2,4-Dihydroxybenzaldehyde → 3-Azido-7-hydroxycoumarin

HRID 19453

Reaction equation

HRID 19453 reaction equation
[OH:1][C:2]1[CH:9]=[C:8]([OH:10])[CH:7]=[CH:6][C:3]=1[CH:4]=O.C([NH:14][CH2:15][C:16]([OH:18])=O)(=O)C.C([O-])(=O)C.[Na+].N([O-])=O.[Na+].[N-:28]=[N+:29]=[N-].[Na+].[K+].[Br-]>C(OC(=O)C)(=O)C>[N:14]([C:15]1[C:16](=[O:18])[O:1][C:2]2[C:3]([CH:4]=1)=[CH:6][CH:7]=[C:8]([OH:10])[CH:9]=2)=[N+:28]=[N-:29]

Participants

8

Reactant 6

HCID 72132,4-DihydroxybenzaldehydeHCID 10972AcetylglycineHCID 33557Sodium AzideHCID 253877Potassium BromideHCID 517045Sodium AcetateHCID 23668193Sodium Nitrite

Product 1

HCID 251276083-Azido-7-hydroxycoumarin

Reagents, catalysts & solvents 1

HCID 7918Acetic AnhydrideSolvent

Procedure

A mixture of 2,4-dihydroxy benzaldehyde (2.76 g, 20 mmol), N-acetylglycine (2.34 g, 20 mmol), anhydrous sodium acetate (60 mmol) in acetic anhydride (100 ml) was refluxed under stirring for 4 hours. The reaction mixture was poured onto icde to give a yellow precipitate. After filtration, the yellow solid washed with ice water before it was refluxed in a solution of concentrated HCl and ethanol (2:1, 30 ml) for 1 hour, then ice water was added to dilute the solution. The solution was then cooled in an ice bath and NaNO2 (40 mmol) was added. The mixture was stirred for 5-10 minutes and NaN3 (60 mmol) was added in portions. After stirring for another 15 minutes, the resulting precipitate was filtered off, washed with water, and dried under reduced pressure to afford a brown solid: 2.2 g (54% overall yield). The product was pure enough for further reactions. 1H NMR (DMSO-d6, 300 MHz) δ 6.74 (d, J=2.2 Hz, 1H), 6.79 (dd, J=8.4. 2.2 Hz, 1H), 7.47 (d, J=8.5 Hz, 1H), 7.56 (s, 1H). 13C NMR (DMSO-d6, 75 MHz) δ 161.0, 158.0, 153.4, 128.7, 128.5, 121.8, 114.5, 112.0, 102.7. IR (KBr): 3296 (s), 2125 (vs), 1680 (s), 1620 (m), 1321 (s). EI-HRMS m/e calculated for M+ C9H5N3O3 203.0331; found 203.0326.

Workup

  1. temperaturewas refluxed
  2. additionThe reaction mixture was poured onto icde
  3. customto give a yellow precipitate
  4. filtrationAfter filtration
  5. washthe yellow solid washed with ice water before it
  6. temperaturewas refluxed in a solution of concentrated HCl and ethanol (2:1, 30 ml) for 1 hour
  7. additionice water was added
  8. additionto dilute the solution
  9. temperatureThe solution was then cooled in an ice bath
  10. stirringThe mixture was stirred for 5-10 minutes
  11. stirringAfter stirring for another 15 minutes
  12. filtrationthe resulting precipitate was filtered off
  13. washwashed with water
  14. customdried under reduced pressure
  15. customto afford a brown solid
  16. custom2.2 g (54% overall yield)

Sources & evidence

ORD record
ord-c0881cfbc35f402383893d4b47b7ad1f
Source dataset
uspto-grants-2010_06
Patent number
US07745229B2

Linked notes

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