Volume 60, Issue 1

Chromium compounds and hydrogen peroxide are usually identified by their reaction to form blue chromium oxide peroxide hydrate, which is extracted with diethyl ether as a co-ligand. Findings suggest that diethyl ether can be replaced without loss in analytical performance using solvents from the alcohol, arene, ester, ether, halogenated hydrocarbon, and ketone series. DFT calculations have been performed for several solvates. Results indicate that some of the solvates studied may exist as two rotamers.

Thiazolo[3,2-d][1,4,2]diazaphospholes as well as their 5,6-dihydro and benzo derivatives undergo Diels-Alder reactions at the >C=P- functionalities with 2,3-dimethylbutadiene and with isoprene. 1,3-Azaphospholo[5,1-b]benzothiazole, however, exhibits reduced reactivity and reacts with 1,3- dienes only in the presence of an oxidising agent (O 2 , S 8 or Se n ). Reactions with isoprene occur regioselectively.

The reaction between [MoTp∗(O)Cl 2 ], [Tp* = hydrotris(3,5-dimetylpyrazol-1-yl)borate] and 4-bromoaniline in refluxing toluene gave geometric isomers of [MoTp*(O)Cl](μ-O)[MoTp*(Cl) (≡NC 6 H 4 Br)] (1a, cis; 1b, trans), but a similar reaction between [MoTp*(O)Cl 2 ] and 4-chloroaniline yielded only one product, [MoTp*(O)Cl](μ-O)[MoTp∗(Cl)(≡NC 6 H 4 Cl)] (2) as a red crystalline solid. The new compounds were characterized by microanalytical data, mass, IR and 1 H NMR spectroscopy. The X-ray structure analysis of 1a and 1b revealed that the complexes are geometric isomers, the two chloro ligands being cis in 1a and trans in 1b. Both compounds have Mo-O-Mo linkages and nearly linear arylimido moieties.

The reaction of tetramethylpyrazine with SeO 2 yields 2,5-dimethylpyrazine-3,6-dicarboxaldehyde (1) from which the 2,5-dimethyl-3,6-bis[(2,6-diisopropylphenylimino)methyl]pyrazine (2) was synthesized by treatment with 2 equivalents of 2,6-diisopropylaniline. 2,6-Dimethylpyrazine reacts with benzaldehyde to give 2,6-distyrylpyrazine (3). Ozonolysis of 3, followed by treatment with Na 2 SO 3 and 2,6-diisopropylaniline resulted in the formation of 2,6-bis[(2,6-diisopropylphenylimino) methyl]pyrazine (5) together with [(2,6-diisopropylphenylimino)methyl]benzene (6).

From fruit bodies of the basidiomycete Hygrophorus eburneus (Bull.: Fr.) Fr. (Tricholomataceae) eight fatty acids (C 16 , C 18 ) with γ -oxocrotonate partial structure could be isolated. Initial tests demonstrate their bactericidal and fungicidal activity. The structures of (2E,9E)-4-oxooctadeca- 2,9,17-trienoic acid (1), (2E,11Z)-4-oxooctadeca-2,11,17-trienoic acid (2), (E)-4-oxohexadeca-2,15- dienoic acid (3), (E)-4-oxooctadeca-2,17-dienoic acid (4), (2E,9E)-4-oxooctadeca-2,9-dienoic acid (5), (2E,11Z)-4-oxooctadeca-2,11-dienoic acid (6), (E)-4-oxohexadec-2-enoic acid (7), and (E)-4- oxooctadec-2-enoic acid (8) were elucidated on the basis of their spectroscopic data.

A new one-dimensional coordination polymer [Co(CCl 3 COO) 2 (CH 3 OH) 2 (μ-4,4’-bipy)] n (1), has been synthesised and its crystal structure determined by single-crystal X-ray diffraction. The structure consists of a one-dimensional linear chain of cobalt(II) centres linked by bridging 4,4’-bipyridine units. The Co(II) ion lies at an inversion centre forming an elongated octahedral coordination sphere. There is an intramolecular hydrogen bond [2.02(5) Å ] between a trichloroacetate oxygen and a methanolic hydrogen forming a planar six-membered ring.

Two new triterpenoids, lawsowaseem and lawsoshamim, have been isolated from Lawsonia inermis and their structures established as 3β -hydroxy-24-p-E-coumaroyloxy-olean-12-en-28-oic acid, and 2-acetoxy-3β -hydroxy-olean-12-en-28-oic acid on the basis of spectral evidences, particularly 2D NMR studies.

