N-tert-Butyl-3-(hydrazonomethyl)-5,5-dimethyl-5,6-dihydro-4H-cyclopenta[b]thiophene-2-carboxamide → 7,7-Dimethyl-7,8-dihydro-3H-cyclopenta[4,5]thieno[2,3-d]pyridazin-4(6H)-one

HRID 1843281Notes

Reaction equation

HRID 1843281 reaction equation
C(N[C:6]([C:8]1[S:12][C:11]2[CH2:13][C:14]([CH3:17])([CH3:16])[CH2:15][C:10]=2[C:9]=1[CH:18]=[N:19][NH2:20])=[O:7])(C)(C)C>OS(O)(=O)=O>[CH3:17][C:14]1([CH3:16])[CH2:13][C:11]2[S:12][C:8]3[C:6](=[O:7])[NH:20][N:19]=[CH:18][C:9]=3[C:10]=2[CH2:15]1

Participants

3

Reactant 1

HCID 86683781N-tert-Butyl-3-(hydrazonomethyl)-5,5-dimethyl-5,6-dihydro-4H-cyclopenta[b]thiophene-2-carboxamide

Product 1

HCID 866837837,7-Dimethyl-7,8-dihydro-3H-cyclopenta[4,5]thieno[2,3-d]pyridazin-4(6H)-oneYield 60.1%

Reagents, catalysts & solvents 1

HCID 1118Sulfuric AcidSolvent

Procedure

A solution of 131g (3.8 g, 13.0 mmol) in 30% H2SO4 (100 mL) was heated at reflux for 16 h. See FIG. 15. The reaction mixture was cooled to room temperature and extracted with dichloromethane (3×200 mL). The combined organic layer was concentrated under reduced pressure and the residue was purified by silica-gel column chromatography eluting with 100:1 dichloromethane/methanol to afford 131h as a yellow solid (1.72 g, 60%). MS-ESI: [M+H]+ 221.0

Workup

  1. temperatureat reflux for 16 h
  2. extractionextracted with dichloromethane (3×200 mL)
  3. concentrationThe combined organic layer was concentrated under reduced pressure
  4. customthe residue was purified by silica-gel column chromatography
  5. washeluting with 100:1 dichloromethane/methanol

Sources & evidence

ORD record
ord-df3652be127747b68d6a0e40f669214a
Source dataset
uspto-grants-2015_02
Patent number
US08946213B2

Reaction notes

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