1-(1-NAPHTHYL)-2-THIOUREA Chemical Properties

Melting point:

193 °C

Boiling point:

377.6±25.0 °C(Predicted)

Density 

1.333

refractive index 

1.5500 (estimate)

storage temp. 

Poison room

solubility 

4.3 and 86 g/L in acetone and triethylene glycol, respectively (Windholz et al., 1983)

pka

13.12±0.70(Predicted)

form 

Crystals or Crystalline Powder

color 

Grayish to beige-brown

Odor

bitter taste

Water Solubility 

600 mg/L at 20 °C (quoted, Windholz et al., 1983)

Merck 

14,722

BRN 

778118

Exposure limits

NIOSH REL: TWA 0.3 mg/m3, IDLH 100 mg/m3; OSHA PEL: TWA 0.3 mg/m3

CAS DataBase Reference

86-88-4(CAS DataBase Reference)

IARC

3 (Vol. 30, Sup 7) 1987

EPA Substance Registry System

.alpha.-Naphthylthiourea (86-88-4)

Safety Information

Hazard Codes 

T+

Risk Statements 

28-40

Safety Statements 

28-36/37-45-25-23

RIDADR 

1651

WGK Germany 

2

RTECS 

YT9275000

TSCA 

Yes

HazardClass 

6.1

PackingGroup 

I

HS Code 

29309090

Hazardous Substances Data

86-88-4(Hazardous Substances Data)

Toxicity

Acute oral LD50 for Norwegian rats 6–8 mg/kg (Hartley and Kidd, 1987).

MSDS

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1-(1-NAPHTHYL)-2-THIOUREA Usage And Synthesis

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.

Chemical Properties

greyish to beige-brown crystals or cryst. powder

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.

Chemical Properties

ANTU is a noncombustible, white crystalline solid or gray powder. Odorless.

Physical properties

Colorless crystals when pure. Technical product is grayish-blue. Odorless solid. Bitter taste.

Uses

Rodenticide

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.

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.

Air & Water Reactions

Slightly soluble in water.

Reactivity Profile

1-(1-NAPHTHYL)-2-THIOUREA is incompatible with the following: Strong oxidizers, silver nitrate .

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.

Fire Hazard

Emits sulfur dioxide, oxides of nitrogen, and carbon monoxide fumes upon decomposition. 1-(1-NAPHTHYL)-2-THIOUREA reacts with silver nitrate and strong oxidizers. Avoid decomposing heat.

Safety Profile

Poison by ingestion and intraperitoneal routes. Moderately toxic to humans by an unspecified route. Questionable carcinogen with experimental tumorigenic data. Mutagenic data. A rodenticide used extensively. Death is caused by pulmonary edema. Chronic toxicity has been known to cause dermatitis and a decrease in the white blood cells. When heated to decomposition it emits toxic fumes of NOx and SOx.

Potential Exposure

ANTU or its formulations are used as a rodenticide.

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)

storage

α-Naphthalene thiourea should be kept stored in a tightly closed container in a locked poison room, in a cool, dry, well-ventilated area away from incompatible substances.

Shipping

UN1651 Naphthylthiourea, Hazard Class: 6.1; Labels: 6.1-Poisonous materials.

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.

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.

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.

Precautions

Workers should use/handle α-naphthalene thiourea with adequate ventilation. During use, dust generation and accumulation should be minimum, and avoid contact with the eyes, skin, and clothing.

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