Benzaldehyde → 2-Phenylthiazolidine-4-carboxylic acid methyl ester

To a solution of DL-cysteine (3 g, 24.76 mmol) in MeOH (50 mL) at 0° C., SOCl2 (2.76 mL, 37.14 mmol) was slowly added and warmed to room temperature then refluxed for 3 h. The reaction mixture was concentrated in vacuo to yield a residue. This residue was taken in to aqueous EtOH (1:1, 30 mL), NaHCO3 (2.28 g, 27.23 mmol) was added, after 10 min benzaldehyde (2.5 mL, 24.76 mmol) was added and stirring continued for 3 h. CHCl3 (200 mL) was added to the reaction mixture and washed with water, brine, dried (Na2SO4) and solvent was removed in vacuo. The crude product was purified by column chromatography to afford 2-phenylthiazolidine-4-carboxylic acid methyl ester (compound 31): yield 4.7 g, 85%; 1H NMR (CDCl3) δ 7.51-7.62 (m, 2H), 7.32-7.42 (m, 3H), 5.84 (s, 0.4H), 5.58 (s, 0.6H), 4.24 (t, J=6.3 Hz, 0.4H), 4.01 (t, J=7.5 Hz, 0.6H), 3.83 (s, 3H), 3.39-3.55 (m, 1H), 3.10-3.26 (m, 1H); MS (ESI) m/z 224; (M+1).

1. temperaturethen refluxed for 3 h
2. concentrationThe reaction mixture was concentrated in vacuo
3. customto yield a residue
4. additionwas added
5. washwashed with water, brine
6. dry with materialdried (Na2SO4) and solvent
7. customwas removed in vacuo
8. customThe crude product was purified by column chromatography

ORD record

ord-77a6d758ff424b94bb23882ec9f85a68

Source dataset

uspto-grants-2007_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07307093B2