M.P. Uliana et al. / Tetrahedron 70 (2014) 6963e6973
6971
with water, 5% HCl (aq), water, and brine. The organic layer was
dried over anhydrous MgSO4, filtered, and concentrated to yield the
crude sulfonamide. The product was purified by silica gel column
chromatography using hexanes/EtOAc (9.5:0.5) as eluent.
Compound 6a: mp: 138e139.2 ꢂC (lit.38 mp 143e145 ꢂC).
Compound 6b: mp: 132e133 ꢂC (lit.39 mp 136e137 ꢂC).
Compound 6c: mp: 128.6e128.9 ꢂC (lit.30 mp 127e128 ꢂC).
Compound 6d: mp: 169.9e171.8 ꢂC (lit.31 mp 172e173 ꢂC).
Compound 6e: mp: 193e194 ꢂC (lit.30 mp 190 ꢂC).
Compound 8d: mp: 68e70 ꢂC (lit. mp41 64 ꢂC). 1H NMR
(400 MHz, CDCl3)
d
: 1.46 (s, 3H), 1.54 (dt, J¼8.9 Hz and 1.6 Hz, 1H),
1.68 (dt, J¼8.9 Hz and 1.6 Hz, 1H), 1.93 (d, J¼1.5 Hz, 1H), 2.83 (d,
J¼3.9 Hz, 1H), 3.05e3.08 (m, 1H), 3.40e3.45 (m, 1H), 5.96 (dd,
J¼5.6 Hz and 2.9 Hz, 1H), 6.12 (dd, J¼5.6 Hz and 2.9 Hz, 1H), 6.45 (d,
J¼1.5 Hz, 1H); 13C NMR (100 MHz; CDCl3)
d: 16.8, 26.3, 46.4, 49.3,
53.2, 53.5, 56.9, 134.3, 138.2, 139.2, 151.0, 200.0, 202.8. IR (nmax KBr,
cmꢀ1): 2968, 2871, 1751, 1735, 1664, 1629.
Compound 8f:9,42 mp: 55e56 ꢂC. 1H NMR (400 MHz, CDCl3)
d:
Compound 6f: mp: 195e196 ꢂC (lit.31 mp 200e201 ꢂC).
Compound 6g: mp: 171.9e173.1 ꢂC (lit.38 mp 173e174 ꢂC).
1.02 (d, J¼6.8, 3H), 1.06 (d, J¼6.8 Hz, 3H), 1.46 (s, 3H), 1.53 (dt,
J¼9.1 Hz and 1.4 Hz, 1H), 1.68 (dt, J¼9.1 Hz and 1.4 Hz, 1H), 2.84 (d,
J¼3.7 Hz, 1H), 2.99 (dhept, J¼6.8 Hz and 1.0 Hz, 1H), 3.04e3.08 (m,
1H), 3.39e3.42 (m, 1H), 5.94 (dd, J¼5.4 Hz and 2.7 Hz, 1H), 6.11 (dd,
J¼5.4 Hz and 2.7 Hz, 1H), 6.37 (d, J¼1.0 Hz, 1H); 13C NMR (100 MHz;
5.8. General procedure for the oxidations to the para-ben-
zoquinone N-tosyl-imines with Ag2O21
CDCl3) d: 20.8, 21.4, 26.2, 26.5, 46.4, 49.5, 52.8, 53.7, 57.5, 134.2,
The N-tosyl-para-aminophenol (1 mmol) was dissolved in dry
CH2Cl2 (2 mL) and Ag2O (0.462 g, 2 mmol) added, and stirred for
1 h. The yellow suspension was filtered, the organic phase washed
with water, dried over anhydrous Na2SO4, filtered, and concen-
trated. The N-tosyl-imine was purified by silica gel column chro-
matography using hexanes/EtOAc (9:1) as eluent.
135.9, 138.1, 160.2, 199.2, 203.4. IR (nmax KBr, cmꢀ1): 2968, 2873,
1749, 1663, 1618.
Compound 10a: 1H NMR (400 MHz, CDCl3)
d
: 1.37 (dt, J¼8.9 and
1.6 Hz, 1H), 1.43 (dt, J¼8.9 and 1.6 Hz, 1H), 2.40 (s, 3H), 2.94 (dd,
J¼8.7 and 4.2 Hz, 1H), 3.38e3.42 (m, 1H), 3.55 (dd, J¼8.7 and 4.2 Hz,
1H), 3.64e3.68 (m, 1H), 5.74 (dd, J¼5.6 Hz and 2.9 Hz, 1H), 5.98 (dd,
J¼5.6 Hz and 2.9 Hz, 1H), 6.74 (d, J¼10.4 Hz, 1H), 7.31 (d, J¼8.1 Hz,
5.9. General procedure for the oxidations to the para-ben-
2H), 7.83 (d, J¼8.3 Hz, 2H); 13C NMR (100 MHz; CDCl3)
d: 21.7, 38.4,
22
zoquinone N-tosyl-imines with MnO2
46.9, 48.1, 48.9, 49.4, 128.9, 129.8, 131.9, 134.2, 135.6, 135.7, 139.0,
145.6, 162.7, 198.8. IR (nmax KBr, cmꢀ1): 2920, 1728, 1664, 1373.
