Showing papers by "University of Duisburg-Essen published in 1990"

Zur Reaktion des Diphosphenyl‐Komplexes (η5‐C5Me5)(CO)2Fe – P=P – Aryl (Aryl = 2,4,6‐tBu3C6H2) mit elektronenarmen Alkenen. Röntgenstrukturanalyse des Diphosphetans

Abstract: Transition-Metal-Substituted Diphosphenes, XVIII1). – On the Reactivity of the Diphosphenyl Complex (η5-C5Me5)(CO)2Fe – P=P – Aryl (Aryl = 2,4,6-tBu3C6H2) with Electron-Deficient Alkenes. X-ray Analysis of the Diphosphetane The transition-metal-substituted diphosphene (η5-C5Me5)(CO)2Fe – P=P – Aryl (1) reacts with fumarodinitrile (2a) to give the 1,2 diphosphetane all-trans- as the result of a [2 + 2] cycloaddition. Similarly, compound 1 is converted by either dimethyl fumarate (2b) or dimethyl maleate (2c) into the same cycloadduct all-trans- (3b). Diphosphetane 3a was completely characterized by a single-crystal X-ray analysis.

Pyrazole‐Organoboranes, VI. Monomeric and Dimeric 9‐Pyrazolyl‐9‐borabicyclo[3.3.1]nonanes

Abstract: Bis(9H-9-borabicyclo[3.3.1]nonane) (9H-9-BBN)2 reacts with pyrazole (Pz) and its 4-bromo, 3-methyl, 3-phenyl, 3,5-dimethyl, 3-methyl-5-phenyl, 3,5-diphenyl, 3,5-di-ert-butyl, 3,5-diadamantyl, 3,5-di-tert-butyl-4-methyl, and 3,5-di-tert-butyl-4-ethyl derivatives [brPz, mPz, pPz, m2Pz, mpPz, p2Pz, (tb)2Pz, (ad)2Pz, (tb)2mPz, and (tb)2mPz, and (tb)2ePz, respectively] to give the 9-pyrazolyl-9-borabicyclo[3.3.1]nonanes with the dimeric structure (1)2–(3)2 (X-ray, NMR, and MS analysis), and 4–11 with monomeric structures (X-ray, NMR, MS).

Organosubstituierte 1,6-Dioxa-2-sila-5-bora-3-cycloalkene – Herstellung und Charakterisierung

Abstract: Organosubstituted 1,6-Dioxa-2-sila-5-bora-3-cycloalkenes – Preparation and Characterisation1) The cis-alkenes ROSi(CH3)2C(R) C(C2H5)B(C2H5)OR (R CH3: 11; C2H5: 12; C6H5: 13) are prepared from CH3NSI[CH3)2C(R)C(C2H5)BC2H5 [R CH3: A; R C(CH3) CH2: B] with the monohydroxy compounds ROH (R CH3, C2H5, C6H5). A or B react with aliphatic dihydroxy compounds HOR′OH [R′ CH2CH2: 1; CH(CH3)CH2: 2; CH(CH3)CH(CH3): 3; C(CH3)2C(CH3)2: 4; (CH2)3: 5; (CH2)4: 6] to give 8-, 9-, and 10-membered ring compounds OSi(CH3)2C(R) C(C2H5)OR′ [15a,b, 16/16′, meso/rac-17a, D-17a,b, 18, 19, (20)n]. A is initially cleaved at the SiN bond with formation of 14 Compound 15a crystallises as the 16-membered (15a)2 [X-ray structure analysis). The aromatic dihydroxy compounds catechol (7), resorcinol (8), 2,3-dihydroxynaphthalene (9), 1, 8-dihydroxynaphthalene (10) react with A to form 21 to 24, but mainly by protolytic BCvinyl fission to give the 2,5-dihydro-1,2,3-dioxaboroles (e.g. 7f1, 9f1, 10f1) and the acyclic boron-free compounds 7f′3, 9f3, 10f3. The MS and NMR (1H, 11B, 13C, 29Si) data of the new compounds are discussed.

