HCID 178418361, compound → Carnosine

HRID 1374135Notes

Reaction equation

HRID 1374135 reaction equation
[H][H].[C:3]([CH2:5][C:6]([NH:8][C@@H:9]([CH2:13][C:14]1[N:15]=[CH:16][NH:17][CH:18]=1)[C:10]([OH:12])=[O:11])=[O:7])#[N:4]>N.CO.[Rh]>[CH:18]1[N:17]=[CH:16][NH:15][C:14]=1[CH2:13][C@H:9]([NH:8][C:6]([CH2:5][CH2:3][NH2:4])=[O:7])[C:10]([OH:12])=[O:11]

Participants

6

Reactant 2

HCID 178418361HCID 178418361, compoundHCID 178511198HCID 178511198, compound

Product 1

HCID 439224Carnosine

Reagents, catalysts & solvents 3

HCID 23948RhodiumCatalystHCID 222AmmoniaSolvent2×HCID 887MethanolSolvent2×

Conditions

Temperature
90 °C

Procedure

A 1-litre pressure autoclave was initially charged with 1.76 g of Rh/C (0.4 mol % pure Rh, based on reactant used) in a mixture of 94.2 g of ammonia solution (25% in H2O) and 62.8 g of methanol. The autoclave was closed, and the contents were heated to 90° C. and the autoclave was pressurized with 40 bar of hydrogen. A, solution of 20.0 g (0.09 mol) of (S)-2-(cyanoacetyl-amino)-3-(1H-imidazol-4-yl)propionic acid (prepared according to Example 3) in a mixture of 94.2 g of ammonia solution (25% in H2O) and 62.8 g of methanol was then metered in over the course of one hour. After further reaction at 90° C. for one hour, the reaction mixture was cooled to room temperature. The autoclave was depressurized and the catalyst was filtered off via activated carbon. An in-process HPLC analysis showed that the clear greenish reaction solution (326.2 g) contained 5.74% (m/m) carnosine, corresponding to a selectivity of 92% for complete conversion. The reaction mixture was then concentrated to approx. 60 g in a rotary evaporator. Dropwise addition of 174 g of ethanol caused precipitation of a white solid which was filtered off and dried at 50° C./20 mbar.

Workup

  1. customThe autoclave was closed
  2. customwas then metered in over the course of one hour
  3. customAfter further reaction at 90° C. for one hour
  4. temperaturethe reaction mixture was cooled to room temperature
  5. filtrationthe catalyst was filtered off
  6. concentrationThe reaction mixture was then concentrated to approx. 60 g in a rotary evaporator
  7. additionDropwise addition of 174 g of ethanol
  8. customprecipitation of a white solid which
  9. filtrationwas filtered off
  10. customdried at 50° C./20 mbar

Sources & evidence

ORD record
ord-f7bc1063fa2a4b8494d08df11f44732e
Source dataset
uspto-grants-2007_01
Patent number
US07164028B2

Reaction notes

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