INOSITOLS 311 



Cocositol has been isolated from the leaves of cocos and closely 

 resembles z'-inositol. 



Pinitol is monomethyl ^/-inositol. 

 Quebrachitol is monomethyl /-inositol. 

 /-Inositol. 

 Preparation. 



(1) From phytin. Phytin is extracted from unripe peas or husks of 

 cereals with dilute hydrochloric acid. The acid extract is either neutralised 

 or made alkaline with ammonia, or calcium chloride is added and it is made 

 alkaline with ammonia. The calcium-magnesium or calcium salt of phytic 

 acid, or phytin, is precipitated. It is redissolved in acid and reprecipitated, 

 filtered off and dried. 



Phytin is hydrolysed by heating in a sealed tube with dilute sulphuric acid 

 to about 150 for several hours. On removing the acids with baryta and 

 evaporating to a small volume and adding alcohol, the inositol is precipitated. 



It is recrystallised from a mixture of water and alcohol. 



(2) From muscle. Muscle is extracted with water ; the aqueous extract 

 is boiled to coagulate proteins and the filtrate treated with lead acetate to 

 remove the remaining proteins. The clear solution is precipitated with basic 

 lead acetate. The precipitate is suspended in water and decomposed with 

 hydrogen sulphide and the solution, filtered from lead sulphide, is concen- 

 trated. On adding from 2-4 volumes of alcohol and filtering rapidly from 

 any amorphous precipitate and allowing to stand, inositol crystallises out, or 

 ether may be added until a turbidity appears and the mixture again allowed 

 to stand. The crystals are recrystallised from water to which from 2-4 

 parts of alcohol are added. 



Properties. 



/-inositol separates in large colourless crystals (Fig. 51) or, if impure, in 

 bunches of small crystals, and contains 

 two molecules of water of crystallisation 

 which are given off at 1 1 o. The an- 

 hydrous substance melts at 225. It is 

 soluble in water (i part in 7-5 parts at 

 20) and the solution has a sweet taste. 

 On account of this property and its 

 empirical composition it was formerly 

 called muscle sugar. It does not re- 

 duce Fehling's solution, nor has it any 

 of the properties of a carbohydrate. 



Reactions. 



(1) Sherer's Test. A rose-red 

 colour is formed on evaporating a small 

 quantity with nitric acid in a procelain 

 basin nearly to dryness, adding am- 

 monia and a few drops of calcium 



chloride and again evaporating to dry- FrG - SL Inositol. (After Funke.) 



ness. 



(2) SeideVs Test. If in the above reaction strontium acetate be used 

 instead of calcium chloride, a green colour and a violet precipitate are formed, 



(3) Gallois Test. On evaporating a solution of inositol nearly to dryness, 

 adding a drop of mercuric nitrate and again evaporating to dryness, a yellowish 

 residue is left. This turns a dark rose-red on warming ; the colour disappears 

 on cooling. 



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