Formaldehyde → 1,3-Dioxan-5-yl 3-pyridyl ketone

HRID 354717Notes

Reaction equation

HRID 354717 reaction equation
[C:1]([C:4]1[CH:5]=[N:6][CH:7]=[CH:8][CH:9]=1)(=[O:3])[CH3:2].[CH2:10]=[O:11].B(F)(F)F.C[CH2:17][O:18][CH2:19]C>C(O)(=O)C>[N:6]1[CH:7]=[CH:8][CH:9]=[C:4]([C:1]([CH:2]2[CH2:10][O:11][CH2:19][O:18][CH2:17]2)=[O:3])[CH:5]=1

Participants

5

Reactant 3

HCID 712FormaldehydeHCID 8000Boron trifluoride etherateHCID 95893-Acetylpyridine

Product 1

HCID 119709961,3-Dioxan-5-yl 3-pyridyl ketone

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

A 60.6 g. portion of 3-acetylpyridine was combined with 54 g. of paraformaldehyde and 250 ml. of acetic acid. The mixture was cooled in an ice bath, and 184 ml. (1.5 moles) of boron trifluoride etherate was added dropwise with stirring, over a period of about 40 minutes. The temperature of the mixture ranged from 15° to 26° during the addition. The mixture was then stirred under reflux, at about 67°, for 2 hours 15 minutes, and was then cooled slightly. The volatile portions and most of the acetic acid were removed under vacuum, and the remaining mixture was rinsed with water to a large beaker and was made basic with ammonium hydroxide. The basic mixture was filtered through glass wool, and the filtrate was extracted with chloroform. The organic layer was then washed with saturated aqueous sodium chloride, and was dried over magnesium sulfate and filtered. The filtrate was evaporated under vacuum to obtain 128 g. of crude product, which was recrystallized from isopropanol. The total yield was 59.1 g. of purified product, the first crop of which had a melting point of 98°-100°.

Workup

  1. temperatureThe mixture was cooled in an ice bath
  2. additionThe temperature of the mixture ranged from 15° to 26° during the addition
  3. stirringThe mixture was then stirred
  4. temperatureunder reflux, at about 67°, for 2 hours 15 minutes
  5. temperaturewas then cooled slightly
  6. customThe volatile portions and most of the acetic acid were removed under vacuum
  7. washthe remaining mixture was rinsed with water to a large beaker
  8. filtrationThe basic mixture was filtered through glass wool
  9. extractionthe filtrate was extracted with chloroform
  10. washThe organic layer was then washed with saturated aqueous sodium chloride
  11. dry with materialwas dried over magnesium sulfate
  12. filtrationfiltered
  13. customThe filtrate was evaporated under vacuum
  14. customto obtain 128 g
  15. customof crude product, which was recrystallized from isopropanol

Sources & evidence

ORD record
ord-bd7291a53dde4e17b1cf1d7c5dddc4ca
Source dataset
uspto-grants-1983_03
Patent number
US04376860

Reaction notes

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