248 



CARBOHYDRATES AND GLUCOSIDES 



[155-156. 



Pope, Proc. Ch. Soc. 16, 72 ; Trans. 77, 

 696). 



Graminin, a reserve carbohydrate 

 obtained from Arrhenatherum bulbosum, 

 appears to be a polysaccharide of Isevu- 

 lose (Harlay, Comp. Rend. 132, I, 



Manneotetrose (C 24 H 42 O 21 ), a sugar 

 contained in c manna/ is resolved by 

 Aspergillus, by enzymes, and by hydro- 

 lysing agents generally into Isevulose 

 and manninotriose, C ]8 H 32 O 16 . The 

 latter contains the dextrose and galact- 

 ose complexes (Tanret, Comp. Rend. 

 134, 1586; Bull. Soc. [3] 27, 947). 



A 1-sugar has been found in urine, 

 and this is probably Isevulose (Kiilz, 

 Zeit. Biol. 27, 228 ; Cotton, Bull. Soc. 

 [2] 33, 546). According to Bretet 

 (Ch. Centr. 1898, 1, 67), this sugar 

 occurs in diabetic urine. In certain 

 pathological cases Isevulose occurs in 

 the urine, serum, ascitic and pleural 

 fluids (Neuberg and Strauss, Zeit. 

 physiol. Ch. 36, 227). 



SYNTHETICAL PROCESSES. 



[A.] Dextrose [154] is converted into 

 the osazone by phenylhydrazine, the 

 osazone reduced by zinc dust and acetic 

 acid to isoglucosamine, and the latter 

 decomposed by nitrous acid. Or the 

 osazone is (more conveniently) heated 

 with fuming hydrochloric acid and con- 

 verted into the glucosone. The latter 

 gives Isevulose on reduction (see under 

 sorbitol [52 ; C] ; also Fischer and 

 colleagues, Ber. 19, 1920; 20, 2569; 

 21, 2631; 22, 94; 23, 370; 2I2l). 



Dextrose gives Isevulose among other 

 sugars under the influence of caustic 

 alkaline solutions (Lobry de Bruyn and 

 Van Eckenstein ; see under dextrose 

 [154; B]). 



Dextrose gives glucosone when oxi- 

 dised by hydi'ogen peroxide and ferrous 

 sulphate (Morrell and Crofts, Trans. 

 Ch. Soc. 75, 786; 81, 666), and this 

 can be reduced to Isevulose as above. 



[B.] From d-mannose [156] through 

 the osazone and osone, and then as 

 above (see under sorbitol [52 ; C]). 



Lsevulose is formed with other sugars 

 by the action of alkali on mannose 



(Lobry de Bruyn and Van Eckenstein, 

 Rec. Tr. Ch. 14, 98; 156; 203; 16, 

 257; 274; Ber. 28, 3078). 



[C.] Mannitol [5l], on oxidation by 

 air in presence of platinum black, or by 

 potassium permanganate or nitric acid, 

 gives a mixture of mannose and Isevu- 

 lose (Gorup-Besanez, Ann. Chim. [3] 

 62, 489; Iwig and Hecht, Ber. 14, 

 1760; Dafert, Ber. 17, 227; Ibid. Ref. 

 479; Fischer, Ber. 20, 831; Fischer 

 and Hirschberger, Ber. 21, 1805); also 

 by oxidation with nitroso-camphor 

 (Cazeneuve, Comp. Rend. 109, 185). 



The oxidation of mannitol by bromine 

 water and sodium carbonate solution 

 also yields Isevulose (Fischer, Ber. 23, 

 3686). 



156. d-Mannose ; Seminose; 

 Hexanepentolal. 



H H HO HO 



I I I I 



CHO C C C C- 



I I I I 



HO HO H H 



-CH, . OH 



NATURAL SOURCES. 



An anhydride of mannose occurs in 

 the leaves of Amor phop ft all its konjac = 

 rivieri, and mannose itself has been 

 extracted from the stalk (Tsukamoto, 

 Bull. Imp. Coll. Agric. Tokio, 2, 406 ; 

 Journ. Ch. Soc. 72, Abst. 275 : see 

 also Tsuji, Ibid. 7Q, 44 ; Kinoshita, 

 Ibid. 60). 



Mannose occurs in ordinary cane- 

 sugar molasses, but it appears to result 

 from the heating of the ' invert sugar ' 

 with lime (Lobry de Bruyn, Rec. Tr. 

 Ch. 14, 125; 16. 257 ;_ 274). 



The sugar contained in orange-peel is 

 possibly mannose (Flatau and Labbe, 

 Bull. Soc. [3] 19, 408). 



The mannans or mannosides found 

 in many plants contain the mannose 

 complex. Among such sources are 

 salep mucilage from the tubercles of 

 the root of Orchis morio (Gans and 

 Tollens, Ber. 21, 2150 ; Ann. 249, 245 ; 

 Fischer and Hirschberger, Ber. 22, 

 369; Herissey, Comp. Rend. 134, 721), 

 and the reserve material contained in 

 many nuts, seeds, and berries, of which 



