Hydrochloric Acid → 8-methoxy-1-oxo-1H-2-benzothiopyran-3-carboxylic acid

HRID 328984Notes

Reaction equation

HRID 328984 reaction equation
[C:1]([C:4]1[C:17]([O:18][CH3:19])=[CH:16][CH:15]=[CH:14][C:5]=1[CH:6]=[C:7]1[S:11]C(=S)N[C:8]1=[O:13])([OH:3])=O.[OH-:20].[Na+].Cl>>[CH3:19][O:18][C:17]1[C:4]2[C:1](=[O:3])[S:11][C:7]([C:8]([OH:20])=[O:13])=[CH:6][C:5]=2[CH:14]=[CH:15][CH:16]=1

Participants

4

Reactant 3

HCID 313Hydrochloric AcidHCID 14798Sodium HydroxideHCID 543067415-(2-Carboxy-3-methoxybenzylidene)rhodanine

Product 1

HCID 214407508-methoxy-1-oxo-1H-2-benzothiopyran-3-carboxylic acid

Procedure

A solution of the benzylidenerhodanine of Example 10 in 46 ml. of 15% NaOH is refluxed for 0.75 hour, cooled, and poured into dilute HCl. The resulting tan precipitate is collected and air-dried. Two recrystallizations from methanol (charcoal) give 8-methoxy-1-oxo-1H-2-benzothiopyran-3-carboxylic acid as a pale yellow solid, m.p. 275° (dec.).

Workup

  1. temperaturecooled
  2. customThe resulting tan precipitate is collected
  3. customair-dried
  4. customTwo recrystallizations from methanol (charcoal)

Sources & evidence

ORD record
ord-3bd26851e24f478c840da46cad7af5a4
Source dataset
uspto-grants-1977_04
Patent number
US04018891

Reaction notes

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