Acetic Acid → 1,4-Dihydrocinnoline

HRID 2399115Notes

Reaction equation

HRID 2399115 reaction equation
[N+]([C:4]1[CH:5]=[C:6]2[C:11](=[CH:12][CH:13]=1)[N:10]=[N:9][C:8](C(OCC)=O)=[CH:7]2)([O-])=O.CC(C)=O.C(O)(=O)C.[H][H]>C(O)C.[Pt]=O.[O-2].[O-2].[Mn+4]>[NH:10]1[C:11]2[C:6](=[CH:5][CH:4]=[CH:13][CH:12]=2)[CH2:7][CH:8]=[N:9]1

Participants

8

Reactant 4

HCID 176Acetic AcidHCID 180AcetoneHCID 21432704HCID 21432704, compoundHCID 178418361HCID 178418361, compound

Product 1

HCID 124272971,4-Dihydrocinnoline

Reagents, catalysts & solvents 3

HCID 82844Platinum oxide (PtO)CatalystHCID 178418406HCID 178418406, compoundCatalystHCID 702EthanolSolvent

Procedure

A mixture of ethyl 6 nitrocinnolin-3-yl carboxylate (0.7 g.) and platinum oxide (100 mg.) in dry ethanol (20 ml.) acetone (20 ml.) and glacial acetic acid (0.5 ml.) was shaken in an atmosphere of hydrogen at room temperature and atmospheric pressure for 24 hours. The mixture was then heated to boiling point on a steam bath, and manganese dioxide (10 g.) was added to the boiling solution. (The above-mentioned reducing conditions resulted in the formation of relatively small amount of the 1,4-dihydrocinnoline derivative, and the manganese dioxide was used to convert this into the corresponding cinnoline derivative.) The suspension was heated under reflux for 30 minutes and then filtered through Celite. Kieselgel 60 (1 g.) was added to the filtrate, and the mixture was evaporated to dryness. The residue was placed on the top of a silica column (50 g. Kieselgel 60). Elution with ethyl acetate, evaporation of the appropriate fractions and recrystallisation from aqueous ethanol gave ethyl 6-isopropylaminocinnolin-3-yl carboxylate, m.p. 167°-168° C.

Workup

  1. temperatureThe mixture was then heated

Sources & evidence

ORD record
ord-6d7aeee4a5244bc1b0b6c1de44568363
Source dataset
uspto-grants-1977_05
Patent number
US04027023

Reaction notes

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