It is known that more than 140 interstellar and circumstellar molecules have so far been detected, mainly by means of the radio astronomy observations. Many organic molecules are also detected, including alcohols, ketons, ethers, aldehydes, and others, that are distributed from dark clouds and hot cores in the giant molecular clouds. It is believed that most of the organic molecules in space are synthesized through the grain surface reactions, and are evaporated from the grain surface when they are heated up by the UV radiation from nearby stars. On the other hand the recent claim on the detection of glycine have raised an important issue how difficult it is to confirm secure detection of weak spectra from less abundant organic molecules in the interstellar molecular cloud.
Recent topics regarding observations of organic molecules in the interstellar molecular clouds, including independent observations of glycine by the 45m radio telescope and a detection of amino acetonitrile (NH2CH2CN) that is a precursor to glycine.