Synthesis of 4-Aryl-3-(2-chromonyl)-2-pyrazolines by the 1,3-dipolar cycloaddition of 2-styrylchromones with diazomethane
✍ Scribed by Diana C. G. A. Pinto; Artur M. S. Silva; Lúcia M. P. M. Almeida; José A. S. Cavaleiro; Albert Lévai; Tamás Patonay
- Publisher
- Journal of Heterocyclic Chemistry
- Year
- 1998
- Tongue
- English
- Weight
- 685 KB
- Volume
- 35
- Category
- Article
- ISSN
- 0022-152X
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## Abstract For Abstract see ChemInform Abstract in Full Text.
## Abstract Novel 2‐pyrazolines were obtained by the cycloaddition of diazomethane to bis(arylsulfonylethenyl)‐sulfones (**3**) and 1‐arylsulfonyl‐2‐styrylsulfonylethenes (7). Dehydrogenation of 2‐pyrazolines with chloranil gave pyrazoles.
## Abstract 1,3‐Dipolar cycloadditions of exocyclic α,β‐unsaturated ketones 1‐22 with diazomethane afforded spiro‐1‐pyrazolines 23‐44 in a diastereospecific reaction. The structure and stereochemistry of each compound synthesised has been elucidated by nmr spectroscopic measurements and other analy