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HETEROCYCLES, Vol. 83, No. 8, 2011
ice bath and the mixture was concentrated under reduced pressure. The residue was extracted with EtOAc
(3 x 30 mL). The combined organic layers were washed with brine, dried, filtered and evaporated to
afford crude product under reduced pressure. Purification on silica gel (hexane/EtOAc = 8/1~6/1)
afforded 7 as a white solid (41 mg, 72%). mp 84-86 oC (recrystallized from hexane and EtOAc); HRMS
(ESI, M++1) calcd for C13H18NO4S 284.0957, found 284.0958; 1H NMR (400 MHz): δ 7.76-7.73 (m, 2H),
7.61-7.56 (m, 1H), 7.54-7.49 (m, 2H), 5.50 (t, J = 6.8 Hz, 1H), 4.64 (t, J = 3.2 Hz, 1H), 4.22 (dd, J = 8.4,
12.8 Hz, 1H), 4.02 (dd, J = 6.8, 12.8 Hz, 1H), 3.74-3.67 (m, 1H), 3.66-3.60 (m, 1H), 3.00 (br s, 2H), 2.74
(dt, J = 4.4, 12.8 Hz, 1H), 2.58 (dd, J = 2.4, 12.0 Hz, 1H), 2.45 (dt, J = 3.2, 11.2 Hz, 1H), 2.10 (dt, J = 3.2,
13
14.0 Hz, 1H); C NMR (100 MHz): δ 137.76, 136.01, 132.91, 129.10 (2x), 127.49 (2x), 126.07, 63.76,
57.24, 52.74, 47.26, 31.15.
6-Benzenesulfonyl-2,4,5,6,7,7a-hexahydrofuro[2,3-c]pyridine (8). MsCl (35 mg, 0.3 mmol) was added
to a solution of 7 (30 mg, 0.1 mmol) in pyridine (5 mL) at rt. The reaction mixture was stirred at rt for 10
h. CH2Cl2 (10 mL) was added to the reaction mixture and then 2N HCl(aq) (10 mL) was also added to the
reaction mixture. The reaction mixture was extracted with EtOAc (3 x 15 mL). The combined organic
layers were washed with brine, dried, filtered and evaporated to afford crude product. Purification on
o
silica gel (hexane/EtOAc = 3/1~1/1) afforded 8 as a white solid (23 mg, 80%). mp 92-93 C
(recrystallized from hexane and EtOAc); HRMS (ESI, M++1) calcd for C13H16NO3S 266.0851, found
1
266.0853; H NMR (400 MHz): δ 7.78-7.75 (m, 2H), 7.61-7.57 (m, 1H), 7.55-7.50 (m, 2H), 5.49 (br s,
1H), 4.68-4.61 (m, 1H), 4.59-4.53 (m, 2H), 4.19 (ddd, J = 1.6, 5.6, 10.4 Hz, 1H), 3.96 (ddt, J = 1.6, 5.6,
11.2 Hz, 1H), 2.53 (ddd, J = 1.6, 3.6, 14.0 Hz, 1H), 2.44-2.35 (m, 1H), 2.20 (dd, J = 3.2, 11.2 Hz, 1H),
2.07 (t, J = 10.4 Hz, 1H); 13C NMR (100 MHz): δ 137.37, 137.05, 132.80, 129.13 (2x), 127.36 (2x),
118.49, 81.02, 75.78, 53.02, 46.83, 26.72; Anal. Calcd for C13H15NO3S: C, 58.85; H, 5.70; N, 5.28.
Found: C, 59.03; H, 5.89; N, 5.52.
6-Benzenesulfonyl-hexahydrofuro[2,3-c]pyridine-3,3a-diol (9). A solution of 2% OsO4 (5 mL, in THF)
was added to a solution of 8 (16 mg, 0.06 mmol) in the co-solvent of THF (5 mL) and water (5 mL).
NMO (100 mg, 50% in water, 0.43 mmol) was added the reaction mixture at reflux for 10 h. 10%
NaHSO3(aq) (5 mL) was added to the reaction mixture and the solvent was concentrated. The residue was
diluted with water (10 mL) and the mixture was extracted with EtOAc (3 x 20 mL). The combined
organic layers were washed with brine, dried, filtered and evaporated to yield crude compound.
Purification on silica gel (hexane/EtOAc = 1/1~1/2) afforded 9 as white solid (15 mg, 85%). mp 153-154
oC (recrystallized from hexane and EtOAc); HRMS (ESI, M++1) calcd for C13H18NO5S 300.0906, found
300.0908; 1H NMR (400 MHz): δ 7.80-7.77 (m, 2H), 7.61-7.56 (m, 1H), 7.54-7.50 (m, 2H), 4.12 (dd, J =
5.6, 11.2 Hz, 1H), 3.96 (dt, J = 2.0, 13.6 Hz, 1H), 3.78-3.74 (m, 2H), 3.66-3.63 (m, 1H), 3.61 (t, J = 2.4
Hz, 1H), 2.72 (dd, J = 2.4, 13.6 Hz, 1H), 2.72-2.65 (m, 2H), 1.72-1.63 (m, 2H), 1.67 (dd, J = 4.0, 10.0 Hz,