Crystal structure of nafamostat dimesylate

Nafamostat dimesylate {systematic name: [amino({6-[(4-{[amino(iminiumyl)methyl]amino}phenyl)carbonyloxy]naphthalen-2-yl})methylidene]azanium bis(methanesulfonate)}, C19H19N5O22 +·2CH3O3S−, is a broad-spectrum serine protease inhibitor and has been applied clinically as an anticoagulant agent during hemodialysis and for treatment of severe acute pancreatitis (SAP). Since nafamostat contains flexible moieties, it is necessary to determine the conformation to understand the structure–activity relationships. The divalent cation has a screw-like motif. The guanidinium group is approximately perpendicular to the naphthyl ring system, subtending a dihedral angle of 84.30 (14)°. In the crystal, the nafamostat molecules form columnar structures surrounded by a hydrophilic region.

Benzoylation of gossypol using benzoyl chloride and benzoic anhydride as acylating agents

To understand deeply the process of acylation of natural polyphenol gossypol, its stepwise benzoylation was performed using benzoyl chloride and benzoic anhydride as acylating agents in the presence of pyridine-N-oxides. The influence of the composition of a reaction mixture on the benzoylation process and reaction products was analyzed by the method of reversed-phase high-performance liquid chromatography. It was established that benzoylation of gossypol leads to the tautomeric transition of the respective fragment from aldehyde to lactol tautomeric form. This transition is most likely due to the breaking of the hydrogen bond C(7)–OHO=C(11) in combination with the displacement of the aldehyde group by the benzoyl fragment from the naphthyl ring plane (in the case of benzoylation of C(7)–OH group); benzoylation of C(6)–OH group is accompanied by the breaking of the hydrogen bond C(6)–OHO–C(7). These changes of configuration significantly facilitate the proton transfer from the C(1)–OH group to oxygen at C(11) followed by the formation of the lactol cycle. The use of benzoyl chloride as an acylating agent in combination with triethylamine and 4-methoxypyridine-N-oxide allows benzoylating gossypol quickly. However, the variety of formed benzoates is quite large because of the similar reactivity of different hydroxyl groups. In the case of benzoic anhydride, the number of isomeric gossypol benzoates remains quite high. Much more esters with higher retention time are accumulated due to a higher degree of benzoylation.

3-(2-Methoxyphenyl)-2,3-dihydro-1H-benzo[f]chromen-1-one

In the title compound, C20H16O3, the 2-methoxyphenyl ring is tilted by 50.67 (3)° with respect to the naphthyl ring system. The central pyran ring has an envelope conformation with the C atom bearing the pendant ring system as the flap. The methoxy group attached to the benzene ring is slightly twisted [C—C—O—C = −15.2 (1)°] from the ring. In the crystal, weak C—H...O interactions link the molecules into C(7) chains propagating along [101].

3-(4-Iodophenyl)-2,3-dihydro-1H-benzo[f]chromen-1-one

In the title compound, C19H13IO2, the dihedral angle between the naphthyl ring system and the pendant iodophenyl ring is 72.48 (11)°. In the crystal, C—H...π interactions and I...O [3.293 (2) Å] halogen bonds are observed, which combine to generate a herringbone packing motif.

Novel styryl and aza-styryl cyanine dyes: Synthesis and spectral sensitization evaluation

Novel styryl cyanine dyes and aza-styryl cyanine dyes having the nucleus of furo[(3,2-d)pyrazole;(3',2'-d)oxazole] iodide salt were prepared. Spectral sensitization evaluation for all the synthesized styryl and aza-styryl cyanine dyes was carried out through investigating their electronic visible absorption spectra in 95% ethanol solution. The dyes were thought to be better spectral sensitizers when they absorb light at longer wavelength bands (bathochromic shifted and/or red shifted dyes). Consequently the spectral sensitization of the dyes decreased when they absorb light at shorter wavelength bands (hypsochromic shifted and/or blue shifted dyes). The results discussed in this study revealed that the spectral sensitization properties of the examined dyes is highly effected by the type of the X substituted in the phenyl ring system for the styryl cyanine dyes and by the type of the phenyl and/or the naphthyl ring system for the aza-styryl cyanine dyes. Structural confirmations were identified by elemental analysis, visible spectra, IR and 1H NMR spectroscopic data.

