L-Phenylalanine → DL-Phenylalaninol
Reaction equation
[NH2:1][C@H:2]([C:10](O)=[O:11])[CH2:3][C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1.B(F)(F)F.CCOCC.CSC.B.[OH-].[Na+]>O1CCCC1.O.O1CCCC1>[NH2:1][CH:2]([CH2:3][C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1)[CH2:10][OH:11]Participants
Procedure
A dry, 12-liter glass reaction vessel equipped as described in Example 1 was charged with 1.17 kilograms (7.1 moles) of phenylalanine and 3 liters of tetrahydrofuran. Using the procedure described in Example 1, boron trifluoride diethyl etherate (0.96 liter, 7.8 moles) was added followed by 0.78 liter (7.8 moles) of borane-dimethyl sulfide at reflux. The addition took 7 hours and heating was then continued for an additional 3 hours following the addition. The reaction mixture was then hydrolyzed with 0.75 liter of tetrahydrofuran/water followed by 4 liters of 6N aqueous sodium hydroxide solution. The product was isolated as described in Example 1 giving 822 grams (77% yield) of 2-amino-3-phenyl-1-propanol, bp 110°-111°C at 0.10 mm, as a clear, colorless oil which crystallized in the receiver, mp 65°-66°C. The purity by perchloric acid titration was only 93%. The impure amino alcohol was dissolved in 6 liters of tetrahydrofuran and anhydrous hydrogen chloride was added to precipitate the hydrochloride salt which was collected and dried in a vacuum oven giving 940 grams of 2-amino-3-phenyl-1-propanol hydrochloride, mp 147°-151°C, purity by perchloric acid titration: 100%.
Workup
- customequipped
- additionwas added
- temperatureat reflux
- additionThe addition
- temperatureheating
- waitwas then continued for an additional 3 hours
- additionthe addition
- customThe product was isolated
Sources & evidence
- ORD record
- ord-407ef5c0c9904d709d2e05bcd329485f
- Source dataset
- uspto-grants-1976_01
- Patent number
- US03935280
Reaction notes
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