Description
4-Piperidinone is a derivative of piperidine with the molecular formula C5H9NO. 4-Piperidone is used as an intermediate in the manufacture of chemicals and pharmaceutical drugs.
Piperidones are a class of chemical compounds sharing the piperidone skeleton. A classic named reaction for the synthesis of piperidones is the Petrenko-Kritschenko piperidone synthesis which involves combining an alkyl-1,3-acetonedicarboxylate with benzaldehyde and an amine. This multicomponent reaction is related to the Hantzsch pyridine synthesis.
Synthesis
A method for synthesizing an intermediate 4-piperidone, comprising the following steps:
(1) adding -alanine methyl ester to ethanol, placing it in a reaction kettle, adding ethylene, mixing it well, lowering the temperature to 0C, adding PS-AlCl3-SbCl5 and sodium ethanol, stirring to carry out the reaction, and after the reaction is completed, cooling it down to room temperature, and removing the ethanol by distillation under reduced pressure;
(2) Add DMF to the reaction kettle, stir and mix well, then heat to 110 , reflux reaction under stirring condition, after 1h of reaction, reduce to room temperature, extract with ethyl acetate, evaporate to remove ethyl acetate, and then distill under reduced pressure after that, to produce the said 4-piperidinone.
PS-AlCl3-SbCl5 is prepared by a method comprising the following steps: polystyrene powder is added to carbon tetrachloride, heated to 80 C, AlCl3 and SbCl5 are added, and the reflux reaction is carried out under stirring conditions, and after the reaction is completed, it is lowered to room temperature, filtered, cleaned, and dried, to obtain the said PS-AlCl3-SbCl5; wherein the mass fraction of AlCl3 is 10%. AlCl3 is 10% by mass and SbCl5 is 7% by mass.
The molar volume ratio of the amount of -alanine methyl ester used to ethanol was 1.1 mol/L; the molar ratio of the amount of -alanine methyl ester used to ethylene was 1:1.2; the mass ratio of the amount of -alanine methyl ester used to catalyst additive was 4:13; the molar ratio of the amount of -alanine methyl ester used to sodium ethanol was 9:7; and the ratio of the amount of DMF used to the amount of ethanol used by volume was 1:1. .
The yield of the produced 4-piperidone was 91.7%.
