100 



POLYHYDRIC ALCOHOLS 



[49 A-50 C. 



36 , 257 ; Comp. Rend. 21, 730; Fortes 

 and Brunier, Bull. Soc. [3] 13, 96 ; 

 Imber and Belugou, Ibid. 21, 935 : for 

 technical production, Guedras, Monit. 

 Sci. 13,577; Ch. Centr. 1899, 2, 636). 



5O. Erythritol ; Erythroglucin ; 



Erytliromannite ; Phycite ; 



1:2:3: 4-Butanetetrol. 



H H 



I I 

 HO . H 2 C C C CH 2 . OH 



I I 

 HO HO 



(Inactive modification). 



NATURAL SOURCES. 



Occurs in the free state in Prolo- 

 coccus vulgaris (Lamy, Ann. Chim. [3] 

 35, 138; 51, 232; Comp. Rend. 36, 

 655) and as an ester of a complex acid 

 (orcellic acid) in erythrin and /3-eiythrin, 

 which are found in the lichens Roccella 

 tinctoria, R. montagnei, and R. fuci- 

 formis. (For distribution of erythrin 

 = erythric acid in lichens see also 

 under orcinol [75] : for /3-erythrin see 

 /3-orcinol [77].) Hesse (Journ. pr. Ch. 

 [2] 57, 258) regards erythrin as a con- 

 densation product of erythritol and 

 lecanoric acid. 



Erythritol has been found in the alga 

 Trentepohlia jolithus (Bamberger and 

 Landsiedl, Monats. 21, 571). 



SYNTHETICAL PROCESSES. 



[A.] From acetylene and ethylene (see 

 under methane [l; A; D, &c.]). When 

 these gases are passed through a hot 

 tube a hydrocarbon is formed which is 

 apparently identical with erythrene or 

 pyrrolylene (divinyl ; i : 3-butadiene ; 

 CH 2 : CH . CH : CH 2 ) (Berthelot, Ann. 

 Chim. [4] 9, 466), and this can be 

 converted into an unstable dibromide 

 by bromination in chloroform solution 

 at 2i, then into a stable isomeric 

 dibromide which, with silver acetate, 

 forms a diacetin. The latter is again 

 brominated, the dibromdiacetin con- 

 verted into a tetracetin by further 

 treatment with silver acetate, and the 

 product hydrolysed (Griner, Comp. 



Rend. 116, 723 ; Bull. Soc. [3] 9, 

 218). When the unstable dibromide 

 is heated to 100 there is formed, with 

 the stable dibromide above referred to, 

 another dibromide which, on oxidation 

 with permanganate, gives the dibrom- 

 hy drin of natural erythritol from which 

 the latter can be obtained through the 

 diacetin and hydrolysis, or by heating 

 the dibromhydrin with potassium hy- 

 droxide and then hydrating the di- 

 hydroxybutane thus obtained by heating 

 with water (Griner, Comp. Rend. 117, 

 553 ; Bull. Soc. [3] 9, 21 8 ; also Thiele, 

 Ann. 308, 333; Maquenne and Ber- 

 trand, Comp. Rend. 132, 1565). 



Or the acetylene and ethylene could 

 be indirectly converted into erythrene 

 through pyrrole as under C, this last 

 compound being formed among other 

 products when a mixture of acetylene, 

 ethylene, and ammonia are passed 

 through a hot tube (Dewar, Proc. Roy. 

 Soc. 26, 65). 



[B.] From amyl alcohol [22]. Ery- 

 threne is said to be among the products 

 formed by passing the vapour through 

 a hot tube (Caventou, Ann. 127, 93), 

 or by pyrogenic decomposition by pass- 

 ing the vapour over heated iron (Ipatieff, 

 Ber. 35, 1053). 



[C.] From succ'mic acid [Vol. II] and 

 methyl alcohol [13] through succinimide 

 (D'Arcet, Ann. Chim. [2] 58, 294; 

 Fehling, Ann. 49, 198; Laurent and 

 Gerhardt, Comp. Rend. d. Travaux de 

 Chim. 1849, 108; Menschutkin, Ann. 

 162, 165; 187; 182,93; Bogert and 

 Eccles, Journ. Am. Ch. Soc. 24, 20), 

 pyrrole [Vol. II] by distilling succinim- 

 ide with zinc dust (Bell, Ber. 13, 877). 

 N-methylpyrrole (C 4 H 4 .N.CH 3 ) by 

 the action of methyl iodide on potassium 

 pyrrole (Ciamician and Dennstedt, Ber. 

 17, 2951), dihydro methyl pyrrole (me- 

 thylpyrroline) by reduction with zinc 

 dust and acetic acid (Ciamician and 

 Magnaghi, Ber. 18, 725 : see also 

 Knorr and Rabe, Ber. 34, 3491; Cia- 

 mician, Ibid. 3952), tetrahydromethyl- 

 pyrrole (N-methylpyrrolidine) by 

 further reduction with hydriodic acid 

 and phosphorus (C. and M. I/jid. 2080), 

 the methiodide by addition of methyl 

 iodide, dimethylpyrrolidine (C 4 H 7 . 



