Crystal structure of hyoscyamine sulfate monohydrate, (C₁₇H₂₄NO₃)₂(SO₄)(H₂O)

Abstract

The crystal structure of hyoscyamine sulfate monohydrate has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional techniques. Hyoscyamine sulfate monohydrate crystallizes in space group P21 (#4) with a = 6.60196(2), b = 12.95496(3), c = 20.93090(8) Å, β = 94.8839(2)°, V = 1783.680(5) Å3, and Z = 2. Despite the traditional description as a dihydrate, hyoscyamine sulfate crystallizes as a monohydrate. The two independent hyoscyamine cations have different conformations, which have similar energies. One of the cations is close to the minimum-energy conformation. Each of the protonated nitrogen atoms in the cations acts as a donor to the sulfate anion. The hydroxyl group of one cation acts as a donor to the sulfate anion, while the hydroxyl group of the other cation acts as a donor to the water molecule. The water molecule acts as a donor to two different sulfate anions. The cations and anions are linked by complex chains of hydrogen bonds along the a-axis. The powder pattern has been submitted for inclusion in the Powder Diffraction File™ (PDF®).

Crystal structure of atropine sulfate monohydrate, (C17H24NO3)2(SO4)·(H2O)

“…Intermolecular interactions play a role in determining the observed solid-state conformations. Since atropine is the racemic version of hyoscyamine, it is worth comparing the cations in this structure to the two independent cations in the hyoscyamine crystal structure (Kaduk et al, 2019). The root-mean-square Cartesian displacements of the non-H atoms are reported in Table I.…”

“…A reduced cell search in the Cambridge Structural Database (Groom et al ., 2016) combined with the chemistry C, H, N, O, and S only yielded no hits. Two copies of the hyoscyamine molecule from Kaduk et al (2019), a sulfate anion, and an oxygen atom (water molecule) were used as fragments. The structure was solved by Monte Carlo simulated annealing using DASH (David et al , 2006), including Mogul Distribution Bias and {010} preferred orientation (guessed based on the anisotropy of the lattice parameters).…”

“…A two-dimensional molecular diagram is shown in Figure 1. Atropine is the racemic form of hyoscyamine (Kaduk et al , 2019).

Figure 1.Molecular structure of atropine sulfate monohydrate.

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“…A twodimensional molecular diagram is shown in Figure 1. Atropine is the racemic form of hyoscyamine (Kaduk et al, 2019).…”