Hydrazine hydrate (1:1) → ethyl 4,5,6,7-tetrahydro-1H-indazole-3-carboxylate

HRID 2064641Notes

Reaction equation

HRID 2064641 reaction equation
[CH2:1]([O:3][C:4](=[O:14])[C:5](=O)[CH:6]1[CH2:11][CH2:10][CH2:9][CH2:8][C:7]1=O)[CH3:2].O.[NH2:16][NH2:17]>C(O)(=O)C>[CH2:1]([O:3][C:4]([C:5]1[C:6]2[CH2:11][CH2:10][CH2:9][CH2:8][C:7]=2[NH:17][N:16]=1)=[O:14])[CH3:2]

Participants

4

Reactant 2

HCID 24654Hydrazine hydrate (1:1)HCID 219637Ethyl 2-oxo-2-(2-oxocyclohexyl)acetate

Product 1

HCID 6624328ethyl 4,5,6,7-tetrahydro-1H-indazole-3-carboxylate

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

A solution of oxo-(2-oxo-cyclohexyl)-acetic acid ethyl ester [7.5 g, Reference Example 19(a)] in acetic acid (150 ml) was treated dropwise with hydrazine monohydrate (1.65 ml). The mixture was refluxed for 8 hours, then cooled and then evaporated. The residue was partitioned between ethyl acetate (200 ml) and saturated sodium bicarbonate solution (200 ml) and the organic layer was dried over sodium sulfate and then evaporated. The residual orange oil was subjected to flash column chromatography on silica eluting with a mixture of ethyl acetate and hexane (1:1, v/v) to give 4,5,6,7-tetrahydro-1H-indazole-3-carboxylic acid ethyl ester (606 mg) as an orange oil which solidified on standing. LC-MS (METHOD B): RT=2.79 minutes; 195 (M+H)+.

Workup

  1. temperatureThe mixture was refluxed for 8 hours
  2. temperaturecooled
  3. customevaporated
  4. customThe residue was partitioned between ethyl acetate (200 ml) and saturated sodium bicarbonate solution (200 ml)
  5. dry with materialthe organic layer was dried over sodium sulfate
  6. customevaporated
  7. additionThe residual orange oil was subjected to flash column chromatography on silica eluting with a mixture of ethyl acetate and hexane (1:1, v/v)

Sources & evidence

ORD record
ord-c3020bc638f745bcb8d64f95cb665698
Source dataset
uspto-grants-2012_10
Patent number
US08288425B2

Reaction notes

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