11-Bromo-1-undecanol → Methyl 17-hydroxy-6-thia-heptadecanoate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a solution of 11-bromo-1-undecanol (10 g, 40 mmol) in DMSO (80 mL) was added thiourea (3.64 g, 48 mmol), and the mixture was allowed to react at room temperature for 21 hr. The mixture was extracted twice with hexane (20 mL) to remove the unreacted bromo alcohol. To the DMSO fraction was added 2N KOH (50 mL) and the mixture was heated at 80° C. for 5 min, releasing the thiol 11-mercapto-undecanol. The mixture was acidified (HCl) and extracted twice with ether (40 ml). The combined ether phases were washed successively with water and brine, dried over MgSO4, and evaporated under reduced pressure. The resulting thiol (≅7.2 g) was caused to react with methyl 5-bromo-pentanoate (7 g, 37 mmol) according to the procedure for compound 1. Crystallization of the product in hexane yielded 5.5 g (18 mmol 48% yield from the thiol) of methyl 17-hydroxy-6-thia-heptadecanoate. TLC (hexane/ether 1:1) showed a single product at Rf=0.3. Without further characterization, the hydroxy-ester (4 g, 12 mmol) was caused to react with Ts-Cl (2.7 g, 12 mmol) and pyridine (14 mmol) in CHCl2(40 mL) at 5° C. for 4 hr. The mixture was acidified with ice-diluted HCl, and the organic layer separated, dried (MgSo4) and evaporated under reduced pressure. The product 3 (2.4 g, 34% yield) was isolated by column chromatography (hexane/ethyl acetate 7:3) and recrystallized in hexane. TLC (hexane/ethyl acetate 7:3) Rf=0.6. Melting point=54° C. 1H-NMR δ1.3 (m, 22H, CH2), 2.38 (t. 2H, C(2)H2), 2.5 (m, 7H, C(5)H2, C(7)H2, (tosyl) CH3), 3.7 (s, 3H, —COO—CH3), 4.0 (t, 2H, C(17)H2), 7.6 (m, 4H, aryl).

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