2-(Methylthio)benzaldehyde is an aromatic aldehyde bearing an ortho-methylthio substituent. The electron-donating thio-ether directs electrophilic substitution to the 4- and 6-positions, while the formyl group provides a versatile handle for reductive amination, Wittig, Knoevenagel or oxime formation. The methylthio moiety can be chemoselectively oxidised to sulfoxide or sulfone (H₂O₂/AcOH, rt, 1 h, 95 % yield) without affecting the aldehyde, enabling late-stage diversification. The compound is employed as a key building block for:
Regioselective Suzuki, Heck and Buchwald–Hartwig cross-couplings after conversion to the corresponding aryl bromide or boronic acid;
ortho-Lithiation/trans-metalation sequences (n-BuLi, –78 °C → ZnCl₂) for rapid assembly of multisubstituted benzaldehyde scaffolds used in pharmaceuticals and agro-chemicals;
Thio-ether ligand precursors and fragrance intermediates after selective S-oxidation.
The product shows excellent shelf-life (≥ 24 months when stored sealed, dry and under nitrogen) and is supplied with comprehensive QC documentation (GC-MS, ¹H/¹³C NMR, IR, MSDS) suitable for cGMP or ISO-9001 workflows.
