Search Results

You are looking at 1 - 10 of 11 items

  • Author: Thomas Schenk x
Clear All Modify Search

Ruthenium thiolates [cpRu(PR′3)2(SR)] (PR′3 = PPh3,1/2 dppe, 1/2 dppm, R = Me, CH2Ph) are obtained from the corresponding chlorides and NaSR. PPh3 is readily exchanged for CO to give the chiral complexes [cpRu(PPh3)(CO)(SR)]. Alkylation with methyl tosylate yields the cations [cpRu(dppe)(SMeR)]+ and [cpRu(PPh3)(CO)(SMeR)]+, which were isolated as their PF6 - salts. The neutral carbonyls add dimethyl acetylenedicarboxylate giving five-membered metallocycles.

Ruthenium-sulfur dioxide complexes [cpRu(PR3)2(SO2)]Cl ((PR3)2 = (PPh3)2, Ph2PCH2PPh2(dppm), Ph2PC2H4PPh2(dppe)) add alkoxide to give sulfito complexes [cpRu(PR3)2(SO2OR′)] (R′ = Me, Et, /Pr). Reactions of [cpRu(dppm)(SO2)]Cl with LiR′ (R′ = Me, Bu, Ph), MgBrR′ (R′ = Et, CH=CH2) or ZnEt2 give sulfinato complexes [cpRu(dppm)(SO2R′)]. The structure of [cpRu(dppm)(SO2Et)] was determined by X-ray crystallography: Crystals are triclinic, space group P1̄, a = 11,008(1), b = 15,998(6), c = 17,813(2) Å, α = 92,30(2), β = 93,916(8), γ = 107,54(2)°, Z = 4. Salient features are a short Ru-S bond and relatively long S-O bonds which attest to the high π-donor ability of the pseudo-tetrahedral metal fragment.

Ruthenium thiolates [cpRu(PPh3),(SMe)] and [cp*Ru(PPh2Me)2(SR)] (R = Me, Ph) react with sulfur dioxide in two different ways, substitution of phosphine for SO2, and addition of SO2 to the thiolate ligand. The structure of [cpRu(CO)(PPh3)(SMe · SO2)] was determined by X-ray crystallography: Crystals are monoclinic, space group P21/n, a = 10.26(9), b = 16.00(6), c = 14.73(6) Å, β = 90.141(5)°, Ζ = 4. The most remarkable feature is a very long (247,8 pm) S—S single bond. [cp*Ru(PPh2Me)(SO2)(SPh)] and the corresponding sulfur monoxide complex [cp*Ru(PPh2Me)(SO)(SPh)] undergo [3+2] cycloaddition with dimethylacetylene-dicarboxylate.

Zusammenfassung:

Die hämophagozytische Lymphohistiozytose (HLH) ist ein Hyperinflammations-Syndrom, welchem neben genetischen Defekten insbesondere in Genen der die Immunsynapse regulierenden Proteine auch erworbene Defekte der effektiven Pathogen-Elimination zugrunde liegen. Das rasche Erkennen und zielgerichtete Diagnostizieren einer HLH ist bei weiterhin hoher Mortalitätsrate zwischen 40%–70% essentiell, um Therapieverbesserungen zu erreichen. Hierfür ist der wichtigste Schritt für den Kliniker, an eine HLH zu denken. Prolongiertes Fieber unklarer Genese, eine Hepatosplenomegalie und eine Bi- oder Panzytopenie sind die führende Symptomentrias. Bei bekannter Familienanamnese oder bekanntem Gendefekt sind rasche bestätigende Untersuchungen einzuleiten, um die häufig notwendige Stammzelltransplantation nicht zu verzögern. Insbesondere bei Erwachsenen, bei denen auch genetische Defekte mit verzögerter Manifestation vorliegen können (v.a. bei de novo EBV-Infektion), muss eine breite Diagnostik zur Ursachenforschung einer HLH angestrengt werden. Die HLH ist keine eigenständige Erkrankung. Sie ist gemeinsame Endstrecke eines Immundefekts, welcher genetisch bedingt, oder durch infektiöse, autoimmune, autoinflammatorische, maligne oder auch iatrogene Trigger (Immunsuppression, Stammzelltransplantation) erworben werden kann. Diesem breiten Spektrum der Pathogenese der HLH muss die labormedizinische Diagnostik Rechnung tragen, um dem Kliniker sehr zeitnah die klinisch zu stellende Verdachtsdiagnose zu erhärten und schnellstmöglich die Therapie einleiten zu können.

