1002
P. Zajdel et al. / Tetrahedron Letters 54 (2013) 998–1002
resin was stirred gently for 12 h at rt, and then was washed with H2O
(2Â), H2O/DMF (1/1, v/v) (2Â), DMF (2Â), MeOH (1Â), and CH2Cl2
(2Â) and dried under vacuum.
1H), 7.75–7.82 (m, 2H). MS calcd for [M + H]+: C19H19FN3O2S m/z
372.1, found 372.1.
N-[3-(Piperazin-1-yl)phenyl]benzenesulfonamide (15a)
Preparation 1-(3-nitrophenyl)piperazine on Pip-PS resin
Yield: 16 mg (37% isolated yield) as a yellow oil following pre-
parative LC/MS purification; LC/MS purity 99%, tR = 0.99 min. 1H
NMR (300 MHz, acetone-d6): d 2.8–2.84 (m, 4H), 3.29–3.46 (m,
4H), 6.7–6.77 (m, 2H), 6.88 (t, J = 2 Hz, 1H), 7.11 (t, J = 8 Hz, 1H),
7.5–7.56 (m, 2H), 7.57–7.63 (m, 1H), 7.8–7.86 (m, 2H). MS calcd
for [M + H]+: C16H20N3O2S m/z 318.1 found 318.1.
Pip-PS resin (500 mg, 0.39 mmol, 0.78 mmol gÀ1) was sus-
pended in 5 mL of a mixture of anhydrous 1,4-dioxane/tert-butyl
alcohol (2/1, v/v) in an oven-dried microwave reactor purged with
argon. Next, 1-bromo-3-nitrobenzene (790 mg, 3.9 mmol,
10 equiv) was added to the resin. After stirring for 20 min at rt,
Pd2dba3 (70 mg, 0.08 mmol, 0.4 equiv based on Pd), BINAP
(145 mg, 0.125 mmol, 0.6 equiv), and NaOtBu (375 mg, 3.9 mmol,
10 equiv) were added as solids. The reactor was purged with argon
for a few minutes, and was placed into the microwave cavity of a
1600 W CEM Discovery multimode microwave. Initial microwave
irradiation at 300 W was used, and the temperature was increased
from rt to 130 °C, and held at this temperature for 15 min. After
cooling the mixture to rt, it was transferred to a syringe, and
washed with CH2Cl2 (1Â), MeOH (1Â), CH2Cl2 (1Â), DMF (2Â),
THF (1Â), MeOH (1Â), and CH2Cl2 (3Â) and dried under vacuum.
The completion of the reaction was confirmed by a negative
chloranil test. A mixture of Ac2O (5 ml) and DIEA (6.33 ml) in
CH2Cl2 (10 ml) was added to the resin and the mixture was stirred
for 20 min. The acylation was repeated once more followed by
washing with DMF (2Â), MeOH (1Â) and CH2Cl2 (2Â) and drying
under vacuum.
Acknowledgments
This study was partly supported by the Polish Ministry of Sci-
ence and Higher Education (MNiSW), Grant No. N N405 671540.
The authors thank Institut des Biomolécules Max Mousseron for
financial support.
Supplementary data
Supplementary data associated with this article can be found, in
References and notes
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Yield: 24 mg (48% isolated yield) as a yellow oil following pre-
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