Synthesis and crystal structure of 1-acetyl-3-bromo-3-phenylazetidine and 1-phenyl-2-(N-acetyl-N-formyl)-aminoethanone

1-Acetyl-3-bromo-3-phenylazetidine (1), C11H12BrNO, has been synthesized and characterized by spectroscopic methods and single crystal X-ray analysis. It crystallizes in the space group P21/c with a = 8.633(1), b = 7.461(1), c = 17.204(1) A, β = 98.403(7)°, V = 1096.2(2) A3, Z = 4, Dcalc = 1.540 g cm−3. The azetidine ring is nearly planar since the four atoms are within ±0.039(5) A of the mean square plane calculated for the heterocycle. The attempt to obtain a highly strained 2-azetine derivative from the above compound gave, surprisingly, 1-phenyl-2-(N-acetyl-N-formyl)-aminoethanone (2), C11H11NO3. This compound has been also characterized by spectroscopic methods and single crystal X-ray analysis. It crystallizes in the space group P212121, with a = 5.4719(3), b = 8.3205(6), c = 23.298(3) A, V = 1060.7(2) A3, Z = 4, Dcalc = 1.286 g cm−3. The aminoethanone residue is in a near planar conformation where the torsion angles are 7(2)° for N–C–C–=O and −173(2)° for N–C–C–C(Ph).