X-ray Structural Analysis of Ethyl [2,2-dimethyl-6-(D2-thiazolin-2-yl)-4H-1,4-benzoxazin-3-one-4-yl]butyrate.

With the aim of discovering new molecules with K+ channel modulating properties, we have synthesized analogues of cromakalim, an important molecule which shows specific affinity toward the K+ channels, by replacing the benzopyrane ring with a benzoxazine moiety. As a part of this study, we have synthesized and characterized, in solution and in the solid state as well, the compound ethyl [2,2-dimethyl-6-(A2-thiazolin-2-yl)-4H-l,4-benzoxazin-3-one-4-yl]butyrate (V). This compound exhibits in the solid state the following parameters: molecular formula C19H24N2O4S, triclinic, space group PI, Mw = 376.5, a = 12.581(3) A, b = 5.485(4) A, c = 14.612(2) A, a = 91.85(2), 0 = 108.9(3), y = 82.04(4), V = 944.7 A3, Z = 2, d = 1.323 g-cnT3. We describe here the synthesis and discuss the solid-state conformation of this new molecule; when tested on rat aorta ring precontracted with phenylephrine, the compound showed a concentrationdependent relaxation comparable to that measured for cromakalin taken as reference drug.