Methanol → HCID 11172328, Verbindung

Temperatur

0 °C

22 or 23 (2.15 g, 4.81 mmol) was dissolved in dry methylene chloride (20 mL), and 4.0 mL of Et3N (28.7 mmol) was added at room temperature, followed by addition of 3.0 mL (16.6 mmol) of TMSOTf. This mixture was brought to reflux under N2, and stirred for 8 h until the starting material was consumed (monitored by TLC using 30% ethyl acetate in hexanes). The reaction mixture was cooled to 0° C., and the excess TMSOTf was quenched by adding MeOH (1.0 mL, 24.7 mmol), diluted with EtOAc (20 mL), separated, and the aqueous layer was extracted with EtOAc (2×20 mL). The combined organic layers were concentrated via rotary evaporation, dissolved in a mixture of THF (30 mL) and H2O (10 mL). 10 mL of AcOH were added to the mixture and left stirring at room temperature for 3 h. It was then transferred to a 1 L beaker and saturated aqueous NaHCO3 was carefully added until the solution became slightly basic, copious CO2 evolved during this process. The organic layer was separated, and the aqueous layer was extracted with EtOAc (3×50 mL). The combined organic layers were washed by saturated NaHCO3, followed by brine, and dried over Na2SO4. Flash column chromatography (EtOAc-hexane; 1:4) afforded 0.97 g (86%) of 29 as an oil. Care must be taken during purification that the mixture not be exposed to silica for extended time since this will cause some decomposition. The product slowly decomposes at 25° C., but stores well at −10° C. [α]20D=+200.5 (c=0.55, CH2Cl2); 1H NMR (CDCl3, 300 MHz) δ 7.20-7.33 (m, 5H), 6.27 (t, J=5.4 Hz, 1H), 5.92 (d, J=11.4 Hz, 1H), 5.69 (dd, J=4.8, 11.4 Hz, 1H), 4.17 (br s, 1H), 2.59-2.68 (m, 2H), 2.42-2.52 (m, 1H), 1.97 (br s, 1H), 1.22 (d, J=7.2 Hz, 3H); 3C NMR (CDCl3, 75 MHz) δ 137.2, 136.1, 133.9, 131.5, 129.9, 129.5, 129.2, 126.7, 76.4, 40.8, 38.3, 16.7; LRMS (CI): m/z 233 [M+H]+; HRMS (CI) calculated for C14H17OS, 233.1000; found, 233.0991.

1. temperatureto reflux under N2
2. customwas consumed (monitored by TLC using 30% ethyl acetate in hexanes)
3. customthe excess TMSOTf was quenched
4. customseparated
5. extractionthe aqueous layer was extracted with EtOAc (2×20 mL)
6. concentrationThe combined organic layers were concentrated via rotary evaporation
7. dissolutiondissolved in a mixture of THF (30 mL) and H2O (10 mL)
8. addition10 mL of AcOH were added to the mixture
9. waitleft
10. stirringstirring at room temperature for 3 h
11. additionwas carefully added until the solution
12. customThe organic layer was separated
13. extractionthe aqueous layer was extracted with EtOAc (3×50 mL)
14. washThe combined organic layers were washed by saturated NaHCO3
15. dry with materialdried over Na2SO4

ORD-Eintrag

ord-a2addf944a834de8a9024e8dbef1406e

Quelldatensatz

uspto-grants-2009_03

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07501535B2