1-Chloroethyl chloroformate → 1,1-Diphenyltetrahydro-1H-oxazolo[3,4-a]pyrazin-3(5H)-one

HRID 1713501Notes

Reaction equation

HRID 1713501 reaction equation
CC1C=CC(C[N:9]2[CH2:14][CH2:13][N:12]3[C:15](=[O:30])[O:16][C:17]([C:24]4[CH:29]=[CH:28][CH:27]=[CH:26][CH:25]=4)([C:18]4[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=4)[CH:11]3[CH2:10]2)=CC=1.ClC(OC(Cl)C)=O>ClCCCl>[C:24]1([C:17]2([C:18]3[CH:19]=[CH:20][CH:21]=[CH:22][CH:23]=3)[CH:11]3[CH2:10][NH:9][CH2:14][CH2:13][N:12]3[C:15](=[O:30])[O:16]2)[CH:29]=[CH:28][CH:27]=[CH:26][CH:25]=1

Participants

4

Reactant 2

HCID 5213051-Chloroethyl chloroformateHCID 23121897HCID 23121897, compound

Product 1

HCID 231218811,1-Diphenyltetrahydro-1H-oxazolo[3,4-a]pyrazin-3(5H)-oneYield 80.7%

Reagents, catalysts & solvents 1

HCID 111,2-DichloroethaneSolvent

Procedure

Hexahydro-7-[(4-methylphenyl)methyl]-1,1-diphenyl-3H-oxazolo[3,4-a]pyrazin-3-one (65 g, 0.16 mol) was dissolved in 1,2-dichloroethane (300 mL). 1-Chloroethyl chloroformate (22 mL, 0.2 mol) was added thereto, and the mixture was warmed and refluxed for 3 hours. The solvent was distilled off under reduced pressure, and then methanol (300 mL) was added thereto. The mixture was warmed and refluxed for 3 hours. The solvent was distilled off under reduced pressure, and to the residue was added ethyl acetate (500 mL) to obtain powder. The obtained powder was collected by filtration, washed with ethyl acetate, and dried under reduced pressure. To the obtained powder (54 g) were added an aqueous saturated sodium hydrogen carbonate solution (500 mL) and ethyl acetate (500 mL), and the process of phase separation was performed. The resulting organic layer was washed with an aqueous saturated sodium hydrogen carbonate solution (400 mL) and dried over magnesium sulfate. The solvent was distilled off under reduced pressure. The residue was recrystallized from diethyl ether and the resulting crystals (42 g) were recrystallized from ethyl acetate again to obtain the title compound (38 g, yield 78%). 1H NMR of the above obtained compound corresponded with the compound obtained in Reference Example 2.

Workup

  1. temperaturethe mixture was warmed
  2. temperaturerefluxed for 3 hours
  3. distillationThe solvent was distilled off under reduced pressure
  4. additionmethanol (300 mL) was added
  5. temperatureThe mixture was warmed
  6. temperaturerefluxed for 3 hours
  7. distillationThe solvent was distilled off under reduced pressure
  8. additionto the residue was added ethyl acetate (500 mL)
  9. customto obtain powder
  10. filtrationThe obtained powder was collected by filtration
  11. washwashed with ethyl acetate
  12. customdried under reduced pressure
  13. additionTo the obtained powder (54 g) were added an aqueous saturated sodium hydrogen carbonate solution (500 mL) and ethyl acetate (500 mL)
  14. customthe process of phase separation
  15. washThe resulting organic layer was washed with an aqueous saturated sodium hydrogen carbonate solution (400 mL)
  16. dry with materialdried over magnesium sulfate
  17. distillationThe solvent was distilled off under reduced pressure
  18. customThe residue was recrystallized from diethyl ether
  19. customthe resulting crystals (42 g) were recrystallized from ethyl acetate again

Sources & evidence

ORD record
ord-ac69d2828ac64135ba87981fafeb3149
Source dataset
uspto-grants-2010_09
Patent number
US07795267B2

Reaction notes

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