1,1'-Thiocarbonyldiimidazole (TCDI)

Technical Specifications

Product Description & Scientific Applications

1,1′-Thiocarbonyldiimidazole (TCDI) is the thiocarbonyl (C=S) counterpart of 1,1′-carbonyldiimidazole (CDI): a central thiocarbonyl flanked by two imidazole leaving groups. Both are readily displaced by alcohols and amines, so TCDI serves as a thiocarbonyl-transfer reagent that installs a C=S unit into the substrate.

Common Scientific Applications

Barton–McCombie deoxygenation. TCDI activates a hydroxyl group — for example on a protected sugar — as its O-thiocarbonyl imidazolide; treatment with tributyltin hydride and AIBN then effects radical C–O cleavage, replacing the oxygen with hydrogen.

Corey–Winter olefination. TCDI condenses a 1,2-diol to a cyclic thionocarbonate, which a trialkyl phosphite such as trimethyl phosphite desulfurises by stereospecific syn-elimination, delivering the alkene.

Isothiocyanate synthesis. A primary amine is converted directly to the corresponding isothiocyanate, a versatile electrophile for onward C–N bond formation.

Thiourea synthesis. Two equivalents of one amine give a symmetrical thiourea, while two different amines added in sequence give an unsymmetrical 1,3-disubstituted thiourea; an amine may instead be added to a preformed isothiocyanate. In nucleoside chemistry such thioureas serve as non-ionic bridges isosteric with phosphate.

Sulfur- and nitrogen-heterocycle synthesis. As a one-carbon C=S synthon, TCDI cyclises bifunctional substrates: an o-phenylenediamine closes to a benzimidazole-2-thione, whose sulfur is then S-alkylated to 2-(alkylsulfanyl)benzimidazoles; an α-amino amide gives a thiohydantoin; and suitable acyclic adducts close to 1,3,4-thiadiazol-2(3H)-thiones.

Further applications

• Aminothiol derivatisation for analysis: TCDI derivatises the aminothiols cysteine and homocysteine, enabling their rapid determination as total thiols in plasma and urine by capillary electrophoresis.
• Degradable vinyl polymers: TCDI serves as a comonomer in the radical copolymerisation of vinyl monomers such as tert-butyl acrylate, N,N-dimethylacrylamide and styrene, installing TCDI-derived diimidazolyl thioether units in the main chain that render the backbone degradable; under trithiocarbonate-mediated RAFT, molar mass grows linearly with conversion at low dispersity (Đ ≈ 1.2–1.4).

Shipping Destinations

• EU & UK: Priority delivery, 2–5 business days.
• United States (DDP): 3–7 business days, duties and taxes prepaid.
• EFTA Countries (DDP): 3–7 business days, duties and taxes prepaid.
• Worldwide: 7–14 business days, selected locations.