1‐Vinylazulene aus 1‐Azulenylmethylen‐triphenylphosphoran

New Benzo- and Dibenzo-Crown Ethers with (Azulen-1-yl)Vinyl Substituents

“…The commercially availability of several 4'-formylbenzo-crown-ethers prompted us to use them as starting materials for the reaction. As active methylene for the Wittig condensation we used the know (azulen-1-ylmethyl)triphenylphosphonium iodide, 1 [13], obtained as in Scheme 3. Because in some cases the arsonium ylides (Scheme 3) are more reactive than phosphonium ylides [14] we tried to prepare this compound and to test it in the condensation.…”

“…For example, in Figure 2 is presented the mass spectrum of (E)-4'-(azulen-1-ylvinyl)-15-crown-5-eter, (E)-4(3), in the presence of ammonia (M+NH4 + = 438, M +Na + = 443, M + K + = 459) . The complexes can be decomposed during the signal splitting at low energies as can be seen in Figure 3 It is known from the Curie paper [13] that the cis isomers of styrylazulenes are slightly hypsochromic than the trans isomers. However, he took in consideration the very weak band S1, which we did not studied being concentration dependent.…”

Synthesis of azulenic compounds with a homo- or hetero-atomic double bond at position 1

“…Thus, the condensation of 9 with aliphatic aldehydes in benzene in the presence of PhLi 28 affords only the isomer (E) of alkenes 10, slightly stable in the presence of air. By working in DMF, the reactions of 9 is less straightforward because PhLi partially reacts with DMF giving benzaldehyde which, in turn, condenses with the phosphonium salt.…”

“…28 The interesting compounds 11, possessing simultaneous azo and vinyl bonds (Scheme 5), were obtained from (E)-4-(4-methoxyphenyldiazenyl)benzaldehyde or (E)-4-[4-(dimethylamino)phenyldiazenyl]benzaldehyde and (3-guaiazulenylmethyl)triphenylphosphonium bromide in ethanol in the presence of sodium ethoxide at 25 °C for 24 h under argon. 29 The conditions for the condensation of 1,3-bis(triphenylphosphoniummethyl)azulene, 12, with aliphatic or aromatic aldehydes (Scheme 6 and Table 3) resemble those of monosubstituted azulene ylides and yielded 1,3-divinylazulenes, 13, as a mixture of geometric isomers.…”

“…Except for benzyl compounds substituted with a cyano group, the condensation products result in very low yields. Later, Currie et al 28 obtained diethyl azulene-1,3-diacrylate, 22, from azulene-1,3-dicarbaldehyde and triethyl phosphonoacetate in the presence of sodium hydride (Scheme 9, yield 56%).…”