ISSN:
0749-1581
Keywords:
Pyrazolo[1,5-a]pyrimidines
;
Structure determination
;
Coupling constants
;
1H, 13C and 15N NMR spectra
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The condensation of 3(5)-aminopyrazole and 5-amino-3-phenylpyrazole with ethyl 2,4-dioxopentanoate and 2-ethoxymethylidene-3-oxobutyrate has been re-investigated. Contrary to previos reports, the former reaction gives rise to both regioisomeric pyrazolo [1,5-a]pyrimidines (5-carbethoxy-7-methyl-and 7-carbethoxy-5-methyl-), the structures of which were determined by 1H and 13C NMR spectroscopy. The 6-carbethoxy-7-methyl-regioisomer is shown to be the only product in the reaction of the same aminopyrazoles with 2-ethoxymethylidene-3-oxobutyrate; the regiochemical assignment was independently achieved by multimuclear (13C and 15N) NMR spectroscopy.
Additional Material:
3 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1260301116
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