Chemical Properties
clear colorless to slightly yellowish viscous
Uses
(
S)-(+)-2-Amino-1-butanol is a chiral amino alcohol that may be used in the synthesis of (
S)-2-(6-benzylamino-9-isopropyl-9
H-purin-2-ylamino) butan-1-ol, an (
S)-enantiomer of roscovitine. It can also be used to synthesize homochiral 2-methylpyrroles. (S)-(+)-2-Amino-1-butanol is an intermediate for the synthesis of (
S,
S)-ethambutol, an antibacterial agent for treating tuberculosis.
Synthesis
To a 100 mL round-bottomed flask, aBH4 (0.2 g, 5 mmol) and THF (10 mL) were added. The suspension was stirred and the flask was immersed in an ice-water bath, and an ether solution of L--amino acids (1 mmol) and concentrated H2SO4 (0.132 mL) was added to the reaction flask (0.4 mL in total) to maintain the reaction mixture at a rate of less than 20C. The reaction was carried out in the same manner as the reaction. The reaction mixture was added dropwise at a rate that kept the reaction mixture below 20C. The reaction mixture was stirred at room temperature for 6 h. Methanol (0.4 mL) was carefully added to destroy the excess borane and the reaction was neutralized with 2 M NaOH. The reaction was extracted with 4 x 50 mL of CH2Cl2. The organic extract was dried with magnesium sulfate. The reaction was concentrated to give (S)-(+)-2-amino-1-butanol.
Purification Methods
They are purified by shaking with solid NaOH, filtering and distilling through a short column. The oxalate of the racemate has m 176o. They are strong bases and should be stored under N2 in the absence of CO2. The enantiomers have [] 20 ±12.5o (c 2, EtOH). [Johnson & Degering J Org Chem 8 7 1943, Nagao et al. J Org Chem 51 2392 1986, Santaniello et al. J Chem Soc, Perkin Trans 1 919 1985, Beilstein 4 H 291, 4 IV 1705.]
