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Figure 1. Comparison of 13C and 15N chemical shifts (ppm) in the
solid-state (CPMAS) and in DMSO-d6 solution. The straight line cor-
responds to CPMAS ¼ (1.004 ꢂ 0.005)* DMSO, n ¼ 48, R2 ¼ 0.999.
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6,7-Difluoro-3-methyl-5-nitro-1H-indazole
(5). To
a
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[16] Perez Medina, C. Ph.D. Thesis, UNED: Madrid, 2008.
round-bottom flask cooled in an ice-water bath 0.11 g of 4
(0.65 mmol) were introduced, and 0.08 g of potassium nitrate
(0.8 mmol) dissolved in 1 mL of sulfuric acid 95–98% conc.
(d ¼ 1.84 g/mL) was then added dropwise. The mixture was
stirred at room temperature during 24 h and then poured into 5
mL of ice-water mixture resulting in the formation of a yel-
lowish precipitate. The mixture was maintained at 4ꢁC for 6 h
and then filtered. The solid is washed with water, filtered,
dried, and chromatographed over silica using hexane/diethyl
ether 8:1 as eluent to obtain 5, mp 167.5ꢁC (by DSC). Yield:
0.10 g, 72%. Anal. Calcd. for C8H5F2N3O2: C, 45.08; H, 2.36;
N, 19.71. Found: C, 45.82; H, 2.74; N, 19.04.
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zoles, and Condensed Rings, Wiley, R. H., Ed.; Interscience, Wiley:
New York, 1967; p 308.
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Acknowledgment. This research has been financed by the Span-
ish MEC (CTQ2007-62113).
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ed.; Verlag Chemie: Weinheim, 1978; p 185.
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REFERENCES AND NOTES
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Journal of Heterocyclic Chemistry
DOI 10.1002/jhet