(S,S)‐Lactoyllactic acid and (S,S,S)‐lactoyllactoyllactic acid

The dimeric condensation product of lactic acid, namely (S,S)‐2‐(2‐hydroxypropanoyl)oxy]propanoic acid, C₆H₁₀O₅, (I), crystallizes with two independent molecules in the asymmetric unit, which both have an essentially planar backbone. The trimeric condensation product, namely (S,S,S)‐3‐hydroxybut‐3‐en‐2‐yl 2‐(2‐hydroxypropanoyl)oxy]propanoate, C₉H₁₄O₇, (II), has one molecule in the asymmetric unit and consists of two essentially planar parts, with the central C—O bond in a gauche conformation. Both molecules of the dimer are involved in intermolecular hydrogen bonds, forming chains with a C(8) graph set. These chains are connected by D(2) hydrogen bonds to form a two‐dimensional layer. The trimer forms hydrogen‐bonded C(10) and C₂²(6) chains, which together result in a two‐dimensional motif. The Hooft method Hooft, Straver & Spek (2008). J. Appl. Cryst. 41 , 96–103] was successfully applied to the determination of the absolute structure of (I).