Rhodium(II) carboxylates differ greatly in antitumor activity and toxicity depending on the properties of the carboxylate group (methoxyacetate, propionate, butyrate, etc.) involved. The solubility characteristics of rhodium(II) carboxylates correlate well with both the antitumor activity and toxicity that these compounds display. The amount of rhodium which is adsorbed by tumor cells in vitro also correlates with the partition coefficient of the rhodium(II) compounds studied. Survival and toxicity studies show rhodium(II) pentanoate to possess the highest therapeutic index against the Ehrlich ascites tumor strain and also show that lengthening the carboxylate R chain beyond the pentanoate reduces the drugs' therapeutic efficacy.

The formation of glycerol occurs when a solution of DL-glyceraldehyde is heated in the presence of hydrogen sulfide at room temperature. DL-glyceraldehyde and dihydroxyacetone treated with hydrazine, as well as DL-glyceraldehyde incubated with formaldehyde are also partially converted to glycerol. The yields of the above reactions are from approximately 1% to about 3%. The formation of glycerophosphates occurs when glycerol is heated with ammonium dihydrogen phosphate and either urea or cyanamide. The yield of glycerophosphates is about 30%, most of which is sn-glycero-1 (3)-phosphate. These findings indicate that glycerol and sn-glycero-3-phosphate, which are moieties of glycerolipids, could have been formed under conditions which may have prevailed on the primitive Earth.

A mixture of ammonium palmitate, 14C-sn-glycero-1(3)-phosphate, cyanimide and imidazole when heated for several hours formed significant quantities of phospholipids. These reaction products were shown by chromatographic, chemical and enzymatic procedures to be monopalmitoylglycerophosphate (MPGP), dipalmitoylglycerophosphate (DPGP) and monopalmitoyl cyclic glycerophosphate (cMPGP). A portion of the MPGP and DPGP possessed the same steric configuration as naturally occurring lysophosphatidic acid and phosphatidic acid. The yield of total phospholipid was maximal at temperatures between 60 degrees and 90 degrees after 8 h. When ratios of reactants were varied, up to 45% of radioactive glycerophosphate was converted into phospholipids. The average proportions of individual phosphatidic acids were: 60% MPGP, 27% DPGP and 13% cMPGP. Evidence was obtained for a synergistic relationship between cyanamide and imidazole in promoting the formation of phosphatidic acids. These results suggest that phosphatidic acids, which are essential precursors for the biochemical synthesis of more complex membrane phospholipids, could have been produced on the primitive Earth.

Peptides were formed in yields of 5%, 17% and 66%, respectively, when aqueous solutions of glycine, isoleucine or phenylalanine were dried and heated for 24 h at 90 degrees C with adenosine 5'-triphosphate, 4-amino-5-imidazolecarboxamide and cyanamide. Glycine and L-phenylalanine produced mixtures of di-, tri- and tetrapeptides, while L-isoleucine gave only the dipeptide in detectable quantities. The dipeptides of L-isoleucine and L-phenylalanine were identified by mass spectrometry and enzymatic and enzymatic degradation.

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.