Novel styryl and aza-styryl cyanine dyes: Synthesis and spectral sensitization evaluation

Novel styryl cyanine dyes and aza-styryl cyanine dyes having the nucleus of furo[(3,2-d)pyrazole;(3',2'-d)oxazole] iodide salt were prepared. Spectral sensitization evaluation for all the synthesized styryl and aza-styryl cyanine dyes was carried out through investigating their electronic visible absorption spectra in 95% ethanol solution. The dyes were thought to be better spectral sensitizers when they absorb light at longer wavelength bands (bathochromic shifted and/or red shifted dyes). Consequently the spectral sensitization of the dyes decreased when they absorb light at shorter wavelength bands (hypsochromic shifted and/or blue shifted dyes). The results discussed in this study revealed that the spectral sensitization properties of the examined dyes is highly effected by the type of the X substituted in the phenyl ring system for the styryl cyanine dyes and by the type of the phenyl and/or the naphthyl ring system for the aza-styryl cyanine dyes. Structural confirmations were identified by elemental analysis, visible spectra, IR and 1H NMR spectroscopic data.

Crystal structure of benzyl 2-naphthyl ether, a sensitiser for thermal paper

The title compound [systematic name: 2-(benzyloxy)naphthalene], C17H14O, which is used as a sensitiser for thermal paper, has a twisted conformation with a dihedral angle of 48.71 (12)° between the phenyl ring and the naphthyl ring system. In the crystal, one molecule interacts with six neighbouring molecules via intermolecular C—H...π interactions to form a herringbone molecular arrangement.

Salt forms of sulfadiazine with alkali metal and organic cations

The structures of four salt forms of sulfadiazine (SDH) with alkali metal cations are presented. Three contain the deprotonated SD anion (C10H9N4O2S). These are the discrete complex diaqua{4-[(pyrimidin-2-ylazanidyl-κN 1)sulfonyl-κO]aniline}lithium(I), [Li(SD)(H2O)2], (I), and the coordination polymers poly[{μ3-4-[(pyrimidin-2-ylazanidyl)sulfonyl]aniline}sodium(I)], [Na(SD)] n , (II), and poly[diaqua{μ3-4-[(pyrimidin-2-ylazanidyl)sulfonyl]aniline}potassium(I)], [K(SD)(H2O)2] n , (III). Na complex (II) is a three-dimensional coordination polymer, whilst K complex (III) has two crystallographically independent [K(SD)(H2O)2] units per asymmetric unit (Z′ = 2) and gives a two-dimensional coordination polymer whose layers propagate parallel to the crystallographic ab plane. The different bonding modes of the SD anion in these three complexes is discussed. Structure (IV) contains protonated SDH2 cations {4-[(pyrimidin-2-yl)sulfamoyl]anilinium, C10H11N4O2S} and the Orange G dianion [OG, 7-oxo-8-(phenylhydrazinylidene)naphthalene-1,3-disulfonate, C16H10N2O7S2], namely, 4-[(pyrimidin-2-yl)sulfamoyl]anilinium tetraaqua[7-oxo-8-(phenylhydrazinylidene)naphthalene-1,3-disulfonato]sodium(I) sesquihydrate, (SDH2)[Na(OG)(H2O)4]·1.5H2O. The [Na(OG)(H2O)4]2 dimers have antiparallel naphthyl ring structures joined through two Na centres that bond to the hydrazone anions through the O atoms of the ketone and sulfonate substituents. The structures of the salts formed on reaction of SDH with 2-aminopyridine and ethanolamine are also presented as 2-aminopyridinium 4-[(pyrimidin-2-ylazanidyl)sulfonyl]aniline, [C5H7N2][SD], (V), and ethanolaminium 4-[(pyrimidin-2-ylazanidyl)sulfonyl]aniline monohydrate, [HOCH2CH2NH3][SD]·H2O, (VI), respectively. Structure (V) features a heterodimeric R 2 2(8) hydrogen-bond motif between the cation and the anion, whilst structure (VI) has a tetrameric core of two cations linked by a central R 2 2(10) hydrogen-bonded motif which supports two anions linked to this core by R 3 3(8) motifs.

Ethyl (naphthalen-2-yloxy)acetate

In the title compound, C14H14O3, the dihedral angle between the naphthyl ring system and the side chain is 9.00 (14)°, and the ethoxy chain adopts an extended conformation [C—O—C—C = 176.0 (3)°]. There are no directional interactions in the crystal beyond normal van der Waals contacts.