The simple carbohydrates and the glucosides / by E. Frankland Armstrong.

  • Edward Frankland Armstrong
Date:
1912
Catalogue details

Licence: In copyright

Credit: The simple carbohydrates and the glucosides / by E. Frankland Armstrong. Source: Wellcome Collection.

    17/188 (page 5)
    \/ If the regular tetrahedron be adopted as the model of the carbon atom and it be supposed that the four affinities are directed towards its four solid angles from the centre of a sphere within which the tetra- hedron is inscribed, the direction of the affinities is such (109° 24') that, on uniting four such tetrahedra together and interposing as representa- tive of the oxygen atom a ball with two affinities arranged in about the same directions as the two carbon affinities, a closed system or ring is formed almost naturally, in which there is no strain, the internal angles being practically those in a regular pentagon, thus:— H\ >c HCr H H /gT5§\ CH . CH(OH) . CH2(OH) This symbol has been very widely adopted, as it is in general accordance with the interactions of glucose. Fischer has stated re- cently his acceptance of it in preference to the aldehyde formula. It is the representation in a plane surface of a solid model of glucose made by combining tetrahedra in the conventional manner. The reader is advised strongly to construct such a model himself to enable him to follow the argument developed in this chapter. The behaviour of glucose as an aldehyde is accounted for if it be assumed that, when the ring is ruptured by hydrolysis, the closed-chain form passes into the aldehydic form in the following manner:— T-J H OH H OH \/ \/ c c H H OH H OH \/ \/ c c + h2o CH . CH(OH). CHa(OH) H HO > / CH . CH(OH) . CH3(OH) O Closed ring. H OH H OH \/ \/ C C OH HO Aldehydrol. H OH H OH \/ \/ C C HO > \ CH . CH(OH) . CH2(OH) H\/ o \ + h2o CH . CH(OH) . CH2(OH) OH HO Aldehydrol. HO Aldehyde.