Butyn-2-one → Bis(1,1-Dimethylethyl) 2-{3-[(ethyloxy)carbonyl]-6-methyl-2-pyridinyl}-1,4-piperazinedicarboxylate

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Reaction Steps

To a solution of bis(1,1-dimethylethyl) 2-[(1Z)-1-amino-3-(ethyloxy)-3-oxo-1-propen-1-yl]-1,4-piperazinedicarboxylate (may be prepared as described in Intermediate 4; 7.4 g) in ethanol (300 mL), was added 3-butyn-2-one (3.15 g) and the reaction was heated to reflux for 20 hours. The reaction mixture was evaporated and then partitioned between 2× EtOAc and water. The combined organic phases were washed with brine, dried through a hydrophobic frit, and then evaporated to a brown oil (8.54 g), which was purified by silica column (SP4-40M) eluting with 0-40% ethyl acetate in isohexane over 12CV. The clean fractions were combined and evaporated to give the title compound as a yellow oil (4.96 g).

Provenance & Evidence