Solanesol

Solanesol and other prenyl alcohols are important as metabolites in mulberry and tobacco leaves and in the synthesis of isoprenoid quinones. Hence, Sato and collaborators107 have developed a stereoselective synthesis of all-trans-polyprenol alcohols up to C50. Construction of the requisite skeletons was accomplished by the alkylation of a p-toluenesulphonyl-stabilized carbanion, followed by reductive desulphonylation of the resulting allylic sulphonyl group. This was achieved most efficiently by the use of a large excess of lithium metal in ethylamine (equation (43)), although all reaction conditions led to mixtures. The minor product results from double bond rearrangement. 

NT435 Yasumatsu, N., M. Eda, Y. Tsujino, and M. Noguchi. Isolation of oxygenated derivatives of solanesol from burley tobacco. Agr Biol Chem 1976 40 1757. 

NT560 Park, O. S. Isolation of solanesol from Korean native tobacco. Korean J Pharmacol 1981 12 211-214. 

The polyprenols obtained from tobacco and Arum maculatum (solanesol and spadicol), which are all E, are the exceptions. Another interesting fact is that, in most seed-plants, the polyprenols are allylic, as is bacterial undecaprenol. Saturated or slightly modified polyprenols, such as animal dolichol, seem to be present only in fungi. Any of those plant polyprenols, in a phosphorylated form, can be potential sugar acceptors for transfer reactions. Experiments were performed with phosphorylated allylic polyprenols and membrane preparations from Phaseolus aureus. D-Mannose from GDP-D-mannose was incorporated into the exogenous, polyprenyl phosphates,29,49 52 but it was not possible to establish unequivocally the role of these polyprenols as lipid intermediates. 

Solanesol (10 g) was dissolved in 9.5 ml hexane and 13.5 ml diethyl ether containing 1.3 ml pyridine at 0 to 5 °C and 1.8 ml phosphorous tribromide dissolved in 13 ml hexane added over 30 minutes. The mixture was stirred 3 hours, added to ice water, and stirred an additional 10 minutes. The phases were separated, the aqueous layer extracted with diethyl ether, washed with 5% NaHC03, concentrated, and 11 g product isolated. 

Solanesol was isolated from waste tobacco by extracting with hexane, treating with KOH, and purifying by chromatography on alumina with hexane/diethyl ether, 9 1. It is also obtainable from potato leaves. 

Beginning with solanesol, (II), an alternative route for preparing ubiquinone is illustrated in Eq. 1 and described (3). 

A method has been described for the functionalization of the isopropylidene terminus of isoprenoids. For example, geranyl benzyl ether (208) was converted into the phenyl thioether (210) by treatment with PhSCl and elimination of HCl. Oxidation and reaction with trimethyl phosphite gave the primary alcohol (209) stereospecifically in 75% overall yield. Use has been made of this procedure in the synthesis of solanesol (C45) from three C15 units.The tosyl derivative of the hydroxylated farnesol (211) reacts with the bromide (212) prepared from (213) to give the C30 product (215), the bromide (216) of which, after further reaction with (214), affords the solanesol derivative (217) and thence solanesol (205). 

Table 16.2.9. The yields of PAHs in the pyrolysates of several compounds, expressed in mg/g of pyrolysed material. (A = solanesol, B = sterols, C = cholesterol palmitate, D = p-carotene, E = squalene, F = chlorophyll, G = fatty acids, H = cellulose.)...

The substances most commonly utilised as markers of ETS are repairable suspended particulate matter, nicotine, CO, 3-Ethenylpyridine (3-EP) and solanesol [48,49]. All these substances are associated, however, with potential problems, when used as markers. Both CO and repairable suspended particulate matter are not unique to ETS. The use of nicotine as a marker of ETS presents a problem because [50] (1) nicotine is found primarily in the gas phase (90%), making it a relatively poor particle marker, (2) gas-phase nicotine is strongly basic and is removed from indoor environments at a faster rate than particle-phase nicotine or the particle portion of ETS and (3) the fraction of nicotine in ETS varies with measurement conditions. For example, 5-10% of ETS nicotine was found in the particle phase in a controlled atmosphere, while 20% was found... 

In order to assess the reliability of NMR data, Research Group on NMR, the Society of Polymer Science, Japan (SPSJ), collected H and 13C NMR spectra of two identical samples, a radically prepared PMMA and solanesol (a naturally occurring isoprene oligomer) from a number of NMR spectrometers by round robin method.10... 

Polyisoprenoid alcohols consisting of 9 to 20 isoprene units have a widespread occurrence as indicated by their presence in the leaves of higher plants, mammalian tissues, and microorganisms. Most of the polyprenols isolated from higher plants consist of trans and cis isoprene units with the exception of solanesol, which is composed of all-trans isoprene units. The arrangement of trans and cis units in these polyprenols has been determined from a consideration of the mechanism of the formation of betula-prenols, C(30)-C(45), isolated from wood tissue of Betula verrucosa (9). However, up to the present there has been no direct evidence to prove the location of the internal trans and cis units. 

From the results of studies on the pyrolysis of the tobacco paraffins, which comprise the n-, iso-, and anteiso-alkmes, it was suggested by Lam (2255-2258), Wynder et al. (4356), Wynder and Hoffmann (4319, 4332), and Hoffmann and Wynder (1798) that these components were the major precursors in tobacco of the PAHs in tobacco smoke. However, in 1958, Rayburn and his colleagues (3091, 3092) challenged the proposal that the tobacco alkanes were the major precursors of the smoke PAHs, but their experimental data were not overly conclusive in support of their challenge. Nevertheless, it should be realized that in one sense Rayburn et al. were partly correct as PAH precursors, the tobacco alkanes do contribute to the PAHs in tobacco smoke but their contribution is much less significant than other precursors (the phytosterols and terpenoids such as solanesol) in tobacco [cf. Wright (4282), Rodgman and Cook, (3269, 3286), Severson et al. (3616)]. 

Another series of isoprenoid hydrocarbons isolated from cigarette MSS by Rodgman et al. (3297) comprised the solane-sol-related solanesenes. Dehydration of solanesol or pyrolysis of solanesyl acetate yields a mixture of solanesenes similar to that isolated from cigarette MSS. Vll and Vlll are the major components of the solanesene mixture in tobacco smoke. 

In the mid-1950s, the determination of the molecular weight of compounds with a molecular weight above 300 to 400 was difficult and often inaccurate. As a result, Rowland et al. were unable to precisely define the molecular weight of solanesol and therefore its structure. Originally, they had intended to report that solanesol was either a C45 compound (I, n = 8 in Figure II.A-1) or a C50 compound (I, n = 9 in Figure... 

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