Chemical Properties
Alpha-naphthylthiourea (α-naphthalene thiourea) is a pure white or beige-brown solid/
blue-gray powder. It is hard to dissolve in water, acid, and general organic solvents, but
dissolves in boiling ethanol and alkaline solution. On decomposition, ANTU releases carbon
monoxide, toxic and irritating fumes and gases, and carbon dioxide. It is a rodenticide
and a poison bait to lure rodents.
General Description
White crystal or powder; technical product is gray powder. Has no odor but a bitter taste. Used primarily as a rodenticide for control of adult Norway rats. Not produced commercially in the U.S.
Reactivity Profile
ANTU(86-88-4) is incompatible with the following: Strong oxidizers, silver nitrate .
Air & Water Reactions
Slightly soluble in water.
Hazard
Toxic by ingestion
Health Hazard
Moderately toxic: probable oral lethal dose (human) 0.5-5 gm/kg, or between 1 ounce and 1 pint (or l lb.) for 150 lb. person. Chronic sublethal exposure may cause antithyroid activity. Can produce hyperglycemia of three times normal in three hours. People with chronic respiratory disease or liver disease may be especially at risk.
Health Hazard
α-Naphthalene thiourea, a rodenticide, is very toxic and is fatal if swallowed. Exposures
to ANTU cause poisoning with symptoms that include, but are not limited to, headache,
weakness, dizziness, shortness of breath, cyanosis, blood abnormalities, methemoglobinemia,
irritation of the digestive tract, liver and kidney damage, cardiac and CNS
disturbances, convulsions, tachycardia, dyspnea, vertigo, tinnitus, weakness, disorientation,
lethargy, drowsiness, and fi nally coma and death. The target organs include the
blood, kidneys, CNS, liver, lungs, cardiovascular system, and blood-forming organs.
Potential Exposure
ANTU or its formulations are used as
a rodenticide.
Fire Hazard
Emits sulfur dioxide, oxides of nitrogen, and carbon monoxide fumes upon decomposition. ANTU reacts with silver nitrate and strong oxidizers. Avoid decomposing heat.
First aid
If this chemical gets into the eyes, remove any
contact lenses at once and irrigate immediately for at least 15 minutes, occasionally lifting upper and lower lids. Seek
medical attention immediately. If this chemical contacts the
skin, remove contaminated clothing and wash immediately
with soap and water. Seek medical attention immediately.
If this chemical has been inhaled, remove from exposure,
begin rescue breathing (using universal precautions, including
resuscitation mask) if breathing has stopped and CPR if
heart action has stopped. Transfer promptly to a medical
facility. When this chemical has been swallowed, get medical
attention. Give large quantities of water and induce
vomiting. Do not make an unconscious person vomit.
Medical observation is recommended for 24 to 48 hours
after breathing overexposure, as pulmonary edema may be
delayed. As first aid for pulmonary edema, a doctor or
authorized paramedic may consider administering a drug or
other inhalation therapy.
Shipping
UN1651 Naphthylthiourea, Hazard Class: 6.1;
Labels: 6.1-Poisonous materials.
Incompatibilities
Incompatible with oxidizers (chlorates,
nitrates, peroxides, permanganates, perchlorates, chlorine,
bromine, fluorine, etc.); contact may cause fires or explosions.
Keep away from alkaline materials, strong bases,
strong acids, oxoacids, epoxides, silver nitrate.
Description
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.
Waste Disposal
Incinerate in a furnace
equipped with an alkaline scrubber. Consult with environmental
regulatory agencies for guidance on
acceptable disposal practices. Generators of waste containing
this contaminant (≥100 kg/mo) must conform with
EPA regulations governing storage, transportation, treatment,
and waste disposal.
Physical properties
Colorless crystals when pure. Technical product is grayish-blue. Odorless solid. Bitter taste.
Uses
ANTU an organosulfur is a derivative of thiourea. It is a singledose
rodenticide that is specifically used against Norway rats as
a bait. However, it is futile against all other species of rodents.
Because of its tendency to cause resistance and specificity only
toward Norway rodents, this poison rapidly lost popularity and
is no longer manufactured in the United States.
Uses
Rodenticide. Specific control for the adult Norway rat; less toxic to other rat species.
Definition
ChEBI: ANTU is a member of naphthalenes.
Carcinogenicity
ANTU was not carcinogenic in rodent
feeding studies.4 Cases of bladder tumors
among rat catchers exposed to ANTU have
been attributed to b-naphthylamine, a manufacturing
impurity of ANTU. In bacterial
assays ANTU induced mutations.
Environmental Fate
Chemical/Physical. The hydrolysis rate constant for ANTU at pH 7 and 25°C was
determined to be 8 × 10–5/hour, resulting in a half-life of 361 days (Ellington et al., 1988)
Emits very toxic fumes of nitrogen and sulfur oxides when heated to decomposition
(Lewis, 1990)
Purification Methods
Crystallise ANTU from EtOH. [Beilstein 12 III 2941, 12 IV 3086.]
Toxicity evaluation
ANTU toxicity in the rat is thought to depend on metabolic
activation via the hepatic and lung microsomal enzymes. Two
important metabolites are formed: ANU and atomic sulfur.
ANTU pulmonary toxicity may result, in part, from covalent
binding of sulfur or a metabolite containing carbonyl carbon of
ANTU to macromolecules of liver and lung microsomes. The
covalent binding of atomic sulfur released in the cytochrome
P450 monooxygenase-catalyzed metabolism of thiono-sulfur
compounds is responsible for monooxygenase activity being
inhibited. Damage to liver and possibly lung edema and
neoplasia result from the covalent binding of the electrophilic
S-oxides, S-dioxides or carbene derivatives of these S-oxides
and S-dioxides to tissue macromolecules.
However, it is not known if these metabolites are seen in
humans. ANTU is believed to act on certain enzyme systems
involving the sulfhydryl group similar to other sulfhydryl
inhibitors, such as alloxan, iodoacetamide, and oxophenarsine,
which cause pulmonary edema. Hence the mechanism
of action of causing pulmonary edema from the toxic
effects of these sulfhydryl inhibitors and ANTU is assumed to
be similar. Additionally, ANTU-induced lung damage has
been linked to the formation of oxygen free radicals produced
via the cyclooxygenase pathway. Following exposure to
ANTU, there are a number of biochemical events, such as
alteration in carbohydrate metabolism, adrenal stimulation,
and interaction of the chemical with sulfhydryl groups, but
none of these appear to bear any relationship to the observed
signs of toxicity.