82289-99-4

Upstream product

• 82289-98-3 5-ethylidene-3-(α-hydroxy-3,4-dimethoxybenzyl)-4-methoxyfuran-2(5H)-one 
• 104499-43-6 2,2'-(3,4-dimethoxybenzylidene)bis<4-ethylidene-3-hydroxyfuran-2(5H)-one> 
• 82289-95-0 4-ethylidenetetronic acid 
• 120-14-9 3,4-dimethoxy-benzaldehyde 
• 82289-96-1 5-ethylidene-4-methoxyfuran-2(5H)-one 

Relevant academic research and scientific papers

Ethylidenetetronic Acid and its Derivatives. Condensations with Carbonyl Compounds, leading to Reassignment of Ramigenic Acid from Penicillium charlesii

Condensation reactions between ethylidenetetronic acid (6) and aryl aldehydes in the presence of weak bases, lead to the 2:1 adducts (8); with 3,4-dimethoxybenzaldehyde the 1:1 adduct (10) is produced concurrently.Reaction between (6) and acetone initially leads to a similar 2:1 adduct i.e. (12), but on further heating in acetone this adduct disproportionates giving the novel dihydopyran (13).The structure of (13) was solved by single crystal X-ray determination.Comparison of spectral data, and synthesis show that the structure of the analogous compound 'ramigenic acid' isolated from Penicillium charlesii should be reassigned as shown in formula (17b).

DIRECTED METALLATIONS OF 4-ETHYLIDENETERONIC ACID AND ITS DERIVATIVES AS A SYNTHETIC ENTRY TO NATURAL 4-OXY-2-FURANONES

Lithium diisoprpylamide (LDA) removes the α-proton from the O-methyl tetronic acid (2b) leading to the vinylic carbanion (12), whereas treatment of the trimethylsilyl derivative (14) with LDA, followed by reaction with aldehydes gives products resulting from both γ- and ε-addition; the directed metallations provide access to a range of 4-oxy-2-furanone derivatives found amongst natural products.