Kiliani reagent

Kiliani reagent, 144 see also Chromic acid Kdnig s salt, 1052... 

Solacongestidine (2) had already been synthesized from 3/ -aoetoxyptegD 5-en-20-one (i). Two conversions of readily available solasodine (1) to this alkaloid were described later. O-Acetyldihydrosolasodine (5( was hydrogenated to 102. Oxidation of the benzyloxycarbonyl derivative 103 with the Kiliani reagent gave the 16-ketone 104. Reaction with ethanedithiol yielded the thioketal 105. Desulfrirization of the thioketal moiety with Raney led to concomitant elimination of the benzyloxycarbonyl function to afford (225Vdihydrosolacongestidinc acetate (106). FinaUy, 106 was converted to its iV-chloro derivative by means of iV-chlorosuccinimide. the treatment of... 

Kiliani reagent 16, 138 Kindler s. Willgerodt King reaction 16, 777 Kishner s. Wolff Knoevenagel condensation 7, 781... 

Addition of hydrogen cyanide to an aldose to form a cyanohydrin is the first step in the Kiliani-Fischer method for increasing the carbon chain of aldoses by one unit. Cyanohydrins react with Grignard reagents (see Grignard reaction) to give a-hydroxy ketones. 

Reduction of an aldose forms one alditol reduction of a ketose forms two alditols. Br2 oxidizes aldoses, but not ketoses ToUens reagent oxidizes both. Aldoses are oxidized to aldonic acids or aldaric acids. Aldoses and ketoses react with three equivalents of phenyUiydrazine, forming osazones. C-2 epimers form identical osazones. The Kiliani-Fischer synthesis increases the carbon chain of an aldose by one carbon— it forms C-2 epimers. The Ruff degradation decreases the carbon chain by one carbon. The OH groups of monosaccharides react with acetyl chloride to form esters and with methyl iodide/silver oxide to form ethers. 

Cassaidine is a tertiary base and like cassaine may be titrated with the same indicators. It is easily differentiated by color reactions from cassaine. With sulfuric acid it yields an orange-colored solution and with sulfovanadic acid the color is raspberry red. With the Keller-Kiliani-Cloetta reagent (ferric chloride in a mixture of sulfuric and acetic acids) it gives an intense red solution (cassaine—golden yellow). It is much less soluble in the usual organic solvents than is cassaine. 

The Wohl deffvdation, an alternative to the Ruff d radation, is nearly the reverse of the Kiliani-Fischer synthesis. The aldose carbonyl group is converted to the oxime, which is dehydrated by acetic anhydride to the nitrile (a cyanohydrin). Cyanohydrin formation is reversible, and a basic hydrolysis allows the cyanohydrin to lose HCN. Using the following sequence of reagents, give equations for the individual reactions in the Wohl degradation of D-arabiiK>se to D-erythrose. Mechanisms are not required. 

Fischer made extensive use of the reactions of the sugars with phenylhydrazine, a reagent which he had discovered in 1875. Fischer also oxidised the sugars to mono- and dicarboxylic acids, reduced the carbonyl function to a hydroxyl group, and prepared lactones (cyclic esters) from the monocarboxylic acids. Fischer also used a reaction devised by Heinrich Kiliani (1855-1945) in which the carbon chain of a sugar could be extended. Thus a five-carbon sugar could be converted to two six-carbon sugars because a new asymmetric centre had been added. 

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