Volume 62, Issue 8

The crystal structure of the trihydrate of peramivir (C 15 H 28 N 4 O 4 ), a potential influenza A/B and avian-influenza drug, has been determined. The structure, belonging to the tetragonal space group P4 2 2 1 2 with Z = 32, a = 27.216(4), c = 23.084(5) Å, V = 17098(5) Å 3 , contains four organic molecules plus 12 partially disordered water molecules per asymmetric unit. 16 Organic molecules per unit cell form a kind of 1D infinite micelle separated from vicinal micelles by approximately planar water layers. During exposure to X-rays or under long-time storage on air peramivir trihydrate undergoes a phase transition to a structurally closely related phase with reduced water contents.

A star-shaped oligobenzoate with short peripheral propyloxy chains (1) forms single crystals 1· (Me 2 CO) 0.5 with a triclinic unit cell from acetone. The oligobenzoate arms are fully extended, possessing only carboxy groups with s-trans conformation. Aliphatic chains and oligobenzoate scaffold do not nano-segregate as proposed for other derivatives which assemble in liquid crystalline phases, but instead, the polar arms occupy the voids between arms of neighboring stars. Although a model based on this scenario may rationalize the small column diameter in the LC phase of longchain derivatives, the low density of the resulting material points rather to the recently established representation with folded conformers self-assembling in columns by nano-segregation.

Tris(dichloromethyl)amine (4), triformamide (1) and tris(diformylamino)methane (“formylaalen”) (2) can be activated by addition of trifluoromethanesulfonic acid. The formylating systems thus formed transform activated aromatic compounds, such as toluene, anisole or 2,4- dimethoxybenzene to the corresponding aldehydes. The formylating ability of systems from 4 and superacids, such as FSO 3 H, FSO 3 H/SbF 5 , C 4 F 9 SO 3 H, and mixtures of aluminum chloride with C 4 F 9 SO 3 H and chlorosulfonic acid, respectively, is compared. In general, low reaction temperatures (−20 to −10 °C) are necessary to obtain aldehydes with acceptable to good yields. Remarkably, at higher temperatures (~ 100 °C) compound 4 can also act as a formylating agent in the presence of suitable zeolites, as e. g. zeolite HBEA. Reaction mechanisms of the new formylation reactions are proposed.

The orthoamide derivatives 4 react with amidines 10 and guanidines 11 to give 4-dimethylaminopyrimidines 12. The 3-dimethylamino-pyrazoles 13a - c can be prepared from orthoamides 4 and hydrazine. The hydrazine derivative 14, whose constitution was established by crystal structure analysis, is obtained in low yield when hydrazine is added dropwise to a boiling solution of 4d in THF. Methyl- and phenylhydrazine, undergo reaction with the orthoamides 4a, c yielding mixtures of the isomeric pyrazoles 19 and 20. The reaction of 4c with acylhydrazines 21a - e affords the pyrazole 13b. The pyrazole 26 is produced in the reaction of 4a and acet-hydrazide according to this scheme, whereas 4a reacts with aromatic acid hydrazides 21c - e to give condensation products, which are presumably amidrazones 28. The 4,5-diaza-octatetraene derivative 30 results from the reaction of 4c with p-toluenesulfonylhydrazide. Ketene aminals 34a - c are the products of the reaction of the orthoamides 4b - d with 4,4-dimethylthiosemicarbazide 34, which cyclize on heating to give highmelting pyrazolethiones 35a - c. According to the crystal structure analysis of 35c the compounds have zwitterionic character and are associated via hydrogen bridges in the solid state.

Catalytic ring opening reactions of α-epoxyketones by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in methanol solution at r. t. and under reflux conditions resulted in the formation of α-hydroxy-β -methoxyketones through C β -O bond cleavage in excellent yields.Whereas the type and nature of the additional substituent affects the rate of ring opening, the effect of temperature has an extreme influence on the rate of reactions. Cyclic voltammetric studies of DDQ at 15 °C and 33 °C support the increased electron-acceptor ability of DDQ by the increasing of temperature.

