Syringaldehyde → 4-[4-(5,6-dihydro-11H-imidazo[2,1-b][3]benzazepin-11-ylidene)-1-piperidinyl]-2,6-dimethoxyphenol

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Reaction Steps

A mixture of 3,5-dimethoxy-4-hydroxybenzaldehyde (8 g) and 6,11-dihydro-11-(4-piperidinylidene)-5H-imidazo[2,1-b][3]benzazepine (9 g) in methanol (250 ml) and thiophene (4%, 3 ml) was hydrogenated at room temperature with palladium on activated carbon (10%, 2 g) as a catalyst. After uptake of hydrogen (1 equivalent), the catalyst was filtered off and the filtrate was evaporated. The residue was purified by column chromatography over silica gel (eluent: CH2Cl2/CH3OH 95/5). The pure fractions were collected and evaporated, yielding 9.5 g (65%) of 4-[4-(5,6-dihydro-11H-imidazo[2,1-b][3]benzazepin-11-ylidene)-1-piperidinyl]-2,6-dimethoxyphenol (intermediate 8).

Provenance & Evidence