Reaktion #578710

Reaktionsgleichung

potassium carbonate

HCl

TMPH

2,2,6,6-tetramethyl-4-piperidinol

methyl heptanoate

N2

→

TMPH hydrochloride

Ausbeute 41.0%

Lösungsmittel

MeOH

dimethyl formamide

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturAfter cooling
2. 2
   Sonstigethe reaction mixture was partitioned between water and hexanes
3. 3
   SonstigeThe organic layer was separated
4. 4
   Waschenwashed with water (2×) and brine
5. 5
   Trocknendried over anhydrous MgSO4
6. 6
   Sonstigeevaporated
7. 7
   Sonstigeto afford the crude product as an oil
8. 8
   SonstigeThe solvent was removed in vacuo
9. 9
   workup.ADDITIONthe residue was then treated with diethyl ether
10. 10
    SonstigeThe resulting solids were removed by filtration
11. 11
    EinengenThe ethereal filtrate was concentrated in vacuo
12. 12
    Sonstigetriturated with hexane

Vorschrift

TMPH synthesis. To a mixture of 2,2,6,6-tetramethyl-4-piperidinol (472 mg, 3.0 mmol) and methyl heptanoate (476 mg, 3.3 mmol) in 3.0 mL of dimethyl formamide was added 250 mg of powdered potassium carbonate. The resulting mixture was heated at 145˜155° C. for 64 hours under a gentle stream of N2. After cooling, the reaction mixture was partitioned between water and hexanes. The organic layer was separated, washed with water (2×) and brine, then dried over anhydrous MgSO4 and evaporated to afford the crude product as an oil. The oil was dissolved in MeOH and was then treated with 2 equivalents of conc. HCl. The solvent was removed in vacuo, and the residue was then treated with diethyl ether. The resulting solids were removed by filtration. The ethereal filtrate was concentrated in vacuo and triturated with hexane to afford 380 mg (41%) of TMPH hydrochloride. It was recrystallized from boiling ethyl acetate/hexane to afford short colorless needles, mp 113-115° C. FAB-HRMS: calculated (C16H32NO2): 270.2433 found: 270.2435.

Quelle