Synthesis of a Dinuclear μ-(η2-Thioaldehyde)zirconocene Cation Complex

2002 ◽  
Vol 57 (10) ◽  
pp. 1184-1188 ◽  
Author(s):  
Silke Courtenay ◽  
Sarah Smith ◽  
Emily Hollink ◽  
Ulrich Blaschke ◽  
Gerald Kehr ◽  
...  
Keyword(s):  
Similar Reaction ◽  
Subsequent Reaction ◽  
Rapid Elimination ◽  
Cation Complex

Treatment of (butadiene)zirconocene with two molar equivalents of benzylmercaptane results in the formation of Cp2Zr(SCH2Ph)2 (11). Subsequent reaction of 11 with [Cp2ZrCH3+][CH3B(C6F5)3-](12) leads to rapid elimination of methane to yield the dinuclear [μ-(η2-thiobenzaldehyde)(μ-SCH2Ph)(ZrCp2)2+] cation complex 14. A similar reaction is observed upon treatment of Cp2Zr(SC2H5)2 (15) with 12 to yield the thioacetaldehydebridged dinuclear metallocene cation complex Cp2Zr-μ-(η2-MeCHS)-μ-(SEt)ZrCp2 (16).

Reaction of some nucleophiles with 2,6-di-tert-butylpyrylium perchlorate

1987 ◽  
Vol 52 (5) ◽  
pp. 1305-1314 ◽  
Author(s):  
Stanislav Böhm ◽  
Renata Prantová ◽  
David Šaman ◽  
Petr Trška ◽  
Josef Kuthan
Keyword(s):  
Hydrogen Sulfide ◽  
Sodium Borohydride ◽  
Ammonium Acetate ◽  
Sodium Cyanide ◽  
Pyridine Derivative ◽  
Similar Reaction ◽  
Subsequent Reaction ◽  
Tert Butyl ◽  
Electrophilic Reagents ◽  
Pyran Derivative

The title compound IV reacted with sodium borohydride to give the 4H-pyran VIIa and the dienone VIIIa whereas its reaction with sodium cyanide afforded exclusively the dienone VIIIb. Reaction of the salt IV with tert-butylmagnesium chloride or bromide gave a mixture of the 4H-pyran VIIa and the corresponding 4-tert-butyl derivative V. Upon treatment with hydrogen sulfide and hydrogen chloride, this mixture afforded 2,4,6-tri-tert-butyl-4H-thiopyran XI whereas aromatization with chloranil and subsequent reaction with ammonium acetate resulted in 2,4,6-tri-tert-butylpyridine (X). Analogously, the perchlorate IV reacted with ammonium acetate to give 2,6-di-tert-butylpyridine (VI). Addition of triphenylphosphine and potassium phthalimide to IV afforded exclusively the 4H-pyran derivatives XII and XIII. A similar reaction of nitromethyl anion led to the 4,4'-bis(4H-pyran) derivative XIV. Mechanism of the studied reactions and the reasons for the low reactivity of the sterically hindered pyridine derivative VI with electrophilic reagents are discussed.

Scalable Synthesis of Functionalized Ferrocenyl Azides and Amines Enabled by Flow Chemistry

2019 ◽  
Author(s):  
Merlin Kleoff ◽  
Johannes Schwan ◽  
Lisa Boeser ◽  
Bence Hartmayer ◽  
Mathias Christmann ◽  
...  
Keyword(s):  
Reaction Time ◽  
Heterogeneous Reaction ◽  
Reduction Process ◽  
Flow Chemistry ◽  
Subsequent Reaction ◽  
Scalable Synthesis ◽  
High Yields ◽  
Reactor Section

A scalable access to functionalized 1,1’- and 1,2-ferrocenyl azides has been realized in flow. By halogen‒lithium exchange of ferrocenyl halides and subsequent reaction with tosyl azide, a variety of functionalized ferrocenyl azides was obtained in high yields. To allow a scalable preparation of these potentially explosive compounds, an efficient flow protocol was developed accelerating the reaction time to minutes and circumventing accumulation of potentially hazardous intermediates. Switching from homogeneous to triphasic flow amidst process was key for handling a heterogeneous reaction mixture formed after a heated reactor section. The corresponding and synthetically versatile ferrocenyl amines were then prepared by a reliable reduction process.