Abstract

Cytomegalovirus (CMV) infection is a common complication in the postoperative course of liver transplantation. In order to start early prophylactic therapy, but to avoid unnecessary treatment, or expensive screening, a desirable goal in post-transplant monitoring is to find appropriate markers in standard laboratory diagnostics. In the present study, the results of a 6-week CMV replication monitoring schedule by the pp65 antigenemia assay in 100 liver graft recipients were included. The activities of transaminases, glutamate dehydrogenase and γ-glutamyl transpeptidase (γ-GT) were measured by routine laboratory methods. In contrast to the transaminases, the serum activity of γ-GT increased during the first postoperative week. The maximum levels were 246 ± 211 U/l in patients without (n= 46) and 140 ± 89 U/l in patients with early CMV replication (n = 54; p = 0.02). Patients with γ-GT levels below 200 U/l on the 5th postoperative day (n = 72) had a CMV replication risk of 65%, whereas those patients with γ-GT levels above this threshold had a risk of 30% (n = 28; p = 0.0007; relative risk = 2.9). These findings provide a routinely usable marker for the identification of patients at an increased risk of CMV replication. It can be considered that these phenomena may be caused by an additional immunosuppressive effect of the CMV virus.

Nucleophilic phosphanylation of ortho-fluorophenylacetic acid or ortho-fluorobenzylamine with PhPH2 using KOtBu as the base affords the hydrophilic tertiary phosphanes 3 and 4a with terminal CH2-COOH and CH2-NH2 substituents. The corresponding secondary phosphane ligands 2 or 5 may be obtained by Pd-catalyzed P-C coupling of ortho-iodophenylacetic acid with PhPH2 or selective nucleophilic phosphanylation of ortho-fluorophenylacetic acid. Novel phosphonatomethyl derivatives 7a, 7b of triphenylphosphane have been obtained in a two stage synthesis using ortho-iodobenzylchloride or meta-iodobenzylbromide as starting materials. Arbusov reaction with P(OEt)3 and Pd-catalyzed P-C coupling reactions with Ph2PH gave the esters 7a, 7b. Purification of 7a was achieved via its BH3 adduct 8a. Deprotection, hydrolysis and neutralisation with NaOH affords the water soluble sodium salts 9a,9b. α-Hydroxy and α-benzylamino derivatives 12 and 14 of ortho-diphenylphosphanobenzyl phosphonate (e.g. 7a) and the corresponding Me2P(O) analogs 13 and 16 are accessible in a straightforward manner by addition of (MeO)2P(O)H or Me2P(O)H to ortho-phosphanobenzaldehyde 11a or its benzaldimino derivative 15, respectively. An improved synthesis for 11a -11c has been developed. Reaction of 11a with the Wittig reagent Ph3P=C(H)COOEt and subsequent hydrolysis of the intermediate ester 17a affords ortho-diphenylphosphano cinnamic acid 17. The catalytical activity of 1,9a, 9b and related ligands in Suzuki-type coupling reactions has been investigated.

Immunoscreening of a C. paradoxa expression library against water soluble muroplast (“cyanelle”) proteins resulted in isolation of a clone encoding the nucleus-encoded muroplast class-II fructose-1,6-bisphosphate aldolase (class-II FBA§). Its nucleotide sequence was determined. The 1432 bp insert, derived from a single-copy gene transcript, bears a reading frame of 1206 bp in length, representing 402 amino acids with 346 amino acids of mature protein. The leading amino acids match structural features necessary for precursor import across chloroplast envelope membranes. In phylogenetic tree topology, the investigated mature FBA clusters within type B FBAs with Synechocystis sp. as nearest neighbor. This is the first report of a Type B class-II FBA sequence of plastids.

Abstract

Cabalzarite, M1CaM2(Mg,Al,Fe3+ )2(XAsO4)2(H2O,OH)2, is a new mineral of the tsumcorite group occurring in altered Mn ore at the abandoned Falotta mine (Swiss Alps). Together with other arsenates, cabalzarite documents the mobility of As during the retrograde stage of the Tertiary Alpine metamorphism under lowest to sub-greenschist facies conditions. Cabalzarite crystals vary in morphology from hatchet-like to fibrous and tabular. The color is light-brownish to salmon pink or orange brown, and the average refractive index is around 1.7. Cabalzarite is chemically inhomogeneous, with the main variations occurring on the octahedral M2 site occupied by Mg, Al, Fe3+ , and Mn3+ . Al and Mg are the dominant M2 cations, with Al/(Al + Mg) ratios varying between 0.31 and 0.59 (92 analyses). Cabalzarite is the first member of the tsumcorite group with octahedral Mg and Al as major constituents. Single-crystal X-ray structure refinements were performed on two different crystals. Cabalzarite is monoclinic, space group C2/m, Z = 2. The cell parameters for the type crystal CABA11.5, of composition (Ca1.00Sr0.02)(Al0.80Mg0.77Fe0.23Mn0.03)Σ1.83(AsO4)2(H2O1.26OH0.74)2, are a = 8.925(2) Å, b = 6.143(1) Å, c = 7.352(1) Å, β = 115.25(3)˚, ρcalc = 3.73 g/cm3. The structure of cabalzarite is isomorphic with that of tsumcorite. The site M1 (Ca) is eightfold-coordinated (6 + 2) with average M1-O = 2.549 Å; M2 is octahedral with an average M2-O = 2.010 Å; and the average As-O distance of the arsenate group is 1.689 Å. Charge balance for the simultaneous occupation of M2 by two- and three-valent cations is achieved by H2O as well as OH contributing to the M2 coordination.