Reaction #55425

Reaction equation

N-benzyloxycarbonyl-3,4,5-trimethoxyanilinoacetaldehyde diethyl acetal

3,4-dihydroxyphenethylamine hydrochloride

n-butyl alcohol

→

1-(N-benzyloxycarbonyl-3,4,5-trimethoxyanilinomethyl)-6,7-dihydroxy,1,2,3,4-tetrahydroisoquinoline hydrochloride

Yield 70.1%

Solvents

water

Conditions

Workup

1. 1
   Temperaturethe mixture was refluxed for 11 hours in a stream of nitrogen
2. 2
   workup.ADDITIONwere added to the mixture after 5 hours, 6 hours and 7 hours
3. 3
   Otherrespectively, from the beginning of the reaction
4. 4
   ConcentrationThe reaction mixture was concentrated to dryness under reduced pressure
5. 5
   Washthe residue was washed with ether and acetone

Procedure

N-benzyloxycarbonyl-3,4,5-trimethoxyanilinoacetaldehyde diethyl acetal (21 g) and 3,4-dihydroxyphenethylamine hydrochloride (8.3 g) were added to a mixture of n-butyl alcohol (210 ml) and water (30 ml) and then the mixture was refluxed for 11 hours in a stream of nitrogen. In the course of the reaction, amounts of the above-mentioned acetal (2.1 g, 2.1 g and 4.2 g) were added to the mixture after 5 hours, 6 hours and 7 hours, respectively, from the beginning of the reaction, respectively. The reaction mixture was concentrated to dryness under reduced pressure and the residue was washed with ether and acetone to give 1-(N-benzyloxycarbonyl-3,4,5-trimethoxyanilinomethyl)-6,7-dihydroxy,1,2,3,4-tetrahydroisoquinoline hydrochloride (16.3 g). The product was recrystallized from a mixed solvent of ethanol and ether to give a pure product, mp 197° to 199° C. (dec).

Source