X-Ray Structural Analysis of Ethyl [2,2-dimethyl-6-(Δ²-thiazolin-2-yl)-4H-1,4-benzoxazin-3-one-4-yl]butyrate

Abstract

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-(Δ²-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 $P\bar 1$, M_w = 376.5, a = 12.581(3) Å, b = 5.485(4) Å, c = 14.612(2) Å, α = 91.85(2), β = 108.9(3), γ = 82.04(4), V = 944.7 ų, Z = 2, d = 1.323 g·cm⁻³. 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 concentration-dependent relaxation comparable to that measured for cromakalin taken as reference drug.