1,3,6-heptatriene

Obtain the energies, carbon-carbon bond distances and electrostatic potential maps for 3-ethyUdene-l,3-pentadiene and 1,3,5-heptatriene. Which data are consistent with the usual resonance argument and which are not ... 

Pulse radiolysis is used also for preparation of excited states of dienes and polyenes. This is done by irradiation of the diene/polyene in toluene solution. The radiolysis of toluene yield high concentration of molecules in the triplet excited state of the solute. Wilbrandt and coworkers61 pulse-radiolysed 1 mM solution of al I -lrans-1,3,5-heptatriene in toluene solution and observed the absorption spectra of the triplet state of the heptatriene with a maximum at 315 nm. The same group62 produced and measured the absorption spectra of several isomeric retinals in their lowest excited triplet state by pulse irradiation of their dilute solution in Ar-saturated benzene containing 10 2 M naphthalene. Nakabayashi and coworkers63 prepared the lowest triplet states of 1,3-cyclohexadiene,... 

R = H) and 1,3,5-heptatriene (Formula 377) (R = Me), respectively (62,161). The 3,5-cycloheptadienes cannot have the diene system planar and consequently show anomalous ultraviolet absorption (161). The excitation for the elimination of carbon monoxide involves the carbonyl group not the diene system (see Sec. IIC) (161). 

Heptatrien l,7-Bis-[dimethyl-amino]-7-methoxy- E14a/2, 280 (Iminium/R — OK)... 

The modification of polymers by means of Diels-Alder reactions has been previously described in the case of 13 -hexatriene, 1,3,5-heptatriene and 2,4,6-octatriene homopolymers >e ite the tra s-rra s-i, 3-diene structure of the repeat units of 1,6-polytrienes, which is known to react with dienophiles at a rate five times that of cis-trans dienes, the reactions were largely incomplete even after long periods of time when they were carried out at moderate temperature with strong dienophiles. 

Irradiation of 6-methyl-1,3,5-heptatriene (86) gives the expected 6,6-dimethylbicyclo[3.1.0]hex-2-ene (87) as the only monomeric product 66>. Irradiation of 4-deuterio-6-methyl- 1,3,5-hexatriene (88) afforded... 

Diels-Alder condensations of fumaric and maleic acid polyesters with various dienes can serve as another example. These reactions require 20 hours at room temperature. Diels-Alder condensations can also be carried out on polymers of 1,3,5-hexatriene, 1,3,5-heptatriene, and 2,4,6-octatriene. Sulfonate-substituted maleic anhydride adds to low-functionality hydrocarbon elastomers, like EPDM, presumably via an Alder-ene-type reaction ... 

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