2- Methyl-1,3-pentadiene

Open ruthenocenes have been obtained by reaction of hydrated ruthenium trichloride with methylated pentadienes in ethanol in the presence of zinc dust... 

For purposes of comparison it should be noted that very powerful metallating agents (e.g., butyllithium/TMEDA or butyllithium/potassium t-butoxide) are capable of abstracting two or even three protons from various alkylated dienes. Thus, various hexadienes and methyl pentadienes have been converted to dianionic species, while 2,4-dimethyl-l,4-pentadiene, 1,4-heptadiene, and 1,4-cycloheptadiene have all been converted to trianions84-86. ... 

Aus4-Methyl-pentadien-(l,3) erhalt man entspreehend 2-Methyl- pentadien-(/,3)6 >7. 

Although the use of pendant drops is a robust method and produces interfacial tensions of acceptable accuracy, it is dependent on there being a sufficient difference in density between the two polymers. When the densities become very similar, a true axisymmetric pendant drop may not be obtainable. Figure 2.5 shows an example of a distorted drop of polybutadiene surrounded by poly(2-methyl pentadiene). In some of these cases a sessile drop usually conforms more to the desirable profile than would a pendant one. 

Babkin, V. A. Andreev, D. S. Quantum chemical calculation of molecule 4-methyl-pentadien-1, 3 by method MNDO. In Quantum chemical calculation of unique molecular system. I. Publisher VolSU, c. Volgograd, 2010,252-254. 

Methyl Pentadienes Formation. Rate data for methyl pentadienes formation in the presence of H2S are presented in Figure 8. At both temperatures, methyl pentadienes formation is found to be/v/ 0.3 order in H2S. The observed E for the formation of methyl pentadienes based on these data is 26.5 kcal/ mole. When one considers the possible free radical homogeneous mechanism for methyl pentadienes formation, the following mechanism may be proposed ... 

Figure 8. Methyl pentadiene rate data (order in HgS)...

Piperylene forms O. fo heavy material when reacted alone at 600°0 with nitrogen as a diluent. Methyl pentadiene forms 0 7 heavy material and isoprene forms... 

Isoprene appears to have the ability to form heavies by attack on itself and other dienes. These differences can be attributed to steric hindrance by the methyl group. The piperylenes and methyl pentadienes have an alternate reaction pathway--that of cyclization to cyclopentene and 1,3-cyclopentadiene and the methyl cyclopentene and methyl cyclopenta-dienes, respectively. 

Pentadiene alone - 0 5 heavies Methyl Pentadiene alone - 0.7 heavies Isoprene alone - i. 8 heavies... 

Reaction of aqueous glyoxal with 2-methyl pentadiene after 60 h at 100°C gives, in 36% yield, the cycloadduct derivatives 143 and 144 in a 1/1 ratio after reduction (NaBHt) and acylation (AC2O, pyr.) of the initially formed dihydropyran hetero Diels-Alder products, 139 and 140. 

One of the most important results of inclusion polymerization is the synthesis of optically active polymers from nonchiral compounds. Asymmetric polymerization of /ra 5-pentadiene in PHTP has been reported. The optical purity of the polypentadiene is about 7%. DCA and ACA, as natural hosts, induce a greater asymmetric polymerization. The cis and rra/i5-2-methyl-pentadiene gave the highest asymmetric polymerization values [88]. The optical rotatory power disappeared with temperatures higher than 70°C, indicating that this process is reversible and results from a conformational transformation. 

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