Massenspektrometrische Untersuchung von gerinnungsphysiologisch aktiven 3‐(1‐Arylpropyl)‐tetronsäuren

Abstract

Für Metabolitenstudien wurde der massenspektrometrische Abbau der Titelverbindungen unter‐sucht. Dabei zeigt sich, daß die literaturbekannten Fragmentierungswege a, f, g und h von geringerer Bedeutung sind. Das Fragmentierungsmuster wird vielmehr durch eine Reihe substituenten‐spezifischer Peaks bestimmt. Bei den 5‐Aryltetronsäuren 1a‐c ist i (“top half‐Et”) der Basispeak während bei den 5‐Alkyltetronsäuren 1d, 1e sowie bei den in 5‐Stellung unsubstituierten Verbindungen 1f, 1g das Tropyliumion m das intensivste Fragment darstellt.

3‐Functionalized Tetronic Acids From Domino Rearrangement/Cyclization/Ring‐Opening Reactions of Allyl Tetronates

“…Though not isolable, the intermediate spirocyclopropanes 11 could be intercepted by ring-opening reactions with amines and alcohols, showing their intermediacy in [2,3]-sigmatropic rearrangements and also opening synthetic routes to functionalized 3-alkyltetronic acids with alkyl instead of aryl residues at C β of the side chain. When a mixture of allyl tetronate 9b and 5 equiv.…”

“…Table 2 shows additional examples. Thanks to their selectivity and predictability, these [2,3]-rearrangement reactions offer convenient access to various types of 3-alkylidenetetronic acids and -furan-2,4-diones. It is worthy of note that the congenerous benzo-annulated six-membered systems (i.e., 4-allyloxycoumarins and 4-allyloxyquinolones) undergo [3s,3s]-sigmatropic rearrangement reactions.…”

“…A conceivable attack on the ester carbonyl carbon atom, resulting in cleavage of the lactone ring and formation of a cyclopropanecarboxylate, was observed on only one occasion, when 2a was heated at 100°C in a mixture of methanol and THF under The 3-(Spirocyclopropyl)dihydrofuran-2,4-diones 2 with residues R 3 bearing α-hydrogen atoms have not as yet been isolated from rearrangements of allyl tetronates. Derivatives 9 bearing two or three alkyl substituents on the alkene are instead converted directly into [2,3]-rearranged 3-alkylidenetetronic acids under thermal conditions (sealed bomb tube, 140Ϫ180°C or microwave, 120°C). The dimethyl derivative 9b had previously been found to give the 3-(1Ј,2Ј-dimethylpropylidene)-5-spirodihydrofuran-2,4-dione 13 as an unassigned 2:1 mixture of (Z) and (E) isomers when heated at 180°C in a bomb tube.…”

Synthesis and Chemistry of Tetronic Acids

“…3,5-Disubstituted tetronic acids present medicinal interest as potential antibiotic, antivirial and antineoplastic agents. [2][3][4][5][6][7] Among them, the 3-acyl derivatives comprise a structural motif present in a great number of active natural products. The base-promoted Dieckmann cyclization of glycolyl acetoacetates 4 (Scheme 1) is one of the most synthetically useful methods for the preparation of these 3-acyl derivatives.…”