Four additional meroterpenes were isolated and identified from rice cultures of Penicillium sp, a fungus obtained from the root bark of Melia azedarach. These new compounds were named preaustinoid B2 (1), preaustinoid A3 (2), austinolide (3), and isoaustinone (4) in analogy with the formerly described compounds. The structures were identified by extensive spectroscopic studies, including 1 D and 2 D NMR spectroscopy and HRMS. Compounds 1 - 4 are probably biosynthetic intermediates to Austin.

Ethyl 7,8-diamino-1-cyclopropyl-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylate (6) and its free acid 7 are prepared by chemical reduction of the respective 7-azido-8-nitroquinoline 5. Consecutive nucleophilic addition and cyclocondensation reactions of 6 with α-acetyl-N-arylhydrazonoyl chlorides 8a - c in ethanol and triethylamine are site-selective and yield the corresponding 3-(aryldiazinyl)- 2-methylpyrido[2,3- f ]quinoxalines 10a - c. Analytical and spectral (IR, MS, NMR) data of 6, 7, and 10a - c are in conformity with the assigned structures.

The crystal structures of Ni(AlCl 4 ) 2 , Ni(GaCl 4 ) 2 and Na[Ni(AlCl 4 ) 3 ] were determined by single crystal X-ray structure analysis. Ni(AlCl 4 ) 2 and Ni(GaCl 4 ) 2 are isotypic and crystallize in the Co(AlCl 4 ) 2 structure type (I2/c, a = 1276.40(9)/1268.48(7), b = 771.41(5)/757,74(3), c = 1145.47(8)/1154.34(7) pm, β = 92.067(3)/91.778(4)°, Z = 4). The structure contains chains of NiCl 6 octahedra and AlCl 4 /GaCl 4 tetrahedra linked by corners and edges. Na[Ni(AlCl 4 ) 3 ] represents a new structure type (P2 1 /c, a = 1356.34(6), b = 1200.82(6), c = 1213.31(6) pm, β = 105.647(6)°, Z = 4). Its characteristic feature is the chiral [Ni(AlCl 4 ) 3 ]− anion which is found here for the first time. The tetrachloroaluminate ions serve as bidentate ligands leading to an octahedral coordination of the nickel atom.

In the ternary system Ba-Al-Ge new intermetallic compounds which are lying on or close to the binary section BaAl 2 -BaGe 2 were synthesized from the elements and characterized on the basis of X-ray single crystal data. The Al-content x in the compounds BaAl x Ge 2−x forming the AlB 2 structure type ranges from x = 1.4 [BaAl 1.4 Ge 0.6 space group P6/mmm, a = 443.5(1), c = 512.4(1) pm, Z = 1, R1 = 0.0222] to the stoichiometric ordered compound BaAlGe [space group P6̅m2, a = 434.9(1), c = 513.6 pm, Z = 1, R1 = 0.0252]. In the two new Ge-rich barium intermetallics Ba 5 Al 2 Ge 7 [space group C2/m, a = 859.8(4), b = 1031.5(4), c = 1847.8(6) pm, β = 103.23(3)°, Z = 4, R1 = 0.0553] and Ba 7 Al 4 Ge 9 [space group Fmm2, a = 1032.7(5), b = 2559(2), c = 862.1(4) pm, Z = 4, R1 = 0.1197] complex Al/Ge polyanions are present, which consist of (1) Al/Ge-ribbons of condensed planar sixmembered rings comparable to the anions in Ba 3 Al 2 Ge 2 , and (2) [Ge/Al] 5 clusters comparable to the anions in the tetrelides Ba 3 M 5 . The building units (1) and (2) are connected via Al-Ge bonds to form complex ribbons in the case of Ba 5 Al 2 Ge 7 and sheets in the case of Ba 7 Al 4 Ge 9 . The electron count in the two compounds supports an interpretation of the structures according to the Zintl concept and the Wades rules. The small formal electron excess, caused by the incomplete transfer of charge from Ba towards the Al/Ge polyanions, decreases with the Ge content of the compound.

