152 B-153 B.] 



d-ERYTHRULOSE 



243 



Oilier Syntheses of Tet 'roses. 



[B.] From tartaric acid [Vol. II] 

 through glycollic aldehyde (see under 

 furfural [126 ; B]). The latter in con- 

 tact with dilute alkali at o undergoes 

 aldol condensation with the formation 

 of erythrose (Fischer and Landsteiner, 

 Ber. 25, 2553 > Jackson, Trans. Ch. 

 Soc. 77, 131 : see also Fischer, Ber. 27, 

 3200; Neuberg, Ber. 35, 2630). 



NOTE : The generators of glycollic aldehyde 

 referred to under furfural [126 ; F ; G, &c.] 

 thus become generators of erythrose. These 

 are : acetal [93] ; ethyl alcohol [14] ; ethylene. 



[C.] From d-gluconic acid [Vol. II] 

 through d-araMnose [153] by oxidising 

 the calcium salt with bromine in presence 

 of lead carbonate or with hydrogen 

 peroxide and ferric acetate (see under 

 153 ; B). d-Arabinose on further 

 oxidation with bromine and water gives 

 d-arabonic acid, and this on oxidation 

 as above yields d-erythrose (Ruff, Ber. 

 32, 3672). The erythrose has the 

 constitution : 



CHO- 



HO HO 



H H 



-CH 2 . OH 



[D.] Dextrose [154] gives an oxime 

 which on treatment} with acetic anhy- 

 dride yields the nitrile of pentacetyl- 

 gluconic acid (see under 153; A). 

 The nitrile gives d-arabinose on hydro- 

 lysis with acids (Ibid.}. Subsequent 

 steps as above under C. 



[E.] From glycerol [48] through 

 acrole'in [lOl], which, on treatment with 

 hydrogen chloride in alcoholic solution, 

 gives the diethylacetal of /3-chlorpro- 

 pionic aldehyde (Alsberg, Jahresber. 

 1864, 495 ; Wohl, Ber. 31, 1797). The 

 latter yields acrole'in-acetal on treat- 

 ment with potassium hydroxide (Ibid. 

 1798), and the acetal, on heating with 

 dilute sulphuric acid, gives (racemic) 

 glyceric aldehyde (Ibid. 2394), of which 

 the oxime on heating with aqueous 

 caustic alkali yields glycollic aldehyde 

 (Wohl and Neuberg, Ber. 33, 3106). 

 Subsequent steps as above under B. 



NOTE : A conversion of 1-arabinose into 

 a tetrose is possible through the following 



steps : 1-arabinoseoxime ; tetra-acetylarabonic 

 nitrile ; tetrose (Wohl, Ber. 26, 743). 



J-Arabinose has been converted through 1-ara- 

 bonic acid into 1-erythrose by oxidising the 

 calcium arabonate with hydrogen peroxide in 

 presence of a ferrous salt. An isomeric tetrose 

 (1-threose) is obtained by similar processes from 

 1-xylose through 1-xylonic acid (Ruff, Ber. 34, 

 1362). The 1-arabinose and 1-xylose employed 

 in these processes are not synthetical products. 



153. d-Arabinose ; Peiitanetetrolal. 



H HO HO 



CHO C C C CH 2 . OH 



HO H H 



NATURAL SOURCE. 



A pentose has been found in the 

 urine in a case of morphinism (Sal- 

 kowski and Jastrowitz, Centr. med. 

 Wiss. 1892, Nos. 19 and 32) which, 

 according to Neuberg (Ber. 33, 2243), 

 is racemic arabinose, and may therefore 

 be considered to contain the d-arabinose 

 complex. (For behaviour of the stereo- 

 isomeric arabinoses in the animal body 

 see Neuberg and Wohlgemuth, Ber. 

 34, 1745.) This urine pentose is 

 synthesised in the organism (Neuberg, 

 Ber. 35, 1472 : for the separation 

 of d-arabinose from the racemic com- 

 pound by 1-menthylphenylhydrazine see 

 Neuberg, Ber. 36, 1192). 



SYNTHETICAL PROCESSES. 



[A.] From dextrose [154], the oxime 

 of which on treatment with sodium 

 acetate and acetic anhydride gives the 

 cyanacetate = pentacetylgluconitrile. 

 The latter on hydrolysis yields d-ara- 

 binose. Or the nitrile, on treatment 

 with ammoniacal silver oxide solution, 

 gives the pentose in combination with 

 acetamide (Wohl, Ber. 26, 730 : see 

 also Neuberg and Wohlgemuth, Zeit. 

 physiol. Ch. 35, 31). 



[B.] From d-gluconic acid [Vol. II] by 

 oxidation with bromine in presence of 

 lead carbonate, or with hydrogen per- 

 oxide in presence of basic ferric acetate 

 (Ruff, Ber. 31, 1573 ; 32, 553; 33, 

 1799; 35 > 2 36o, note). 



R 2 



