Reacción #481606

Ecuación de reacción

3,4,5-trimethoxy benzaldehyde

sulphuric acid

→

syringaldehyde

Condiciones de reacción

Tratamiento posterior

1. 1
   Otroat 40° C.
2. 2
   Otrofor 8 hours

Procedimiento

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%.

Fuente