Adenine Synthesis in Interstellar Space: Mechanisms of Prebiotic
Pyrimidine Ring-Formation in Monocyclic HCN-Pentamers

Rainer Glaser, Brian Hodgen, Dean Farrelly, and Elliott McKee

Department of Chemistry, University of Missouri-Columbia, Columbia, Missouri, 65211 (USA)

The free CHIME plugin is required for the display of the pdb files of the following structures.

FIG. 4. Molecular models of the stationary structures along the paths 8 to TS(8,(E)-9) to (E)-9, of
8 to TS(8,(Z)-9) to (Z)-9, and along (E)-9 to TS((E)-9,10) to 10.

FIG. 6. Molecular models of mono- and bicyclic HCN-pentamers: Formamidines 6a, 5a and 5b (top row),
keteneimines 7b and 7c (center row), and pentamers (E)-2, (Z)-2, and adenine 1 itself.

Animation I: Formation of (E)-2.

Animation II: Formation of (Z)-2.

Animation III: Proton-Transfer from (Z)-2 to 10.

Animation IV = II + III: Sequence involving Formation of (Z)-2 and Subsequent Proton-Transfer to form 10.