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A glucoside is a glycoside that is derived from glucose. Glucosides are common in plants, but rare in animals. Glucose is produced when a glucoside is hydrolysed by purely chemical means, or decomposed by fermentation or enzymes. The name was originally given to plant products of this nature, in which the other part of the molecule was, in the greater number of cases, an aromatic aldehydic or phenolic compound (exceptions are sinigrin and jalapin or scammonin). It has now been extended to include synthetic ethers, such as those obtained by acting on alcoholic glucose solutions with hydrochloric acid, and also the polysaccharoses, e.g. cane sugar, which appear to be ethers also. Although glucose is the most common sugar present in glucosides, many are known which yield rhamnose or iso-dulcite; these may be termed pentosides. Much attention has been given to the non-sugar parts (aglyca) of the molecules; the constitutions of many have been determined, and the compounds synthesized; and in some cases the preparation of the synthetic glucoside effected. The simplest glucosides are the alkyl ethers which have been obtained by reacting hydrochloric acid on alcoholic glucose solutions. A better method of preparation is to dissolve solid anhydrous glucose in methanol containing hydrochloric acid. A mixture of alpha- and beta-methylglucoside results. Classification of the glucosides is a matter of some intricacy. One method based on the chemical constitution of the non-glucose part of the molecules has been proposed that posits four groups: (I) alkyl derivatives, (2) benzene derivatives, (3) styrolene derivatives, and (4) anthracene derivatives. A group may also be constructed to include the cyanogenic glucosides, i.e. those containing prussic acid. Alternate classifications follow a botanical classification, which has several advantages; in particular, plants of allied genera contain similar compounds. In this article the chemical classification will be followed, and only the more important compounds will be discussed herein. == Ethylene derivatives == These are generally mustard oils, which are characterized by a burning taste; their principal occurrence is in mustard and ''Tropaeolum'' seeds. Sinigrin, or the potassium salt of inyronic acid not only occurs in mustard seed, but also in black pepper and in horseradish root. Hydrolysis with baryta, or decomposition by the ferment myrosin, gives glucose, allyl mustard oil and potassium hydrogen sulfate. Sinalbin occurs in white pepper; it decomposes to the mustard oil, glucose and sinapin, a compound of choline and sinapic acid. Jalapin or scammonin occurs in scammony; it hydrolyses to glucose and jalapinolic acid. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Glucoside」の詳細全文を読む スポンサード リンク
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