thiosemicarbazide

Chemical properties

Thiosemicarbazide is an odorless, white crystalline powder.

The Uses of thiosemicarbazide

The thiosemicarbazide derivative (fluorescein-5-thiocarbamoylhydrazide) is a hydrazide derivative of fluorescein that spontaneously reacts with molecules containing aldehydes or ketones to form covalent hydrazone linkages. It is also used to detect metals. It is also used in photography. In addition, it is effective in controlling bacterial leaf blight of rice. In addition, it is used in the preparation of 1,3,4-thiadiazole.

What are the applications of Application

Thiosemicarbazide is a useful precursor that has been widely used in heterocyclic synthesis. They react with systems containing C=O and C=N groups and can be used to prepare biologically active compounds (e.g., pyrazoles, thiazoles, triazoles, thiadiazoles, oxadiazoles, triazines, and thiadiazines). From the point of view of biological activity, thiosemicarbazide derivatives are useful intermediates and subunits for the development of molecules with pharmaceutical or biological uses.

Definition

ChEBI: Hydrazinecarbothioamide is a member of the class of thioureas that is thiourea in which a hydrogen of one of the amino groups is replaced by an amino group. It is a member of hydrazines, a thiocarboxamide and a member of thioureas.

Synthesis

The synthesis of thiosemicarbazides may be carried out in several ways. The general method involves the preparation of thiosemicarbazides by nucleophilic additions of amines or carbohydrazides to isothiocyanates or carbon disulfide.

General Description

Thiosemicarbazide is a white crystalline powder and is odorless. It is used as a reagent for ketones and certain metals, for photography and as a rodenticide. It is also effective for control of bacterial leaf blight of rice. Not a registered pesticide in the U.S. N-Aminothiourea is a chemical intermediate for herbicides and a reagent for detection of metals.

Reactivity Profile

Isocyanates and thioisocyanates are incompatible with many classes of compounds, reacting exothermically to release toxic gases. Reactions with amines, aldehydes, alcohols, alkali metals, ketones, mercaptans, strong oxidizers, hydrides, phenols, and peroxides can cause vigorous releases of heat. Acids and bases initiate polymerization reactions in these materials. Some isocyanates react with water to form amines and liberate carbon dioxide. Base-catalysed reactions of isocyanates with alcohols should be carried out in inert solvents. Such reactions in the absence of solvents often occur with explosive violence, [Wischmeyer(1969)].

Health Hazard

N-Aminothiourea is highly toxic by ingestion. May induce goiter and cause delayed toxic effects in blood and skin. May be mutagenic in human cells.

Fire Hazard

When heated to decomposition, very toxic fumes of sulfur oxides and nitrogen oxides are emitted.

Flammability and Explosibility

Non flammable

Safety Profile

Poison by ingestion, intraperitoneal, and intravenous routes. Questionable carcinogen with experimental tumorigenic data. Human mutation data reported. When heated to decomposition it emits very toxic fumes of NOx and SOx.

Potential Exposure

Thiosemicarbazide is a dithiocarbamide compound is used as an intermedialte for pharmaceuticals and herbicides; as a reagent for ketones and certain metals; in certain photography and dye operations; as a rodenticide. It is also effective for control of bacterial leaf blight of rice.

Shipping

UN2771 Thiosemicarbazide, pesticides, solid, toxic, Hazard Class: 6.1; Labels: 6.1-Poisonous materials. UN2811 Toxic solids, organic, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required.

Purification Methods

Crystallise thiosemicarbazide from H2O (solubility is 20.3% w/w at 80o). The hydrochloride has m 190-191o(dec, 184o also reported). It forms salts with heavy metals. [Beilstein 3 H 195, 3 I 79, 3 II 134, 3 III 315, 3 IV 374.]

Incompatibilities

Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.) and strong reducing agents; contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides. May react with nitrates.