Benzyl chloroformate → N-Cbz-d-alanine

HRID 371805

Reaction equation

HRID 371805 reaction equation
[NH2:1][C@@H:2]([C:4]([OH:6])=[O:5])[CH3:3].[OH-].[Na+].[CH2:9]([O:16][C:17](Cl)=[O:18])[C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1>>[CH2:9]([O:16][C:17]([NH:1][C@@H:2]([C:4]([OH:6])=[O:5])[CH3:3])=[O:18])[C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1

Participants

4

Reactant 3

HCID 10387Benzyl chloroformateHCID 14798Sodium Hydroxide2×HCID 71080D-Alanine

Product 1

HCID 70832N-Cbz-d-alanine

Conditions

Temperature
4 °C

Procedure

Nα -Benzyloxycarbonyl-D-alanine is prepared in the following manner. To a solution of 12.5 g. of D-alanine in 70 ml. of 2N sodium hydroxide, with ice cooling and stirring, is added in simultaneous dropwise addition 24 g. of benzyloxycarbonyl chloride and 35 ml. of 4N sodium hydroxide. The pH is maintained at 10 to 12 using a pH electrode in the reaction vessel. The reaction is stirred for one hour further at 4° C. and then extracted with 100 ml. of ethyl ether and acidified to pH 3 with concentrated hydrochloric acid. The product precipitates and is separated by filtration and dried in air; 23.5 g., m.p. 82°-85° C.; [α]D25 + 14.8° (c. 1, 1N acetic acid). A second crop can be obtained from the filtrate by concentration and cooling.

Workup

  1. additionis added in simultaneous dropwise addition 24 g
  2. temperatureThe pH is maintained at 10 to 12 using a pH electrode in the reaction vessel
  3. extractionextracted with 100 ml
  4. customThe product precipitates
  5. customis separated by filtration
  6. customdried in air
  7. custom[α]D25 + 14.8° (c. 1, 1N acetic acid)
  8. customA second crop can be obtained from the filtrate by concentration
  9. temperaturecooling

Sources & evidence

ORD record
ord-0dc1313d594d45d9929c79609c6ae7a8
Source dataset
uspto-grants-1978_05
Patent number
US04087418

Linked notes

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