X-ray mapping in heterocyclic design: VII. Diffraction study of the structure of N-pyridoneacetic acid and the product of its intramolecular dehydration

The structure of pyridoneacetic acid C₇H₇N₁O₃(I) is determined by the single-crystal X-ray diffraction technique. The crystals of I are monoclinic, a = 7.4502(15) Å, b = 10.006(6) Å, c = 9.960(3) Å, β = 109.96(2)°, Z = 4, and space group P2₁/c. The structure of pyridoneacetic acid is solved by the direct method and refined by the least-squares procedure in the anisotropic approximation to R = 0.0387. The structure of the product of its intramolecular dehydration, C₇H₆N₁O₂B₁F₄(II), is determined by the grid search procedure and refined by the Reitveld method (R _p = 0.045, R _wp = 0.58, R _e = 0.026, and χ² = 4.69). The crystals of II are monoclinic, a = 10.4979(3) Å, b = 11.4467(3) Å, c = 7.6027(1) Å, β = 100.83(2)°, Z = 4, and space group P2₁/n. The system of two conjugated heterocycles is planar.