1,2,3,4-Tetrahydroisoquinoline → Benzamide, N-(1,2,3,4-tetrahydro-2-methylisoquinolin-8-yl)-3,4,5-trimethoxy-

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Reaction Steps

8-Amino-2-methyl-1,2,3,4-tetrahydroisoquinoline (2 g) prepared from 8-nitro-2-methyl-isoquinolinium p-toluenesulfonate as described for the 5-nitro isomer in Example 4 was dissolved in dry benzene (100 ml) and 0.5 g of dry potassium bicarbonate was added. A 0.1 mole excess of 3,4,5-trimethoxybenzoyl chloride was dissolved in dry benzene (50 ml) and this solution was added to the solution of the tetrahydroisoquinoline. The solutions clouded on mixing and were then refluxed for 12 hours. After refluxing, the benzene was removed in vacuo leaving a viscous, yellow oil. This was suspended in 10% sodium carbonate solution to remove excess acid chloride. The insoluble oil was extracted from the aqueous sodium carbonate with chloroform which was dried over anhydrous magnesium sulfate. The chloroform was distilled off to leave a viscous, yellow oil. This was washed with ether and a white solid (3 g) formed. This was recrystallized from ethanol-water to yield the desired product as white felted needles, m.p. 177°-178.3° C.

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