Nitrogen Base – Dialkyl-1,2,4,3,5-triselenadiborolanes

Abstract: Stickstoffbase – Dialkyl-1,2,4,3,5-triselenadiborolane 3,5-Dialkyl-1,2,4,3,5-triselenadiborolane RBSe3BR (1) [R = C2H5 (1a) und R = C3H7 (1b)] bilden bei Raumtemperatur mit uberschussigen N-Basen [Pyridin (P), 3,5-Dimethylpyridin (m2P), 3-Chlorpyridin (cP) und Chinuclidin (Q)] stabile 2:1-Additionsverbindungen [P2-1a,b, (m2P)2-1a, cP-1a, Q2-1a, b]. In Losung existieren Gemische von (syn/anti)Q2-1a (1H-, 11B-NMR). (syn)Q2-1a steht bei –80°C mit Q-1a und Q im Gleichgewicht. Festes Q2-1a liegt als (anti) Q2-1a vor (Kristallstrukturanalyse). In Losung bilden 1 bei Raumtemperatur mit aquimolaren Mengen an N-Basen die 1:1-Addukte [(N-Base)-1], in denen nur ein Bor-Atom vierfach koordiniert ist. 1: 1-Addukte mit fluktuierender N-Base zwischen den beiden Bor-Atomen werden bei Temperatursteigerung beobachtet (120°C: 11B-NMR). Hexamethylentetramin (Ur) bildet stabile, feste 1: 1- und 2: 1-Addukte (Ur-1a, Ur2-1a).

Übergangsmetall-substituierte Diphosphene, XIX. Zur Reaktivität von Disilylphosphido-Eisenkomplexen gegenüber 2,4,6-(CF3)3C6H2PCl2 und 2,6-(CF3)2C6H3PCl2 — Diphosphenylkomplexe mit Fluorarylsubstituenten

Abstract: Transition-Metal-Substituted Diphosphenes. XIX. - On the Reactivity of Disilylphosphido Iron Complexes towards 2,4.6-(CF3)3C6H2PCl2 and 2.6-(CF3)2C6H3PCl2. Diphosphenyl Complexes with Fluoroaryl Substituents (η5-C5Me5)(CO)2FeP(SiMe3)2 (2a) and (η5-C5H5)(CO)(PPh3)-FeP(SiMe3)2 (2c) react with ArylPCl2 [3a: Aryl 2,4,6-(CF)3-C6H2; b: Aryl 2,6-(CF)2C6H3] to yield the thermolabile diphosphenyl complexes (η5-C5Me5)(CO)2FePP-Aryl (4a,b) and (η5-C5H5)(CO)(PPh3)FePP-Aryl (4c,d), respectively. The isolation of the pure compounds 4a-d failed. They are, however, intercepted as their (CO)5Cr adducts 5a–d by treatment with [(Z)-cyclooctene]Cr(CO)5- Complex (η5C5Me5)(CO)2FeP[Cr(CO)5] P-C6H2(CF3)3-(2,4,6) (5a) is characterized by single-crystal X-ray diffraction analysis.

Pyrazole-Organoboranes, VII. Addition Complexes of Pyrazolylboranes

Abstract: The monomeric 9-pyrazolyl-9-borabicyclo[3.3.1]nonanes react in situ with either excess of 9H-9-BBN or of some pyrazoles to form the 2:1 or 1:2 adducts 1–5 or 7–11, respectively. Spectroscopic data (NMR, IR) suggest and the solid state structure of 4 confirms the presence of a central heterocycle in complexes of the type 1–5. In solutions of 7–11 NMR data at room temperature indicate a rapid exchange of the four nitrogen atoms of the two pyrazole rings at the boron atom of the 9-BBN moiety. In the solid state (X-ray structure of 8) intermolecular N–H N bonds lead to dimeric structures. In the almost insoluble adduct 7 a polymeric structure is suggested. Pyrazoles with large substituents, e. g. 3,5-diphenylpyrazole (P2Pz) give addition complexes of the type 1–5 only in solution in equilibrium with the corresponding monomeric species (11B NMR) and none of the type 7–11.

Recombinant human granulocyte-macrophage colony-stimulating factor and low-dose cytosine-arabinoside in the treatment of patients with myelodysplastic syndromes. A phase II study.

Abstract: As part of a multicenter trial 12 patients with myelodysplastic syndromes (MDS) were treated with 14-day-cycles of recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF; 250 μg/

9-Fluor-9-borabicyclo[3.3.1]nonan - Charakterisierung in Lösung und im Kristall

Abstract: 9-Fluoro-9-borabicyclo[3.3.l]nonane — Characterization in Solution and in the Solid State 9-Fluoro-9-borabicyclo[3.3.1]nonane (1), prepared from bis(9-borabicyclo[3.3.1]nonane) with SbF3 or SbF5 in high yields, is characterized by IR, mass, and multi-NMR spectroscopy. Pure 1 in solution has a small 11B-NMR singlet signal in contrast to the freshly prepared 1 with the normal JPB-split 11B resonance. The X-ray structure analysis of 1 with three differently bonded molecules I–III (Abb. 2) in the cell shows a monomer and a dimer of 1 with DFB coordination bond. – Some Lewis base adducts of 1 are prepared, the others were characterized by 11B-NMR spectra.

