Synthesis of purines under possible primitive earth conditions

On the Interaction of Adenine With Ionizing Radiation: Mechanistical Studies and Astrobiological Implications

“…The pioneering work of Miller (1953) provided the first evidence that complex organics (amino acids, sugars, and nu-cleic acid precursors) could potentially be created by electric discharge in a primordial Earth-like environment and was the motivation for many successive experiments in the following decades. The synthesis of adenine (C 5 N 5 H 5 ; Figure 1) from concentrated ammonium cyanide solutions, heated to 80 • C-90 • C, was first demonstrated by Oró (1960) and Oró & Kimball (1962). Since then, numerous studies have reported nucleobase formation under various terrestrial conditions (Ponnamperuma et al 1963;Levy & Miller 1999;Saladino et al 2001;Hill & Orgel 2002;Borquez et al 2005); however, due to low yields and susceptibility to hydrolysis (Shapiro 1995;Levy & Miller 1998), the accumulation of a large quantity of terrestrially synthesized nucleobases remains troublesome.…”

Chemical evolution: The mechanism of the formation of adenine under prebiotic conditions

“…However, clues are provided by four putative intermediates detected in the product mixtures ( Fig. 1): formamidine, 2,3-diaminomaleonitrile (DAMN), 4-amino-5-cyanoimidazole (4-aminoimidazole-5-carbonitrile; AICN) (10,11,(13)(14)(15), and 4-aminoimidazole-5-carboxamidine (9,11).…”

Rewarming the Primordial Soup: Revisitations and Rediscoveries in Prebiotic Chemistry

“…Chronology of selected historically innovative one-pot and multistep syntheses of nucleic acid building blocks. Oró (1960): [3a] ammonium hydroxide, HCN,H 2 Oa t9 08C. Orgel(1966): [4] step 1: formamidine, NH 2 CH(CN) 2 ,EtOH at reflux;step 2: imidazole intermediate, formamidine, methylc ellosolve at reflux.…”