Acetaldehyde → 5-ethylidene-1-(pyridin-4-yl)-5,7,8,9-tetrahydrocyclohepta[f]indazol-6(1H)-one

HRID 718820Notes

Reaction equation

HRID 718820 reaction equation
[N:1]1[CH:6]=[CH:5][C:4]([N:7]2[C:15]3[C:10](=[CH:11][C:12]4[CH2:20][C:19](=[O:21])[CH2:18][CH2:17][CH2:16][C:13]=4[CH:14]=3)[CH:9]=[N:8]2)=[CH:3][CH:2]=1.[Li+].C[Si]([N-][Si](C)(C)C)(C)C.[CH:32](=O)[CH3:33]>C1COCC1>[CH:32](=[C:20]1[C:12]2[CH:11]=[C:10]3[C:15](=[CH:14][C:13]=2[CH2:16][CH2:17][CH2:18][C:19]1=[O:21])[N:7]([C:4]1[CH:5]=[CH:6][N:1]=[CH:2][CH:3]=1)[N:8]=[CH:9]3)[CH3:33]

Participants

5

Reactant 3

HCID 177AcetaldehydeHCID 2733832Lithium Hexamethyldisilazide2×HCID 867224291-(pyridin-4-yl)-5,7,8,9-tetrahydrocyclohepta[f]indazol-6(1H)-one

Product 1

HCID 867224305-ethylidene-1-(pyridin-4-yl)-5,7,8,9-tetrahydrocyclohepta[f]indazol-6(1H)-one

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
-77 °C

Procedure

A round bottom flask was charged with 1-(pyridin-4-yl)-5,7,8,9-tetrahydrocyclohepta[f]indazol-6(1H)-one (14.419 g, 52.0 mmol) and THF (200 mL). The solution was cooled to about −77° C. and then 1 M LiHMDS solution (54.6 mL, 54.6 mmol) was added over about 30 min, keeping the internal temp below about −75° C. After complete addition of the LiHMDS the mixture was stirred for about 5 min, the cold bath was removed and the mixture was allowed to warm to about 0° C. (over about 1 h). The mixture was re-cooled to about −65° C. then acetaldehyde (14.6 mL, 260 mmol) was added. The cold bath was removed and the mixture was allowed to warm to about 0° C. brine (50 mL) and water (50 mL) were added to the mixture, then collected the organic layer. Extracted the aqueous layer with EtOAc (2×50 mL). Combined organics and dried over MgSO4 and concentrated in vacuo. Purified by 120 g silica column, eluting with 20-100% EtOAc/DCM to provide 5-ethylidene-1-(pyridin-4-yl)-5,7,8,9-tetrahydrocyclohepta[f]indazol-6(1H)-one (83, R1=4-Pyridyl, R2′=Methyl) (12.3 g, 78%); LC/MS, method 3, Rt=2.17 min MS m/z 304 (M+H)+, 1H NMR (400 MHz, DMSO) δ 8.75-8.72 (m, 2H), 8.50-8.49 (m, 1H), 8.13 (s, 1H), 7.98-7.95 (m, 2H), 7.75 (s, 1H), 7.18-7.11 (q, J=7.3 Hz, 1H) 2.93-2.85 (m, 2H), 2.35-2.22 (m, 2H), 2.04-1.95 (m, 2H), 1.90-1.85 (d, J=7.4 Hz, 3H).

Workup

  1. customthe internal temp below about −75° C
  2. customthe cold bath was removed
  3. temperatureto warm to about 0° C. (over about 1 h)
  4. temperatureThe mixture was re-cooled to about −65° C.
  5. customThe cold bath was removed
  6. temperatureto warm to about 0° C. brine (50 mL) and water (50 mL)
  7. additionwere added to the mixture
  8. customcollected the organic layer
  9. extractionExtracted the aqueous layer with EtOAc (2×50 mL)
  10. dry with materialCombined organics and dried over MgSO4
  11. concentrationconcentrated in vacuo
  12. customPurified by 120 g silica column
  13. washeluting with 20-100% EtOAc/DCM

Sources & evidence

ORD record
ord-986317867f56486c9d45a531025e651b
Source dataset
uspto-grants-2015_11
Patent number
US09193744B2

Reaction notes

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