2,2-DIMETHYL-3-PHENYLPROPANOIC ACID

2,2-DIMETHYL-3-PHENYLPROPANOIC ACID Property

Melting point:

59-60 °C(Solv: ligroine (8032-32-4))

Boiling point:

200 °C(Press: 1.5 Torr)

Density 

1.070±0.06 g/cm3(Predicted)

storage temp. 

Sealed in dry,Room Temperature

pka

4.73±0.11(Predicted)

Appearance

White to off-white Solid

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Warning

Hazard statements

H302Harmful if swallowed

H315Causes skin irritation

H319Causes serious eye irritation

H335May cause respiratory irritation

Precautionary statements

P264Wash hands thoroughly after handling.

P264Wash skin thouroughly after handling.

P270Do not eat, drink or smoke when using this product.

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

P301+P312IF SWALLOWED: call a POISON CENTER or doctor/physician IF you feel unwell.

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.

P321Specific treatment (see … on this label).

P330Rinse mouth.

P332+P313IF SKIN irritation occurs: Get medical advice/attention.

P362Take off contaminated clothing and wash before reuse.

P501Dispose of contents/container to..…

2,2-DIMETHYL-3-PHENYLPROPANOIC ACID Chemical Properties,Usage,Production

Synthesis

The general procedure for the synthesis of 2,2-dimethyl-3-phenylpropionic acid from benzyl isobutyrate was as follows: hexamethyldisilazane (34 g, 0.21 mol) was dissolved in tetrahydrofuran (280 mL) at -78 °C, and a hexane solution of 1.67 M n-butyllithium (127 mL, 0.21 mol) was slowly added dropwise. The reaction solution was warmed to 0 °C within 1 h and subsequently cooled again to -78 °C. A solution of tetrahydrofuran (70 mL) of benzyl isobutyrate (25 g, 0.14 mol) was added dropwise and kept stirring at -78 °C for 1 hour. At the same temperature, chlorotrimethylsilane (36 mL, 0.12 mol) was continued to be added dropwise with stirring for 1 h. The reaction was warmed up to room temperature and stirred continuously for 19 h. The reaction was completed by adding a solution of benzyl isobutyrate (25 g, 0.14 mol) in tetrahydrofuran (70 mL). Upon completion of the reaction, some of the solvent was concentrated under reduced pressure and the resulting white suspension was diluted with hexane (200 mL) and the white solid was removed by filtration through diatomaceous earth under nitrogen protection. The filtrate was distilled under reduced pressure to yield a light yellow oil, which was converted to a brown oil by heating at 100 °C for 2 hours. The oily substance was mixed with 10 mL of 1 M hydrochloric acid, stirred at 60 °C for 4 h. After neutralization with saturated aqueous sodium bicarbonate solution, it was extracted with ethyl acetate (100 mL x 2) and chloroform (100 mL x 2), respectively. The organic layers were combined, concentrated and purified by medium-pressure silica gel column chromatography (80 g of silica gel, 100% ethyl acetate) to afford 8.41 g of the target product, 2,2-dimethyl-3-phenylpropionic acid, as white crystals.1H NMR (CDCl3, Me4Si, 300 MHz) δ 7.20-7.30 (m, 3H), 7.16 (d, J = 7.1 Hz, 2H). 2.89 (s, 2H), 1.21 (s, 6H).

References

[1] Tetrahedron Letters, 2002, vol. 43, # 33, p. 5837 - 5840
[2] Journal of Organic Chemistry, 1980, vol. 45, # 5, p. 891 - 894
[3] Patent: US2013/253204, 2013, A1. Location in patent: Paragraph 0217; 0218
[4] Patent: US9212348, 2015, B2. Location in patent: Page/Page column 173; 174