Über γ‐Alkyliden‐tetronsäuren, I

Abstract

y -Alkyliden-tetronsaure-derivate kommen als Inhaltsstoffe einiger Flechtenarten vor. Ein Beispiel ist die sog. Vulpinsaure (11)2) 3), die in der Usneacee Evernia vulpina (Achatius) u. a. Flechten gefunden wird. Nahe Verwandte davon sind das Calycin4) und die P i n a~t r i n s i i u r e~) aus einigen Cetraria-und Lepraria-Arten.

Synthesis and structural peculiarities of disodium 1,6-dioxoalka-2,4-diene-3,4-diolates

“…Their oxo-functionalized analogs, i.e., metal enolates derived from 1,3,5,7-tetracarbonyl compounds, have been studied to a much lesser extent [3][4][5][6]. The structure and properties of sodium 1,6-dioxoalka-2,4-diene-3,4-diolates formed by condensation of dialkyl oxalates with alkyl acetates or with alkyl acetates and alkyl methyl ketones were not reported previously.…”

“…), 2925 (OCH 3 , asym. ), 1650 (C 1 =O), 1610 (C 6 =O), 1526 (C=C), 1484 (δ as CH3 ), 1356 (δ s CH 3 ), 1172 (C-O). 1 H NMR spectrum, δ, ppm: 1.76 s (3H, CH 3 , A, C), 3.40 s (3H, OCH 3 , A, C), 4.88 s (1H, 2-H, A, 95%), 5.29 s (1H, 2-H, C, 5%), 5.39 s (1H, 5-H, A, C).…”