Key indicators: single-crystal X-ray study; T = 200 K; mean (C-C) = 0.005 Å; some non-H atoms missing; disorder in main residue; R factor = 0.051; wR factor = 0.139; data-to-parameter ratio = 15.8.The structure of the title compound, [C 12 H 24 NO 4 ][C 7 H 7 O 3 S]Á-1.5H 2 O, contains alternating layers parallel to (001) of hydrophobic and polar character, stabilized by C-HÁ Á ÁO hydrogen bonding. The furan ring adopts an envelope conformation with the C(OMe) atom as the flap, and the dioxolane ring is twisted about one of the O-C(methine) bonds. A comparison to related compounds is presented. The tosylate-O atoms were disordered over two positions with the major component having a site occupancy factor = 0.566 (12). The structure was refined as a rotary twin with regard to rotation about the c axis with the contribution of the second component being 0.0048 (6). Solvate water molecules are highly disordered and were removed using the SQUEEZE procedure; the unit cell characteristics take into account the presence of the disordered solvent. High-resolution 1 H and 13 C NMR spectroscopic data are also presented.
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