ISSN 00310301, Paleontological Journal, 2013, Vol. 47, No. 9, pp. 1093–1096. © Pleiades Publishing, Ltd., 2013. 1093 INTRODUCTION The question of reaction conditions, in which bio logically significant organic compounds (amino acids, sugars, nucleotides, etc.) could have selectively been synthesized from elementary substrates at prebiotic developmental stages of the biosphere, is widely dis cussed. Terrestrial ponds, thermal springs, space dust, comets, and even protoplanet circumstellar disk were proposed among possible objects that could have been “reactors” for prebiotic synthesis. Therefore, the study of chemical transformations of elementary com pounds, yielding biologically significant substances, enables the revelation of conditions, in which this syn thesis provides a rather large yield and, hence, supple mentary arguments for certain models of prebiotic chemical evolution. It has been generally accepted for a long time that the most probable way of the synthesis of carbohy drates from the simplest C 1 substrate is the formose reaction of condensation of formaldehyde (FA) in the presence of Ca(OH) 2 to give sugars. The presence of FA in prebiotic conditions seems rather probable; the lowtemperature interaction of amorphous carbon with water results in the formation of hydroxymethyl ene, isomerization of which produces FA (Ahmed et al., 1983). However, a distinctive feature of the clas sical formose reaction is simultaneous synthesis of sev eral dozen products, including linear and branched sugars, organic acids, and polyols (Medvedeva et al., 1983; Partridge et al., 1972). In addition, the reaction mixture rapidly becomes yellowish brown (Riccardo et al., 2004) as a result of polymerization, dehydra tion, and destruction of carbohydrates. The low selec tivity of this process casts doubt on the possibility that it could have yielded biologically significant carbohy drates in sufficient concentration for further chemical reactions, such as synthesis of ATP, nucleic acids, polysaccharides, etc. As was previously shown, the selectivity of synthe sis of monosaccharides increases as the reaction occurs in alkalescent medium and in the absence of Ca 2+ ions (Simonov, 2007). As a result of condensation of FA with lower monosaccharides, i.e., glycolic (GA) and glyceric (GCA) aldehydes, and dihydroxyacetone (DHA), the formation of erythrulose and 3pentulose with the total yield ca. 75% was observed (Delidovich et al., 2009; Simonov et al., 2007a, 2007b). Monosaccharides of the aldopentose class (ribose, xylose, arabinose, lyxose) are stereoisomers differing in spatial arrangement of hydroxyl and hydrogen groups. In modern biochemistry, aldopentoses play an important role, being the building blocks of polysac charides, glycosides, natural gums, and slime; ribose, which is included in ATP and RNA, is of particular importance. In the present study, the possibility of synthesis of aldopentoses in a high yield in abiogenic conditions by catalytic condensation of GA with FA is analyzed. The reaction of GA and FA was investigated in the pres ence of homogeneous (phosphates, borates) and het erogeneous (montmorillonites, apatite) catalysts, a sufficient amount of which could have been present on Plausible Prebiotic Synthesis of Aldopentoses from Simple Substrates, Glycolaldehyde and Formaldehyde I. V. Delidovich a , O. P. Taran b , and V. N. Parmon c a Boreskov Institute of Catalysis, Siberian Branch, Russian Academy of Sciences, pr. akademika Lavrent’eva 5, Novosibirsk, 630090 Russia b Novosibirsk State Technical University, pr. K. Marksa, 20, Novosibirsk, 630073 Russia c Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090 Russia email: div@catalysis.ru Received February 15, 2012 Abstract—Possible ways of abiotic catalytic synthesis of biologically significant aldopentoses (ribose, xylose, arabinose, lyxose) from elementary substrates, i.e., formaldehyde (FA) and glycolaldehyde (GA) in aqueous solutions are discussed. Conditions in which the process of synthesis of pentoses yields up to 65% relative to the initial concentration of GA: homogeneous borate catalyst NaOH + H 3 BO 3 , pH 9, [GA] 0 5 mM, [FA] 0 50–100 mM have been found. Keywords: prebiotic synthesis, aldopentoses, formaldehyde, borates, minerals DOI: 10.1134/S0031030113090062