(-)-Bis[(S)-1-phenylethyl]amine Property

Melting point:

~260 °C

Boiling point:

86 °C0.05 mm Hg(lit.)

alpha 

-197 º (NEAT)

Density 

0.987 g/mL at 25 °C(lit.)

refractive index 

n20/D 1.5525(lit.)

Flash point:

>230 °F

storage temp. 

Keep in dark place,Inert atmosphere,Room temperature

solubility 

readily sol common organic solvents (ether, THF, chloroform, etc.); insol H2O.

pka

8.79±0.29(Predicted)

form 

liquid

color 

Clear, colourless

optical activity

[α]/D 159°, c = 2 in ethanol

Water Solubility 

Immiscible with water.

CAS DataBase Reference

56210-72-1

Safety

Hazard Codes 

Xi

Risk Statements 

36/37/38

Safety Statements 

26-36/37

WGK Germany 

3

F 

3

HS Code 

2921199990

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Warning

Hazard statements

H315Causes skin irritation

H319Causes serious eye irritation

H335May cause respiratory irritation

Precautionary statements

P261Avoid breathing dust/fume/gas/mist/vapours/spray.

P264Wash hands thoroughly after handling.

P264Wash skin thouroughly after handling.

P271Use only outdoors or in a well-ventilated area.

P280Wear protective gloves/protective clothing/eye protection/face protection.

P302+P352IF ON SKIN: wash with plenty of soap and water.

P305+P351+P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.

(-)-Bis[(S)-1-phenylethyl]amine Chemical Properties,Usage,Production

Uses

(-)-Bis[(S)-1-phenylethyl]amine is used as a chiral resolution reagent in organic synthesis.

Preparation

Preparative Methods of (-)-(S,S)-α,α′-Dimethyldibenzylamine: minor improvements to the original catalytic hydrogenation procedure have been described (eq 1). This method provides (S,S)-(-)-(1) with an optical purity of only 70%. Enantiomerically pure (S,S)-(-)-(1) can be obtained by recrystallization of the hydrochloride salt of this enriched material from water or the benzoate salt from isopropanol. A chemical reduction procedure has also been described that yields optically active (S,S)-(1) with 74% enantiomeric excess (eq 2). A significant improvement to the former procedures is the diastereoselective hydrogenation of imines catalyzed by rhodium/chiral diphosphines, which yields (S,S)-(1) with an optical purity of 99.4% (eq 3).

General Description

(-)-(S,S)-α,α′-Dimethyldibenzylamine is a starting material for the formation of chiral amide reagents; useful in the stereospecific deprotonation of prochiral ketones, and as a chirality transfer agent in the reactions of prochiral enolates; stereoselective conjugate addition of organometallic reagents to unsaturated carbonyl systems.^[1]

storage

(-)-(S,S)-α,α′-Dimethyldibenzylamine is no special precautions have been noted in the literature. The free base is a clear distillable liquid that should be stored under an inert atmosphere to prevent air oxidation. Long term storage may lead to some coloration of the material.

Purification Methods

Purification of (-)-(S,S)-α,α′-Dimethyldibenzylamine: the free base can be distilled. The HCl salt can be recrystallized from water, which removes diastereomeric impurities. The benzoate salt can be recrystallized from isopropanol.

References

1. (a) Eleveld, M. B.; Hogeveen, H.; Schudde, E. P. JOC 1986, 51, 3635. (b) Yoshida, T.; Harada, K. BCJ 1972, 45, 3706.