Safety of a Clozapine Trial Following Quetiapine-Induced Leukopenia: A Case Report

2019 ◽  
Vol 14 (1) ◽  
pp. 80-83 ◽  
Author(s):  
Asma H. Almaghrebi
Keyword(s):  
Treatment Options ◽  
Young Female ◽  
Similar Reaction ◽  
Careful Monitoring ◽  
Treatment Resistant ◽  
Blood Cell Count ◽  
Antipsychotic Medications ◽  
Case Presentation ◽  
Clozapine Treatment ◽  
History Of

Background: The clozapine-derivative quetiapine has been shown in some cases to cause leukopenia and neutropenia. Case Presentation: We reported on a case of a young female diagnosed with treatment-resistant schizophrenia. After failed trials of three antipsychotic medications and despite a history of quetiapineinduced leukopenia, clozapine treatment was introduced due to the severity of the patient’s symptoms, the limited effective treatment options, and a lack of guidelines on this issue. Result: Over a ten-week period of clozapine treatment at 700 mg per day, the patient developed agranulocytosis. Her white blood cell count sharply dropped to 1.6 &#215; 10<sup>9</sup> L, and her neutrophils decreased to 0.1 &#215; 10<sup>9</sup> L. There had been no similar reaction to her previous medications (carbamazepine, risperidone, and haloperidol). Conclusion: The safety of clozapine in a patient who has previously experienced leukopenia and neutropenia with quetiapine requires further investigation. Increased attention should be paid to such cases. Careful monitoring and slow titration are advisable.

The melanocyte stimulating activity of N-nitroso-2-chloroethyl-carbamoyl derivatives of α-melanotropin fragments

1988 ◽  
Vol 53 (11) ◽  
pp. 2574-2582 ◽  
Author(s):  
Hedvig Medzihradszky-Schweiger ◽  
Helga Süli-Vargha ◽  
József Bódi ◽  
Kálmán Medzihradszky
Keyword(s):  
Biological Activity ◽  
Active Site ◽  
Frog Skin ◽  
Terminal Sequence ◽  
Subsequent Reaction ◽  
Affinity Labels ◽  
Derivatives Of

A number of N-nitroso-2-chloroethyl-carbamoyl (Q(NO)) derivatives of α-melanotropin fragments have been synthesized and their effect on the frog skin melanocytes studied. Peptides substituted in this way possess the biological activity of the parent compounds, indicating that they preserved their receptor recognizing ability. These compounds can therefore serve as affinity labels. Some of these derivatives, related to the C-terminal sequence of α-melanotropin show prolonged darkening reaction, which does not influence the subsequent reaction of melanocytes with α-melanotropin. The Q(NO)-derivative of a fragment derived from the classical active site of the hormone shows, however, inhibition of the effect of α-melanotropin. It can be concluded that the latter peptide acts through the melanotropin receptor, while others, related to the C-terminal sequence of the hormone through another mechanism.

Macropolyhedral Boron-Containing Cluster Chemistry. A Metallathiaborane from S2B17H17: Isolation and Characterisation of [(PMe2Ph)2PtS2B16H16]; A neo-arachno Ten-Vertex Cluster Shape, and the Constitution of the [arachno-B10H15]- Anion

2005 ◽  
Vol 70 (4) ◽  
pp. 430-440 ◽  
Author(s):  
Michael J. Carr ◽  
Michael G. S. Londesborough ◽  
Jonathan Bould ◽  
Ivana Císařová ◽  
Bohumil Štíbr ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Sodium Hydride ◽  
Hydrogen Atoms ◽  
Subsequent Reaction ◽  
Cluster Chemistry ◽  
Cluster Shape ◽  
Open Face

