Hydrochloric Acid → 5-Formyl-benzo[b]thiophene-2-carboxylic acid ethyl ester

HRID 545481Notes

Reaction equation

HRID 545481 reaction equation
[CH2:1]([O:3][C:4]([C:6]1[S:10][C:9]2[CH:11]=[CH:12][C:13](I)=[CH:14][C:8]=2[CH:7]=1)=[O:5])[CH3:2].C([Mg]Br)(C)C.CN(C1C=CC=CN=1)[CH:23]=[O:24].Cl>C(Cl)Cl>[CH2:1]([O:3][C:4]([C:6]1[S:10][C:9]2[CH:11]=[CH:12][C:13]([CH:23]=[O:24])=[CH:14][C:8]=2[CH:7]=1)=[O:5])[CH3:2]

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 572611N-Methyl-N-(pyridine-2-yl)formamideHCID 12094044Ethyl 5-iodobenzo[b]thiophene-2-carboxylateHCID 178418365HCID 178418365, compound

Product 1

HCID 574439705-Formyl-benzo[b]thiophene-2-carboxylic acid ethyl ester

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Conditions

Temperature
-40 °C

Procedure

To a solution of 5-iodo -benzo[b]thiophene-2-carboxylic acid ethyl ester (14.09 g, 42.42 mmol) at −40° C. was slowly added a solution of isopropylmagnesium bromide (0.7 M in THF, 85 mL, 59.5 mmol). The mixture was allowed to stir at −40° C. for 2 h and N-methyl-N-pyridin-2-yl-formamide (7.65 mL, 63.9 mmol) was added slowly. After warming to rt, the mixture was allowed to stir for additional 2.5 h. To the mixture was carefully added 250 mL of 1N HCl. After stirring for 10 min, the reaction mixture was diluted with CH2Cl2 (800 mL). The organic layer was separated, washed with 200 mL of saturated NaHCO3 and dried over Na2SO4. After filtration, the filtrate was concentrated and the residue was recrystallized from MeOH to give 5-formyl-benzo[b]thiophene-2-carboxylic acid ethyl ester as a yellow solid. 1H NMR (CDCl3, 200 MHz) δ 10.12 (s, 1H), 8.37 (s, 1H), 8.18 (s, 1H), 8.08-7.90 (m, 2H), 4.44 (q, J=7.2 Hz, 2H), 1.44 (t, J=7.4 Hz, 3H). MS (EI): cal'd 235.0 (MH+), exp 235.1 (MH+).

Workup

  1. temperatureAfter warming to rt
  2. stirringto stir for additional 2.5 h
  3. stirringAfter stirring for 10 min
  4. customThe organic layer was separated
  5. washwashed with 200 mL of saturated NaHCO3
  6. dry with materialdried over Na2SO4
  7. filtrationAfter filtration
  8. concentrationthe filtrate was concentrated
  9. customthe residue was recrystallized from MeOH

Sources & evidence

ORD record
ord-0b2ae26168f14901aa5ae8b56e7d5468
Source dataset
uspto-grants-2011_05
Patent number
US07935724B2

Reaction notes

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