Hydrochloric Acid → 1-tert-Butyl 3-ethyl piperazine-1,3-dicarboxylate

HRID 1437275Notes

Reaction equation

HRID 1437275 reaction equation
Cl.[CH2:2]([O:4][C:5]([CH:7]1[N:12](C(OC(C)(C)C)=O)[CH2:11][CH2:10][N:9]([C:20]([O:22][C:23]([CH3:26])([CH3:25])[CH3:24])=[O:21])[CH2:8]1)=[O:6])[CH3:3]>C(O)C>[CH2:2]([O:4][C:5]([CH:7]1[NH:12][CH2:11][CH2:10][N:9]([C:20]([O:22][C:23]([CH3:24])([CH3:26])[CH3:25])=[O:21])[CH2:8]1)=[O:6])[CH3:3]

Participants

4

Reactant 2

HCID 313Hydrochloric AcidHCID 23122072HCID 23122072, compound

Product 1

HCID 114026711-tert-Butyl 3-ethyl piperazine-1,3-dicarboxylate

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

Concentrated hydrochloric acid (5 mL) was added to the above-obtained 1,4-di-tert-butoxycarbonylpiperazine-3-carboxylic acid ethyl ester (5.5 g) in ethanol (50 mL), followed by stirring at room temperature for 3 days. The solvent of the reaction mixture was removed under reduced pressure, to thereby give piperazine-2-carboxylic acid ethyl ester hydrochloride (3.4 g, 95.7%). Under cooling with ice, triethylamine (5 mL) and 2-(tert-butoxycarbonyloxyimino)-2-phenylacetonitrile (4.0 g) were added to the thus-obtained piperazine-2-carboxylic acid ethyl ester hydrochloride (3.4 g) in tetrahydrofuran (30 mL), followed by stirring at room temperature for 16 hours. The reaction mixture was partitioned by use of methylene chloride. The organic layer was dried over magnesium sulfate anhydrate, followed by filtration. The solvent was removed under reduced pressure, and the residue was purified through silica gel column chromatography (methylene chloride-methanol), to thereby give the title compound as an oily product (3.14 g, 49%).

Workup

  1. customThe solvent of the reaction mixture was removed under reduced pressure
  2. temperatureUnder cooling with ice, triethylamine (5 mL) and 2-(tert-butoxycarbonyloxyimino)-2-phenylacetonitrile (4.0 g)
  3. additionwere added to the thus-obtained piperazine-2-carboxylic acid ethyl ester hydrochloride (3.4 g) in tetrahydrofuran (30 mL)
  4. stirringby stirring at room temperature for 16 hours
  5. customThe reaction mixture was partitioned by use of methylene chloride
  6. dry with materialThe organic layer was dried over magnesium sulfate anhydrate
  7. filtrationfollowed by filtration
  8. customThe solvent was removed under reduced pressure
  9. customthe residue was purified through silica gel column chromatography (methylene chloride-methanol)

Sources & evidence

ORD record
ord-35c68de577d8444083ab782fbd1ae058
Source dataset
uspto-grants-2009_11
Patent number
US07622471B2

Reaction notes

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