HCID 178511198, compound → Carnosine

HRID 1374136

Reaction equation

HRID 1374136 reaction equation
[C:1]([CH2:3][C:4]([NH:6][C@@H:7]([CH2:11][C:12]1[N:13]=[CH:14][NH:15][CH:16]=1)[C:8]([OH:10])=[O:9])=[O:5])#[N:2]>N.CO.[Rh]>[CH:16]1[N:15]=[CH:14][NH:13][C:12]=1[CH2:11][C@H:7]([NH:6][C:4]([CH2:3][CH2:1][NH2:2])=[O:5])[C:8]([OH:10])=[O:9]

Participants

4

Reactant 1

HCID 178511198HCID 178511198, compound

Product 1

HCID 439224Carnosine

Reagents, catalysts & solvents 2

HCID 23948RhodiumCatalystHCID 21705897Ammonia methanolSolvent

Conditions

Temperature
90 °C

Procedure

In a 1-litre pressure autoclave, a solution of 10.00 g (45.0 mmol) of (5)-2-(cyanoacetylamino)-3-(1H-imidazol-4-yl)propionic acid (prepared according to Example 3) in a mixture of 157 g of conc. NH3/methanol (m/m=3:2) was added to 0.88 g of Rh/C (0.4 mol % pure Rh, based on reactant used). The autoclave was closed and flushed twice with 40 bar of nitrogen and once with hydrogen. The mixture was heated to 90° C. and the autoclave was pressurized with 40 bar of hydrogen. After 3 h at 90° C., the reaction mixture was cooled to room temperature, the autoclave was depressurized and the catalyst was filtered off by filtration. An in-process analysis (HPLC) showed that the reaction solution (147.2 g) contained 6.38% (m/m) carnosine, corresponding to a selectivity of 92% for complete conversion. The reaction mixture was then concentrated in a rotary evaporator to 41.2 g. 124 g of ethanol were added dropwise at room temperature and the flask was stored in a refrigerator overnight. On the next day, the precipitate was filtered off, washed with ethanol and dried in a drying oven at 40° C./20 mbar. 7.96 g (78%) of a slightly greenish solid with a content (HPLC) of 98% (m/m) were obtained.

Workup

  1. customThe autoclave was closed
  2. customflushed twice with 40 bar of nitrogen and once with hydrogen
  3. temperaturethe reaction mixture was cooled to room temperature
  4. filtrationthe catalyst was filtered off by filtration
  5. concentrationThe reaction mixture was then concentrated in a rotary evaporator to 41.2 g
  6. addition124 g of ethanol were added dropwise at room temperature
  7. customwas stored in a refrigerator overnight
  8. filtrationOn the next day, the precipitate was filtered off
  9. washwashed with ethanol
  10. customdried in a drying oven at 40° C./20 mbar
  11. custom7.96 g (78%) of a slightly greenish solid with a content (HPLC) of 98% (m/m) were obtained

Sources & evidence

ORD record
ord-a64551029581496587ffbd89fd23a637
Source dataset
uspto-grants-2007_01
Patent number
US07164028B2

Linked notes

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