New ultraviolet stabilizers: 3-and 5-(2'-Hydroxyphenyl) pyrazoles

…, F Hernandez Cano, M Martinez-Ripoll…

Index: Catalan, Javier; Fabero, Fernando; Claramunt, Rosa M.; Dolores Santa Maria; De la Concepcion Foces-Foces; Cano, Felix Hernandez; Martinez-Ripoll, Martin; Elguero, Jose; Sastre, Roberto Journal of the American Chemical Society, 1992 , vol. 114, # 13 p. 5039 - 5048

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Citation Number: 127

Abstract

Abstract: A new class of ultraviolet stabilizers, the C-(2'-hydroxyphenyl) pyrazoles, is described. The combined use of X-ray crystallography [3 (5)-(2'-hydroxypheny1) pyrazole (5), I-methyl-3-(2'-hydroxyphenyl) pyrazole (7), and l-methyl-5-(2'-hydroxypheny1) pyrazole (8)], NMR ('H and" C), and UV spectroscopies allows the determination of the major tautomers, the coplanarity of both rings if present, and the existence of hydrogen bonds. ...