1-(spiro[indoline-3,4'-piperidin]-1-yl)ethanone hcl synthesis

Yield:167484-19-7 2.93 g (77%)

Reaction Conditions:

with acetic acid;palladium-carbon in ethanol;dichloromethane;

Steps:

8 1-Acetyl-spiro(indoline-3,4'-piperidine)

1-Acetyl-spiro(indoline-3,4'-piperidine) Acetyl chloride (1.4 mL, 19.9 mmol) was added to a solution of 5.35 g (16.6 mmol) of 1'-benzyloxycarbonyl-spiro(indoline-3,4'-piperidine) in 33 mL of CH₂ Cl₂ and 3.2 mL (23.2 mmol) of Et₃ N keeping the temperature between 0-5° C. by cooling in ice bath. After 10 min the cold bath was removed and reaction was stirred for 30 min at which time a TLC indicated complete reaction. The solution was diluted with CH₂ Cl₂ and washed with water, brine and dried over Na₂ SO₄. The filtrate was concentrated to a thick oil and the oil was dissolved in 40 mL of EtOH. Acetic acid (3 mL) and 0.8 g of 10% Pd/C were added to the solution and the resulting mixture was hydrogenated on a Parr apparatus for 3 h. The catalyst was filtered and washed with EtOAc and the combined filtrate was concentrated. The residue was partitioned between CH₂ Cl₂ and water and 2N NaOH was added to this mixture until the aqueous layer was basic. The layers were separated and the aqueous layer was extracted with CH₂ Cl₂. The combined organic layer was washed with brine, dried over Na₂ SO₄ and the filtrate was concentrated to give 2.93 g (77%) of the title compound sufficiently pure for use in the next reaction.

References:

US5962462,1999,A