Nitric Acid → 4-(4-Nitrophenyl)piperidine

Temperature

25 °C

4-Phenylpiperidine (8 g, 49 mmol) was dissolved in 40 mL acetic acid and stirred with cooling below 25° C. while adding a solution of 2.64 mL sulphuric acid in 40 mL acetic acid. The solution was stirred at 20° C. while adding a solution of 2.08 mL 99% nitric acid in 20 mL acetic acid. Sulphuric acid (40 mL) was added without cooling, the temperature peaking at 58° C. When the solution had cooled to 25° C. it was added to 100 g ice/water and basified with a total of 150 g sodium hydrogen carbonate at 40° C. The mixture was then brought to pH 14 with 5M-sodium hydroxide solution. The mixture was extracted with dichloromethane (3×150 mL), dried with sodium sulphate and evaporated giving a pale yellow solid. Recrystallisation from a total of 180 mL cyclohexane (hot filtration) gave the product as pale beige solid. NMR δ 8.18(d,2H), 7.40(d,2H), 3.21(m,2H), 2.77(m,3H), 1.82(m,3H), 1.68(m,2H).

1. temperaturewith cooling below 25° C.
2. stirringThe solution was stirred at 20° C.
3. temperaturewithout cooling
4. customat 58° C
5. extractionThe mixture was extracted with dichloromethane (3×150 mL)
6. dry with materialdried with sodium sulphate
7. customevaporated
8. customgiving a pale yellow solid
9. customRecrystallisation from a total of 180 mL cyclohexane (hot filtration)

ORD record

ord-ee271dfb7b754cd991b3672af842bdb6

Source dataset

uspto-grants-2008_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07442698B2