Ethyl 6‐acetylamino‐6,7‐dihydro‐5H‐dibenzo[a,c]cycloheptene‐6‐carboxylate

The title compound, C₂₀H₂₁NO₃, is a derivative of Aib (α‐­aminoisobutyric acid) and is cyclized at the C^α position by bi­phenyl rings. The seven‐membered ring possesses C2 symmetry. The C^α cyclization causes the backbone to assume a helical conformation in the crystal structure. The packing of the mol­ecules is stabilized by intermolecular C—H?O, C—H?π and N—H?O hydrogen bonds.