2-Chlorobenzaldehyde → Methyl 2-(2-chlorobenzylidene)-4,4-dimethoxy-3-oxovalerate

HRID 894651Notes

Reaction equation

HRID 894651 reaction equation
[Cl:1][C:2]1[CH:9]=[CH:8][CH:7]=[CH:6][C:3]=1[CH:4]=O.[CH3:10][O:11][C:12]([O:21][CH3:22])([CH3:20])[C:13](=[O:19])[CH2:14][C:15]([O:17][CH3:18])=[O:16].N1CCCCC1>C1C=CC=CC=1>[Cl:1][C:2]1[CH:9]=[CH:8][CH:7]=[CH:6][C:3]=1[CH:4]=[C:14]([C:13](=[O:19])[C:12]([O:11][CH3:10])([O:21][CH3:22])[CH3:20])[C:15]([O:17][CH3:18])=[O:16]

Participants

5

Reactant 3

HCID 69962-ChlorobenzaldehydeHCID 8082PiperidineHCID 5076552Methyl 4,4-dimethoxy-3-oxopentanoate

Product 1

HCID 54451845Methyl 2-(2-chlorobenzylidene)-4,4-dimethoxy-3-oxovalerateYield 112.6%

Reagents, catalysts & solvents 1

HCID 241BenzeneSolvent2×

Procedure

A mixture of 2-chlorobenzaldehyde (2.81 g), methyl 4,4-dimethoxy-3-oxovalerate (3.81 g) and piperidine (0.2 ml) in benzene (20 ml) was refluxed under azeotropic dehydration for 7.5 hours. A small amount of benzene was added to the reaction mixture and the resultant solution was washed with water and dried over magnesium sulfate. The solvent was removed from the solution to give a reddish oil (7.04 g) of methyl 2-(2-chlorobenzylidene)-4,4-dimethoxy-3-oxovalerate. The mixture of the oily product (6.39 g) obtained above and methyl 3-aminocrotonate (2.33 g) was heated at 132° C. for 3.5 hours, allowed to stand and then dissolved in ethyl acetate. The resultant solution was washed with water and an aqueous sodium chloride solution, and dried over magnesium sulfate. The solvent was removed from the solution under reduced pressure to give a viscous and brown oil (8.28 g). This oil was subjected to column chromatography on silica gel with an eluent (a mixture of 20 parts of benzene and one part of ethyl acetate by volume) to give an oily substance (5.26 g). This substance was dissolved in a mixture of ethyl acetate and diethyl ether and the solvent was removed under reduced pressure to give colorless powder (1.0625 g). This powder was recrystallized from a mixture of n-hexane and ethyl acetate to give faint yellow granules of dimethyl 2-methyl-4-(2-chlorophenyl)-6-(1,1-dimethoxyethyl)-1,4-dihydropyridine-3,5-dicarboxylate, m.p. 145° to 146° C.

Workup

  1. temperaturewas refluxed under azeotropic dehydration for 7.5 hours
  2. washthe resultant solution was washed with water
  3. dry with materialdried over magnesium sulfate
  4. customThe solvent was removed from the solution

Sources & evidence

ORD record
ord-b68632f098164b768c22bf4234cb4dd1
Source dataset
uspto-grants-1981_08
Patent number
US04284634

Reaction notes

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