Methanol → 12-(12-p-Methoxybenzylthio-1-dodecylthio)-dodecanoic acid

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Na (116 mg, 5 mmol) was dissolved it dry MeOH. 12-mercapto-1-dodecanoic acid (340 mg, 1.46 mmol)—synthesized according to JACS 115, 3458–3474, 1993 was added to the methoxide solution. After stirring with some heating for 5 min, (2) (497 mg, 1.24 mmol) was added to the reaction. The reaction became very viscous and an additional 1.75 mL of MeOH was introduced. The reaction was then left overnight. The reaction was quenched with 10% acetic acid. The paste-like reaction mixture was transferred to a 500 mL separatory funnel dissolved in equal volumes of EtOAc/Hex (1:1) and the acetic acid solution. The organic layer was separated. The aqueous layer was then extracted two more times. The combine extracts were concentrated yielding 740.3 mg (1.34 mmol) of crude product. The excess acetic acid was removed as a toluene azeotrope. The solid was crystallized from isopropyl ether giving 483 mg (71%). TLC and NMR show an impurity believed to be a disulfide side product. The material was further purified by flash chromatography eluting with CHCl3/MeOH/AA (99:0.5:0.5) yielding 334 mg (0.604 mmol, 49%) of pure product. 1H NMR (CDCl3): d 9.45 (brs, 1H, COOH), 7.23 (d, J=8.8 Hz, 2H, AA′ of AA′ BB′ aromatic system), 6.85 (d, J=8.7 Hz, 2H, BB′ of AA′ BB′ aromatic system), 3.80 (s, 3H, methoxy), 3.66 (s, 2H, benzyl), 2.50 (t, J=7.3 Hz, 4H, RCH2SCH2R), 2.40 (t, J=7.3 Hz, 2H, RSCH2R), 2.35 (t, J=7.5 Hz, 2H, RCH2COOH), 1.5–1.7 (cm, 8H, CH2 b to heteroatoms), 1.15–1.45 (cm, 30H, bulk methylenes). 13C NMR (CDCl3): d 179.5 (COOH), 129.9 (aromatic, 2C), 113.9 (aromatic, 2C), 55.2 (MeOR), 35.6 (CH2), 33.7 (CH2), 32.2 (CH2), 31.3 (CH2), 29.7 (CH2), 29.4 (CH2), 29.2 (CH2), 28.9 (CH2), 24.6 (CH2).

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