In the ternary systems Ca-Al-Ge and Sr-Al-Ge three germanides with new structure types have been synthesized from stoichiometric ratios of the elements. Their crystal structures were determined using single crystal X-ray data. In the structure of Sr 3 Al 2 Ge 4 (monoclinic, space group C2/m, a = 1267.6(4), b = 416.2(2), c = 887.4(3) pm, β = 110.37(2)°, Z = 2, R1 = 0.0354) Al-Ge sheets with Al in tetrahedral (i. e. Al − ) and Ge in threefold ψ-tetrahedral (i. e. Ge−) coordination against Ge are present. Thus, the compound can be classified as an electron precise Zintl phase. This finding is verified by the result of a band structure calculation (within the FP-LAPW approach), that shows a distinct minimum of the total density of states at the Fermi level. The structure of Ca 10 Al 6 Ge 9 (trigonal, space group R3̅m, a = 1398.45(14), c = 2107.4(3) pm, Z = 6, R1 = 0.0613) contains complicated sheets of trigonal planar building units [AlGe 3 ] and [AlGe 4 ] tetrahedra. The compound Ca 20 [Al 3 Ge 6 ] 2 [Ge] (hexagonal, space group P6 3 /m, a = 1600.9(2), c = 458.48(7) pm, Z = 1, R1 = 0.0282) shows two planar trimers of [AlGe 3 ] triangles of formula [Al 3 Ge 6 ] besides isolated Ge atoms (i. e. Ge 4− ). The overall electron count of the latter compounds, that contain trigonal planar coordinated Al atoms and considerable multiple bond character of the Al-Ge bonds, shows a very small deviation from the Zintl concept, comparable to the one observed in other aluminium-germanides like SrAlGe.

Me 3 Si-substituted indenes of type 1-SiMe 3 -3,4-(CH 2 ) 3 C 9 H 5 (9), 1-SiMe 3 -4-R-7-R′C 9 H 5 (11a, R = R′ = Me; 11b, R = R′ = Ph; 11c, R = Me, R′′ = Ph) and 1,1′ -(SiMe 3 ) 2 -4,7-Me 2 C 9 H 4 (12) were synthesised as precursors for piano-stool type halfsandwich indenyl-titanium trichloride complexes.Treatment of 9, 11, and 12 with equimolar amounts of TiCl 4 gives the complexes (η 5 -3,4-(CH 2 ) 3 C 9 H 5 )TiCl 3 (13), (η 5 -4-R-7-R′C 9 H 5 )TiCl 3 (14a, R =R′ = Me; 14b, R =R′= Ph; 14c, R = Me, R′ = Ph), and (η 5 -1-SiMe 3 -4,7-Me 2 C 9 H 4 )TiCl 3 (15), respectively, with liberation of Me 3 SiCl.Detailed UV/vis spectroscopic and cyclic voltammetric studies were carried out which allow a comparison of substituent effects in 13 - 15.

The reactions of anhydrous metal chlorides MCl 2 [M = Co(II), Zn(II), Pd(II)] with aziridines (az) in CH 2 Cl 2 at r. t. in a 1 : 5 molar ratio afforded the bis(aziridine)dichloro complexes M(az) 2 Cl 2 . After purification, all complexes were fully characterized. The solid state structures were determined using single crystal X-ray diffraction, and showed tetrahedral coordination geometries for the Co(II) and Zn(II) centers and trans-configurated square planar geometries for Pd(II).

Single crystals of (NH 4 ) 4 P 2 S 6 ・ 2H 2 O could be obtained and the crystal structure determined (monoclinic, P2 1 /c with a = 6.931(1), b = 12.730(2), c = 17.446(2) Å , β = 96.87(1)°, V = 1528.2(4) Å 3 , Z = 4). The NH 4 + , and [P 2 S 6 ] 4− ions and the water molecules are involved in an extended hydrogenbonding network. The FT-Raman and FT-IR spectra have been recorded and the observed vibrational frequencies assigned to tetrahedral NH 4 + and [P 2 S 6 ] 4− (D 3d ) ions as well as to H 2 O molecules. The thermogravimetric analysis has shown that (NH 4 ) 4 P 2 S 6 · 2H 2 O starts to decompose at around 60 °C (up to 170 °C), but no distinct intermediates could be observed.