Glucosan

Physical Constants of 1,6-Anhydro-fi-o-glucofuranose and 1,6-Anhydro-a-o-galactofuranose and Their Derivatives 

The trimethyl-D-glucose proved instead to be 2,3,5-trimethyl-D-glucose, which had been synthesized by Smith.14 It was characterized as the crystalline phenylhydrazide of the corresponding trimethyl-D-gluconic acid, the derivative being identical with an authentic sample of 2,3,5-trimethyl-D-gluconic acid phenylhydrazide prepared by Smith.14 

To isolate the new D-galactosan, Hann and Hudson converted the accompanying levogalactosan to its monoisopropylidene derivative by condensing the acetone-soluble portion of the pyrolysis sirup with acetone in the presence of anhydrous copper sulfate. After concentration of the reaction solution the bulk of the 3,4-isopropylidene-D-galactosan 1,5 /8- 

The method of preparation was modified somewhat by Alexander, Dimler and Mehltretter, a product of higher purity thereby being obtained. For the pyrolytic vacuum distillation, the same apparatus was employed as for the preparation of levoglucosan and l,6-anhydro- 8-D-glucofuranose from starch. The use of an electrically heated jacket instead of a burner for heating the flask resulted in better control of the reaction. In addition, the dextrorotation of a solution of the sirupy distillate was about twice that reported by Hann and Hudson for their product from the same weight of galactose. 

The acetonation was carried out on the entire distillate, thereby avoiding the steps of decolorization, concentration and acetone extraction. The acetonated mixture was extracted directly with chloroform, care being taken to minimize the possibility of hydrolysis of the 3,4-isopropyl-idene-D-galactosan 1,5 /3 1,6 while in the presence of the residual sirups. Acetylation of the chloroform-insoluble residue, followed by vacuum distillation, yielded crystalline triacetyl D-galactosan 1,4 a- 

---

Starch is a homopolymer of glucose forming an a-glucosidic chain, called a glucosan or glucan. It is the most abundant dietary carbohydrate in cereals, pota-... 

The most common is the seven-membered ring type represented by levo-glucosan. Examples have been recorded of a fourth type, namely that in which the anhydro ring is four-membered, but only two of these examples are well authenticated.9 10... 

Synthesen mit 3,4,6-Triacetyl-glucosan (Brigl-Anhydrid), by E. Hardegger and H. Leeman, Chimia, 5 (1951) 108-109. 

C6H10O4S 1,6-Anhydro-l(6)-thio-/3-D-glucopyranose l(6)-thiolevo-glucosan (TLEVGL)19... 

Ref 4). Prepd by foe mixed acid nitration of levo-glucosan... 

Effect of other factors on cellulose. Dry distillation at a temperature above 150°C causes cellulose to produce compounds of low molecular weight, such as water, methane, ethylene, carbon monoxide, carbon dioxide, acetic acid, and acetone. According to Pictet [49] dry distillation under reduced pressure yields a substance having the empirical formula C6H10Oj, laevo-glucosan which probably is /3-D-glucopyranose anhydride ... 

D-glucose glucosan trinitrate, C6H702(0N02)3 (m.p. about 80°C) ... 

---