Methanol → Methyl DL-prolinate hydrochloride

HRID 35845Notes

Reaction equation

HRID 35845 reaction equation
S(Cl)([Cl:3])=O.[NH:5]1[CH2:12][CH2:11][CH2:10][C@H:6]1[C:7]([OH:9])=[O:8].[CH3:13]O>>[ClH:3].[NH:5]1[CH2:12][CH2:11][CH2:10][CH:6]1[C:7]([O:9][CH3:13])=[O:8]

Participants

4

Reactant 3

HCID 887MethanolHCID 24386Thionyl ChlorideHCID 145742L-Proline

Product 1

HCID 12223519Methyl DL-prolinate hydrochloride

Conditions

Temperature
40 °C

Procedure

600 ml of technical-grade methanol are introduced into a multinecked flask equipped with dropping funnel and internal thermometer, with ice/sodium chloride cooling. 2.4 mol of thionyl chloride are added dropwise in such a way that the temperature of the reaction solution does not exceed -5° C. Then, 2.18 mol of proline are added in portions in the course of approximately 10 minutes. The mixture is stirred for approximately 4 hours at 40° C. and subsequently for three days at room temperature, and the solution is greatly concentrated, the residue is taken up several times in methanol to remove excess thionyl chloride, and the mixture is reconcentrated. After drying the product for several hours in a lukewarm water bath in an evacuated flask, the target compound is obtained in quantitative yield. Some of the oily crude product crystallises after being left to stand over several days.

Workup

  1. customequipped
  2. customdoes not exceed -5° C
  3. concentrationthe solution is greatly concentrated
  4. customto remove excess thionyl chloride
  5. customAfter drying the product for several hours in a lukewarm water bath in an evacuated flask
  6. customthe target compound is obtained in quantitative yield
  7. customSome of the oily crude product crystallises
  8. waitafter being left
  9. waitto stand over several days

Sources & evidence

ORD record
ord-488748cf39d5499db0d16b607b8d5389
Source dataset
uspto-grants-1995_05
Patent number
US05411955

Reaction notes

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