Structure of an isoxazole amino ester

2'-(N-Methylamino)-2-methylpropyl 5-methyl-3-phenylisoxazole-4-carboxylate hydroiodide, C16H21N2O3+.I-, Mr = 416.26, orthorhombic, Pna21, a = 23.293 (7), b = 10.276 (3), c = 7.971 (1) A, V = 1908.0 (8) A3, Z = 4, Dx = 1.448 g cm-3, Mo K alpha, lambda = 0.71069 A, mu = 17.1 cm-1, F(000) = 832, T = 293 K, R = 0.0610 for 1846 unique observed reflections with F greater than 3 sigma. In the title compound, the isoxazole ring is distorted only slightly from planarity, with C(3) being 0.045 A out of the mean plane. Steric interactions force the isoxazole ring out of planarity with both the phenyl ring and the ester carbonyl O(2), which show dihedral angles of 34.9 (9) degrees and 47.2 (7) degrees, respectively. The N(2) amino methyl group is oriented approximately anti to the ester carbonyl O(2). The minimum iodide to nitrogen distance is from I to N(2)', 3.46 (2) A.