Maleic Acid → 79494-81-8

HRID 1680815Notes

Reaction equation

HRID 1680815 reaction equation
[CH3:1][O:2][C:3]1[C:8]([O:9][CH3:10])=[CH:7][C:6]2[C:11]3[CH2:16][CH2:15][N:14]([CH2:17][CH:18]([CH3:25])[N:19]4[CH2:24][CH2:23][CH2:22][CH2:21][CH2:20]4)[CH2:13][C:12]=3[C:26](=[O:28])[O:27][C:5]=2[CH:4]=1.[C:29]([OH:36])(=[O:35])/[CH:30]=[CH:31]\[C:32]([OH:34])=[O:33]>C(OCC)(=O)C>[C:29]([OH:36])(=[O:35])/[CH:30]=[CH:31]\[C:32]([OH:34])=[O:33].[CH3:1][O:2][C:3]1[C:8]([O:9][CH3:10])=[CH:7][C:6]2[C:11]3[CH2:16][CH2:15][N:14]([CH2:17][CH:18]([CH3:25])[N:19]4[CH2:20][CH2:21][CH2:22][CH2:23][CH2:24]4)[CH2:13][C:12]=3[C:26](=[O:28])[O:27][C:5]=2[CH:4]=1

Participants

4

Reactant 2

HCID 444266Maleic AcidHCID 1289970260629-86-9

Product 1

HCID 1289970379494-81-8Yield 90.2%

Reagents, catalysts & solvents 1

HCID 8857Ethyl AcetateSolvent2×

Procedure

To a solution of 1100 g (2.85 m) 1,2,3,4-tetrahydro-8,9-dimethoxy-3-[2-methyl-2-(1-piperidinyl)ethyl]-5H-[1]benzopyrano[3,4-c]pyridin-5-one in 18.95 L ethyl acetate was added a solution of 345.6 g (2.97 m) maleic acid in 8.2 L ethyl acetate at 70° C. over a 30 minute period. Solid appeared when the addition was 45% complete. After the addition was complete the mixture was allowed to cool to room temperature with stirring for 2 hours. The solid was collected by filtration, washed with ethyl acetate and dried at 50° C. to yield 1290 g of 1,2,3,4-tetrahydro-8,9-dimethoxy-3-[2-methyl-2-(1-piperidinyl)ethyl]-5H-[1]benzopyrano[3,4-c]pyridin-5-one maleate as a yellow solid, mp 171°-175° C.

Workup

  1. additionthe addition
  2. additionAfter the addition
  3. filtrationThe solid was collected by filtration
  4. washwashed with ethyl acetate
  5. customdried at 50° C.

Sources & evidence

ORD record
ord-8faea49500b54f5d80b2607409a75c1a
Source dataset
uspto-grants-1981_06
Patent number
US04276296

Reaction notes

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