212 AMINO-COMPOUNDS 



C 2 H 3 (NH 2 ) - co OH" * s f un ^ m tne J u * ce ^ tne as P ar agus, in many 

 fruits, roots and tubers, in the young shoots of vetches, beans, peas, 

 etc. Asparagine crystallises in prisms with one molecule of water. 

 It has a cooling, unpleasant taste, and is soluble in about 80 parts 

 of water. By boiling with alkalies or other bases, aspartic acid or 

 amino-succinic acid, C.,H 3 (NH 2 )(COOH) 2 , is formed, with evolution 

 of ammonia. 



Dilute hydrochloric acid produces the same acid and ammonium 

 chloride, the nitrogen of the amide ( CONH 2 ) group being converted 

 into ammonia. This is a general reaction with amides. 



2. Glutamine, amino-glutamic acid, NH 2 .CO.C 3 H 5 (NH 2 ).COOH, is 

 found in beetroot, in the shoots of the vetch and in the pumpkin. It 

 crystallises in slender white needles, which contain no water of crys- 

 tallisation. It is very soluble in hot water, but insoluble in absolute 

 alcohol. 



3. Choline, hydroxyethyl - trimethyl - ammonium hydroxide, 

 C 2 H 4 (OH).N(CH 3 ) 3 .OH, occurs in cotton seed, in beets, in hops and 

 in many other plants. It is a syrupy liquid with a strong alkaline 

 reaction. It appears to possess poisonous properties, which are some- 

 times apparent when cotton seed is used as a food for very young 

 animals. It forms a characteristic reddish yellow crystalline compound 

 with platinum tetrachloride, (C H 14 ON) 2 PtCl (5 . 



4. Betaine, inner anhydride of trimethyl glycocoll, is said to have 

 the composition 



CH 2 



CO N(CH 3 ) 3 

 \/ 

 O 



It is found in beet juice, in mangolds and in cotton seed. It is 

 formed by the oxidation of choline. It crystallises with one molecule 

 of water. 



Many derivatives of betaine have been prepared artificially * and 

 one trigonelline, occurs in fenugreek. 2 Trigonelline has the consti- 

 tution 



CH 



HC C-CO 

 HC CH 



V I 



N O 



CH, 



5. Allantoin, C 4 H 6 N 4 O 3 , found principally in animal products, has 



1 Willstatter, Ber. 1902, 584; Jour. Chem. Soc., 1902, Abstracts, i. 266. 



2 Jahns, Ber. 1885, 2518 ; Jour. Chem. Soc., 1886, Abstracts, 85. 



