Efficient Syntheses of Some Versatile 3,5-Bifunctional Pyrazole Building Blocks

Abstract

A series of convenient synthetic procedures are reported for pyrazole derivatives with carbonyl or ester groups in the 3- and 5-positions and variable substitution pattern at C4 and at the functional side arms. All compounds have been characterized by ¹H and ¹³C NMR spectroscopy, elemental analyses, and mass spectrometry. In addition, the structures of several pyrazole derivatives have been determined by single crystal X-ray diffraction, which provides insight into the effect of functional side arms on the hydrogen-bonded­ supramolecular motifs of NH-pyrazoles.

Key words

pyrazoles - N-heterocycles - X-ray crystal structure - H-bonding

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Klingele, J.; Dechert, S.; Meyer, F. Coord. Chem. Rev., manuscript in preparation.

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CCDC-664760 (2), CCDC-664761 (5), CCDC-664762 (6), and CCDC-664763 (8) contain the supplementary crystallographic data for this paper. These data can be obtained free of charge at www.ccdc.cam.ac.uk/conts/retrieving.html [or from the Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: [phone]; E-mail: [e-mail]].