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Diels‐alder adducts of a spirocyclopentenotriazoloazodienophile. Assignment of their 1 H and 13 C NMR spectra
Author(s) -
Alexandrou N. E.,
Mertzanos G. E.,
StephanidouStephanatou J.,
Tsoleridis C. A.
Publication year - 1996
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570330329
Subject(s) - chemistry , adduct , chemical shift , two dimensional nuclear magnetic resonance spectroscopy , nuclear magnetic resonance spectroscopy , nmr spectra database , spectroscopy , stereochemistry , diels–alder reaction , carbon 13 nmr , spectral line , organic chemistry , catalysis , physics , quantum mechanics , astronomy
1‐Phenyl‐cyclopenteno[1,2‐ d ]‐1,2,3‐rriazolo‐5‐spiro‐4′‐[perhydropyrazolino‐3′,5′‐dione] (5) afforded in situ , by oxidation with lead tetraacetate, the corresponding cyclopentenotriazolo‐spiropyrazolodione 6 , which was trapped with dienes giving the hetero‐Diels‐Alder adducts 10–12 in good yields. The Diels‐Alder reactions were examined on the basis of AM1 MO calculations. Total assignment of the 1 H‐ and 13 C‐nmr chemical shifts as well as the relative configuration of these adducts was accomplished with the help of 2D ( 1 H‐ 1 H COSY, 1 H ‐ 1 H NOESY, 1 H‐ 13 C XHCORR, 1 H‐ 13 C COLOC) and NOE difference spectroscopy. The structures of compounds 11a and 11b were also examined by molecular modeling.