68 THE SIMPLER NATURAL BASES 



Neosine, C 6 H 17 O 2 N. 



There is still a good deal of doubt concerning the nature of this 

 base, one of those obtained by Kutscher [1905, Ch. V, creatine] from 

 extract of meat. Krimberg [1906, 1, Ch. V, methylguanidine] could not 

 find neosine in fresh meat and doubted whether it is present in faultless 

 meat extract. Ackermann and Kutscher [1907, 4, Ch. Ill, betaine] 

 afterwards isolated the base from a commercial extract of shrimps 

 which is the most abundant source. They [1908] found that tri- 

 methylamine is given off on heating and accordingly surmised that 

 neosine is a homologue of choline, but various attempts to identify it 

 with synthetic choline homologues have failed, including the most re- 

 cent and thorough attempt of Berlin [1911] who found that Kutscher's 

 neosine was contaminated with choline. 



The uncertainty with regard to this base is shown by the various melting points ascribed 

 to the aurichloride. Kutscher found 202-205 ; Kutscher and Ackermann 205 ; Engeland 

 [1908, i] for the base from meat extract 150-152 ; Berlin, after freeing the crude neosine 

 from choline, obtained a few grams of a gold salt melting at 244-245 from 6 kilos, of 

 Liebig's extract of meat. 



Berlin has also reinvestigated the synthetic homocholines of previous authors and con- 

 cludes that Morley, Weiss, Partheil and more recently Malengreau and Lebailly [1910] 

 obtained 0-homocholine (CH 3 ) 3 N(OH) . CH, . CHOH . CH 8 of which the aurichloride 

 melts at 163-164. 



By the action of trimethylamine on trimethylene chlorohydrin CH 2 C1 . CH 2 . CH a OH and 

 (less readily) by the methylation of 7-amino-propylalcohol Berlin [1910, 2, 1911] prepared 

 7-homocholine (CH 3 ) 3 N(OH) . CH 2 . CH 2 . CH 2 OH which yields an aurichloride crystallising 

 in leaflets and melting at 193, a mercurichloride C 6 H J6 ONC1 . 6HgCl 2> mp. 208, and a picrate 

 exploding at 255. The constitution of this base follows from its oxidation to homo-betaine 

 (CH 8 ) 3 N(OH) . CH 3 . CH 2 . COOH, and since it does not contain an asymmetric carbon atom, 

 neosine, which is optically inactive, was at first regarded as identical with it. But the melting 

 points of neosine aurichloride (244-245) and of neosine mercuric chloride C 6 H 16 ONC1 . 6HgCl 2 

 (252) render this hypothesis untenable. The physiological action of y-homocholine is similar 

 to that of choline but slightly more intense (Berlin [1910, I, 1911]). 



Addendum to Muscarine. 



While this book was in the press Dr. H. H. Dale and Mr. A. J. Ewins have, according 

 to a private communication, established that the />s<?wdo-muscarine of Schmiedeberg and 

 Harnack and of Schmidt and Nothnagel is not an aldehyde at all, but the nitrous acid ester 

 of choline. The platinichloride has the formula [(CH 3 ) S N . CH a . CH 2 ONO] 2 PtCl 8 , instead 

 of [(CH 3 ) 3 N . CH 2 . CH(OH) 2 ] 2 PtCl 6 . 2H 2 O. This explains why no water of crystallisa- 

 tion is given off at 100 ; the loss of weight at 130 is due to decomposition. The percent- 

 age composition required by the two formulae is very similar, except as regards nitrogen, 

 the estimation of which presents difficulties here. This discovery further disposes of the 

 inherent improbability that two hydroxyls should be attached to the same carbon atom ; 

 such an arrangement has so far only been observed in compounds in which the carbon atom 

 is attached to negative groups, as in chloral hydrate, mesoxalic acid and triketohydrindene 

 hydrate. An analogy for the great modification of the physiological action of choline by 

 esterification is to be found in the case of acetyl choline, p. 63, and of the nitric acid ester, 

 p. 153. In its action the latter, according to Dale and Ewins, resembles natural muscarine 

 even more closely than does the nitrous acid ester. (Comp, Proc. Physiol. Soc., March 

 14, 1914.) 



