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Two tetrahydroisoquinoline alkaloids were extracted from the alkaloid fraction of a methanol extract of the seeds of Calycotome Villosa Subsp. intermedia. Their structures were established as (R)-1-hydroxymethyl-7-8-dimethoxy-1,2,3,4-tetrahydro- isoquinoline (1) and (S)-7-hydroxymethyl-2-3-dimethoxy-7,8,9,10-tetrahydroisoquinoline chloride (2) by spectroscopic techniques and X-ray diffraction analysis.
Supersilylated tetrachlorodigermane (tBu3Si)Cl2GeGeCl2(SitBu3) and trigermoxetane (tBu3Si)3Ge3Cl3O
(2004)
In contrast to the tetrachlorodigermane (tBu3Si)Cl2Ge-GeCl2(SitBu3), the cis,transcyclotrigermane (tBu3SiGeCl)3 is sensitive to oxygen. Its treatment with O2 at ambient temperature leads to the trigermoxetane (tBu3Si)3Ge3Cl3O. According to an X-ray structure analysis of single crystals consisting of cocrystallized (tBu3Si)3Ge3Cl3O and (tBu3Si)Cl2Ge-GeCl2(SitBu3) the trigermaoxetane contains an almost planar Ge3O-ring while the tetrachlorodigermane (tBu3Si)Cl2Ge- GeCl2(SitBu3) possesses a Si-Ge-Ge-Si chain which is exactly all trans,
Benzene solutions of Me3SnCl when exposed to moisture yield the adduct Me3SnCl·Me3SnOH·H2O. This adduct represents an intermediate in Me3SnCl hydrolysis. The structure of Me3SnCl·Me3SnOH·H2O features an array of Me3Sn units connected alternatingly by bridging Cl and OH ligands.
In the paper by Bolte [Acta Cryst. (2006), E62, m1609-m1610], the chemical name in the title and the chemical diagram are incorrect. The correct title is {5-[4'-(2,2,5,5-Tetramethyl-3-pyrroline-1-oxyl-3-carbonyloxy)biphenyl-4-ylethynyl]-2,3,7,8,12,13,17,18-octaethylporphyrinato}copper(II) benzene solvate' and the correct diagram is given below.
Pyrazolyl-substituted 1,4-dihydroxybenzene and 1,4-dihydroxynaphthene derivatives have been synthesized by reaction of 1,4-benzoquinone and 1,4-naphthoquinone, respectively, with pyrazole. Cyclovoltammetric measurements have shown that 1,4-benzoquinone possesses the potential to oxidize 2-(pyrazol-1-yl)- and 2,5-bis(pyrazol-1-yl)-1,4-dihydroxybenzene. The 2,5-bis(pyrazol-1-yl)- 1,4-dihydroxybenzene reacts with air to give quantitatively black insoluble 2,5-bis(pyrazol-1-yl)-1,4- quinhydrone. Black crystals of 2,5-bis(pyrazol-1-yl)-1,4-quinhydrone suitable for X-ray diffraction were grown from methanol at ambient temperature (monoclinic C2/c). The poor yields of pyrazolylsubstituted 1,4-dihydroxybenzene and 1,4-dihydroxynaphthene derivatives can be explained by the formation of insoluble black quinhydrons in the reaction of benzoquinone and naphthoquinone with pyrazole. The dianions of 2-(pyrazol-1-yl)- and 2,5-bis(pyrazol-1-yl)-1,4-dihydroxybenzene react with oxygen to give the corresponding semiquinone anions. 2,5-Bis(pyrazol-1-yl)-1,4-benzoquinone shows two reversible one-electron reduction processes in cyclovoltammetric measurements, whereas pyrazolyl-substituted 1,4-dihdroxybenzene and -naphthene derivatives undergo irreversibile electrontransfer processes.
The geometric parameters of the title compound, C8H6N2O·C6H3N3O7, are in the usual ranges. The three nitro groups are almost coplanar with the aromatic picrate ring [dihedral angles 10.2 (2)°, 7.62 (16) and 8.08 (17)°]. The molecular conformation of the picric acid is stabilized by an intramolecular O-H...O hydrogen bond. The phthalazin-1(2H)-one molecules are connected via N-H...O hydrogen bonds, forming centrosymmetric dimers. Key indicators: single-crystal X-ray study; T = 173 K; mean σ(C–C) = 0.002 Å; R factor = 0.034; wR factor = 0.091; data-to-parameter ratio = 11.1.
The thermolabile triazenides M[tBu3SiNNNSiMetBu2] (M = Li, Na) are accessible from the reaction of tBu2MeSiN3 with the silanides MSitBu3 (M = Li, Na) at −78 °C in THF. At r. t. N2 elimination from the triazenides M[tBu3SiNNNSiMetBu2] (M = Li, Na) takes place with the formation of M[N(SiMetBu2)(SitBu3)] (M = Li, Na). X-Ray quality crystals of Li(THF)[N(SiMetBu2)(SitBu3)] (orthorhombic, Pna21) are obtained from a benzene solution at ambient temperature. In contrast to the structures of the unsolvated silanides MSitBu3 (M = Li, Na), the THF adduct Li(THF)3SitBu3 is monomeric in the solid state (orthorhombic, Pna21).
2-Aminopyrimidinium picrate
(2008)
The geometric parameters of the title compound, C4H6N3+·C6H2N3O7-, are in the usual ranges. While two nitro groups are almost coplanar with the aromatic picrate ring [dihedral angles 3.0 (2) and 4.4 (3)°], the third is significantly twisted out of this plane [dihedral angle 46.47 (8)°]. Anions and cations are connected via N-H...O hydrogen bonds. The molecules crystallize in planes parallel to (1\overline{2}1). Key indicators: single-crystal X-ray study; T = 173 K; mean σ(C–C) = 0.002 Å; R factor = 0.036; wR factor = 0.099; data-to-parameter ratio = 10.9.
The title compound, C16H14N2O2, was derived from 1-(2-hydroxyphenyl)-3-(2-methoxyphenyl)propane-1,3-dione. The molecule is essentially planar (r.m.s. deviation for all non-H atoms = 0.089 Å). Two intramolecular hydrogen bonds stabilize the molecular conformation and one N-H...O hydrogen bond stabilizes the crystal structure. Key indicators: single-crystal X-ray study; T = 173 K; mean σ(C–C) = 0.003 Å; R factor = 0.035; wR factor = 0.091; data-to-parameter ratio = 9.3.