Glycolonitrile oligomerization:  structure of isolated oxazolines, potential heterocycles on the early earth.
A study of glycolonitrile polymerization has led to the isolation and characterization of two 2,5-dihydro-4-aminooxazoles, 4 and 5. Previous reports have misassigned these structures as s-triazines or pyrimidines. X-ray diffraction analysis of crystals of 4 and an acetylated oxazole derivative of 5 (6) confirm the proposed structures. Ab initio computations are used to assess the relative thermodynamic stability of three trimer isomers (an s-triazine, an aminohydroxypyrimidine, and an aminooxazoline), and the results indicate that 4 is a novel kinetic product. Mechanistic considerations rationalize kinetic oxazole formation over the more customary triazine or pyrimidine trimers.
Arrhenius
G
G
Department of Chemistry, University of California, San Diego, La Jolla 92093-0358, USA.
Baldridge
K K
KK
Richards-Gross
S
S
Siegel
J S
JS
D000097:Acetonitriles / Q000138:chemical synthesis*; D003460:Crystallization; D018534:Earth, Planet; D019418:Evolution, Chemical; D005557:Formaldehyde / Q000737:chemistry*; D006860:Hydrogen Bonding; D006856:Hydrogen Cyanide / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010080:Oxazoles / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D013696:Temperature; D014961:X-Ray Diffraction
D000097:Acetonitriles; D010080:Oxazoles; D011108:Polymers; D005557:Formaldehyde; D006856:Hydrogen Cyanide; C035740:glycolonitrile