Sulfuric Acid → N-ethyltetrahydro-2H-pyran-4-amine

HRID 650867Notes

Reaction equation

HRID 650867 reaction equation
S(=O)(=O)(O)O.[CH2:6]([NH2:8])[CH3:7].[O:9]1[CH2:14][CH2:13][C:12](=O)[CH2:11][CH2:10]1.[Na]>CO>[CH2:6]([NH:8][CH:12]1[CH2:13][CH2:14][O:9][CH2:10][CH2:11]1)[CH3:7]

Participants

6

Reactant 4

HCID 1118Sulfuric AcidHCID 6341EthylamineHCID 121599Tetrahydro-4H-pyran-4-oneHCID 5360545Sodium

Product 1

HCID 10964527N-ethyltetrahydro-2H-pyran-4-amine

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

At 0° C. and with efficient cooling, 51 g (0.5 mol) of conc. sulfuric acid were added dropwise to a solution of 105 g (2.3 mol) of ethylamine in 0.5 l of methanol. 50 g (0.5 mol) of tetrahydro-2H-pyran-4-one and 18.8 g (0.3 mol) of sodium cyanoborhydride were then added successively. After 16 hours at room temperature, the methanol was distilled off, an excess of 10% strength aqueous sodium hydroxide solution was added and the aqueous phase was extracted three times with dichloromethane. The combined organic phases were washed neutral with water, dried over magnesium sulfate and filtered and the residue was distilled. Bp. 76-82° C. (20 mbar), yield 24 g. 1H NMR (250 MHz, in CDCl3): δ=0.86 (s, 1H), 1.13 (t, 3H), 1.40 (dq, 2H), 1.84 (m, 2H), 2.68 (m, 3H), 3.40 (dt, 2H), 3.98 (m, 2H).

Workup

  1. distillationthe methanol was distilled off
  2. additionan excess of 10% strength aqueous sodium hydroxide solution was added
  3. extractionthe aqueous phase was extracted three times with dichloromethane
  4. washThe combined organic phases were washed neutral with water
  5. dry with materialdried over magnesium sulfate
  6. filtrationfiltered
  7. distillationthe residue was distilled

Sources & evidence

ORD record
ord-adfa32b3afdb4153819d84692425decc
Source dataset
uspto-grants-2001_08
Patent number
US06277790B1

Reaction notes

Loading…