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Chemical product profile

HONGKUN / PRODUCT DIRECTORY

Methyl (S)-2-chloropropionate | CAS 73246-45-4

A small chiral alpha-chloro ester used in published phenoxypropionic-acid chemistry, with chlorine on the stereogenic carbon and a methyl ester that must remain explicit in identity and assay specifications.

CAS73246-45-4
Molecular formulaC4H7ClO2
Molecular weight122.55 g/mol

Product overview

The S stereocentre in methyl 2-chloropropionate bears chlorine next to the ester carbonyl, creating the alpha-substitution site used in chiral building-block chemistry. The ester is methyl, which distinguishes this material from the free acid and ethyl or isobutyl esters. CAS 73246-45-4 and the complete S designation should accompany the purchase specification. Chemical assay and enantiomeric composition require separate attention: an achiral GC method may resolve chemical impurities while leaving R and S together. Agree a suitable chiral measurement and review residual lactate precursor, free acid or other volatile components where they are relevant to the selected preparation and intended transformation.

Chemical identity

Chemical name
Methyl (S)-2-chloropropionate
CAS number
73246-45-4
Molecular formula
C4H7ClO2
Molecular weight
122.55 g/mol

Application context

Published phenoxypropionic-acid sequences use methyl (S)-2-chloropropionate in substitution at the carbon bearing chlorine. Confirm the stereochemical outcome for the receiving sequence and measure incoming chemical content separately from R/S composition. The methyl ester must match the route’s work-up and hydrolysis stages. Review free acid and lactate-derived residues where relevant to the manufacturing process, together with any water requirement of the substitution step.

Chemistry and synthetic role

The C–Cl bond is on the stereogenic alpha carbon, not on the ester methyl group. Nucleophilic substitution therefore involves the stereochemical centre. Ester conversion and substitution at that carbon are different transformations and should not be confused in material identification.

Quality review

Separate GC purity from enantiomeric quality

Ask whether the proposed GC method resolves R and S or only chemical components. Specify a separate chiral result when the routine assay is nonchiral.

Distinguish ester and acid species

Review methyl ester identity and any free chloropropionic acid relevant to the source process. The acid changes acidity and the mass balance for the receiving reaction.

Review lactate-related carry-over

Where preparation starts from a lactate ester, establish the method for residual hydroxy precursor and other relevant components, with limits suited to the receiving substitution step.

Preparing a specification

Specify methyl (S)-2-chloropropionate with chemical assay, enantiomeric acceptance criteria and test methods. Add free-acid, water and precursor controls when justified by the receiving substitution or hydrolysis stage.

Packaging and storage

Confirm packaging format, net weight and transport arrangements for the selected grade, order quantity and destination. Request the applicable SDS and label to establish storage and handling conditions.

Documentation

Request a chiral chromatogram or equivalent stereochemical evidence, the ordinary GC method and its reporting basis. Confirm availability of batch COA, SDS and relevant precursor or acidity data from the selected source.

Procurement questions

Does GC purity establish S content?

Only when the method separates and measures the enantiomers; otherwise it is a different quality result.

Can the isobutyl ester be supplied instead?

It is a separate compound and requires technical agreement on the changed ester group.

Where is the chlorine located?

On the stereogenic alpha carbon of the propionate chain, not on the ester methyl group.

Technical sources
  1. Methyl (S)-(-)-2-Chloropropionate C1634Tokyo Chemical Industry
  2. Methyl S-2-chloropropanoate CID 135535NCBI PubChem
  3. (-)-Methyl (S)-2-chloropropionateECHA
  4. Synthesis of methyl S-2-chloropropionateCN103232344A / Google Patents
  5. Biosynthesis of R-hydroxyphenoxypropionic acidCN116355969A / Google Patents