1H-isothiochromen-4-one

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Ethyl trifluoroacetate (3.67 g, 25.8 mmol) was dissolved in tetrahydrofuran (15 mL) and treated with 25% sodium methoxide (6.46 g, 29.9 mmol) followed by a solution of isothiochroman-4-one (4.15 g, 25.3 mmol) in tetrahydrofuran (15 mL). The reaction was stirred at room temperature for 70.8 hours and treated with 3N hydrochloric acid (10 mL). The organic layer was collected, washed with brine, dried over MgSO4, concentrated in vacuo, and passed through a column of silica gel eluting with 40% ethyl acetate/hexane to give a brown solid (5.40 g, 82%): 1H NMR (CDCl3) 300 MHz 15.30 (s, 1H) 7.99 (d, J=7.9 Hz, 1H) 7.54 (m, 1H) 7.43 (m, 1H) 7.23 (m, 1H) 3.81 (s, 3H). The organic layer was collected washed with brine dried over MgSO4 concentrated in vacuo

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 1.642 g (10 mmol) isothiochroman-4-one (J. Am. Chem. Soc. 1973, 95, 2923) was alkylated with triethyloxonium tetrafluoroborate (10 mmol, 1M in methylene chloride) according to the method described for compound B2. Recrystallization in ethanol gave 1.26 g (50%) of D1 as white crystals; mp=89.6° C. 1H-NMR (acetone-d6) δ 7.65-8.14 (4 H, m, Ar--H), 5.23 (1 H, d, J=16.1 Hz, --CHH--C(O)--), 5.03 (1 H, d, J=16.1 Hz, --CHH--C(O)--), 4.80 (1 H, d, J=17.2 Hz, --CHH--Ar), 4.55 (1 H, dd, J=2.0 and 17.2 Hz, --CHH--Ar), 3.45-3.85 (2 H, m, >S+ --CH2 --CH3), 1.55 (3 H, t, J=7.5 Hz, >S+ --CH2 -- CH3); 13C-NMR (acetone-d6) δ 183.64, 136.04, 131.78, 130.97, 130.75, 130.51, 128.93, 40.06, 34.45, 34.40, 8.85; UV-absorption max. (ethanol): 254, 293 nm; Anal. Calcd for C11H13BF4OS: C, 47.2%; H, 4.7%; S, 11.5%. Found: C, 47.3%; H, 4.6%; S, 11.5%. Recrystallization in ethanol

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Ethyl trifluoroacetate (3.67 g, 25.8 mmol) was dissolved in tetrahydrofuran (15 mL) and treated with 25% sodium methoxide (6.46 g, 29.9 mmol) followed by a solution of isothiochroman-4-one (4.15 g, 25.3 mmol) in tetrahydrofuran (15 mL). The reaction was stirred at room temperature for 70.8 hours and treated with 3N hydrochloric acid (10 mL). The organic layer was collected, washed with brine, dried over MgSO4, concentrated in vacuo, and passed through a column of silica gel eluting with 40% ethyl acetate/hexane to give a brown solid (5.40 g, 82%): 1H NMR (CDCl3) 300 MHz 15.30 (s, 1H) 7.99 (d, J=7.9 Hz, 1H) 7.54 (m, 1H) 7.43 (m, 1H) 7.23 (m, 1H) 3.81 (s, 3H). The organic layer was collected washed with brine dried over MgSO4 concentrated in vacuo