t, J=4.5 Hz, 1H), 4.61 (t, J=5.1 Hz, 1H), 4.816 (d, J=6.0 Hz, 1H), 5.23 (d, J=4.5 Hz, 1H), 5.89 (s, 1H).

1. customIn a 200 ml round-bottom flask fitted with a stirring bar
2. temperaturereflux condenser
3. temperaturethe slurry was heated
4. temperatureto reflux for 26 h
5. customthe completion of reaction
6. additionwas added to the cooled reaction mixture
7. stirringThe mixture was stirred for 1 h at room temperature
8. filtrationfiltered
9. stirringThe collected solid was again stirred with a 1:1 mixture of EtOAc and 17eptanes (100 mL) for 1 hr at room temperature
10. filtrationfiltered
11. additionwith a 1:1 mixture of EtOAc and 17eptanes (100 mL)
12. customthe precipitate collected

ORD record

ord-3667bbc3b5274899a32f3173de1f265d

Source dataset

uspto-grants-2014_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08906965B2