Citric Acid → 1-tert-Butyl 3-methyl 2,3-dihydropyridine-1,3(6H)-dicarboxylate

HRID 1003384Notes

Reaction equation

HRID 1003384 reaction equation
[C:1](N1C=CN=C1)(N1C=CN=C1)=O.[C:13]([O:17][C:18]([N:20]1[CH2:25][CH:24]=[CH:23][CH:22]([C:26]([OH:28])=[O:27])[CH2:21]1)=[O:19])([CH3:16])([CH3:15])[CH3:14].CO.C(O)(=O)CC(CC(O)=O)(C(O)=O)O>C(Cl)Cl>[C:13]([O:17][C:18]([N:20]1[CH2:25][CH:24]=[CH:23][CH:22]([C:26]([O:28][CH3:1])=[O:27])[CH2:21]1)=[O:19])([CH3:16])([CH3:14])[CH3:15]

Participants

6

Reactant 4

HCID 311Citric AcidHCID 887MethanolHCID 682631,1'-CarbonyldiimidazoleHCID 113791591-(1,1-Dimethylethyl) 3,6-dihydro-1,3(2H)-pyridinedicarboxylate

Product 1

HCID 541197991-tert-Butyl 3-methyl 2,3-dihydropyridine-1,3(6H)-dicarboxylate

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

1,1'-Carbonyldiimidazole (4 g, 24.7 mmol) in methylene chloride (100 ml) was added dropwise to a solution of 1-tert-butoxycarbonyl-1,2,3,6-tetrahydropyridine-3-carboxylic acid (5 g, 22 mmol) in methylene chloride (200 ml) under a nitrogen atmosphere. Stirring was continued for 1 h followed by addition of methanol (300 ml), and reflux for 26 h. 10% aqueous citric acid (100 ml) was added and the mixture extracted with methylene chloride. The organic layer was dried over magnesium sulphate, evaporated to dryness in vacuo and purified on a silica gel column (Eluent: methylene chloride/methanol (90/1)) to give methyl 1-tert-butoxycarbonyl-1,2,3,6-tetrahydropyridine-3-carboxylate as yellow oil. (Yield: 3.9 g, 73%)

Workup

  1. temperaturereflux for 26 h
  2. extractionthe mixture extracted with methylene chloride
  3. dry with materialThe organic layer was dried over magnesium sulphate
  4. customevaporated to dryness in vacuo
  5. custompurified on a silica gel column (Eluent: methylene chloride/methanol (90/1))

Sources & evidence

ORD record
ord-d9ddf0c9fc404657811d4afebb3f78ac
Source dataset
uspto-grants-2000_04
Patent number
US06046214

Reaction notes

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