ISSN:
0009-2940
Keywords:
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Description / Table of Contents:
Ring Contraction of 2,2-Dimethyl-2H-chromenes by Oxidation with Thallium(III) Nitrate. The Synthesis of CorylinExcept for the 5-acetoxy derivatives, which react very slowly, 2,2-dimethyl-2H-chromenes and 3,4-dihydro-2H-pyran are oxidized smoothly with TI(NO3)3. 2 H2O in methanol to give generally by ring contraction -3(dimethoxymethyl)-2,3-dihydrobenzofurans and -2(dimethoxymethyl)-tetrahydrofuran, respectively. Ring-contracted products were isolated as by-products in the synthesis of the pyranoisoflavone corylin (11).
Notes:
Mit Ausnahme der 5-Acetoxy-Derivate, die nur sehr langsam reagieren, unterliegen 2,2-Dimethyl-2H-chromene und 3,4-Dihydro-2H-pyran einer glatten Oxidation mit T1(NO3)3. 3H2O in Methanol, die im allgemeinen durch Ringverengung zu -3(Dimethoxymethyl)-2,3-dihydrobenzo-furanen bzw. -2(Dimethoxymethyl)tetrahydrofuran führt. Ringverengte Verbindungen wurden bei der Synthese des Pyranoisoflavons Corylin (11) als Nebenprodukte isoliert.
Additional Material:
1 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19791121212
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