Ethanimine is an organonitrogen compound classified as an imine. It is not well known terrestrially, but has been detected in abundance towards Sagittarius B2 (Sgr B2), a dense interstellar cloud in between stars towards the galactic center of the Milky Way. The distance between the Sgr B2 cloud and center of galaxy is 100 pc (1 pc=3.26l y). Ethanimine is mainly found in hot cores of ISM clouds; in case of Sgr B2, the region would be the Sgr B2 N and Sgr B2 M. The radio telescopes such as the Green Bank Telescope and NRAO (measures radio frequency light lambda ranging from 1–300 GHz) are able to detect organic molecules such as ethanimines because its internal energy transition, more specifically the rotational transition is within the radio frequency of 14085 MHz=140.8 GHz.
It has 2 tautomers: ethanimine and aminoethylene, an amine. Ethanimine places the extra hydrogen on the carbon, while aminoethylene has it on the nitrogen atom.