Ethyl chloroformate → 5-tert-Butyl 2-ethyl 3-amino-6,6-dimethylpyrrolo[3,4-c]pyrazole-2,5(4H,6H)-dicarboxylate

HRID 1626278Notes

Reaction equation

HRID 1626278 reaction equation
[NH2:1][C:2]1[NH:6][N:5]=[C:4]2[C:7]([CH3:18])([CH3:17])[N:8]([C:10]([O:12][C:13]([CH3:16])([CH3:15])[CH3:14])=[O:11])[CH2:9][C:3]=12.C(N(CC)C(C)C)(C)C.Cl[C:29]([O:31][CH2:32][CH3:33])=[O:30]>C1COCC1.CCOC(C)=O>[NH2:1][C:2]1[N:6]([C:29]([O:31][CH2:32][CH3:33])=[O:30])[N:5]=[C:4]2[C:7]([CH3:18])([CH3:17])[N:8]([C:10]([O:12][C:13]([CH3:16])([CH3:15])[CH3:14])=[O:11])[CH2:9][C:3]=12

Participants

6

Reactant 3

HCID 10928Ethyl chloroformateHCID 81531DiisopropylethylamineHCID 178451523HCID 178451523, compound

Product 1

HCID 575232455-tert-Butyl 2-ethyl 3-amino-6,6-dimethylpyrrolo[3,4-c]pyrazole-2,5(4H,6H)-dicarboxylateYield 38%

Reagents, catalysts & solvents 2

HCID 8028TetrahydrofuranSolventHCID 8857Ethyl AcetateSolvent

Procedure

15 g of tert-Butyl 3-amino-6,6-dimethyl-2,6-dihydropyrrolo[3,4-c]pyrazole-5(4H)-carboxylate (59.4 mmol) were dissolved in anhydrous THF (150 ml) and treated, at 0° C. under Ar atmosphere, first with N,N-diisopropylethylamine (50 ml) and then with ClCO2Et (4.65 ml, 1 eq.) dropwise. 90 minutes later, the solvent was diluted with EtOAc (1 l), washed with water and then with brine, dried over sodium sulfate and evaporated. The crude product was purified by flash chromatography (hexane/EtOAc 2/8) to afford 7.3 g of 5-tert-butyl 2-ethyl 3-amino-6,6-dimethylpyrrolo[3,4-c]pyrazole-2,5(4H,6H)-dicarboxylate as the major compound in 38% yield, together with 5.7 g of 5-tert-butyl 1-ethyl 3-amino-6,6-dimethyl-4,6-dihydropyrrolo[3,4-c]pyrazole-1,5-dicarboxylate in 30% yield.

Workup

  1. washwashed with water
  2. dry with materialwith brine, dried over sodium sulfate
  3. customevaporated
  4. customThe crude product was purified by flash chromatography (hexane/EtOAc 2/8)

Sources & evidence

ORD record
ord-a02f9d77ca4c46359a7d4c62d6963c83
Source dataset
uspto-grants-2014_07
Patent number
US08785448B2

Reaction notes

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