title: Geometry of the dry-state oligomerization of 2',3'-cyclic phosphates.
abstract: Evaporation of a solution of thymidine plus either the exo or the endo diastereomer of uridine cyclic 2',3'-O, O-phosphorothioate (U greater than p(S) in 1,2-diaminoethane hydrochloride buffer gave the 2',5' and 3',5' isomers of (P-thio) uridylylthymidine (Up(S)dT) in a ratio of 1:2 with a combined yield of about 20%. These isomers were re-converted to U greater than p(S) and dT by a reaction that is known to proceed by an in-line mechanism. Both the 2',5' and 3',5' isomers gave as product the same diasteromer of U greater than p(S) that had been used originally in their formation. These dry-state 'prebiotic' reactions (Verlander, Lohrmann, and Orgel 1973) are thus shown to be stereospecific, and both the 2',5' and 3',5' internucleotide bonds are formed by an in-line mechanism.
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D009712:Nucleotides, Cyclic; D009841:Oligonucleotides; D013237:Stereoisomerism; D013936:Thymidine; D014500:Uracil Nucleotides
chemical_list: D009712:Nucleotides, Cyclic; D009841:Oligonucleotides; D014500:Uracil Nucleotides; D013936:Thymidine