A one-pot multistep cyclization yielding thiadiazoloimidazole derivatives

• Debabrata Samanta,
• Anup Rana,
• Jan W. Bats and
• Michael Schmittel

Beilstein J. Org. Chem. 2014, 10, 2989–2996, doi:10.3762/bjoc.10.317

• unit. The structure of the intricate heterocycle 2a was confirmed by single-crystal X-ray analysis and its mechanism of formation supported by DFT computations. Keywords: carbodiimide; cyclization; dithiourea; DFT; 1,2,4-thiadiazoles; Introduction Heterocyclic rings are key components in many

• substituents) in good yield. Results and Discussion The synthesis of benzimidazole-fused 1,2,4-thiadiazoles 2a–c was accomplished by treating dithiourea derivatives with methanesulfonyl chloride in presence of triethylamine and a catalytic amount of 4-dimethylaminopyridine at 0 °C (Scheme 1). The reaction of

• dimensions 0.08 × 0.10 × 0.60 mm) was measured on a Siemens SMART 1K CCD diffractometer at a temperature of about −87 °C. General procedure for the preparation of dithiourea 1a–c. A solution of o-phenylenediamine (2.00 g, 18.5 mmol) and the corresponding isothiocyanate (37.0 mmol) in tetrahydrofuran (100 mL