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This rules the birch reduction out as a safe method.

Birch reduction - Wikipedia

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SUBSTANCE: method for making allobetulin exhibits an evident antiviral activity and is of the upmost interest for chemical-pharmaceutical industry. Allobetulin is made of upper birch bark by combining the stages of betulinole extraction from birch bark with aromatic hydrocarbon, and betulinole isomerisation in allobetulin with 30-70% sulphuric acid added.

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The Birch reduction of methoxybenzenes is a useful synthesis of cyclohexenones: Desogestrel: Corey, E. J.; Huang, A. X. 1999, , 710. Note that the isolated double bond is not reduced.

General & Introductory Chemistry

One-step methods include obtaining allobetulin bark of birch or from betulin by isomerization under the action of acid agents.
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The Birch reduction (Birch, A.J.; Smith, H. , 1958, , 17.) of aromatic compounds involves reaction with a solution of lithium or sodium in ammonia, basically solutions of M+ e-. Usually a proton donor such as t-butanol or ethanol is present to avoid the buildup of very basic LiNH2, which can be harmful to the integrity of the products. The major product is normally a 1,4-diene, resulting from protonation of the intermediate pentadienyl anion at the center carbon, which bears the highest electron density. Substituted benzenes lead to 1,4-cyclohexadienes with the more highly substituted double bonds

If Birch reductions are run without an alcohol proton source, the basic LiNH2 formed can cause double bond isomerization, and over-reduction (Rabideau JOC 1983, , 4266).

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- the use of expensive reagents, such as dimethylsulfate, triperoxonane acid, is unacceptable to conduct aggregative synthesis;
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Metalated sulfones have a number of important in synthetic chemistry, including alkylations, acylation, and condensation with ketones and aldehydes (). The sulfonyl group is often reductively removed during the process, or needs to be removed after the task is done. Buffered sodium or aluminum amalgam are commonly used reagents.

Modified Birch reduction conditions for the selective dechlorination of 1,2,3,4-tetrachloro-5,5-dimethoxycyclopentadiene Diels-Alder adducts are described. Inverse addition of a suspension of lithium in liquid ammonia to a dilute ethereal solution of the adduct at - 78°C gives clean dechlorination with no accompanying alkene reduction.

Marek, Adamczak1, Uwe T., Bornscheuer2 and Włodzimierz Bednarski1,
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  • 10.1021/jf051960d - ACS Publications Home Page

    The Birch reduction is an organic reaction which is particularly useful in synthetic organic chemistry

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    Birch reduction - Wikiquote

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    Birch reduction

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Runic Meanings and Divination - The Witches Collective

Polypyrrole salt was obtained in a very high percent yield (83.77 %) with respect to the amount of pyrrole used and the reaction time was considerably reduced (1 hour and 10 minutes) as compared to previously reported synthesis methods.

Joanna Briggs Collaboration Centres - JBI

Manganese toxicity is a major factor limiting crop growth on acidic, poorly drained, or steam-sterilized mineral soils. Acidic (pH 4.4) oxisol soils in Hawaii, USA, containing 15 g total manganese/kg need to be limed to raise the pH to 5.7 or above, resulting in soluble manganese concentrations of less than 2 mg/litre, for normal watermelon () growth (Hue & Mai, 2002). Soil acidification enhances the solubility of metals such as aluminium and manganese. Soil acidification can be caused by acidic deposition, acid soils brought to the surface by construction projects, and industrial acid deposition. The pH of soils containing toxic levels of manganese is generally higher () and at >1 mg manganese/litre for brown speckle at the leaf marginal and interveinal area in older leaves (Kitao et al., 2001). Kaus & Wild (1998) found that Douglas-fir () showing symptoms similar to iron deficiency chlorosis had accumulated significantly more manganese than trees without chlorosis. Excess manganese in soil has been found to accumulate in leaves of broad-leaved deciduous plants of northern Japan. This resulted in declines in light-stimulated net photosynthetic rate (Kitao et al., 1997).

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In the laboratory, microorganisms have been shown to transform both soluble and solid manganese; thus, they potentially have substantial effects on local manganese cycles. Physiological, biochemical, and structural studies of manganese oxidizers and reducers in the laboratory form the basis on which models of the participation of microorganisms in the cycling of manganese have been proposed. Field analyses of the distribution of manganese oxidizers and reducers, structural properties of manganese precipitates, and activity measurements support the hypothesis that microorganisms play an integral role in the cycling of manganese in some environments (Nealson, 1983). Microbial oxidation of Mn(II) occurs at rates up to 5 orders of magnitude greater than those of abiotic Mn(II) oxidation (Tebo, 1991). Johnson et al. (1995) found that microbial catalysis was overwhelmingly responsible for manganese oxidation in the lower epilimnion of a freshwater dam during the summer months. Microbial oxidation of Mn(II) to Mn(IV) by spores of the marine sp. was observed by Bargar et al. (2000), whereas Stein et al. (2001) found three freshwater bacterial isolates capable of manganese oxidation. Elevated manganese levels on the carapace of crayfish () are thought to be the result of manganese-oxidizing bacteria forming biofilms (King et al., 1999). Nealson et al. (1991) isolated and identified manganese-reducing bacteria in the Black Sea. The major group of organisms isolated from the 80- to 90-m (manganese reduction) zone were in the genus . Microbially mediated reduction of complexed Mn(III) has also been observed in the laboratory (Kostka et al., 1995). Further studies have isolated manganese-reducing bacteria in marine sediments, oxic regions of lake water columns, and the rhizosphere of non-mycorrhizal plants (Posta et al., 1994; Bratina et al., 1998; Thamdrup et al., 2000).

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SUBSTANCE: method for making allobetulin exhibits an evident antiviral activity and is of the upmost interest for chemical-pharmaceutical industry. Allobetulin is made of upper birch bark by combining the stages of betulinole extraction from birch bark with aromatic hydrocarbon, and betulinole isomerisation in allobetulin with 30-70% sulphuric acid added.

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