Pyridine → Butyl 6,7-dimethoxy-2-methyl-4-oxo-1,2,3,4-tetrahydroquinoline-1-carboxylate

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Reaction Steps

To a cooled mixture of 1.15 g. (5.17 mmol) of the quinoline product of Example 4, 751 mg. (10.15 mmol) of dry pyridine and 5.5 ml. of methylene chloride stirred under a nitrogen atmosphere was added dropwise 1.03 g. (7.60 mmol) of butyl chloroformate in 1 ml. methylene chloride over 10 min. at a rate to maintain a 10°-15° temperature. After the addition was complete the bath was removed, the reaction stirred at room temperature for 45 min., and poured onto 25 ml. saturated sodium bicarbonate solution. The organic phase was collected and washed with 25 ml. of saturated sodium bicarbonate solution, 50 ml. saturated sodium chloride solution, dried over magnesium sulfate, then gravity filtered and evaporated to a viscous amber oil. Evaporative distillation at 110° C (0.05 mm) gave 1.4 g. of a very viscous amber oil.

Provenance & Evidence