Ethyl D-(-)-pyroglutamate Chemical Properties

Melting point:

53-57 °C

Boiling point:

176 °C12 mm Hg(lit.)

alpha 

3.5 º (C=5, H2O)

Density 

1.2483 (rough estimate)

refractive index 

n20/D 1.478(lit.)

Flash point:

>230 °F

storage temp. 

Sealed in dry,2-8°C

solubility 

Chloroform (Slightly), Methanol (Slightly)

form 

Solid

pka

14.78±0.40(Predicted)

color 

White to Light Brown

optical activity

[α]/D 4.0±1°, c = 10 in ethanol

BRN 

82622

CAS DataBase Reference

68766-96-1(CAS DataBase Reference)

Safety Information

Hazard Codes 

Xi

Risk Statements 

36/37/38

Safety Statements 

37/39-26

WGK Germany 

3

F 

3-10

HS Code 

29337900

MSDS

• Language:English Provider:ACROS
• Language:English Provider:SigmaAldrich

Ethyl D-(-)-pyroglutamate Usage And Synthesis

Chemical Properties

Waxy Solid

Uses

(R)-(-)-5-Ethylcarboxyl-2-pyrrolidinone (cas# 68766-96-1) is a compound useful in organic synthesis.

reaction suitability

reaction type: solution phase peptide synthesis

Synthesis

General procedure for the synthesis of D-pyroglutamic acid ethyl ester from ethanol and D-(+)-pyroglutamic acid: thionyl chloride (10 ml, 139.68 mmol) was slowly added to an ethanolic solution (100 ml) of D-(+)-pyroglutamic acid (10 g, 69.84 mmol; purchased from Aldrich, Art. No. 422614) which was cooled down to -5 °C. The reaction mixture was stirred at room temperature for 3 hours. After completion of the reaction, the solvent was removed by vacuum evaporation and the residue was dissolved in ethyl acetate (350 ml). The organic phase was washed sequentially with water/triethylamine (40/12 ml) and water (40 ml). The organic phases were combined and concentrated by drying with anhydrous sodium sulfate. The concentrate was separated by column chromatography on a SNAP-Si column (50 g) with the eluent dichloromethane/ethyl acetate (gradient elution from 90/10 to 50/50). The fraction containing the target product was collected and the solvent was evaporated to give the first batch of ethyl D-pyroglutamate (D23) (6.4 g). The aqueous phase was saturated with sodium chloride and extracted with ethyl acetate (400 ml). The organic phase was washed with water (20 ml), dried over anhydrous sodium sulfate and concentrated to give the second batch of ethyl D-pyroglutamate (D23) (3.7 g). The product was characterized by 1H NMR (400 MHz, CDCl3), δ (ppm): 6.58 (broad single peak, 1H), 4.29-4.17 (multiple peaks, 3H), 2.53-2.29 (multiple peaks, 3H), 2.28-2.17 (multiple peaks, 1H), 1.35-1.22 (triple peaks, 3H).

References

[1] Journal of Medicinal Chemistry, 2012, vol. 55, # 3, p. 1368 - 1381
[2] Journal of Medicinal Chemistry, 1985, vol. 28, # 12, p. 1760 - 1765
[3] Patent: WO2011/79114, 2011, A1. Location in patent: Page/Page column 81
[4] Patent: WO2013/4290, 2013, A1. Location in patent: Page/Page column 51; 52
[5] Patent: US2014/58117, 2014, A1. Location in patent: Paragraph 0049-0050

Ethyl D-(-)-pyroglutamate(68766-96-1)Related Product Information

• H-GLU(OET)-OH
• D-Pyroglutamic acid
• Polyglutamic acid
• L-Pyroglutamic acid
• Ethyl propionate
• Ethylbenzene
• Polyvinylpyrrolidone
• Tris(trimethylsilyl)phosphate
• Ethyl vanillin
• Ethyl acrylate
• 2-Pyrrolidinone
• Povidone iodine
• N-Vinyl-2-pyrrolidone
• Ethyl acetate
• Ethyl formate
• N-Methyl-2-pyrrolidone
• Diethyl pyrocarbonate
• DL-Pyroglutamic acid