(S)-4-METHYLENE-PYRROLIDINE-1,2-DICARBOXYLIC ACID 1-TERT-BUTYL ESTER

(S)-4-METHYLENE-PYRROLIDINE-1,2-DICARBOXYLIC ACID 1-TERT-BUTYL ESTER Property

Melting point:

110-115 °C

Boiling point:

349.9±42.0 °C(Predicted)

Density 

1.18±0.1 g/cm3 (20 ºC 760 Torr)

storage temp. 

2-8°C(protect from light)

form 

solid

pka

3.80±0.20(Predicted)

Appearance

Off-white to light yellow Solid

optical activity

[α]22/D 58°, c = 0.5 in chloroform

Water Solubility 

Insoluble in water.

CAS DataBase Reference

84348-38-9

Safety

Hazard Codes 

Xi

Risk Statements 

36/37/38

Safety Statements 

26

WGK Germany 

3

HS Code 

2933998090

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.

(S)-4-METHYLENE-PYRROLIDINE-1,2-DICARBOXYLIC ACID 1-TERT-BUTYL ESTER Chemical Properties,Usage,Production

Uses

As important intermediates in various areas such as peptide synthesis, asymmetric synthesis, medicinal chemistry, and polymer chemistry. The fluorous prolins were synthesized from commercially available N-Boc-4-methylene- L-proline.

reaction suitability

reaction type: Boc solid-phase peptide synthesis

Synthesis

Example 2. Preparation of (S)-1-(tert-butoxycarbonyl)-4-methylenepyrrolidine-2-carboxylic acid To a suspension of methyltriphenylphosphonium bromide (236.4 g, 2.7 eq.) in tetrahydrofuran (1 L) was rapidly added potassium tert-butoxide (75.6 g, 2.75 eq.) at 0 °C. The reaction mixture was slowly warmed to room temperature and stirred for 2 hours, followed by cooling again to 0 °C. At this temperature, (S)-1-(tert-butoxycarbonyl)-4-oxopyrrolidine-2-carboxylic acid (56.2 g, 0.245 mol) was added batchwise keeping the reaction temperature below 5 °C. The reaction mixture was then cooled to room temperature and stirred for 2 hours. The reaction mixture was then warmed to room temperature and stirred overnight. Upon completion of the reaction, the mixture was cooled to 0 °C and the reaction was quenched with saturated sodium bicarbonate solution (500 mL) and water (200 mL). The solvent was removed by concentration under reduced pressure and the aqueous phase was extracted with tert-butyl methyl ether (2 x 400 mL). The aqueous phase was filtered through a diatomaceous earth pad, acidified with 6N hydrochloric acid (200 mL) and extracted with ethyl acetate (2 x 1 L). The organic phases were combined, washed with saturated brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was dissolved in ethyl acetate (0.7 L) and extracted with 0.5N sodium hydroxide solution (0.7 L and 0.3 L). The aqueous phase was acidified with 6N hydrochloric acid (100 mL) and extracted with ethyl acetate (1 L and 0.8 L). The organic phases were combined, washed with saturated brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was dissolved in a 50% ethyl acetate solution in cyclohexane (150 mL), and the solvent was slowly evaporated to give a pale yellow solid, which was filtered and dried to give (S)-1-(tert-butoxycarbonyl)-4-methylenepyrrolidine-2-carboxylic acid (26 g). The mother liquor was concentrated under reduced pressure to give the same light yellow solid, which was filtered and dried to give additional product (10 g). In total, 36 g of product (65% yield) was obtained as a white solid. In addition, the residue contained 18 g of product with 80% purity. 1H NMR (500 MHz, CDCl3): δ 5.04-5.02 (m, 2H), 4.53 (dd, J = 8.4, 3.2 Hz, 0.5H), 4.42 (d, J = 9.3 Hz, 0.5H), 4.09-3.98 (m, 2H), 3.05-2.69 (m, 2H), 1.49 and 1.43 (2s, 9H).

References

[1] Patent: WO2012/158861, 2012, A2. Location in patent: Page/Page column 19-20
[2] Patent: WO2010/43877, 2010, A1. Location in patent: Page/Page column 51; 52
[3] Patent: WO2007/25307, 2007, A2. Location in patent: Page/Page column 309
[4] Patent: WO2017/35353, 2017, A1. Location in patent: Paragraph 0759
[5] Patent: CN107954990, 2018, A. Location in patent: Paragraph 0080; 0082; 0083; 0153; 0222