Cyanamide mediated syntheses under plausible primitive earth conditions

Abstract

The synthesis of palmitoylglycerols in good yields occurs when a solution of glycerol, ammonium palmitate, cyanamide and imidazole is dried and heated at ambient humidity at temperatures ranging from 60 degrees--100 degrees C for 16 h. Much less product is formed in the absence of either or both cyanamide or imidazole. This work suggests that acylglycerols could have been synthesized on the primitive Earth under plausible prebiotic conditions which were similar but not identical to those which have been shown to condense deoxynucleotides into oligodeoxynucleotides and amino acids into peptides.

Cyanamide mediated syntheses under plausible primitive earth conditions

“…This study indicates that under drying conditions similar to those used for the polymerization of nucleotides , and acylglycerols (Eichberg et al, 1977), amino acids condense to yield di-and in some cases higher peptides.…”

“…Using a cyanamide, 4-amino-5-imidazolecarboxamide system we synthesized p1, p2_dideoxythymidine 5'-pyrophosphate from deoxythymidine 5'-phosphate and deoxythymidine oligonucleotides from deoxythymidine 5'-phosphate and deoxythymidine 5'-triphosphate. Acylglycerols were synthesized from a glycerol, ammonium palmitate, cyanamide, imidazole system (Eichberg et al, 1977). Under similar dehydrating conditions, cyanamide has been used as a condensing agent in the phosphorylation of nucleosides with apatite (Schwartz, 1972).…”

Cyanamide mediated syntheses of peptides containing histidine and hydrophobic amino acids

“…Peptides such as these would have to be tested for catalytic activity in plausible prebiotic reactions. Previous work (Ibanez et al 1971;Lohrmann and Orgel 1973;Sawai et al 1975;Eichberg et al 1977;Schwartz 1972;Weber et al 1977;Lacey and Weber 1974;) has implicated a catalytic role for imidazole in plausible prebiotic reactions. Thus a simple histidyl peptide (or other similar catalytic peptides) could have catalyzed further prebiotic reactions, and so provided the link for the transition from prebiotic reactions catalyzed by organic catalysts to reactions catalyzed by simple peptides.…”

“…It has been found to be more effective under evaporating conditions at moderate temperatures Nooner et al 1977) in promoting peptide synthesis. It has also been used in a variety of other possible prebiotic condensation reactions, such as the synthesis of deoxythymidine oligonucleotides , the synthesis of acylglycerols (Eichberg et al 1977), the synthesis of phosphatidic acids , and the phosphorylation of nucleosides with apatite (Schwartz 1972). All of these findings indicate that cyanamide may have been present on the primitive earth in sufficient supply to participate in a wide variety of prebiotic condensation reactions.…”

The Influence of Environmental Conditions, Lipid Composition, and Phase Behavior on the Origin of Cell Membranes

“…Phospholipids can form abiotically when fatty acids, glycerin, and phosphate are moderately heated (65°C) to dryness. While complex phospholipids can be synthesized under hypothetical early-Earth conditions (Hargreaves et al 1977;Hargreaves and Deamer 1978;Eichberg et al 1977;Epps et al 1978Epps et al , 1979Rao et al 1982Rao et al , 1987, have pointed out that the simultaneous presence of fatty acids, glycerol, and phosphate on the early Earth is highly unlikely. The relevance of a reaction requiring complete dehydration under early-Earth conditions is also questionable.…”