Collect. Czech. Chem. Commun. 1991, 56, 973-983
https://doi.org/10.1135/cccc19910973

Substituted 1,2-diaza-7-oxaspiro[4,4]nonen-6-ones; Preparation, NMR spectra, and crystal structure

Jaroslav Jonasa, Tadeusz Głowiakb, Zdirad Žákc, Petr Trškad and Ctibor Mazala

a Department of Organic Chemistry, Masaryk University, 611 37 Brno, Czechoslovakia
b Institute of Chemistry, University of Wroclaw, 50-383 Wroclaw, Poland
c Department of Inorganic Chemistry, Masaryk University, 611 37 Brno, Czechoslovakia
d Central Laboratories, Prague Institute of Chemical Technology, 166 28 Prague, Czechoslovakia

Abstract

Diazomethane adds to substituted 3-methylene-2-(3H)-dihydrofuranones (Ia-Ii) to give the corresponding title dihydropyrazolospirodihydrofuranones (IIa-IIf, IIi,andIIj) or (IIIa, IIIg, and IIIh). NMR spectra of the adducts are discussed in some detail and the crystal structure has been solved for (4R, 5S)-5-benzoyloxy-1,2-diaza-7-oxaspiro[4.4]non-1-en-6-one (IIa).