Purines, Pyrimidines, and Other Basic N-Compounds

Adenine, guanine, guanylurea, and several s-triazines and ureas have been detected in HCl-extracts of Orgueil and Murchison (Hayatsu, 1964 Hayatsu et al, 1968, 1975). The first 3 were confirmed by Stoks and Schwartz (1981), but the s-triazines were not they may have formed from guanylurea in the isolation and identification procedure. Other compounds detected are xanthine, hypoxanthine, and uracil (van der Velden and Schwartz, 1977 Stoks and Schwartz, 1979). A report of 4-hydroxy-pyrimidine and several related compounds (Folsorae et al, 1973) was not confirmed (Hayatsu et al, 1975 van der Velden and Schwartz, 1977) these compounds, which 

Basic nitrogen compounds form in FTT reactions in the presence of NHj (Fig. 6). In the early experiments, the temperature was briefly raised to 500-700 °C (Hayatsu et al., 1968, 1972 Yang and Oro, 1971), but this may not be necessary, at least with a montmorillonite catalyst (Anders et al., 1974). The reaction mechanism is obscure, but probably involves reactive intermediates such as HCN, nitriles, or acetylenes (Hayatsu et al., 1968, 1972 Anders et al., 1974). It is not clear whether a liquid water phase, as generally formed in the cold neck of the vessel, is e ntial. A detail, systematic study of this reaction would be very desirable, to see what conditions are required, and whether they are realistic for the solar nebula. 

The Miller-Urey reaction has been notably less successful in producing N-hetero-cyclics. Only adenine has thus far been made, by electron irradiation of CH, NHj, HjO, and Hj (Ponnamperuma et al., 1963). The yield was only 0.01 %. Better success was achieved by reactions involving unstable reactants, such as HCN (Lemmon, 1970), but the reactions, being spontaneous, actually are related no less to FTT than to Miller-Urey reactions (Sec. 3.3). 

Hayatsu et al. (1975) suggested the presence of aliphatic amines in Murchison, but did not identify individual compounds. Jungclaus et al. (1976) found that at least 10 aliphatic amines (Cj-C ), including 8 primary amines, were present in Murchison extracts. Several aliphatic amines have been seen in FTT syntheses (Kolbel and Trapper, 1966 Yoshino et al., 1971 Anders et al., 1974), but thus far not in the Miller-Urey synthesis. 

Nucleotide Boses Mode by Fische-Tropsch -Type Synthesis 

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