Sulfuric Acid → 2,4,4-trimethyl-5,6-dihydro-1,3(4H)oxazine

HRID 1795996Notes

Reaction equation

HRID 1795996 reaction equation
OS(O)(=O)=O.[CH3:6][C:7](O)([CH3:11])[CH2:8][CH2:9][OH:10].[C:13](#[N:15])[CH3:14]>>[CH3:14][C:13]1[O:10][CH2:9][CH2:8][C:7]([CH3:11])([CH3:6])[N:15]=1

Participants

4

Reactant 3

HCID 1118Sulfuric AcidHCID 6342Acetonitrile2×HCID 247470Isopentyldiol

Product 1

HCID 105346742,4,4-trimethyl-5,6-dihydro-1,3(4H)oxazineYield 50%

Conditions

Temperature
5 °C

Procedure

Acetonitrile (22.6 g, 0.25 mol) was dripped into concentrated H2SO4 (150 mL) at 0° C. Upon complete addition of acetonitrile, 3-methyl-butane-1,3-diol (Fluka, 22.6 g, 0.55 mol) was added over 0.5 h maintaining the reaction temperature at or below 5° C. The resulting mixture was stirred for 1.5 h at 5° C. then poured onto crushed ice. When the ice had melted, the aqueous was extracted with ether (2×250 mL). The organic was discarded and the aqueous was treated with 40% NaOH to pH 12. The basic aqueous was extracted with ether. The organic was washed with brine and dried (MgSO4). The ether was removed under vacuum at 25° C. affording the desired product as a colorless oil (25.4 g, 50%): 1H NMR (DMSO-d6) δ 4.04 (t, 2H, J=6 Hz), 1.72 (s, 3H), 1.61 (t, 2H, J=6 Hz), 1.07 (s, 6H).

Workup

  1. additionwas added over 0.5 h
  2. temperaturemaintaining the reaction temperature at or below 5° C
  3. additionthen poured
  4. customonto crushed ice
  5. extractionthe aqueous was extracted with ether (2×250 mL)
  6. additionthe aqueous was treated with 40% NaOH to pH 12
  7. extractionThe basic aqueous was extracted with ether
  8. washThe organic was washed with brine
  9. dry with materialdried (MgSO4)
  10. customThe ether was removed under vacuum at 25° C.

Sources & evidence

ORD record
ord-7fbb2eecdfb54192962d2b3392177a7e
Source dataset
uspto-grants-2006_04
Patent number
US07030118B2

Reaction notes

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