3-piperidin-4-ylpropanal

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Alternatively, hydrogenation of the 3-pyridin-4-yl-2-propen-1-one is carried out by (i) hydrogenating the 2-propen-1-one until conversion to the corresponding 3-pyridin-4-ylpropan-1-one is complete, (ii) optionally alkylating the propan-1-one with a compound of the formula L-R20 or X-R21 (wherein R20 and R21 are as defined above), and then (iii) continuing hydrogenation to give the corresponding 3-piperidin-4-ylpropan-1-one. Hydrogenation of the propenone to the 3-pyridin-4-ylpropan-1-one is carried out with an appropriate catalyst (5% palladium on carbon, 20% palladium hydroxide, etc.) in a suitable solvent (e.g., THF, acetic acid, DMF, ethanol, etc.) at 5 to 60 psi and requires 1 to 48 hours. The preparation of a compound of Formula I(b) in which R7 is 3-(4-methoxyphenyl)prop-1-yl is described in Example 13.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Alternatively, hydrogenation of the 3-pyridin-4-yl-2-propen-1-one is carried out by (i) hydrogenating the 2-propen-1-one until conversion to the corresponding 3-pyridin-4-ylpropan-1-one is complete, (ii) optionally alkylating the propan-1-one with a compound of the formula L-R20 or X-R21 (wherein R20 and R21 are as defined above), and then (iii) continuing hydrogenation to give the corresponding 3-piperidin-4-ylpropan-1-one. Hydrogenation of the propenone to the 3-pyridin-4-ylpropan-1-one is carried out with an appropriate catalyst (5% palladium on carbon, 20% palladium hydroxide, etc.) in a suitable solvent (e.g., THF, acetic acid, DMF, ethanol, etc.) at 5 to 60 psi and requires 1 to 48 hours. The preparation of a compound of Formula I(b) in which R7 is 3-(4-methoxyphenyl)prop-1-yl is described in Example 13.