Hydrochloric Acid → 5-Nitro-1-benzothiophene-2-carboxylic acid

HRID 507516Notes

Reaction equation

HRID 507516 reaction equation
[N+:1]([C:4]1[CH:16]=[CH:15][C:7]2[S:8][C:9]([C:11]([O:13]C)=[O:12])=[CH:10][C:6]=2[CH:5]=1)([O-:3])=[O:2].Cl>CO.[OH-].[Na+]>[N+:1]([C:4]1[CH:16]=[CH:15][C:7]2[S:8][C:9]([C:11]([OH:13])=[O:12])=[CH:10][C:6]=2[CH:5]=1)([O-:3])=[O:2]

Participants

5

Reactant 2

HCID 313Hydrochloric AcidHCID 1489057Methyl 5-nitro-1-benzothiophene-2-carboxylate

Product 1

HCID 2389395-Nitro-1-benzothiophene-2-carboxylic acidYield 98%

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 14798Sodium HydroxideSolvent

Procedure

A suspension of methyl 5-nitrobenzo[b]thiophene-2-carboxylate (32.49 g, 0.137) in methanol (400 mL) and 1 N aqueous sodium hydroxide (150 mL) was heated to reflux for 1 h after which time everything had gone into solution. After cooling to r.t. the solution was acidified with concentrated hydrochloric acid. The resulting solid was filtered off, washed with water (3×50 mL), air dried, and then placed in a vacuum oven at 60° C. for 20 h to yield 5-nitrobenzo[b]thiophene-2-carboxylic acid (29.87 g, 98%) as a cream amorphous solid. 1H NMR δ (d6-DMSO, 400 MHz) 8.30 (dd, J=9, 2 Hz, 1H), 8.35 (d, J=9 Hz, 1H), 8.36 (s, 1H), 8.98 (s, 1H), 13.89 (br. s., 1H).

Workup

  1. temperaturewas heated
  2. temperatureto reflux for 1 h after which time everything
  3. filtrationThe resulting solid was filtered off
  4. washwashed with water (3×50 mL), air
  5. customdried

Sources & evidence

ORD record
ord-61b8a669e255486fa1bf4932fb510d8f
Source dataset
uspto-grants-2010_08
Patent number
US07786132B2

Reaction notes

Loading…