In order to study hydrogen bonding networks in cyclic sulfin- and sulfonamides, X-ray structures were determined for 3-oxosultams 3a, c - e, 3-alkoxysultams 5b, f and 3-oxosultim 2f, all of which show predominantly weak intermolecular hydrogen bonds. The 3-oxosultam 3a forms tetrameric units by combining two symmetry-independent molecules through weak aromatic C-H· · ·O-S-O hydrogen bonds without participation of the carbonyl groups. The 3-oxosultam 3c, with two chloro substituents in the N-aryl ring show a polymer arrangement of the molecules through intermolecular association of the SO 2 and CO groups also with the aromatic H-atoms of the aryl rings. Sultam 3d shows the first polymer chain in the 3-oxosultam series by the strong O-H· · ·O=C hydrogen bonds without participation of the SO2 group. Two new ‘head-to-head’ dimers with a 10-membered ring are found for 3-alkoxysultams 5b, 5f through weak C-H· · ·O-S-O hydrogen bonds. In the 3-oxosultim 2f weak intermolecular hydrogen bonds are observed to form a two-dimensional network with the two methylene groups, the carbonyl function and the chloro atom but, surprisingly, without the strong S-oxide acceptor group.

Vinylogous hydrazides of type 1 react with methyleniminium salts only in 2-position to form aminomethylated compounds 2·HX. The oxidation of 1 with Hg(II)-EDTA results in a twofold dehydrogenation to the lactams 3, which may be aminomethylated in 2-position. The methylpiperidine derivatives 4 and 5 with Hg(II)-EDTA yield in a monodehydrogenation cyclic iminium compounds. These are isolated as 6 · ClO 4 and 7 · ClO 4 respectively, and show an enolimine structure, which is not accessible to intramolecular aminoalkylation. With the 2-methylsubstituted enhydrazinones 11 methyleniminium salts cause an attack at 4-position, vinylogous to the carbonyl function, and produce the aminomethylated derivatives 13. Oxidation of 11 gives rise to the lactams 12, which are inert to Mannich reagents. The Mannich bases 2 undergo an amine elimination to form the pyrazolinium betaines 15. The aminomethylated lactams 20 show, in addition to amine eliminations, retro Mannich reactions and from the cleavage products methylenebis(lactam-enhydrazinones) 21 result. Formaldehyde and primary amines generate with 1 and 3 the tetrahydropyrimidine derivatives 24/25 and 22/23, respectively. Hexahydroacridinediones 27 are obtained from the reaction of 21 with formaldehyde and acetic acid.

The ethyl acetate extract of the strain Streptomyces sp. GW23/1540 has yielded four new 2-alkyl-5-(hydroxymethyl)pyridine-3,4-diols, 5-hydroxymethyl-2-isopropyl-pyridine-3,4-diol (1a), 5-hydroxymethyl-2-propyl-pyridine-3,4-diol (1b), 2-sec-butyl-5-hydroxymethyl-pyridine-3,4-diol (1c), and 5-hydroxymethyl-2-isobutyl-pyridine-3,4-diol (1d). Similarly, the strain Streptomyces sp. GW63/1571 afforded 2-sec-butyl-5-hydroxymethyl-pyridine-3,4-diol (1c) and another new natural product, (3aS, 7aR)-3a-hydroxy-3a,4,7,7a-tetrahydro-1-benzofuran-2(3H)-on e (3), together with anthranilic acid, anthranilamide, and phenylacetamide. The new natural products were inactive against three micro algae, the fungus Mucor miehei, the yeast Candida albicans, and the bacteria Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Streptomyces viridochromogenes.

Some new N-benzyl phosphoramidic acid (4-methylphenyl)ester derivatives were synthesized and characterized by 1 H, 13 C, 31 P NMR and IR spectroscopy and elemental analysis. The structure of [(C 6 H 5 )(CH 3 )CH-NH]P(O)(p-OC 6 H 4 CH 3 ) 2 (2) was investigated. This compound exists in polymeric zigzag chains in the crystalline lattice produced by hydrogen bonding built from two alternating independent molecules. NMR data indicate two diastereotopic p-cresol groups as confirmed by Xray crystallography. Ab initio calculations were performed on the geometry of compound 2 at the UHF/6-311G** and B3LYP/6-311G** levels. The optimized structure of each independent molecule contains two different p-cresol groups, in agreement with the experimental results.

The photoswitching of optical and electrochemical properties of di-donor, di-acceptor and donor-acceptor substituted photochromic tetrahydropyrene - [2,2]metacyclophanene and dihydropyrene - [2,2]metacyclophanediene systems has been studied theoretically. A switching of the halfwave oxidation and reduction potentials should be possible in the case of bis(pyridinium) and bis(hydroxyphenyl) substituted systems. Because of the relatively great perturbation of the planarity of the π-electron systems by large torsion of the substituents out of the π-electron structure of the photochromic system and the stair-like structure of the ring-opened isomer, relatively large excitation energies for CT transitions have been calculated with the AM1-CI procedure. The ring-closed structures should absorb in the visible spectral region, and the open-ring isomers should have a longest-wavelength absorption in the UV region.

