Ethyl chloroformate → 5-(4-nitrobenzyl)-1,3,4-oxadiazol-2(3H)-one

HRID 30647

Reaction equation

HRID 30647 reaction equation
[N+:1]([C:4]1[CH:9]=[CH:8][C:7]([CH2:10][C:11]([NH:13][NH2:14])=[O:12])=[CH:6][CH:5]=1)([O-:3])=[O:2].[C:15](Cl)(=O)[O:16]CC.O=P12OP3(OP(OP(O3)(O1)=O)(=O)O2)=O.C[Si](C)(C)O[Si](C)(C)C>O.ClC1C=CC=CC=1Cl.CN(C)C(=O)C>[N+:1]([C:4]1[CH:5]=[CH:6][C:7]([CH2:10][C:11]2[O:12][C:15](=[O:16])[NH:14][N:13]=2)=[CH:8][CH:9]=1)([O-:3])=[O:2]

Participants

8

Reactant 4

HCID 10928Ethyl chloroformateHCID 14812Phosphorus oxide (P4O10)HCID 24764HexamethyldisiloxaneHCID 2873312-(4-Nitrophenyl)acetohydrazide

Product 1

HCID 218227135-(4-nitrobenzyl)-1,3,4-oxadiazol-2(3H)-oneYield 51.2%

Reagents, catalysts & solvents 3

HCID 962WaterSolvent2×HCID 72391,2-DichlorobenzeneSolventHCID 31374DimethylacetamideSolvent

Procedure

A mixture of 2-(4-nitrophenyl)acetohydrazide (0.50 g), ethyl chlorocarbonate (0.34 g) and N,N-dimethylacetamide (10 mL) was stirred at room temperature for 1 hr. Water was added to the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed successively with saturated aqueous sodium hydrogen carbonate and saturated brine, dried over anhydrous magnesium sulfate, and concentrated to give colorless crystals. A mixture of the obtained crystals, diphosphorus pentaoxide (1.50 g), hexamethyldisiloxane (2.96 g) and 1,2-dichlorobenzene (10 mL) was stirred at 160° C. for 2 hrs. Water was added to the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed successively with saturated aqueous sodium hydrogen carbonate and saturated brine, dried over anhydrous magnesium sulfate, and concentrated to give 5-(4-nitrobenzyl)-1,3,4-oxadiazol-2(3H)-one as pale-yellow crystals (0.29 g, yield 50%). Recrystallization thereof from ethyl acetate-hexane gave pale-yellow prism crystals. melting point: 170-171° C.

Workup

  1. extractionthe mixture was extracted with ethyl acetate
  2. washThe organic layer was washed successively with saturated aqueous sodium hydrogen carbonate and saturated brine
  3. dry with materialdried over anhydrous magnesium sulfate
  4. concentrationconcentrated
  5. customto give colorless crystals
  6. stirringwas stirred at 160° C. for 2 hrs
  7. extractionthe mixture was extracted with ethyl acetate
  8. washThe organic layer was washed successively with saturated aqueous sodium hydrogen carbonate and saturated brine
  9. dry with materialdried over anhydrous magnesium sulfate
  10. concentrationconcentrated

Sources & evidence

ORD record
ord-eaed8ae426304e12b0a1ad020e1f21cf
Source dataset
uspto-grants-2008_09
Patent number
US07423159B2

Linked notes

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