Zur Reaktivität von Phosphaalkenyl‐ und Phosphavinyliden‐Komplexen des Molybdäns und Wolframs gegenüber dem Schwefelylid Me2S(O)=CH2 Röntgenstrukturanalyse von

Abstract: Transition-Metal-Substituted Acylphosphanes and Phosphaalkenes. XIV. – Transition-Metal Sulfur Ylide Complexes, XXVIII. – Reactivity of Phosphaalkenyl and Phosphavinylidene Complexes of Molybdenum and Tungsten towards the Sulfur Ylide Me,S(O) = CH2. X-ray Structure Analysis of The phosphavinyliden complexes (η5-C5H5)(CO)2M=P=C(SiMe3) 2 [3, M = Mo (a); W (b)] react with equimolar amounts of sulfur ylide Me2S(O)=CH2 (2) to afford the red metallophosphane-substituted sulfur ylides (η5-C5H5)(CO)2M=P[CH-(SiMe32][CH=S(O)Me2] (5a, b). Compounds 3a, b as well as 5a, b are trans-formed to the metallaheterocycles (η5-C5H5)- (6a, b) by excess of ylide. Constitution and configuration of 5 and 6 were established by spectroscopic means (IR, 1H, 13C, 31P NMR and MS). In addition, the molecular structure of 6a was elucidated by single crystal X-ray diffraction analysis.

B2N4Se‐Bicyclo[2.2.1]heptanes and B2N4Se2‐Bicyclo[2.2.2]octanes

Abstract: B2N4Se2-Bicyclo[2.2.2]octanes Aus 3,5-Dialkyl-1,2,4,3,5-triselenadiborolanen [Alkyl = C2H5 (1a) und Alkyl = n-C3H7 (1b)] werden mit Pyrazol (Pz), 3-Methylpyrazol (mPz) und 3-Phenylpyrazol (pPz) die Diselenabicyclo[2.2.2]octane 2–4 hergestellt. Demgegenuber reagieren 3,5-Dimethyl- und 3,5-Diphenylpyrazol (m2Pz, P2Pz) mit 1a zu den Monoselenabicyclo[2.2.1]heptanen 5 und 6. Von 2a und 5 liegen Kristallstrukturanalysen vor.

Organobor‐Schwefel‐Verbindungen mit Bicyclo[x.3.0]alk‐3‐en‐Struktur — Herstellung und Charakterisierung

Abstract: La reaction de (E)-ClSi(CH 3 ) 2 C(R 3 )=C(C 2 H 5 )B(C 2 H 5 )Cl [R 3 =CH 3 (A) ; R 3 =C(CH 3 )=CH 2 (B) avec LiS(CH 2 ) n SLi (n=2 a 4) donne des derives de Thionathiasilaboratabicycloalcene. Ces composes se coordinent avec Fe(CO) 4 et Cr(CO) 5 . La reaction de 1,2-bis[lithiothio] benzene avec C(A) fournit un derive de thionathiasilaboratatricyclododecatetraene. Analyse de sa structure par RX. La reaction de 1,3-bis [lithiothio] benzene avec (A) conduit au (hexamethyl tetradeshydro tetraethyl) tetrathiadisilodibora [«6.6»] metacyclosphane

Maximal immediate extensions are not necessarily maximally complete

Abstract: An extension Rl of a right chain ring R is called immediate if Rl has the same residue division ring and the Same lattice of principal right ideals as R . Properties of such immediate extensions are studied. It is proved that for every R , maximal immediate extensions exist, but that in contrast to the commutative case maximal right chain rings are not necessarily linearly compact.

Säurekatalysierte Umlagerung von Tetracyclo[6.3.0.04,11.05,9]undec‐6‐en‐2‐on

Abstract: La reaction de tetracyclo [6.3.0.0 4,11 .0 5,9 ] undecene-6one-3 avec l'acide formique donne un melange de formate d'oxo-2 tetracyclo [6.3.0.0 4,11 .0 5,9 ] undecyle-6 (ou 7) et d'un compose pentacyclique. Le compose du titre reagit avec l'α-diazo diphenylmethane ou le N-oxyde benzonitrile pour donner des derives de diazapentacyclotetradecene et d'oxaazapentacyclotetradecene

Synthese und seitenselektive Diels-Alder-Reaktion von Homodehydroisodicyclopentadien

Abstract: Synthesis and Face-Selective Diels-Alder Reaction of Homodehydroisodicyclopentadiene Under alkaline conditions the mesylate 6c, obtained from the tetracyclic ketone 6b fragments into the enone 8a. The latter is transformed via alcohol 9 into the homodehydroisodicyclopentadiene 3 and via tosylhydrazone 8b into the triene 4. Cyclopentadiene 3 reacts with a series of non-acetylenic dienophiles from the sterically less hindered side to give the products 14-17. Acetylenic dienophiles yield the adducts 19–22 in a 1:1 ratio. The UV and PE spectra of triene 4 are discussed.

