Highly Regio‐ and Diastereoselective 1,3‐Dipolar Cycloaddition of Nitrile Oxides to 2,4‐Dimethyl‐3H‐1,5‐Benzodiazepines: Synthesis of Bis[1,2,4‐Oxadiazolo][1,5]Benzodiazepine Derivatives

Abstract

The 1,3‐dipolar cycloaddition reaction of nitrile oxides to 2,4‐dimethyl‐3H‐1,5‐benzodiazepines 1a–1c led, with completely regio‐ and diastereoselectivity, to new 3a,4a,8,13‐tetrahydro‐4H‐bis[1,2,4‐oxadiazolo][4,5‐a:5′,4′‐d][1,5]benzodiazepines 3a–3g. The structures of the synthesized bis‐adducts 3a–3g were elucidated by spectral methods and X‐ray crystallographic analysis.

Keywords:

• Benzodiazepines
• Diastereoselective
• Nitrile oxides
• Regioselective

Acknowledgments

The authors are grateful to Dr. Philippe Compain for spectral data measurements.

Notes

^aCrystal data for 3e: formula C₂₆H₂₂Cl₂N₄O₂, M = 493.38, monoclinic, P2₁/c, a = 13.1829 (5), b = 12.3225 (5), c = 15.2605 (5) Å, β = 106.861 (1)°, V = 2372.44 (15) Å³, Z = 4, Mo‐Kα radiation, θ = 2.4–26.4°, μ = 0.31 mm⁻¹, T = 293 K, 13,006 measured reflections, 4710 independent reflections, R = 0.035. Our crystal structure has been deposited at the Cambridge Crystallographic Data Centre and allocated the deposition number CCDC 227004.