Hydrochloric Acid → 7-methoxy-1-oxo-1H-2-benzothiopyran-3-carboxylic acid

HRID 328981Notes

Reaction equation

HRID 328981 reaction equation
[C:1]([C:4]1[CH:17]=[C:16]([O:18][CH3:19])[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:16]1[CH:15]=[CH:14][C:5]2[CH:6]=[C:7]([C:8]([OH:20])=[O:13])[S:11][C:1](=[O:3])[C:4]=2[CH:17]=1

Participants

4

Reactant 3

HCID 313Hydrochloric AcidHCID 14798Sodium HydroxideHCID 537228345-(2-Carboxy-4-methoxybenzylidene)rhodanine

Product 1

HCID 214407427-methoxy-1-oxo-1H-2-benzothiopyran-3-carboxylic acid

Procedure

A solution of the benzylidenerhodanine of Example 7 in 18 ml. of 15% NaOH is refluxed for 0.75 hour and poured into dilute HCl, whereupon a yellow solid forms. The solid is collected and recrystallized from ethanol to give 7-methoxy-1-oxo-1H-2-benzothiopyran-3-carboxylic acid as pale yellow needles, m.p. 291°-292°.

Workup

  1. customThe solid is collected
  2. customrecrystallized from ethanol

Sources & evidence

ORD record
ord-acc51ab18e79457fb5a70174af9861a6
Source dataset
uspto-grants-1977_04
Patent number
US04018891

Reaction notes

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