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Stanozolol Wikipedia

Aldicarb – a broad‑spectrum carbamate insecticide




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1. Overview


Aldicarb (chemical formula C₁₂H₁₇NO₄S) is an organosulfur carbamate that was first synthesized in the early 1980s by a team of chemists working for a major agrochemical company. Its high potency against a wide range of soil‑borne pests, coupled with its relatively low cost and ease of application, led to rapid adoption in crop protection programs worldwide.



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2. Chemical properties




Property Value


Molecular weight 251.34 g mol⁻¹


Boiling point ~250 °C (under reduced pressure)


Solubility in water 0.6 mg mL⁻¹ (at 25 °C)


LogP 3.1


pKa (acidic proton) 5.8






The compound is a moderately lipophilic organic ester, with limited aqueous solubility.


It possesses an electrophilic carbonyl center that reacts readily with nucleophiles such as thiols.




Mechanistic Insight into the Thiol–Acetylation Reaction


The reaction between the acetylating agent and the cysteine side-chain sulfur proceeds via a nucleophilic acyl substitution mechanism:





Nucleophilic Attack


The lone pair on the sulfur atom of the thiol group attacks the electrophilic carbonyl carbon of the ester, forming a tetrahedral intermediate.



Collapse of Intermediate


The tetrahedral intermediate collapses, expelling the alkoxy leaving group (e.g., methanol). This step generates an S‑acetylated cysteine residue and releases the alcohol byproduct.



Product Formation


The final product is a cysteine side chain with a thioester linkage to the acetyl group, effectively blocking its reactivity for further chemical or enzymatic modifications.

This simple yet powerful reaction is widely used in proteomics to protect cysteine residues during sample preparation and to prevent disulfide bond formation that could interfere with downstream analyses.

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