| Popis: |
Substituted 2,8-decadien-4,6-diyndials (I, II and III) were synthesized by the oxidative coupling of corresponding substituted pentenynals (VII and XIII) or acetal (XI). It was found that decadiendiyndials (I, II and III) give readily dihydrofuranylidene derivatives (X, XIV and XXV) by the addition of methanol followed by intramolecular cyclization. Thermal reaction of dialdehyde (I, II, and III) afforded difuranylacetylene derivatives (IX, XXI and XXII). 5-Phenyl-2,4-heptadien-6-ynal (XXXII) was prepared from 3-phenyl-2-penten-4-ynal (VIII) or its acetal (XI) by a modified Wittig reaction or by the condensation of ethyl vinyl ether. Oxidative Coupling of XXXII or 5-t-butyl-2,4-heptadien-6-ynal afforded 5,10-diphenyl-(XXIX) or 5,10-di-t-butyl-2,4,10,12-tetradecatetraen-6,8-diyndial (XXX) which showed no tendency for intramolecular cyclization. |
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