9-Methyl- 4- Methylheptane

Within Hymenoptera, pheromones produced by workers in social colonies are the best studied across many genera, principally in ants [6], with those eliciting trail following most extensively studied. The distinct behavior and the relative ease of the bioassay have resulted in chemical identifications in many species [ 113,114]. Those that have been recently identified are listed in Table 5. In addition, several alarm and recruitment signals have recently been identified. Many of the compounds recently identified in ants have previously been reported as trail or alarm pheromones in other ant species. For example, methyl 4-methylpyrrole-2-carboxylate 64, 3-ethyl-2,5-dimethylpyrazine 65, (9Z)-hexadec-9-enal 66,4-methylheptan-3-ol 67, and methyl 6-methylsalicy-late 68 have been identified as trail pheromone components, and heptan-2-one 69,4-methylheptan-3-one 70, formic acid 71, undecane 61,4-methylheptan-3-ol 67, methyl 6-methylsalicylate 68, and citronellal 72 have been identified as alarm pheromone components [6]. The use of the same chemicals across genera, with some used for very different functions, is an interesting phenomenon. 

Table I gives the compositions of alkylates produced with various acidic catalysts. The product distribution is similar for a variety of acidic catalysts, both solid and liquid, and over a wide range of process conditions. Typically, alkylate is a mixture of methyl-branched alkanes with a high content of isooctanes. Almost all the compounds have tertiary carbon atoms only very few have quaternary carbon atoms or are non-branched. Alkylate contains not only the primary products, trimethylpentanes, but also dimethylhexanes, sometimes methylheptanes, and a considerable amount of isopentane, isohexanes, isoheptanes and hydrocarbons with nine or more carbon atoms. The complexity of the product illustrates that no simple and straightforward single-step mechanism is operative rather, the reaction involves a set of parallel and consecutive reaction steps, with the importance of the individual steps differing markedly from one catalyst to another. To arrive at this complex product distribution from two simple molecules such as isobutane and butene, reaction steps such as isomerization, oligomerization, (3-scission, and hydride transfer have to be involved.

Methylenecyclopropanes, 50, 30 3-Methylheptan-4-ol, 52, 22 Methyl iodide, with triphenyl phosphite and cyclohexanol,... 

Two propanoate units (see Fig. 2) seem to be coupled in 1-ethylpropyl (2S,3.R)-2-methyl-3-hydroxypropanoate 221, the male produced aggregation pheromone of the granary weevil, Sitophilus granarius [390-393]. Even the ester-moiety may origin from two propanoate units after decarboxylation and reduction Three propanoate units (and decarboxylation, see Fig. 2) may produce (4S,5 )-5-hydroxy-4-methyl-3-heptanone, sitophilure 222, the aggregation pheromone of the rice weevil, Sitophilus oryzae [394, 395]. The same carbon skeleton is present in the achiral 4-methylheptan-3,5-dione 223, the pheromone of the pea weevil, Sitona lineatus [396-398]. 

Methyl groups, as hydrocarbon surface species, vibrational spectra, 42 214—219 Methylheptane, ring closure, 25 154 3-Methylhexane dehydrocyclization, 30 13 isomerization, 30 7, 14, 39-40 Methylhexane, ring closure, 25 155 Methyl hydroperoxide, catalytic decomposition, 35 161... 

There are very few data available on alkane isomers above C7 for comparison of petroleum or any other natural product. Some analyses, however, are available for the Cs isomers from alkanes from crude oils. Predicted results from the Fischer-Tropsch equation with / = 0.1 are given in Table II along with analyses of Cs alkanes from two crude oils (2, 4). A very definite exception to the predicted values appears in Table I, namely, the predominance of 2-methylheptane over 3-methylheptane. This observation is contrary to the prediction of the equation. According to scheme B (1) other Ck analyses from crudes made available to the author by M. J, O Neal show the same predominance cf the 2-methyl isomers. A total of four Ch analyses available for comparison represent crudes from western and southwestern United States. As mentioned in (8), 11 out of 14 analyses through the Ct s showed the reversal the three that did not have the predicted reversal also came from the Southwest. It would be of interest to have analyses of Cs s in crudes from other parts of the world in order to study this reversal. For Cn alkanes only partial analyses are available they are Ponca City, Okla. crude (4) and a commercial mixture... 

