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Thioacetic acid is an organosulfur compound with the molecular formula CH 3 C(O)SH. It is a thioic acid: the sulfur analogue of acetic acid (CH 3 C(O)OH), as implied by the thio-prefix. It is a yellow liquid with a strong thiol-like odor. It is used in organic synthesis for the introduction of thiol groups (−SH) in molecules. [4]
Acid anhydrides and some lactones also give thioesters upon treatment with thiols in the presence of a base. Thioesters can be conveniently prepared from alcohols by the Mitsunobu reaction, using thioacetic acid. [6] They also arise via carbonylation of alkynes and alkenes in the presence of thiols. [7]
In a common application, potassium thioacetate is combined with alkylating agents to give thioacetate esters (X = halide): . CH 3 COSK + RX → CH 3 COSR + KX. Hydrolysis of these esters affords thiols:
At neutral pH, thiocarboxylic acids are fully ionized. Thiocarboxylic acids are about 100 times more acidic than the analogous carboxylic acids. Thiobenzoic acid has a pK a of 2.48 compared with 4.20 for benzoic acid, and thioacetic acid has a pK a near 3.4 compared with 4.72 for acetic acid. [8]
The reaction was first reported in 1949 with thioacetic acid as reagent [3] [4] and rediscovered in 2009. [5] It is used in click chemistry [ 6 ] [ 7 ] [ 8 ] and in polymerization , especially with dendrimers .
Thioacetic acid This page was last edited on 21 November 2022, at 01:33 (UTC). Text is available under the Creative Commons Attribution-ShareAlike 4.0 License ...
General structure of a monothioacetal General structure of a dithioacetal. In organosulfur chemistry, thioacetals are the sulfur analogues of acetals (R−CH(−OR) 2).There are two classes: the less-common monothioacetals, with the formula R−CH(−OR')−SR", and the dithioacetals, with the formula R−CH(−SR') 2 (symmetric dithioacetals) or R−CH(−SR')−SR" (asymmetric dithioacetals).
Thioacetic acid reacts with acetyl-protected α-galactosyl trichloroacetimidate even without additional acid catalysis to thioglycoside, from which (after cleavage of the protective groups) 1-thio-β-D-galactose is easily accessible, which is useful for the separation of racemates of amino acids.