Hydrogen Bromide → HCID 13341555, compound

HRID 1981122Notes

Reaction equation

HRID 1981122 reaction equation
C(OC([N:11]1[CH2:16][CH2:15][CH2:14][CH:13]([C:17]([O:19][CH3:20])=[O:18])[N:12]1[C:21](=[O:26])[CH:22]([Br:25])[CH2:23]Br)=O)C1C=CC=CC=1.Br>C(O)(=O)C>[Br:25][CH:22]1[CH2:23][N:11]2[CH2:16][CH2:15][CH2:14][CH:13]([C:17]([O:19][CH3:20])=[O:18])[N:12]2[C:21]1=[O:26]

Participants

4

Reactant 2

HCID 260Hydrogen BromideHCID 13341554HCID 13341554, compound

Product 1

HCID 13341555HCID 13341555, compoundYield 78%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

5.8 g of methyl 1-benzyloxycarbonyl-2-(2,3-dibromopropionyl)-hexahydro-3-pyridazinecarboxylate (2 racemates) were stirred for 1 hour at room temperature with 15 ml of 45% hydrogen bromide solution in glacial acetic acid and the mixture was then evaporated. The resulting oily solid was washed with diethyl ether and then partitioned between dichloromethane and saturated aqueous sodium bicarbonate solution. The organic phase was separated, dried over sodium sulphate and evaporated. The residue was chromatographed on silica gel. Elution with tert.butyl methyl ether gave firstly 0.4 g (12%) of methyl 2-bromo-hexahydro-3-oxo-1H-pyrazolo[1,2-a]pyridazine-5-carboxylate (racemate A) in the form of a white solid of melting point 115°-117° C. (from ethyl acetate/hexane) and secondly 2.54 g (78%) of methyl 2-bromo-hexahydro-3-oxo-1H-pyrazolo[1,2-a]pyridazine-5-carboxylate (B) in the form of a white solid of melting point 109°-112° C. (from ethyl acetate/n-hexane).

Workup

  1. customthe mixture was then evaporated
  2. washThe resulting oily solid was washed with diethyl ether
  3. custompartitioned between dichloromethane and saturated aqueous sodium bicarbonate solution
  4. customThe organic phase was separated
  5. dry with materialdried over sodium sulphate
  6. customevaporated
  7. customThe residue was chromatographed on silica gel
  8. washElution with tert.butyl methyl ether

Sources & evidence

ORD record
ord-4e4bec1581a34ef5be6a66b3cef6607d
Source dataset
uspto-grants-1985_04
Patent number
US04512924

Reaction notes

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