Cytosine and uracil, which are components of RNA molecules, were obtained f
rom complex organic matter produced by quenching a CO-N-2-H2O high-temperat
ure plasma. The carbon yields of cytosine and uracil were 0.01% and 0.08%,
respectively, which were almost as much as those of amino acids. It was und
erstood that processes of high activation and rapid quenching, which may be
found in meteoritic impact or lightning, are important for the formation o
f bioorganic compounds from the CO-N-2-H2O gas mixture.