Propyl mercaptan → (1R,10S,11S,16S)-3-methoxy-11,15,15-trimethyl-8,8-dioxo-8lambda6-thiatetracyclo[8.8.0.02,7.011,16]octadeca-2,4,6-triene-5-carboxylic acid

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Reaction Steps

A mixture of lithium hydride (0.66 g, 83 mmol) and n-propanethiol (8.7 mL, 99 mmol) in HMPA (20 mL) was stirred at room temperature for 30 min under N2. To the mixture (1R,10S,11S,16S)-3-methoxy-11,15,15-trimethyl-8,8-dioxo-8λ6-thiatetracyclo[8.8.0.02,7.011,16]octadeca-2,4,6-triene-5-carboxylate (59) (3.6 g, 8.3 mmol) in HMPA (10 mL) was added. The mixture was heated at 130° C. for 1 h. The mixture was cooled to room temperature and quenched with 1 M HCl, then extracted with EtOAc. The organic layer was concentrated to dryness. The residue was purified by flash chromatography on silica gel (CH2Cl2/MeOH, 10:1) to yield (1R,10S,11S,16S)-3-methoxy-11,15,15-trimethyl-8,8-dioxo-8λ6-thiatetracyclo[8.8.0.02,7.011,16]octadeca-2,4,6-triene-5-carboxylic acid (61) (3.2 g, 95% yield) as a white solid. 1H NMR (CD3OD): δ 7.91 (d, 1H), 7.54 (d, 1H), 3.59 (m, 1H), 3.38 (m, 2H), 2.24 (m, 1H), 1.86 (m, 8H), 1.36-1.16 (m, 3H), 1.09-1.03 (m, 2H), 1.02 (s, 3H), 0.89 (s, 3H), 0.87 (s, 3H). MS m/z 405 (C22H30NO5S−H+).

Provenance & Evidence