Spirobipyrans from o-Hydroxyarytvinylpyrylium SaltsStructurally defined o-hydroxyarylvinylpyrylium salts can be cyclized to spirobipyrans of type 1-5 and to the hitherto unknown 2,2'-spirobi[ZH-naphtho[l ,Z-b]pyrans] (6). Asymmetric monosubstituted spirobipyrans of type 2,3, and 5 show a correlation between thermochromism and position of the substituent (Table I).Trotz einer relativ grokn Zahl von Untersuchungen iiber das Verhalten von Spirobipyranen wurde bislang nur wenig iiber einfach substituierte Spirobipyrane bekannt. Nachdem wir iiber die Eigenschaften strukturspezifisch aufgebauter o-Hydroxyarylvinylpyryliurnsalze berichteten 1.2), sollen hier die Daten einiger aus diesen dargestellter Spirobipyrane vom Typ 1-6 rnitgeteilt werden. Von diesen waren unseres Wissens 2.2'-Spirobi[2H-naphtho[ 1.2-blpyraneI (6) bisher unbekannt.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.