Acetoacetic Acid → 2,6-Dimethyl-1,4-dihydropyridine-3,5-dicarboxylic acid

HRID 847785Notes

Reaction equation

HRID 847785 reaction equation
[CH:1]1(C)CCC(C(C)C)C(O)C1.[CH2:12]=[C:13]1[O:17][C:15](=[O:16])[CH2:14]1.COC.[C:21]([OH:27])(=[O:26])[CH2:22][C:23](C)=O.C1N2CN3[CH2:37][N:31](C2)CN1C3.C([O-])(=O)C.[NH4+]>C1C=CC=CC=1.C(O)C.C(N(CC)CC)C>[CH3:12][C:13]1[NH:31][C:37]([CH3:1])=[C:22]([C:21]([OH:27])=[O:26])[CH2:23][C:14]=1[C:15]([OH:17])=[O:16]

Participants

10

Reactant 6

HCID 96Acetoacetic AcidHCID 1254MentholHCID 4101HexamethylenetetramineHCID 8254Dimethyl EtherHCID 12661DiketeneHCID 517165Ammonium Acetate

Product 1

HCID 157329562,6-Dimethyl-1,4-dihydropyridine-3,5-dicarboxylic acid

Reagents, catalysts & solvents 3

HCID 241BenzeneSolvent2×HCID 702EthanolSolventHCID 8471TriethylamineSolvent

Procedure

In 400 ml of benzene there are dissolved 100 g of menthol, added with 1 ml triethylamine, at refluxing and stirring for one hour there are added 55 ml of diketene and benzene is distilled-off under a reduced pressure (150 mm Hg). The remaining oily product consisting mainly of methyl ether of acetoacetic acid is dissolved in 400 ml of ethanol, added with 28 g of hexamethylenetetramine and 5 g of ammonium acetate and the reaction mixture is boiled on a water bath for 30 minutes. After cooling, the precipitated yellow substance is filtered-off and recrystallized from ethanol. There are obtained 105 g (69% of the theoretical value) of menthyl ester of 2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylic acid in the form of a bright-yellow crystalline substance having its melting temperature of from 180°-182° C.

Workup

  1. temperatureat refluxing
  2. waitthe reaction mixture is boiled on a water bath for 30 minutes
  3. temperatureAfter cooling
  4. customrecrystallized from ethanol

Sources & evidence

ORD record
ord-0b2b9470a6c24e658961699ce0759f77
Source dataset
uspto-grants-1981_10
Patent number
US04293700

Reaction notes

Loading…