Iodine → 4,5,6,7-tetrahydro-3-iodo-N-methoxy-N,5,5-trimethyl-benzo[c]thiophene-1-carboxamide

HRID 1665950Notes

Reaction equation

HRID 1665950 reaction equation
C(NC(C)C)(C)C.C([Li])CCC.[CH3:13][O:14][N:15]([CH3:29])[C:16]([C:18]1[S:19][CH:20]=[C:21]2[CH2:26][C:25]([CH3:28])([CH3:27])[CH2:24][CH2:23][C:22]=12)=[O:17].[I:30]I>C1COCC1>[CH3:13][O:14][N:15]([CH3:29])[C:16]([C:18]1[S:19][C:20]([I:30])=[C:21]2[CH2:26][C:25]([CH3:27])([CH3:28])[CH2:24][CH2:23][C:22]=12)=[O:17]

Participants

6

Reactant 4

HCID 807IodineHCID 7912DiisopropylamineHCID 598608664,5,6,7-tetrahydro-N-methoxy-N,5,5-trimethyl-benzo[c]thiophene-1-carboxamideHCID 178418339Butyllithium

Product 1

HCID 598608624,5,6,7-tetrahydro-3-iodo-N-methoxy-N,5,5-trimethyl-benzo[c]thiophene-1-carboxamideYield 52.2%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent3×

Conditions

Temperature
-78 °C

Procedure

To a solution of diisopropylamine (11.02 g, 109 mmol) in THF (400 mL) is added n-butyl lithium (72.7 mL, 109 mmol, 1.5 M in pentane) at 0-5° C. The solution is cooled to −78° C. and a solution of 5,5-dimethyl-4,5,6,7-tetrahydro-benzo[c]thiophene-1-carboxylic acid methoxy-methyl-amide (23 g, 91 mmol) in THF (100 mL) is added. Upon complete addition, the mixture is stirred for 20 min at −78° C. before a solution of iodine (30 g, 119 mmol) in THF (100 mL) is added. Stirring is continued at −78° C. for 30 min. The reaction is quenched by slowly adding a 1:1 mixture of water/methanol (20 mL). The solution is diluted with water (400 mL) and extracted with diethyl ether (3×100 mL). The combined organic extracts are washed with 10% aq. citric acid solution and brine, dried over Na2SO4, filtered and evaporated. The crude product is purified by CC on silica gel eluting with DCM to afford 3-iodo-5,5-dimethyl-4,5,6,7-tetrahydro-benzo[c]thiophene-1-carboxylic acid methoxy-methyl-amide (18 g) as a brownish oil; LC-MS: tR=1.09 min, [M+1]=380.21.

Workup

  1. additionUpon complete addition
  2. additionis added
  3. customThe reaction is quenched
  4. additionby slowly adding
  5. additiona 1:1 mixture of water/methanol (20 mL)
  6. additionThe solution is diluted with water (400 mL)
  7. extractionextracted with diethyl ether (3×100 mL)
  8. washThe combined organic extracts are washed with 10% aq. citric acid solution and brine
  9. dry with materialdried over Na2SO4
  10. filtrationfiltered
  11. customevaporated
  12. customThe crude product is purified by CC on silica gel eluting with DCM

Sources & evidence

ORD record
ord-42340bc6cb9b49ea9fb0f00f0837fe96
Source dataset
uspto-grants-2011_10
Patent number
US08039644B2

Reaction notes

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