[Value of microbiologic studies for diagnosis of post-enteritis reactive arthritis].

Abstract: Reactive arthritis may develop within a period of some days until upto 3 weeks after infections with Yersinia enterocolitica, Yersinia pseudotuberculosis, Campylobacter jejuni/coli, Shigella and Salmonella. Intestinal infections with Klebsiella pneumoniae, Clostridium perfringens, Clostridium difficile, Cryptosporidium, Strongyloides stercoralis, Taenia saginata and Schistosoma mansoni are, in some cases, considered to be responsible for reactive arthritis. Detection of pathogenic bacteria in feces is generally most successful in the early stage of the infection. A large spectrum of special tests is required in order to detect all the causative agents and to ensure reliable results. It is therefore necessary that the laboratory is provided with information about the diagnostic object and the tentative diagnosis. The detection of serum antibodies to Y. enterocolitica, Y. pseudotuberculosis, C. jejuni/coli, and Schistosoma may suggest connections between infection and reactive arthritis.

A Novel Slipped Tripledecker Complex with a 3,4-Diborafulvene as Bridging Ligand.

Abstract: Reaction of the 3,4-diboratafulvene deriv. Li2[CH2C[CHB(NEt2)]2] (I) with [RhCl(COD)]2 (COD = cyclooctadiene) gives m-[1-5-h5:1,2,5,6-h4-[CH2C[CHB(NEt2)]2]][Rh(h-COD)]2 (II), the first 3,4-diborafulvene complex which possesses a doubly-opened triple-decker structure with a bridging 3,4-diborafulvene ligand. The crystal structure of II was detd. I serves as a gallium nitride precursor.

Influence of treatment modality, patient/donor characteristics, and disease stage on the risk of relapse after allogeneic marrow transplantation for acute leukemia.

Abstract: For patients with acute leukemia, allogeneic marrow transplantation (BMT) following myeloablative radiochemotherapy currently represents the most effective treatment to reduce the risk of leukemic recurrence. Approximately 50% of patients receiving allografts in first remission (CR) of acute myeloid leukemia (AML) or acute lymphoblastic leukemia (ALL) have become long-term survivors [1]. Substantial evidence for the high antileukemic efficacy of BMT comes from experiences in adult patients treated after first remission, who seldom achieve lasting remissions by conventional chemotherapy. Patients undergoing BMT in first early relapse or second remission still have a 25%–30% chance of becoming long-term disease-free survivors. A significant, albeit low, rate of long-term remissions and possibly cures has also been demonstrated in patients receiving allografts in end-stage relapse. Nevertheless, leukemic relapse still remains a prominent cause of treatment failure.

Allogeneic and autologous bone marrow transplantation in acute leukemia: the Essen Experience.

Abstract: Chemo-/radiotherapy followed by bone marrow transplantation from sibling donors has been used successfully in many centers to treat patients with leukemia in whom primary chemotherapy failed or who were at high risk for relapses after therapy. However, only 30%–40% of patients have a matched allogeneic marrow donor. Therefore several groups initiated programs of autologous bone marrow transplantation with or without attempts to remove residual leukemic cells from the transplant by in vitro purging methods.

Complotyping and Subtyping of MHC Class I Gene Products in Haplotype Determination for Bone Marrow Transplantation

Abstract: In order to prevent major histocompatibility complex (MHC)-induced graft-versus-host disease (GvHD) after allogeneic bone marrow transplantation (BMT), the best possible match between donor and recipient is achieved between monozygotic twins [1]. It is well known that this is only possible in very few patients. In cases where parents share an HLA haplotype, or are phenotypically homozygous, or even appear to be identical, problems in the inheritance of HLA haplotypes among the offspring do occur. These uncertainties cannot be solved by the serological HLA typing or cellular typing of HLA-D-encoded gene products. For that reason we introduced two following additional biochemical typing methods: 1. Complotyping, i.e., definition of the MHC-encoded polymorphic complement components Bf, C2, C4A, and C4B. The C4A and C4B allotypes are as polymorphic as the HLA-A and HLA-B antigens, with 12 C4A and 18 C4B variants. In addition, a duplication of one of the C4 genes is observed in 1% of the cases [2]. 2. Subtyping of class I gene products by one-dimensional isoelectric focusing (1D-IEF). As we showed recently, the application of 1D-IEF followed by an immunoblotting raises the number of serologically defined antigens by nearly 60% [3, 4].