An Improved Commercially Feasible Process for Flecainide Acetate

Commercially viable manufacturing process for Flecainide Acetate (I) conforming to regulatory specification and cost effective process is reported. Specifically, an improved process for the preparation of Flecainide Acetate allows isolation of anhydrous hydrochloride salt of Compound III, which facilitates the reduction of the pyridine ring with the only catalytic amount of platinum on carbon within 2 hours Therefore, simplifies the synthesis and isolation of Flecainide acetate on a commercial scale to a considerable extent.

Crystal structure and Hirshfeld surface analysis of the hydrochloride salt of 8-{4-[(6-phenylpyridin-3-yl)methyl]piperazin-1-yl}-3,4-dihydroquinolin-2(1H)-one

The amine 8-{4-[(6-phenylpyridin-3-yl)methyl]piperazin-1-yl}-3,4-dihydroquinolin-2(1H)-one was crystallized as the hydrochloride salt, 4-(2-oxo-1,2,3,4-tetrahydroquinolin-8-yl)-1-[(6-phenylpyridin-3-yl)methyl]piperazin-1-ium chloride, C25H27N4 +·Cl− (I·HCl). The conformation of the organic cation is half-moon in shape enclosing the chloride anion. The piperidine ring of the 3,4-dihydroquinolin-2(1H)-one moiety has a screw-boat conformation, while the piperazine ring has a chair conformation. In the biaryl group, the pyridine ring is inclined to the phenyl ring by 40.17 (7) and by 36.86 (8)° to the aromatic ring of the quinoline moiety. In the crystal, the cations are linked by pairwise N—H...O hydrogen bonds, forming inversion dimers enclosing an R 2 2(8) ring motif. The Cl− anion is linked to the cation by an N—H...Cl hydrogen bond. These units are linked by a series of C—H...O, C—H...N and C—H...Cl hydrogen bonds, forming layers lying parallel to the ab plane.

The hydrochloride salt of 4-hydroxy-N,N-di-n-propyltryptamine (4-HO-DPT)

The title compound, 4-hydroxy-N,N-di-n-propyltryptammonium (4-HO-DPT) chloride {systematic name: N-[2-(4-hydroxy-1H-indol-3-yl)ethyl]-N-propylpropan-1-aminium chloride}, C16H25N2O+·Cl−, has a singly protonated tryptammonium cation and one chloride anion in the asymmetric unit. A series of N—H...Cl and O—H...Cl hydrogen bonds connect the ions together in ladder chains along [010].

An unusually short intermolecular N—H...N hydrogen bond in crystals of the hemi-hydrochloride salt of 1-exo-acetamidopyrrolizidine

The title compound [systematic name: (1R*, 8S)-2-acetamidooctahydropyrrolizin-4-ium chloride–N-[(1R, 8S)-hexahydro-1H-pyrrolizin-2-yl)acetamide (1/1)], 2(C9H16N2O)·HCl or C9H17N2O+·Cl−·C9H16N2O, arose as an unexpected product when 1-exo-acetamidopyrrolizidine (AcAP; C9H16N2O) was dissolved in CHCl3. Within the AcAP pyrrolizidine group, the unsubstituted five-membered ring is disordered over two orientations in a 0.897 (5):0.103 (5) ratio. Two AcAP molecules related by a crystallographic twofold axis link to H+ and Cl− ions lying on the rotation axis, thereby forming N—H...N and N—H...Cl...H—N hydrogen bonds. The first of these has an unusually short N...N separation of 2.616 (2) Å: refinement of different models against the present data set could not distinguish between a symmetrical hydrogen bond (H atom lying on the twofold axis and equidistant from the N atoms) or static or dynamic disorder models (i.e. N—H...N + N...H—N). Computational studies suggest that the disorder model is slightly more stable, but the energy difference is very small.