A series of antiviral compounds consisting of an intercalating acridine derived part, a spacer region and a reactive EDTA-derived conjugate was synthesized in an easy sequence. In the presence of ascorbate a reduction of the phage-titer of MS2 phages by several logarithmic decades was achieved.

A series of antiviral compounds consisting of an intercalating acridine derived part, a spacer region and a reactive EDTA-derived conjugate was synthesized in an easy sequence. Suitably monoprotected 1,ω-alkyldiamines gave upon reaction with 6,9-dichloro-2-methoxyacridine (1) followed by deprotection and reaction with EDTA dianhydride the target molecules. In the presence of ascorbate a reduction of the phage-titer of the MS2 phages by > 8 logarithmic decades was achieved.

Two new complexes of manganese(II) and cobalt(II), [Mn(tptz)(OCH 3 CO)(H 2 O) 2 ]ClO 4 (1) and [Co(tptz) (OSO 3 ) (H 2 O) 2 ](H 2 O) 2 (2) {where tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine}, have been prepared and characterised by elemental analyses, spectroscopic, electrochemical studies and single crystal X-ray diffraction. Single crystal X-ray analysis reveals complexes of Mn(II) and Co(II), where tptz remains intact and behaves as a tridentate ligand and forms heptacoordinated Mn(II) and hexacoordinated Co(II) complexes for 1 and 2, respectively.

Syntheses of various classes of fused-imidazoles are reported. The key to their successful synthesis depends on the reaction of N-vinyl-1H-imidazole with the π-deficient compounds under basic conditions. Reaction of the target imidazole with 1,1,2,2-tetracyanoethylene and dimethyl acetylenedicarboxylate afforded pyrrolo[1,2-a]imidazoles. On the other site, reaction of the target imidazole with 2-dicyanomethyleneindane-1,3-dione, 2,3-dicyano-1,4-naphthoquinone gave indanylimidazolo- [1,2-a]azepine and imidazolo[2,1-a]phenanthridine derivatives, respectively. Under basic reaction condition, various classes of imidazolo[2,1-a]isoquinolines were obtained by the reaction of N-vinyl- 1H-imidazole with 2,3,5,6-tetrachloro-1,4-benzoquinone, 2,3-dichloro-1,4-naphthoquinone, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and 3,4,5,6-tetrachloro-1,2-benzoquinone.

From the aerial parts of the plant Verbascum salviifolium, two new iridoid glucosides, 6-O- β-D-glucopyranosylcatalpol (1) and 6-O-(6″-O-trans-p-hydroxycinnamoyl)- β -D-glucopyranosylaucubin (2) along with five known iridoid glycosides, 6-O- β -D-glucopyranosylaucubin (3), 6-O-α-L-rhamnopyranosylcatalpol (4), verbaspinoside [= 6-O-(2″-O-trans-cinnamoyl)-α-L-rhamnopyranosylcatalpol] (5), pulverulentoside I [= 6-O-(2″-O-trans-p-methoxycinnamoyl-3″ -O-acetyl)-α-L-rhamnopyranosylcatalpol] (6), and buddlejoside A 8 [= 6-O-(4″-O-trans-3,4-dimethoxycinnamoyl)- α-L-rhamnopyranosylcatalpol] (7) were isolated. The structures of the new compounds were established on the basis of spectroscopic evidence.

BaIrIn 2 was synthesized from the elements in a sealed tantalum tube in an induction furnace. The indide was investigated by powder and single crystal X-ray data: Cmcm, a = 443.3(1), b = 1151.3(2), c = 806.0(1) pm, wR2 = 0.0471, 352 F 2 values, and 16 variable parameters. The iridium and indium atoms build up two-dimensional [IrIn 2 ] 2− polyanions (279 - 281 pm Ir-In and 310-314 pm In-In) which are separated and charge-balanced by the barium atoms. The two-dimensional character of the polyanion is responsible for the strong moisture sensitivity of BaIrIn 2 . The coordination numbers for barium, iridium, and indium are 15, 9, and 12, respectively.

The indide SmRhIn (ZrNiAl type, P6̅2̅m, a = 750.93(8), c = 397.52(4) pm) was synthesized from the elements by arc-melting. SmRhIn orders antiferromagnetically at 8.0(5) K. The non-linearity of the temperature dependence of the inverse susceptibility points to a large van Vleck term for the samarium atoms. Magnetization measurements indicate a metamagnetic transition at a flux density of 3 T.

The crystal structure of 1,3-dicyclohexyl-4,5-dimethylimidazolium dicyanomethylide (6, [ImH][HC(CN) 2 ]), obtained from the carbene Im and malodinitrile, reveals the presence of ion pairs connected by NHC hydrogen bonds.