Hydrochloric Acid → Proxicromil

HRID 236954Notes

Reaction equation

HRID 236954 reaction equation
[OH:1][C:2]1[C:15]2[C:14](=[O:16])[CH:13]=[C:12]([C:17]([O:19]CC)=[O:18])[O:11][C:10]=2[C:9]([CH2:22][CH2:23][CH3:24])=[C:8]2[C:3]=1[CH2:4][CH2:5][CH2:6][CH2:7]2.C(=O)(O)[O-].[Na+].Cl>C(O)C.O>[OH:1][C:2]1[C:15]2[C:14](=[O:16])[CH:13]=[C:12]([C:17]([OH:19])=[O:18])[O:11][C:10]=2[C:9]([CH2:22][CH2:23][CH3:24])=[C:8]2[C:3]=1[CH2:4][CH2:5][CH2:6][CH2:7]2

Participants

6

Reactant 3

HCID 313Hydrochloric AcidHCID 516892Sodium Bicarbonate2×HCID 13226749HCID 13226749, compound

Product 1

HCID 65493ProxicromilYield 81.8%

Reagents, catalysts & solvents 2

HCID 702EthanolSolventHCID 962WaterSolvent

Procedure

A refluxing solution of ethyl 6,7,8,9-tetrahydro-5-hydroxy-4-oxo-10-propyl-4H-naphtho[2,3-b]pyran-2-carboxylate (45.4 g) in ethanol (600 ml) was stirred whilst adding a solution of sodium bicarbonate (11.5 g) in water (300 ml) over 15 minutes. After refluxing a further 4 hours, an additional quantity of sodium bicarbonate solution (1.5 g in 30 ml water) was added and the mixture refluxed for a further 1 hour. The hot solution was acidified with dilute hydrochloric acid and the yellow precipitate filtered off. The damp solid was recrystallised from acetone to give 6,7,8,9-tetrahydro-5-hydroxy-4-oxo-10-propyl-4H-naphtho[2,3-b]pyran-2-carboxylic acid (34.0 g) mp 265°-268°.

Workup

  1. temperatureAfter refluxing a further 4 hours
  2. temperaturethe mixture refluxed for a further 1 hour
  3. filtrationthe yellow precipitate filtered off
  4. customThe damp solid was recrystallised from acetone

Sources & evidence

ORD record
ord-5894e7f3674a4adf8afe6bc173936904
Source dataset
uspto-grants-1979_06
Patent number
US04159273

Reaction notes

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