Need Assistance?
  • US & Canada:
  • UK: +


* Please kindly note that our products are not to be used for therapeutic purposes and cannot be sold to patients.

Cyclic Amino Acids
Catalog number
CAS number
Molecular Formula
Molecular Weight
(2R)-1-(4-methylphenyl)sulfonylpyrrolidine-2-carboxylic acid
Tos-D-Pro-OH; (2R)-1-(4-methylphenyl)sulfonylpyrrolidine-2-carboxylic acid
White powder
≥ 98% (TLC)
1.377±0.06 g/cm3(Predicted)
Melting Point
55-60 ºC
Boiling Point
467.6±55.0 °C(Predicted)
Store at 2-8 °C
InChI Key
Canonical SMILES
1. Proline-catalyzed asymmetric addition reaction of 9-tosyl-3,4-dihydro-beta-carboline with ketones
Takashi Itoh, Masashi Yokoya, Keiko Miyauchi, Kazuhiro Nagata, Akio Ohsawa Org Lett. 2003 Nov 13;5(23):4301-4. doi: 10.1021/ol030103x.
[reaction: see text] 9-Tosyl-3,4-dihydro-beta-carboline (1) reacted with a ketone in the presence of (S)-proline as a catalyst to give the corresponding addition product in good yield and high enantioselectivity. In the process, a small amount of water was found to affect the stereoselectivity of the products. The system was applied to reaction of compound 1 and 3-buten-2-one to give 3,4,6,7,12,12b-hexahydro-1H-indolo[2,3-a]quinolizin-2-one, which is a versatile precursor for the synthesis of some indole alkaloids.
2. N-Tosyl-L-proline benzene hemisolvate: a rare example of a hydrogen-bonded carboxylic acid dimer with symmetrically disordered H atoms
Joanna Wojnarska, Katarzyna Ostrowska, Marlena Gryl, Katarzyna Marta Stadnicka Acta Crystallogr C Struct Chem. 2019 Sep 1;75(Pt 9):1228-1233. doi: 10.1107/S2053229619010829. Epub 2019 Aug 7.
The carboxylic acid group is an example of a functional group which possess a good hydrogen-bond donor (-OH) and acceptor (C=O). For this reason, carboxylic acids have a tendency to self-assembly by the formation of hydrogen bonds between the donor and acceptor sites. We present here the crystal structure of N-tosyl-L-proline (TPOH) benzene hemisolvate {systematic name: (2S)-1-[(4-methylbenzene)sulfonyl]pyrrolidine-2-carboxylic acid benzene hemisolvate}, C12H15NO4S·0.5C6H6, (I), in which a cyclic R22(8) hydrogen-bonded carboxylic acid dimer with a strong O-(1/2H)...(1/2H)-O hydrogen bond is observed. The compound was characterized by single-crystal X-ray diffraction and NMR spectroscopy, and crystallizes in the space group I2 with half a benzene molecule and one TPOH molecule in the asymmetric unit. The H atom of the carboxyl OH group is disordered over a twofold axis. An analysis of the intermolecular interactions using the noncovalent interaction (NCI) index showed that the TPOH molecules form dimers due to the strong O-(1/2H)...(1/2H)-O hydrogen bond, while the packing of the benzene solvent molecules is governed by weak dispersive interactions. A search of the Cambridge Structural Database revealed that the disordered dimeric motif observed in (I) was found previously only in six crystal structures.
3. Convenient synthesis of L-proline benzyl ester
A Córdova, N N Reed, J A Ashley, K D Janda Bioorg Med Chem Lett. 1999 Nov 1;9(21):3119-22. doi: 10.1016/s0960-894x(99)00546-6.
Mesylates or tosylates of delta-hydroxy-L-norvaline esters spontaneously afford L-proline esters upon exposure to aqueous buffer in near quantitative yield. This novel reaction has led to the development of a simple route to optically active proline esters.
Online Inquiry
Verification code
Inquiry Basket