Sulfuric Acid → Syringaldehyde

HRID 394424Notes

Reaction equation

HRID 394424 reaction equation
[CH3:1][O:2][C:3]1[CH:4]=[C:5]([CH:8]=[C:9]([O:13][CH3:14])[C:10]=1[O:11]C)[CH:6]=[O:7].S(=O)(=O)(O)O>>[CH:6](=[O:7])[C:5]1[CH:4]=[C:3]([O:2][CH3:1])[C:10]([OH:11])=[C:9]([O:13][CH3:14])[CH:8]=1

Participants

3

Reactant 2

HCID 1118Sulfuric AcidHCID 68583,4,5-Trimethoxybenzaldehyde

Product 1

HCID 8655Syringaldehyde

Procedure

Monodemethylation of 3,4,5-trimethoxy benzaldehyde using sulphuric acid at 40° C. for 8 hours as described above in Example 1 yields syringaldehyde. Transesterfication of diethyl malonate using 2-ethylhexyl alcohol in neat condition at 140-155° C. for 2 hours under nitrogen blanketing in the presence of sulphuric acid and after work up, followed by high vacuum distillation, yields di-6-ethylhexyl malonate. Condensation of 3,5-Dimethoxy-4-hydroxy benzaldehyde (Syringaldehyde) with di-2-ethylhexyl malonate in the presence of piperidine—acetic acid and benzene as the reaction medium at reflux temperature under continuous azeotropic water removal yields di-2-ethylhexyl-3,5-dimethoxy-4-hydroxy benzylidene malonate. The reaction takes about nine hours for completion. The yield typically obtained is 91%.

Workup

  1. customat 40° C.
  2. customfor 8 hours

Sources & evidence

ORD record
ord-a1c677779ef440ee8fe0368662d58c1d
Source dataset
uspto-grants-2003_08
Patent number
US06602515B2

Reaction notes

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