Methyl heptanoate

Examples The mass spectrum of methyl heptanoate perfectly meets the standard, and thus all peaks may be explained by following Scheme 6.39 (Fig. 6.26a). In principle, the same is true for the isomeric methyl 2-methylhexanoate, but here care has to be taken not to interpret the mass spectmm as belonging to an ethyl ester. This is because the 2-methyl substituent resides on the ionic products of McLafferty rearrangement and y-cleavage, shifting both of them 14 u upwards. Nevertheless, a look at the a-cleavage products, [M-OMe], and [COOMe], m/z 59, reveals the methyl ester. 

Fig. 6.26. El mass spectra of methyl heptanoate (a) and methyl 2-methylhexanoate (b). Spectra used by permission of NIST. NIST 2002.

Transesterification. The product obtained from cerate oxidation of the methoxyhydroperoxide from 1-octene in ethanol contained methyl heptanoate but no ethyl heptanoate, and the oxidation product of the ethoxyhydroperoxide in methanol contained ethyl heptanoate but no methyl heptanoate. 

The fruity-sweet flavours in elderberry juice and products have primarily been associated with aliphatic esters such as ethyl 2-methylbutanoate, ethyl 3-methylbutanoate, methyl heptanoate, methyl octanoate, methyl nonanoate, alcohols (2-methyl-l-propanol, 2-methyl-1-butanol and 3-methyl-1-butanol) and the aldehydes pentanal, heptanal and octanal [127, 129, 130, 132],... 

The authenticity of the peaks in GC and GC-MS analyses were tested by the relative retention time of the standards with reference to methyl heptanoate. In addition to this, the I values were calculated on OV-17 column, for the standards ana sample peaks. Compounds for which standards were not there, but had very good mass spectral agreement (correlation ratio >0.95) were also considered as present positively. A few peaks for which... 

In 1950, Letsinger reported that carbonation of 2-lithiooctane, 15, prepared by exchange of (—)-2-iodooctane with s-butyllithium in petroleum ether at —70 °C, gave (—)-2-methyl-heptanoic acid21. However, after first warming the 2-lithiooctane solution to 0°C over 20 minutes the resulting carboxylic acid was racemic. This was the first observation that a secondary alkyllithium compound inverts much more slowly than does a primary RLi compound. 

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