Paper
Organic & Biomolecular Chemistry
4.92 mmol) in 18 mL of MeOH and cooled in an ice bath and the University of Salamanca for a predoctoral grant. The
the solution was stirred. The reaction was monitored by TLC authors thank the mass spectrometry service, NMR service and
(DCM–EtOAc 1 : 1). The ice bath was removed and within X-ray diffraction service of the NUCLEUS Platform of the Uni-
minutes a precipitate corresponding to the hydrochloride of versity of Salamanca. The authors are also grateful to Dr César
compound 7 appeared. The solid thus obtained was filtered, Raposo and Juan F. Boyero for fruitful discussions.
obtaining 1.0 g of compound 7 as the hydrochloride. Solid
Na2CO3 was added to the filtrate, and the carbonate was fil-
tered off and washed with more EtOAc. The solution was left
to stand for 12 h and a precipitate, which corresponded to the
neutral compound 7 (700 mg), appeared. Receptor 7 hydro-
Notes and references
chloride was suspended in CHCl3 and washed with aqueous
saturated Na2CO3 yielding 0.5 g of compound 7 (total yield
49%). Mp >230 °C; 1H NMR (400 MHz, CDCl3) δ (ppm) 1.03
(9H, s), 1.23 (6H, s), 1.48 (1H, d, J = 14.9 Hz), 1.74 (1H, d, J =
14.9 Hz), 2.46 (3H, s), 2.89 (1H, d, J = 18.1 Hz), 3.40 (1H, dd,
J = 7.2, 18.1 Hz), 3.76 (3H, s), 4.39 (1H, d, J = 7.2 Hz), 5.45 (NH,
s), 5.60 (1H, s), 6.93 (1H, d, J = 7.6 Hz), 7.42 (1H, s), 7.57 (1H, t,
J = 7.9 Hz), 7.84 (1H, s), 7.89 (1H, d, J = 8.2 Hz), 9.23 (NH, s);
13C NMR (100 MHz, CDCl3) δ (ppm) 23.9 (CH3), 29.0 (CH2),
29.2 (CH3), 29.5 (CH3), 31.6 (CH3 × 3) 31.6 (C), 41.9 (CH), 54.5
(CH2), 56.4 (CH3), 59.1 (C), 90.2 (C), 102.6 (CH), 111.0 (CH),
114.4 (C), 120.2 (CH), 129.0 (C), 129.7 (CH), 130.3 (CH), 132.2
(C), 138.4 (CH), 149.2 (C), 152.2 (C), 157.4 (C), 165.6 (C), 176.2
(C), 188.7 (C); IR (nujol) ν 3377, 3338, 2929, 2955, 2852, 1697,
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1664, 1612, 1463, 1379, 1346, 1203, 1145, 1048, 976, 918 cm−1
HRMS Calcd for C28H35BrN3O6S 620.1424, found 620.1432.
(4aS,9bR)-8-Bromo-4-hydroxy-N-(6-methylpyridin-2-yl)-2-oxo-
;
6-(N-(2,4,4-trimethylpentan-2-yl)sulfamoyl)-1,2,4a,9b-tetrahydro-
dibenzo[b,d]furan-4a-carboxamide ((+)-8). Compound (+)-7
(100 mg, 0.16 mmol) was dissolved in a homogeneous mixture
of THF–H2O (9 : 1) and pTsOH (30.3 mg, 0.18 mmol) was
added. After 12 h, the reaction mixture was added over a
sodium formate solution and extracted with EtOAc, yielding
60 mg of (+)-8 (62% yield). [α]2D0 = +212.3 (c = 0.99, CHCl3); mp:
1
228–230 °C; H NMR (400 MHz, DMSO-d6) δ (ppm) 0.94 (9H,
s), 1.09 (3 H, s), 1.19 (3H, s), 1.42 (1H, d, J = 14.6 Hz), 1.63 (1H,
d, J = 14.6 Hz), 2.41 (3H, s), 3.00 (2H, br s), 4.44 (1H, t, J =
5.1 Hz), 5.47 (1H, s), 7.06 (1H, d, J = 7.3 Hz), 7.63 (1H, d, J =
2.6 Hz), 7.72 (1H, dd, J = 7.3, 8.0 Hz), 7.80 (1H, d, J = 8.0 Hz),
7.83 (1H, s), 9.99 (NH, s); 13C NMR (100 MHz, DMSO-d6)
δ (ppm) 23.5 (CH3), 28.7 (CH3), 29.1 (CH3), 31.0 (CH2), 31.2
(C), 31.4 (CH3 × 3), 41.8 (CH), 53.6 (CH2), 57.5 (C), 109.1 (C),
111.6 (CH), 112.9 (C), 120.0 (CH), 121.6 (C), 128.7 (CH), 129.1
(C), 130.3 (CH), 134.5 (CH), 138.6 (CH), 149.4 (C), 151.8 (C),
156.9 (C), 166.9 (C), 175.7 (C), 196.9 (C); IR (nujol) ν 3390,
3306, 2916, 2839, 1710, 1606, 1521, 1456, 1366, 1249, 1203,
1152 cm−1; HRMS Calcd for C27H33BrN3O6S 606.1268, found
606.1284.
Acknowledgements
The authors would like to thank the Junta de Castilla y León
(SA223A11–2) and the University of Salamanca for financial
support. The Spanish “Ministerio de Educación” is acknowl-
edged for the fellowship (A. L. F. A.). O. H. R. wishes to thank
5 Q.-B. Li, F.-T. Zhou, Z.-G. Liu, X.-F. Li, W.-D. Zhu and
J.-W. Xie, J. Org. Chem., 2011, 76, 7222.
Org. Biomol. Chem.
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