Premium
Thermisch und photochemisch induzierte intramolekulare, 1,3‐dipolare Cycloadditionen von 5‐(2‐Allyloxyphenyl)‐2‐phenyltetrazol. Vorläufige Mitteilung . 54 Mitteilung über Photoreaktionen
Author(s) -
Meier Hansruedi
Publication year - 1977
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19770600855
Subject(s) - chemistry , cycloaddition , dehydrogenation , intramolecular force , chloranil , tetrazole , yield (engineering) , stereochemistry , medicinal chemistry , photochemistry , organic chemistry , catalysis , materials science , metallurgy
Thermal and Photochemically Induced Interamolecular 1,3‐Dipolar Cycloaddition Reactions of 5‐(2‐Allyloxyphenyl)‐2‐phenyltetrazole The title compound 5 is easily obtained by a recently described procedure ( Scheme 2 ). The tetrazole 5 reacts at 165–170° or on irradiation at room temperature to yield 2‐phenyl‐3,3a‐dihydrochromano[4,3‐ c ]pyrazole ( 7 , Scheme 3 ), which probably arises by intramolecular [3+2]‐cycloaddition of the intermediate nitrilimine. Dehydrogenation of 7 with chloranil leads to 2‐phenylchromano[4,3‐ c ]pyrazole ( 8 , Scheme 3 ).