Protocatechuic Acid → 3,4-Dihydroxybenzaldehyde

HRID 841857Notes

Reaction equation

HRID 841857 reaction equation
C1C=[N+]([C@@H]2O[C@H](COP(OP(OC[C@H]3O[C@@H](N4C5N=CN=C(N)C=5N=C4)[C@H](OP(O)(O)=O)[C@@H]3O)(O)=O)(O)=O)[C@@H](O)[C@H]2O)C=C(C(N)=O)C=1.P(OC[C@H]1O[C@@H](N2C3N=CN=C(N)C=3N=C2)[C@H](O)[C@@H]1O)(OP(OP(O)(O)=O)(O)=O)(=O)O.[C:80](O)(=[O:90])[C:81]1[CH:89]=[CH:88][C:86]([OH:87])=[C:83]([O:84]C)[CH:82]=1.O=CC1C=CC(O)=C(OC)C=1.C(O)(=O)C1C=CC(O)=C(O)C=1>>[CH:80](=[O:90])[C:81]1[CH:89]=[CH:88][C:86]([OH:87])=[C:83]([OH:84])[CH:82]=1

Participants

6

Reactant 5

HCID 72Protocatechuic AcidHCID 1183VanillinHCID 5886NADP nicotinamide-adenine-dinucleotide phosphateHCID 59575'-AtpHCID 8468Vanillic Acid2×

Product 1

HCID 87683,4-DihydroxybenzaldehydeYield 33%

Procedure

Aryl-aldehyde dehydrogenase (Gross, G. G. et al., Biochem. Biophy. Res. Commun. 32:173 (1968); Gross, G. G. et al., Eur. J. Biochem. 8:413 (1969); Gross, G. G., Eur. J. Biochem. 31:585 (1972); Zenk, M. H. et al., Recent Adv. Phytochem. 4:87 (1972)) in Neurospora crassa mycelial extract was purified away from an unwanted dehydrogenase which reduced vanillin to vanillyl alcohol. Vanillic, protocatechuic, and isovanillic acids were extracted into EtOAc after acidification of fermentor broth. A subsequent reprecipitation step increased the vanillic acid/protocatechuic acid ratio from 1:2 to 2.5:1 (mol/mol). The resulting aromatic mixture was incubated with glucose 6-phosphate dehydrogenase (to recycle NADP+) 25 and aryl-aldehyde dehydrogenase at 30° C. and pH 8.0 using 0.07 equiv of NADP+ and 2 equiv of ATP relative to vanillic acid. Reduction of vanillic acid to vanillin (FIG. 2) proceeded in 92% yield in 7 h. Reduction of protocatechuic acid was slower with a 33% yield of protocatechualdehyde obtained after 7 h. Vanillin was extracted from the enzymatic reduction with CH2Cl2 leaving protocatechualdehyde and protocatechuic acid in the aqueous phase. Isovanillin at 10 mol % remained as the only contaminant. Extraction of the fermentor broth, selective precipitation to remove excess protocatechuic acid, aryl-aldehyde dehydrogenase reduction, and the final CH2Cl2 extraction led to a 66% overall yield (mol/mol) for conversion of vanillic acid into vanillin.

Workup

  1. extractionAryl-aldehyde dehydrogenase (Gross, G. G. et al., Biochem. Biophy. Res. Commun. 32:173 (1968); Gross, G. G. et al., Eur. J. Biochem. 8:413 (1969); Gross, G. G., Eur. J. Biochem. 31:585 (1972); Zenk, M. H. et al., Recent Adv. Phytochem. 4:87 (1972)) in Neurospora crassa mycelial extract
  2. customwas purified away from an unwanted dehydrogenase which reduced vanillin to vanillyl alcohol
  3. extractionVanillic, protocatechuic, and isovanillic acids were extracted into EtOAc after acidification of fermentor broth
  4. customA subsequent reprecipitation step
  5. temperatureincreased the vanillic acid/protocatechuic acid ratio from 1:2 to 2.5:1 (mol/mol)
  6. customwas incubated with glucose 6-phosphate dehydrogenase (to recycle NADP+) 25 and aryl-aldehyde dehydrogenase at 30° C.

Sources & evidence

ORD record
ord-767f5c552847497e9cc04949693dacd3
Source dataset
uspto-grants-2002_04
Patent number
US06372461B1

Reaction notes

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