Fischer and Tafel

The first, total synthesis of sugar-like compounds was performed as early as 1861 in that year, Butlerov2 reported the formation of methylenitan on treatment of aqueous formaldehyde with calcium hydroxide. The first, defined sugar derivative, DL-mannitol ( a-acrit ), was obtained by Emil Fischer and Tafel,3 and the first, optically active, totally synthetic sugars, D- and L-mannose and D- and L-fructose, were also prepared by Fischer.4... 

L-Rhammose Phenylhydrazone. This was prepared by the method of Fischer and Tafel (57), mp 159°C. 

An important and common method for lengthening and shortening the carbon chains of organic molecules, both chemically and biochemically, is the aldol-type reaction. Fischer and Tafel (in 1887) first described an alkali-catalyzed condensation of two trioses to form a hexose. 

From Formaldehyde.—Historically and physiologically, the most important synthesis of hexose mono-saccharoses is from formaldehyde. In 1861 Butlerow found that dioxymethylene (tri-oxymethylene), produced by polymerizing formaldehyde, yielded with hot lime water a sweet substance to which he gave the name of methylenitan. The substance reduced Fehling s solution, but was optically inactive and non-fermentable with yeast zymase. Later, Loew obtained a sweet, non-fermentable syrup by the direct action of lime-water on formaldehyde. This substance he called formose. He afterward obtained what he considered another sugar by the action of magnesium hydroxide upon formaldehyde. This substance was fermentable by yeast and to it he gave the name of methose. In 1887, Fischer and Tafel... 

The conversion of 1-amino-1-deoxy-D-fructose, isoglucosamine, to sirupy n-fructose (reported by Fischer and Tafel ) may also take place... 

Formaldehyde condenses in the presence of weak bases to form a complex mixture of sugars called formose or methose The polymerization undoubtedly proceeds through a combination of acyloin and aldol condensations. Fischer and Tafel 125) obtained a similar sugar mixture by the action of dilute alkali on acrolein dibromide. Presumably, the reaction sequence is the following (Chapter I) ... 

Fischer and Tafel s Complete Synthesis of Hexose Sugars a-ACROSE (from formaldehyde, glyceraldehyde, or acrolein dibromide) c H6NHNH2... 

Polyols are oxidized by alkaline solutions of halogens. Fischer and Tafel 203) obtained 20 % yields of glycerosazone by the action of bromine and sodium carbonate on glycerol and subsequent treatment with phenylhy-drazine. Galactitol gave an osazone which appeared to be galactosazone. Presumably, the oxidation takes place mainly at the primary alcoholic group. 

Similar calculations have been carried out for the inhibition of iron corrosion in hydrochloric acid by Victoria blue which, according to Elze and Fischer (m) does not affect the Tafel slopes, but reduces both the anodic and cathodic partial reactions to a different degree. In this particular case 0q and 02 have to be adjusted by way of a trial and error calculation. 

It was not until 1884 that Fischer found that phenylhydrazine reacts with aldehydes and ketones to form compounds which he thought might be cyclic. He later gave their correct structures (used below) and called them hydrazones. The use of phenylhydrazine with sugars began in 1884. Fischer, partly with J. Tafel, found that hydrazones are also formed with sugars ... 

---