a-Naphthylthiourea (ANTU; also called DIRAX) is toxic by
inhalation, ingestion, or skin contact. Due to its very narrow
spectrum of activity, production was discontinued a long time
ago. Exposure to ANTU causes pulmonary edema; therefore, it
is often used as an experimental pneumotoxin. ANTU is a graycolored,
prism-shaped, odorless powder with a bitter taste. It
has a molecular weight of 202.28 and melting point of 200 ℃
and does not ignite readily. However, on interaction with
potential oxidizing agents, it may cause fire and explosions,
which can lead to hazardous decomposition products such as
sulfur dioxide, nitrogen dioxide, and carbon monoxide. The
structure of ANTU contains the naphthalene chromophore,
which absorbs UV light at ～311 nm. This suggests that ANTU
can undergo photolysis.
