Decane Decarboxylation

Mercuric o-carborane-l-carboxylate complexes decarboxylated when heated above their melting points or when refluxed in decane or benzene solution [Eq. (102), L = phen, bpy, or (py)2] (109,110). Asymmetric organomercury carboranes and their 1,10-phenanthroline complexes were also formed by thermal decarboxylation [e.g., Eq. (103), R = Me or Ph] (111). 

Michael additions to acceptor-substituted dienes are often followed by (spontaneous or induced) cyclizations. This was already noted by Vorlander and Groebel" who obtained a substituted 1,3-cyclohexanedione by treatment of 6-phenyl-3,5-hexadien-2-one with diethyl malonate (equation 5). Obviously, the 1,4-addition product which is formed initially then undergoes cyclization, ester hydrolysis and decarboxylation. Similarly, reaction of methyl sorbate with methyl 4-nitrobutyrate gave the 1,6-adduct which was reductively cyclized to 6-methyl-l-azabicyclo[5,3,0]decane (equation 6). 

DeCA METHYLENE BROMIDE, 20, 24 Decamethylenediamine, 27,18 Decamethylene glycol, 20, 25 1,10-Decanediamine, 27,18 Decane, 1,10-dibromo-, 20, 24 Decarboxylation, 23, 18 of l,3-dihydroxy-2-naphthoic acid, 25, 75... 

It was found for the oxidation of heptane [140] that up to 90% of C02 is formed in parallel with the acids and only 10% by decarboxylation of acids. Oxy- and ketoacids (up to 18% of all acids) were found to be produced in parallel with fatty acids in the oxidation of n-decane [141]. All the above facts are inconsistent with the assumption that the a-C—C bond only is broken on oxidation of ketones. Undoubtedly, some ketones are oxidized with scission of two C—C bonds. This conclusion is confirmed by the prevailing amount of lower fatty acids and parallel formation of C02 and acids in the oxidation of paraffins. Obviously, not only the a-CH2 group but also other CH2 groups are attacked in the ketone molecule. This results in the formation of bifunctional compounds with subsequent oxidation to acids, oxyacids, and ketoacids. The competing attack by peroxy radicals at the a-CH2 and other CH2 groups will be discussed later. 

In addition to decarboxylation, the oxidation of acids yields hydro-peroxy, hydroxy, keto groups, lactones, and mono- and dicarboxylic acids of lower molecular weight. The mechanism of the oxidation of acids is similar to that for hydrocarbons. The reactivity of mono- [300] and dicarboxylic acids [216] with respect to cumylperoxy radicals was measured by oxidation in the presence of cumyl hydroperoxide as source of R02 (see Table 15). The reactivities of methylenic groups in mono- and dicarboxylic acids and in rc-paraffin acids are close. For example, at 100° C, feCH2 X 102 (1 mole-1 s-1) = 4.8 (n-decane), 10.0 (glutaric, sebacic, j3,7 groups), 6.4 (a-CH2 of dibasic acids), 8.0 (for monocarboxylic acids), and 11.0 (>CH2 for propionic acid). 

A soln. of 7,10-trans -2,6-epi-7-isopropenyl-10-methyl-4-oxotricyclo[4.4.0.0b5]de-cene-2-carboxylic acid in acetic acid triethylamine-tert- hut2Lno electrolyzed 20 hrs. at 10° with Pt-electrodes at a constant current of 0.08 amp./cm2 and ca. 20 V. -> 7,10-rrfln5--2,6-epi-2-acetoxy-7-isopropyl-10-methyltricyclo[4.4.0.0l 5]decan-4-one. Y 72%. - Under the above conditions, hydrogenation of the isopropenyl function occurs spontaneously. S. Torii and T. Okamoto, Bull. Chem. Soc. Japan 49, 111 (1976) 1-acoxy-l-acylamines by decarboxylative acoxylation s. T. Iwasaki, et al., J. Org. Chem. 42, 2419 (1977). 

A mixture of 4-ethoxycarbonyl-5-m-dithianone and ethylene glycol satd. with dry HCl, heated 1 hr. on a steam bath, the resulting crude 6-ethoxy carbonyl-1,4-dioxa-7,9-dithiaspiro [4.5] decane (23 from 20.6 g.) kept overnight in aq.-alc. NaOH at room temp., then heated 5 hrs. on a steam bath to complete the saponification and to evaporate the alcohol, cooled, acidified with coned. HCl, the mixture containing l,4-dioxa-7,9-dithiaspiro[4.5jdecane-6-carboxylic acid (Y 90% when isolated) heated 4 hrs. on a steam bath 5-m-dithianone (Y 96%). Overall Y 83%. F. e., also decarboxylation without cleavage of the ketal, s. E.G. Howard and R. V. Lindsey, Jr., Am. Soc. 82, 158 (1960). 

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