Sodium Bicarbonate → Proxicromil

HRID 236973Notes

Reaction equation

HRID 236973 reaction equation
C[O:2][C:3]1[C:16]2[C:15](=[O:17])[CH:14]=[C:13]([C:18]([OH:20])=[O:19])[O:12][C:11]=2[C:10]([CH2:21][CH2:22][CH3:23])=[C:9]2[C:4]=1[CH2:5][CH2:6][CH2:7][CH2:8]2.C(=O)(O)[O-].[Na+]>Br>[OH:2][C:3]1[C:16]2[C:15](=[O:17])[CH:14]=[C:13]([C:18]([OH:20])=[O:19])[O:12][C:11]=2[C:10]([CH2:21][CH2:22][CH3:23])=[C:9]2[C:4]=1[CH2:5][CH2:6][CH2:7][CH2:8]2

Participants

4

Reactant 2

HCID 516892Sodium BicarbonateHCID 20304533HCID 20304533, compound

Product 1

HCID 65493Proxicromil

Reagents, catalysts & solvents 1

HCID 260Hydrogen BromideSolvent

Procedure

A suspension of 5-methoxy-4-oxo-10-propyl-6,7,8,9-tetrahydro-4H-naphtho[2,3-b]pyran-2-carboxylic acid (5 g) in 48% aqueous hydrobromic acid (130 ml) was heated under reflux for 7 hours. The reaction mixture was cooled and excess saturated aqueous sodium bicarbonate added. The resulting solution was filtered, the filtrate acidified with concentrated hydrochloric acid and then extracted with chloroform (100 ml). The chloroform solution was dried (Na2SO4) and evaporated leaving a residue which, when crystallised from acetone, gave the title compound as an orange crystalline solid mp 259°-260°.

Workup

  1. temperaturewas heated
  2. temperatureunder reflux for 7 hours
  3. temperatureThe reaction mixture was cooled
  4. filtrationThe resulting solution was filtered
  5. extractionextracted with chloroform (100 ml)
  6. dry with materialThe chloroform solution was dried (Na2SO4)
  7. customevaporated
  8. customleaving a residue which, when
  9. customcrystallised from acetone

Sources & evidence

ORD record
ord-f288f2f4c35048cca5a96695426d704b
Source dataset
uspto-grants-1979_06
Patent number
US04159273

Reaction notes

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