BIOCHEMICALLY IMPORTANT COMPOUNDS 203 



The question of the possibility that amino acids might 

 have been formed under conditions similar to those which 

 prevailed in the primitive hydrosphere has recently been 

 studied by S. Fox/®^ He showed that in a medium resembling 

 a natural hot spring (an aqueous medium containing calcium 

 salts at pH 80 - 90 and at a temperature of 100 - i20°C) the 

 interaction of malic acid and urea gives rise to the formation 

 of aspartic acid and, what is specially interesting, to ureido- 

 succinic acid. 



We must now turn our attention to the question of the 

 possibility of the primary abiogenic formation of nucleosides 

 and nucleotides, in view of the extremely important part 

 played by polynucleotides and, in particular, nucleic acids 

 in the vital processes of organisms. As concerns the possi- 

 bility of the formation of pyridine from acetylene and hydro- 

 cyanic acid Berthelot established the following equation: 



H 



CH KC^ CH 



2 III +HCN^ I II 



CH HCy yCH 



According to the results of Chichibabin, Ishigura, Ellis 

 and others, pyridine and pyrimidine bases can easily arise 

 from ammonia and unsaturated hydrocarbons. 



Urea can also serve as the starting substance for the prim- 

 ary formation of pyridine and pyrimidine bases, and the 

 urea itself can arise either from ammonium cyanate (as in 

 Wohler's synthesis) or, as we have already shown, by the 

 combination of carbon monoxide and ammonia in silent 

 electric discharges. 



The first synthesis of uric acid was carried out as early as 

 1882 by I. Gorbachevskii by heating urea with glycerine. 

 Numerous syntheses of purines and pyrimidine bases have 

 been brought about by the condensation of urea with organic 

 acids. For example, uracil was obtained by D. Davidson and 

 O. Baudisch^'*^ by condensing urea with malic acid. An 



