Ethyl cyanoformate → Ethyl 2-benzyl-6-oxo-2,6,7,8-tetrahydrocyclopenta[e]indazole-7-carboxylate

HRID 2076356Notes

Reaction equation

HRID 2076356 reaction equation
[CH2:1]([N:8]1[CH:16]=[C:15]2[C:10]([CH:11]=[CH:12][C:13]3[C:19](=[O:20])[CH2:18][CH2:17][C:14]=32)=[N:9]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.C[Si]([N-][Si](C)(C)C)(C)C.[Li+].C([C:33]([O:35][CH2:36][CH3:37])=[O:34])#N>C1COCC1>[CH2:1]([N:8]1[CH:16]=[C:15]2[C:10]([CH:11]=[CH:12][C:13]3[C:19](=[O:20])[CH:18]([C:33]([O:35][CH2:36][CH3:37])=[O:34])[CH2:17][C:14]=32)=[N:9]1)[C:2]1[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=1

Participants

5

Reactant 3

HCID 69336Ethyl cyanoformateHCID 2733832Lithium HexamethyldisilazideHCID 593972312-benzyl-7,8-dihydrocyclopenta[e]indazol-6(2H)-one

Product 1

HCID 59397246Ethyl 2-benzyl-6-oxo-2,6,7,8-tetrahydrocyclopenta[e]indazole-7-carboxylate

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Conditions

Temperature
-70 °C

Procedure

A stirred suspension of 2-benzyl-7,8-dihydrocyclopenta[e]indazol-6(2H)-one (10.3 g, 39.3 mmol) in 180 mL of THF was cooled to −70° C. and a 1.0M solution of lithium bis(trimethylsilyl)amide in THF (86 mL, 86 mmol) was added dropwise during 20 minutes. The reaction mixture was allowed to warm to −33° C. during approximately 1 hour giving a reddish brown solution. The solution was re-cooled to −65° C. and ethyl cyanoformate (5.9 mL, 60 mmol) was added during 1 minute. The reaction mixture was allowed to warm to 15° C. during 2¾ hours and was then partitioned between ethyl acetate and 1N aqueous HCl. The organic phase was washed successively with water, saturated NaHCO3 and brine. After drying over Na2SO4 the solution was filtered through a short column of silica gel and evaporated under vacuum to give ethyl 2-benzyl-6-oxo-2,6,7,8-tetrahydrocyclopenta[e]indazole-7-carboxylate as a brown oil.

Workup

  1. temperatureto warm to −33° C. during approximately 1 hour
  2. customgiving a reddish brown solution
  3. temperatureThe solution was re-cooled to −65° C.
  4. temperatureto warm to 15° C. during 2¾ hours
  5. customwas then partitioned between ethyl acetate and 1N aqueous HCl
  6. washThe organic phase was washed successively with water, saturated NaHCO3 and brine
  7. dry with materialAfter drying over Na2SO4 the solution
  8. filtrationwas filtered through a short column of silica gel
  9. customevaporated under vacuum

Sources & evidence

ORD record
ord-aff995a5b5ce401f8162d7193ed5b090
Source dataset
uspto-grants-2011_04
Patent number
US07923568B2

Reaction notes

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