Nitromethane → ethyl 5,6-dihydro-2-methyl-3-[4-(methyl-thio)benzoyl]-4H-cyclopenta[b]thiophene-6-carboxylate

HRID 2308997Notes

Reaction equation

HRID 2308997 reaction equation
[S:1]1[CH:5]=[CH:4][C:3]2[CH2:6][CH:7]=[C:8]([C:9]([O:11][CH2:12][CH3:13])=[O:10])[C:2]1=2.[CH3:14][S:15][C:16]1[CH:24]=[CH:23][C:19]([C:20](Cl)=[O:21])=[CH:18][CH:17]=1.Cl[Sn](Cl)(Cl)Cl.[N+]([CH3:33])([O-])=O>>[CH3:33][C:5]1[S:1][C:2]2[CH:8]([C:9]([O:11][CH2:12][CH3:13])=[O:10])[CH2:7][CH2:6][C:3]=2[C:4]=1[C:20](=[O:21])[C:19]1[CH:23]=[CH:24][C:16]([S:15][CH3:14])=[CH:17][CH:18]=1

Participants

5

Reactant 4

HCID 6375NitromethaneHCID 24287Tin tetrachlorideHCID 740424-(Methylthio)benzoyl chlorideHCID 20186626ethyl 4H-cyclopenta[b]thiophene-6-carboxylate

Product 1

HCID 13934075ethyl 5,6-dihydro-2-methyl-3-[4-(methyl-thio)benzoyl]-4H-cyclopenta[b]thiophene-6-carboxylate

Conditions

Temperature
-20 °C

Procedure

A 14.25 g (0.068 moles) sample of ethyl 4H-cyclopenta[b]thiophene-6-carboxylate, the product of Example 1g., and 13.92 g p-(methylthio)benzoyl chloride were dissolved in 410 ml of dry nitromethane and placed under argon and cooled to -20° C. An 8 ml sample of SnCl4 was added dropwise controlling the temperature at -20° C. After the addition was complete the reaction mixture was stirred at -20° C. for 15 min. after which it was allowed to warm slowly to room temperature and stirred for 30 min. The reaction was poured into ice water and extracted three times with Et2O. The organics were combined, washed with 3-dimethylaminopropylamine solution, 3N hydrochloric acid, water, brine, and dried (MgSO4). Evaporation of the solvent gave a dark green oil which was flash chromatographed on silica gel using 1:20 EtOAc:hexane as the eluant. The resulting solid was recrystallized from methylcyclohexane/EtOAC to give 15.32 g of ethyl 5,6-dihydro-2-methyl-3-[4-(methylthio)benzoyl]-4H-cyclopenta[b]thiophene-6-carboxylate, mp 62-64° C.

Workup

  1. customat -20° C
  2. additionAfter the addition
  3. temperatureto warm slowly to room temperature
  4. stirringstirred for 30 min
  5. extractionextracted three times with Et2O
  6. washwashed with 3-dimethylaminopropylamine solution, 3N hydrochloric acid, water, brine
  7. dry with materialdried (MgSO4)
  8. customEvaporation of the solvent
  9. customgave a dark green oil which
  10. customchromatographed on silica gel using 1:20 EtOAc
  11. customThe resulting solid was recrystallized from methylcyclohexane/EtOAC

Sources & evidence

ORD record
ord-70ec1ac219914034952f73c1c656bd32
Source dataset
uspto-grants-1987_09
Patent number
US04692460

Reaction notes

Loading…