Thiocarbonyldiimidazole

1,1'-Thiocarbonyldiimidazole (TCDI) is a thiourea containing two imidazole rings.[1] It is the sulfur analog of the peptide coupling reagent carbonyldiimidazole (CDI).

Thiocarbonyldiimidazole

Names
IUPAC name Di(imidazol-1-yl)methanethione
Other names TCDI
Identifiers
CAS Number	6160-65-2
3D model (JSmol)	Interactive image
ECHA InfoCard	100.025.622
EC Number	228-183-4
PubChem CID	80264
CompTox Dashboard (EPA)	DTXSID70210614
InChI InChI=1S/C7H6N4S/c12-7(10-3-1-8-5-10)11-4-2-9-6-11/h1-6H Key: RAFNCPHFRHZCPS-UHFFFAOYSA-N
SMILES C1=CN(C=N1)C(=S)N2C=CN=C2
Properties
Chemical formula	C7H6N4S
Molar mass	178.21 g·mol^−1
Melting point	101 to 103 °C (214 to 217 °F; 374 to 376 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Synthesis

TCDI is commercially available but can also be prepared via the reaction of thiophosgene with two equivalents of imidazole.[1]

Reactions

The imidazole groups on TCDI can be easily displaced, allowing it to act as a safer alternative to thiophosgene. This behaviour has been used in the Corey–Winter olefin synthesis.[2] It may also replace carbonothioyl species (RC(S)Cl) in the Barton–McCombie deoxygenation. Other uses include the synthesis of thioamides and thiocarbamates. Like the analogous CDI, it may be used for peptide coupling.[3]

References

1. Adrian, L. Schwan; Jeffrey, H. Byers (15 March 2007). "1,1′‐Thiocarbonyldiimidazole". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/9780470842898.rt094.pub2.
2. Corey, E. J.; Winter, Roland A. E. (September 1963). "A New, Stereospecific Olefin Synthesis from 1,2-Diols". Journal of the American Chemical Society. 85 (17): 2677–2678. doi:10.1021/ja00900a043.
3. Esser, Franz; Roos, Otto (June 1978). "N-Terminal Cyclization of Peptides withN,N′-Carbonyldiimidazole orN,N′-Thiocarbonyldiimidazole". Angewandte Chemie International Edition in English. 17 (6): 467–468. doi:10.1002/anie.197804671.