Thioacetamide

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Thioacetamide
Structural formula of thioacetamide
Ball-and-stick model of the thioacetamide molecule
Names
IUPAC name
Thioacetamide
Preferred IUPAC name
Ethanethioamide
Other names
acetothioamide, TAA, thioacetimidic acid, TA, TAM
Identifiers
62-55-5 YesY
ChEBI CHEBI:32497 YesY
ChEMBL ChEMBL38737 YesY
ChemSpider 2006126 YesY
Jmol-3D images Image
KEGG C19302 N
PubChem 2723949
RTECS number AC8925000
UNII 075T165X8M YesY
Properties
C2H5NS
Molar mass 75.13 g/mol
Appearance colourless crystals, slight mercaptan odor
Density 1.269 g/cm3
Melting point 115 °C (239 °F; 388 K)
Boiling point decomposes
good
Structure
monoclinic
Hazards
Main hazards Foul stench, carcinogenic
Safety data sheet MSDS
R-phrases R22R36R37R45
S-phrases S45S53
Related compounds
Related compounds
acetamide, dithioacetic acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Thioacetamide is an organosulfur compound with the formula C2H5NS. This white crystalline solid is soluble in water and serves as a source of sulfide ions in the synthesis of organic and inorganic compounds. It is a prototypical thioamide.

Coordination chemistry[edit]

Thioacetamide was widely used in classical qualitative inorganic analysis as an in situ source for sulfide ions. Thus, treatment of aqueous solutions of many metal cations to a solution of thioacetamide affords the corresponding metal sulfide:

M2+ + CH3C(S)NH2 + H2O → MS + CH3C(O)NH2 + 2 H+ (M = Ni, Pb, Cd, Hg)

Related precipitations occur for sources of soft trivalent cations (As3+, Sb3+, Bi3+) and monovalent cations (Ag+, Cu+).

Preparation[edit]

Thioacetamide is prepared by treating acetamide with phosphorus pentasulfide as shown in the following idealized reaction:[1]

CH3C(O)NH2 + 1/4 P4S10 → CH3C(S)NH2 + 1/4 P4S6O4

Structure[edit]

The C2NH2S portion of the molecule is planar; the C-S and C-N distances are 1.713 and 1.324 Å, both indicating multiple bonding.[2]

Safety[edit]

Thioacetamide is carcinogen class 2B. It is known to produce marked hepatotoxicity in exposed animals. Toxicity values are 301 mg/kg in rats (LD50, oral administration), 300 mg/kg in mice (LD50, intraperitoneal administration).[3] This is evidenced by enzymatic changes, which include elevation in the levels of serum alanine transaminase, aspartate transaminase and aspartic acid.[4]

References[edit]

  1. ^ Schwarz, G. (1945). "2,4-Dimethylthiazole". Org. Synth. 25: 35. ; Coll. Vol. 3, p. 332 
  2. ^ Truter, M. R. (1960). "An accurate determination of the crystal structure of thioacetamide". Journal of the Chemical Society 1960: 997–1007. doi:10.1039/JR9600000997. 
  3. ^ "HSDB: THIOACETAMIDE CASRN: 62-55-5". Hazardous Substances Data Bank. 
  4. ^ Ali, S.; Ansari, K. A.; Jafry, M. A.; Kabeer, H.; Diwakar, G. (2000). "Nardostachys jatamansi protects against liver damage induced by thioacetamide in rats". Journal of Ethnopharmacology 71 (3): 359–363. doi:10.1016/S0378-8741(99)00153-1.