V. Lamm

A cyclopentabenzopyranone produced by the fungus heterobasidion annosum in dual cultures

Abstract A crystalline compound secreted by hyphae of Heterobasidion annosum in the presence of the antagonistic fungi Radulomyces confluens, Gloeophyllum abietinum, Trametes versicolor or Nectria fuckeliana was isolated. By both spectral and X-ray structure analysis, the compound was identified as 7,8-dihydro-9-hydroxy-5,7,7-trimethylcyclopenta-(g)-2-benzopyran- 1( 6H )-one.

Doppelte Kupplungsreaktion eines Diazoniumsalzes mit 2,10-Dimethoxy-1,6-methano[10]annulen sowie Röntgenstrukturanalyse / Double Coupling Reaction of a Diazonium Salt with 2,10-Dimethoxy-1,6-methano[10]annulene and X-Ray Structure Analysis

The synthesis of 8a by coupling reaction of 2.10-dim ethoxy-1,6-m ethano[10]annulene (6) with 2-nitro-4-chlorophenyl-diazonium-tetrafluoroborate (7) as well as its spectroscopic properties are described; an X-ray structure analysis of 8 a × CHC13 is reported.

Die Kristallstrukturen des Benzo[1.2-c:3.4-cʹ]bis[1.2.5]thiadiazols und des semihomologen [1.2.5]Selenadiazolo[3.4-e]-2.1.3-benzothiadiazols [1]/The Crystal Structures of the Benzo [1,2-c : 3,4-cʹ]bis[1,2,5]thiadiazole and of the Semihomologous [1,2,5]Selenadiazolo[3,4-e]-2,1,3-benzothiadiazole [1]

The X-ray structure analyses of the title compounds 1 and 2 were performed. 1: monoclinic, C 2/c, a = 9.532(2), b = 11.469(2), c = 7.030(3) Å, β = 110.58(2)°, Z = 4; 2: monoclinic, P21/a, a = 7.650(2), b = 7.729(2), c = 12.948(3) Å, β = 74.26(2)°, Z = 4. The structure of 1 was solved by direct methods, that of 2 by Patterson- and successive Fourier-synthesis techniques. The least squares refinement converged for 894 independent reflections with I > 2δI to an R-value of 0.032 (Rw = 0.035) in the case of 1 and for 1440 independent reflections to an R-value of 0.045 (Rw = 0.045) in the case of 2. The bond lengths in the [1,2,5]thiadiazole rings in 1 and 2 and also in the Se-homologous ring in 2 indicate to a quasi-aromatic π-system, whereas the aromatic character of the central benzene ring in 1 and 2 is strongly disturbed. The substitution of one S by the homologous Se in 2 induces significant changes of comparable bond lengths in 1 and 2. In the crystal structures of both compounds molecular layers and columnar stacks are formed. Quasipolymers in form of ribbon like structures are established in 1 by short S···N contacts and in 2 by short Se···N contacts. In 2 (SeN2)x-chains are formed.

Röntgenstrukturanalyse von N-[3,3-Dimethyl-5,5-bis- (trifluormethyl) -1 -pyrazolinio] pentafluoranilid / X-ray Structure Analysis of N-[3,3-Dimethyl-5.5-bis(trifluoromethyl)- ] -pyrazoliniojpentafluoroanilid

The title compound crystallizes in the monoclinic space group P21/n with a - 8.761(3), b - 9.773(5), c = 18.727(7) Å, y = 100.86(3)°, V = 1574.7.Å3, Z = 4. The structure was solved by direct methods and the refinement converged for 2030 independent reflections to an JR-value of 0.060 (Rw = 0.071). The N-N distances in the mesoionic -N⊖-N⊕(R) = Nmoiety are asymmetric with 1.304 and 1.263 Å, respectively. The almost planar heterocyclic pyrazolinium ring system and the plane of the aromatic pentafluorophenyl group include an angle of 60° caused mainly by a torsion around the N-C bond to the phenyl ring. The crystal packing contains columnar stacks of parallel phenyl rings with distances of 3.30 and 3.35 Å. Also H-F contacts play a dominant role