Found m/z¼344.0942 [MþH]þ calcd for C18H18NO4Sþ¼344.0951.
The N-tosyl-para-aminophenol (1 mmol) was dissolved in dry
CH2Cl2 (2 mL) and oxidized with MnO2 (0.172 g, 2 mmol) with
stirring for 1 h. The yellow suspension was filtered, the organic
phase washed with water, dried over anhydrous Na2SO4, filtered,
and concentrated. The N-tosyl-imine was purified by silica gel
column chromatography using hexanes/EtOAc 9:1 as eluent.
Compound 7a: mp: 112.6e113.2 ꢂC (lit.40 mp 114e116 ꢂC).
Compound 7b: mp: 139.3e140.9 ꢂC (lit.38 mp 136e137 ꢂC).
Compound 7c: mp: 98.1e98.8 ꢂC (lit.30 mp 97e98 ꢂC).
Compound 10b: mp: 101.8e102.3 ꢂC. 1H NMR (400 MHz, CDCl3)
d:
1.43 (dt, J¼8.7Hzand1.6Hz,1H),1.47(dt,J¼8.7Hzand1.6Hz,CH),1.93
(d, J¼1.0 Hz, 3H), 2.47 (s, 3H), 2.97 (dd, J¼8.5 Hz and 4.2 Hz, 1H),
3.42e3.44 (m,1H), 3.64 (dd, J¼8.5 Hz and 4.2 Hz,1H), 3.68 (m, H), 5.75
(dd, J¼5.8 Hz and 3.2 Hz,1H), 5.95 (dd, J¼5.6 Hz and 2.9 Hz, 1H), 6.05
(d, J¼1.0 Hz,1H), 7.39 (d, J¼8.1 Hz, 2H), 7.90 (d, J¼8.3 Hz, 2H); 13C NMR
(100 MHz; CDCl3/TMS): 18.2, 21.7, 38.3, 47.3, 48.2, 49.0, 49.4, 128.7,
129.6,132.0,133.8,135.0,135.8,145.5,148.8,162.9,198.6. IR (nmax KBr,
cmꢀ1): 2999, 2970, 2947, 2867,1731,1658,1623,1595,1375. Found m/
z¼380.0931 [MþNa]þ calcd for C19H19NNaO4Sþ¼380.0927.
Compound 7d: mp: 114.1e114.9 ꢂC (lit.31 mp 116e117 ꢂC).
Compound 7e: mp: 113.4e113.7 ꢂC (lit.30 mp 110 ꢂC).
Compound 7f: mp: 118.5e119.2 ꢂC (lit.31 mp 116e118 ꢂC).
Compound 7g: mp: 119.4e119.8 ꢂC (lit.31 mp 121e122 ꢂC).
Compound 11a: 1H NMR (400 MHz, CDCl3)
d: 1.36 (m, 1H), 1.50
(m, 1H), 2.38 (s, 3H), 3.07 (m, 1H), 3.37 (m, 1H), 3.45 (m, 1H), 4.00
(m, 1H), 4.32 (m, 1H), 5.97 (m, 1H), 6.04 (m, 1H), 6.34 (m, 1H), 5.59
(m, 1H), 7.27 (m, 1H), 3.37 (m, 1H), 7.80 (m, 1H), 7.99 (m, 1H); 13C
5.9.1. The DielseAlder reactions with cyclopentadiene. The dien-
ophile (1 mmol) was dissolved in dry CH2Cl2 (3 mL) and recently
cracked cyclopentadiene (2 mmol) was added. The reaction was
stirred at room temperature for 10 min (dienophiles 2a, 3a, 4a, and
7a) or 48 h (dienophiles 2bef, 3bef, 3bef, and 7bef). The solvent
and excess cyclopentadiene were removed under reduced pressure,
and the reaction product was purified by silica gel column chro-
matography using hexanes/EtOAc (9.5:0.5) as eluent.
NMR (100 MHz; CDCl3) d: 21.6, 43.8, 47.2, 48.0, 48.4, 48.8, 48.9, 49.4,
50.2, 51.0, 52.3, 127.3, 127.3, 129.6, 134.6, 135.0, 135.3, 135.4, 135.5,
136.6, 137.7, 140.3, 140.9, 142.0, 144.1, 144.8, 178.5, 198.2, 198.7. IR
(
nmax KBr, cmꢀ1): 2923, 2864, 1671,1608,1565,1489, 1154. Found m/
z¼328.1008 [MþH]þ calcd for C18H18NO3Sþ¼328.1002.
Compound 11b: mp: 143.2e144.0 ꢂC.1H NMR (400 MHz, CDCl3)
d:
1.56e1.58 (m, 2H), 1.90 (d, J¼1.2 Hz, 3H), 2.45 (s, 3H), 3.13 (dd,
J¼7.9 Hz and 4.0 Hz,1H), 3.49e3.51 (m,1H), 4.02e4.06 (m,1H), 4.46
(dd, J¼7.9 Hz and 4.0 Hz, 1H), 6.03e6.06 (m, 1H), 6.04e6.07 (m, 1H),
Compound 8a: mp: 62e64 ꢂC (lit.1f mp 63e65 ꢂC; lit.41 mp 78 ꢂC).
