Hydrochloric Acid → 1-(Tetrahydro-2H-pyran-2-yl)-1H-imidazole

Temperature

-78 °C

To a solution of imidazole (81.6 g, 1.2 mol) in dry THF (2.5 L) was slowly added NaH (86.4 g, 3.6 mol) in small portions at −78° C. After all NaH was added, the mixture was stirred at −78° C. for 30 min, and 2-chloro-tetrahydropyran solution, prepared by hydrogen chloride gas treatment of dihydropyran, was added to the reaction mixture dropwise. The mixture was slowly warmed to r.t. and it was stirred at r.t. for 2 h. Methanol was added to quench the excess NaH. The mixture was concentrated with a rotary evaporator. Water was added and it was extract with EtOAc (500 mL×3), dried over MgSO4, and purified by neutral Al2O3 column chromatography (petroleum ether 5 L, petroleum ether:CH2Cl2=10:1, petroleum ether:CH2Cl2=3:1, CH2Cl2 and EtOAc). The last four fractions were pooled and concentrated to give 1-(tetrahydro-pyran-2-yl)-1H-imidazole (140 g, 76%). 1H NMR (CDCl3): δ 7.65 (s, 1H), 7.08 (s, 1H), 7.05 (s, 1H), 5.20 (dd, J=2.6, 9.5 Hz, 1H), 4.05-4.02 (m, 1H), 3.68-3.62 (m, 1H), 2.01-1.89 (m, 3H), 1.69-1.60 (m, 3H)

1. customat −78° C
2. additionwas added to the reaction mixture dropwise
3. temperatureThe mixture was slowly warmed to r.t.
4. stirringit was stirred at r.t. for 2 h
5. customto quench the excess NaH
6. concentrationThe mixture was concentrated with a rotary evaporator
7. additionWater was added
8. extractionit was extract with EtOAc (500 mL×3)
9. dry with materialdried over MgSO4
10. custompurified by neutral Al2O3 column chromatography (petroleum ether 5 L, petroleum ether:CH2Cl2=10:1, petroleum ether:CH2Cl2=3:1, CH2Cl2 and EtOAc)
11. concentrationconcentrated

ORD record

ord-7aa593f060924bcc9b8781e7e250614a

Source dataset

uspto-grants-2014_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08785626B2