The hydroformylation of several olefins in the presence of Co2(CO)8 under high carbon monoxide pressure is reported. (S)-5-Methylheptanal (75%) and (S)-3-ethylhexanal (4.8%) were products from (- -)(S)-4-methyl-2-hexene with optical yields of 94 and 72%, respectively. The main products from ( -)(8)-2,2,5-trimethyl-3-heptene were (S)-3-ethyl-6,6-di-methylheptanal (56.6%) and (R)-4,7,7-trimethyloctanal (41.2%) obtained with optical yields of 74 and 62%, respectively. (R)(S)-3-Ethyl-6,6-dimethylheptanal (3.5% ) and (R)(S)-4,7,7-trimethyloctanal (93.5%) were formed from (R)(S)-3,6,6-trimethyl-l-heptene. (+/S)-l-Phenyl-3-methyl-1-pentene, under oxo conditions, was almost completely hydrogenated to (- -)(S)-l-phenyl-3-methylpentane with 100% optical yield. 3-(Methyl-d3)-l-butene-4-d3 gave 4-(methyl-d3)pentarwl-5-d3 (92%), 2-methyl-3-(methyl-d3)-butanal-4-d3 (3.7%), 3-(methyl-d3)pentanal-2-d2,3-d1 (4.3%) with practically 100% retention of deuterium. The reaction mechanism is discussed on the basis of these results. 

C. This is illustrated by the H and 13C spectra of 3-methylheptane shown in Fig. 3.41. The proton spectrum only distinguishes between the methyl and meth-ine protons, whereas the 13C spectrum shows seven distinct peaks. However, the two types of spectra have many features in common which may be illustrated by an examination of the and 13C spectra of toluene, Fig. 3.42 and Fig. 3.43 respectively. 

The 13C spectrum of crotonaldehyde (CH3 CH=CH CHO Fig. 3.52) provides a good example of the way in which the 13C chemical shift is determined both by the state of hybridisation of the carbon atom and the nature of the substituent. The four carbon atoms have markedly different chemical shifts. The methyl carbon appears at 3 17.1. It is shifted downfield slightly compared to the methyl carbon at the end of a chain of methylene groups as in 3-methylheptane (Fig. 3.41) and hex-l-ene (Fig. 3.51). The two alkenyl carbons appear at <5133.4 and 3 152.9. The effect of conjugation of the carbon-carbon double bond is that the (i-carbon is shifted further downfield. The carbon of the carbonyl group is sp2-hybridised and is directly bonded to an electronegative atom. It is shifted furthest downfield and appears at 3 192.2,... 

The 1-methyl-l-ethylpentyl radical [I] and its neighboring molecule may then transfer hydrogen or methyl radical to yield 3-methylheptane or n-heptane (159). Radical [II] was proposed but without any identification. By recombination, it would take part in the formation of H2MEHP. 

AMINO-2-METHYLHEPTANE a,E-DIMETHYL-HEXYLAMINE 1,5-DIMETHYLHEXYLAMINE 2-METHYL-6-AMINOHEPTANE 2-METHYL-2-HEFTYL-AMINE 6-i lETHYL-2-HEPTYLAMINE 2-METIL-6-.-ViMINO-EPTANO (ITALIAN) OCTODRINE SKF51... 

C8H1602 2-methyl-3-pentyl acetate 35897-16-6 422.15 34.519 1.2 15255 C8H17CI 2-chloro-2-methylheptane 4325-49-9 442.45 36.380 2... 

C8H180 2-methyl-3-ethyl-1 -pentanol. .. 210.24 15.546 2 15645 C8H19N 2-amino-6-methylheptane 543-82-8 298.15 29.840 2... 

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