Acetic Acid → Benzoxazole

HRID 728176Notes

Reaction equation

HRID 728176 reaction equation
C([BH3-])#N.[Na+].C(N[C:8]1[O:9][C:10]2[CH:16]=[CH:15][C:14](COC3C=CC=C(C=O)C=3)=[CH:13][C:11]=2[N:12]=1)C.N1CCCCC1.C(O)(=O)C>CO>[O:9]1[C:10]2[CH:16]=[CH:15][CH:14]=[CH:13][C:11]=2[N:12]=[CH:8]1

Participants

6

Reactant 4

HCID 176Acetic AcidHCID 8082PiperidineHCID 5003444Sodium cyanoborohydrideHCID 15171556HCID 15171556, compound

Product 1

HCID 9228BenzoxazoleYield 108.8%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

Sodium cyanoborohydride (0.17 g) was added portionwise to a solution of 2-ethylamino-5-(3-formylphenoxymethyl)benzoxazole (0.80 g), piperidine (0.23 g) and acetic acid (0.76 ml) in methanol (10 ml) at 0° C. with stirring. The mixture was stirred at the same temperature for 2 hours and for further 6 hours at ambient temperature. The solvent was evaporated in vacuo. The residue was mixed with a saturated sodium bicarbonate solution and extracted with ethyl acetate. The extract was washed with water, dried over magnesium sulfate and evaporated in vacuo. The residue was chromatographed on silica gel by eluting with a mixture of chloroform-methanol (20:1, V/V). The pure base was converted to the hydrochloride in a usual manner. The salt was dissolved in ethanol and reprecipitated with diethyl ether to give 2-ethylamino-5-3-piperidinomethylphenoxymethyl)benzoxazole (0.35 g) dihydrochloride.

Workup

  1. stirringThe mixture was stirred at the same temperature for 2 hours and for further 6 hours at ambient temperature
  2. customThe solvent was evaporated in vacuo
  3. additionThe residue was mixed with a saturated sodium bicarbonate solution
  4. extractionextracted with ethyl acetate
  5. washThe extract was washed with water
  6. dry with materialdried over magnesium sulfate
  7. customevaporated in vacuo
  8. customThe residue was chromatographed on silica gel
  9. washby eluting with a mixture of chloroform-methanol (20:1, V/V)
  10. dissolutionThe salt was dissolved in ethanol
  11. customreprecipitated with diethyl ether

Sources & evidence

ORD record
ord-f127db5957b547de9418edc84382dd0b
Source dataset
uspto-grants-1991_09
Patent number
US05047411

Reaction notes

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