1H NMR (400 MHz, CDCl3)
d
: 1.44 (dt, J¼8.4 and 1.7 Hz, 1H), 1.55 (dt,
J¼8.4 and 1.7 Hz, 1H), 3.22e3.26 (m, 2H), 3.53e3.58 (m, 2H), 6.07 (t,
6.37 (d, J¼1.0 Hz,1H), 7.35 (d, J¼8.5 Hz, 2H), 7.88 (d, J¼8.3 Hz, 2H); 13
C
J¼1.7 Hz, 2H), 6.58 (sl, 2H); 13C NMR (100 MHz; CDCl3)
d: 48.3, 48.7,
NMR (100 MHz; CDCl3): 18.7, 21.6, 43.8, 48.7, 49.6, 50.0, 52.6, 127.0,
129.5,134.0,135.8,138.2,139.5,143.8,152.8,179.5,198.6. IR (nmax KBr,
cmꢀ1): 2977, 2958, 2875,1762,1665,1623,1557,1314,1150. Found m/
z¼364.09831 [MþNa]þ calcd for C19H19NNaO3Sþ¼364.09779.
135.3, 142.0, 199.4. IR (nmax KBr, cmꢀ1): 2991, 2948, 1662, 1279.
Compound 8b: mp: 62e63 ꢂC (lit.41 mp 62 ꢂC). 1H NMR
(400 MHz, CDCl3)
d
: 1.43 (dt, J¼8.7 Hz and 1.6 Hz, 1H), 1.54 (dt,
J¼8.7 Hz and 1.6 Hz, 1H), 1.93 (d, J¼1.4 Hz, 3H), 3.21e3.22 (m, 2H),
3.52e3.54 (m, 2H), 6.02 (dd, J¼5.5 Hz and 2.7 Hz, 1H), 6.07 (dd,
J¼5.5 Hz and 2.7 Hz, 1H), 6.48 (q, J¼1.4 Hz, 1H); 13C NMR (100 MHz;
Compound 11c: 1H NMR (400 MHz, CDCl3)
d: 1.34e1.36 (m, 3H),
1.49e1.51 (m, 2H), 1.89e1.91 (m, 3H), 3.23e3.25 (m, 2H), 4.00e4.02
(m, 1H), 5.97e5.99 (m, 2H), 6.51e6.53 (m, 1H), 7.28e7.30 (m, 2H),
CDCl3)
d
: 16.3,48.2, 48.6, 48.8, 48.9, 49.0, 134.9, 135.5, 139.7, 151.7,
7.80e7.82 (m, 1H); 13C NMR (100 MHz; CDCl3)
d: 17.5, 21.6, 26.2,
199.1, 199.6. IR (nmax KBr, cmꢀ1): 2958, 2875, 1762, 1665.
47.3, 51.9, 52.3, 54.2, 56.3, 127.0, 129.5, 132.2, 134.9, 137.7, 140.8,
Compound 8c:41 1H NMR (400 MHz, CDCl3)
d: 1.46 (s, 3H), 1.53
143.8, 150.6, 177.5, 201.9. Found m/z¼378.1138 [MþNa]þ calcd for
(dt, J¼9.1 Hz and 1.6 Hz, 1H), 1.68 (dt, J¼9.1 Hz and 1.6 Hz, 1H), 1.94
(d, J¼1.4 Hz, 3H), 2.84 (d, J¼3.7 Hz, 1H), 3.08e3.09 (m, 1H),
3.40e3.42 (m, 1H), 5.99 (dd, J¼5.8 Hz and 2.9 Hz, 1H), 6.09 (dd,
J¼5.8 Hz and 2.9 Hz, 1H), 6.48e6.45 (m, 1H); 13C NMR (100 MHz;
C
20H21NNaO3Sþ¼378.1134.
Compound 11d: mp: 137.4e138.0 ꢂC. 1H NMR (400 MHz, CDCl3)
d
: 1.46 (s, 3H), 1.57 (dt, J¼9.4 Hz and 1.6 Hz, 1H), 1.82 (dt, J¼9.4 Hz
and 1.6 Hz, 1H), 1.91 (d, J¼1.2 Hz, 3H), 2.45 (s, 3H), 3.01e3.05 (m,
1H), 3.90e3.92 (m,1H), 4.16 (d, J¼3.5 Hz,1H), 5.97 (dd, J¼5.6 Hz and
2.9 Hz, 1H), 6.11 (dd, J¼5.6 Hz and 2.9 Hz, 1H), 6.35 (d, J¼1.4 Hz, 1H),
CDCl3) d: 16.4, 26.5, 46.2, 48.8, 52.3, 53.6, 57.6, 134.8, 137.6, 138.9,
151.2, 199.2, 202.9. IR (nmax KBr, cmꢀ1): 2977, 2875, 1733, 1664.