Saturated Side-Chain Compounds

The disilanickela complex 21 is an effective catalyst for the double silylation of some alkenes. Thus, reaction of 11 with 2 equiv. of4-vinylanisole in the presence of a catalytic amount of 21 afforded a moderate yield of the five-membered disilylene compound 30. However, treatment of 11 with 1.2 equiv. of 1,1-diphenylethylene in the presence of a catalytic amount of 21 gave five-membered disilylene ring compound 31, which contained a saturated side chain. 

The belief that ring transformations of 1,2,4-oxadiazoles require an vinyl substituent in the 3-position had to be abandoned when it was found that compounds like (47) with saturated side chains undergo smooth ring transformation to 4,5-dihydropyrazoles (Scheme 16) <79JCR(S)64, 79JCR(M)801>. 

Since benzoic acid is the product of oxidation, the compound is a monosubstituted benzene, C H,G. Subtracting C Hj from C,H,jO gives CjH, as the formula for a saturated side chain. A positive CrO, test means a 1° or 2° OH. Possible structures are ... 

Our findings lead us to assume that the oxidative degradation of guaiacyl compounds with saturated side chains in the 4-position (para to the hydroxyl group) is proceeding via 0,0 -coupling. Dimerization is then followed by ring fission reactions. 

Compound 20 is consistently detected in the softwood thioacidolysis mixtures. This compound has also been detected in acidolysis product mixtures (Gellerstedt et al. 1984). Its structure confirms the principle that in saturated side chains, substitution of the oxygenated group at Cy by EtSH occurs only if the neighboring group at Cfi has been previously substituted. 

There are two other factors worth noting in regard to the Japanese beetle pheromone. A single compound apparently possesses all the activity of the pheromone. This is even more surprising when we note that the material obtained from females contained about 15% of the (E) Isomer and 3% of the analog with a saturated side chain. However, these other two compounds had no effect on the activity of the (R)(Z)-isomer when added in the appropriate ratios whether the racemic or the pure enantiomeric forms were used. 

Several N-methylpyrrolidines have been identified in the venoms of Monomorium (Monomorium) species. M. latinode, an Old World species, is distinctive in producing an alkaloidal-rich venom containing two N-methylpyrrolidines with saturated side chains (IV) (6J. On the other hand, the poison gland secretions of several North American species contain N-methylated compounds in which one (V) or both side chains (VI) are terminally unsaturated (6 ) they are accompanied by the corresponding norpyrrolidines. 

Such compounds, if they contain more than two hydroxyl carbon groups in the saturated side chain, are plainly phenyl derivatives of the sugars as in the first formula above. 

Guaiacyl compounds with saturated side chains have a fluorescence maximum of modest intensity at 316 nm. The excitation spectra correspond to the absorbance spectra expected for saturated guaiacyl compounds from the data in Table 3.4. The Si state for simple benzenes is a n-n state, where intersystem crossing is inefficient and fluorescence is expected. The only exception to this behavior was the phenylcou-maran structure, which was only weakly fluorescent. The authors attributed this to a low-lying n-jr state, but no corroboration was given for this assignment. 

For resorcinolic lipids, particularly those with long saturated side-chains, the use of polar solvents is important due to their amphiphilicity. The crude extracts in many cases are subjected to preliminary fractionation/purification either by solvent fractionation/partition or by application of chromatography. For prepurification of the material and its separation from polymerized phenolics, gel filtration on hydrophobic Sephadex or TSK gel is sometimes used. Silica gel is most frequently employed for the separation and/or purification of resorcinolic lipids, notably in some studies with Ononis species (12-14). The array of compounds reported appears partly attributable to methylation or acetylation reactions occurring during column chromatographic separation. An interesting approach for I the pre-purification and selective separation of resorcinolic lipid from phenolic lipids or resorcinolic lipids from impurities has recently been reported. A selective partitioning of different non-isoprenoid phenolic lipids... 

A later study (215) of the leaves and fruit of E. rutaecarpa led to the isolation of three new alkaloids, shown by spectroscopy to be dihydroevocarpine (293) and the analogs 294 and 295 containing, respectively, Ci 1 and C15 saturated side chains. The mass spectra of these compounds were particularly informative in each case the base peaks occurred at m/e... 

Tocopherols and tocotrienols comprise the group of eight chromanol homologs that possess vitamin E activity in the diet. They are natural monophenolic compounds with varying antioxidant activities. The a-, P-, y-, and 5-tocopherols are characterized by a saturated side chain consisting of three isoprenoid units, whereas their corresponding tocotrienols have double bonds at the 3, 7, and 11 position of the isoprenoid side chain (Figure 5.3). 

Frantz et al. (1966) have isolated a sterol from the skin of rats treated with triparanol (l-[p-( S-diethylaminoethoxy)phenyl]-l-(p-tolyl)-2-(p-chlorophenyl)ethan-ol). Infrared and NMR spectroscopy were used to characterize the new compound. The close similarity of the spectra of A -cholesten-3p-ol and A -cholestadien-3) -ol was proof of the presence of the bond and of the identity of the ring system in the two compounds. The diminution in the absorption at 1368 cm", prominent in cholesterol, A -cholesten-3j8-ol, and other sterols with a saturated side chain, was evidence for the absence of the isopropyl group and compatible with the presence of a or A bond. The absence of a band at 887 cm" eliminated the latter possi-... 

Homogeneous catalytic deuteration of various unsaturated 5a-spirostane derivatives is an excellent method for the preparation of side chain labeled analogs. Thus, saturation of the double bonds at positions 20(21), 23 and 24 provided the corresponding deuterated compounds (144), (145) and (146) in high isotopic purity. The preparation of (146) is a rare example of the saturation of an isolated trisubstituted double bond in the steroid field. 

A saturated ring with an aliphatic side chain favors cleavage at the bond connecting the ring to the rest of the molecule. Compounds containing cyclohexyl rings fragment at m/z 83, 82, and 81, corre-... 

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