The deprotonation of S2B17H17 with sodium hydride and subsequent reaction with [PtCl2(PMe2Ph)2] gives the new macropolyhedral metallathiaborane [(PMe2Ph)2PtS2B16H16], of which the cluster consists of a conventional eleven-vertex nido {SB10} unit, fused, with two boron atoms in common, with a {PtSB8} unit of unique ten-vertex neo-arachno constitution and geometry. The latter geometry suggests a configuration for the previously structurally uncharacterised [B10H15]- anion; starting from this configuration, DFT calculations of structure and thence of boron nuclear shieldings, which are found very closely to mimic those found experimentally, thence support a fluxional structure for [B10H15]- with three {BHB(bridging)} and two {BH(endo)} hydrogen atoms around a six-membered open face.

scholarly journals Synthesis of luminescent thorium-based metal–organic frameworks with 1,2,4,5-tetrakis(4-carboxyphenyl)benzene

RSC Advances ◽  
2021 ◽  
Vol 11 (28) ◽  
pp. 17431-17436
Author(s):  
Ting Yu ◽  
Zheng-hua Qian ◽  
Lin Li ◽  
Xiao-ling Wu ◽  
Hui He ◽  
...  
Keyword(s):  
Metal Salt ◽  
Metal Organic Frameworks ◽  
Reaction System ◽  
Similar Reaction ◽  
Metal Organic

Three new thorium-based MOFs based on 1,2,4,5-tetrakis(4-carboxyphenyl)benzene (H4TCPB) were obtained under a similar reaction system (metal salt, ligand, solvent, and acid are the same).

scholarly journals Inverse vulcanization of octenyl succinate-modified corn starch as a route to biopolymer–sulfur composites

2021 ◽  
Vol 2 (7) ◽  
pp. 2391-2397
Author(s):  
Moira K. Lauer ◽  
Andrew G. Tennyson ◽  
Rhett C. Smith
Keyword(s):  
Succinic Anhydride ◽  
Elemental Sulfur ◽  
Corn Starch ◽  
Subsequent Reaction ◽  
Octenyl Succinic Anhydride

Herein we report a route to sulfur–starch composites by the modification of corn starch with octenyl succinic anhydride (OSA) and its subsequent reaction with elemental sulfur to generate OSSx (where x = wt% sulfur, either 90 or 95).

scholarly journals Combined Effects of Temperature and Toxic Algal Abundance on Paralytic Shellfish Toxic Accumulation, Tissue Distribution and Elimination Dynamics in Mussels Mytilus coruscus

Toxins ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 425
Author(s):  
Yunyu Tang ◽  
Haiyan Zhang ◽  
Yu Wang ◽  
Chengqi Fan ◽  
Xiaosheng Shen
Keyword(s):  
Tissue Distribution ◽  
Combined Effects ◽  
Mytilus Coruscus ◽  
Paralytic Shellfish Toxins ◽  
Rapid Elimination ◽  
Simulated Environment ◽  
Paralytic Shellfish ◽  
Algal Abundance ◽  
Effects Of Temperature ◽  
The Impact

This study assessed the impact of increasing seawater surface temperature (SST) and toxic algal abundance (TAA) on the accumulation, tissue distribution and elimination dynamics of paralytic shellfish toxins (PSTs) in mussels. Mytilus coruscus were fed with the PSTs-producing dinoflagellate A. catenella under four simulated environment conditions. The maximum PSTs concentration was determined to be 3548 µg STX eq.kg−1, which was four times higher than the EU regulatory limit. The increasing SST caused a significant decline in PSTs levels in mussels with rapid elimination rates, whereas high TAA increased the PSTs concentration. As a result, the PSTs toxicity levels decreased under the combined condition. Additionally, toxin burdens were assessed within shellfish tissues, with the highest levels quantified in the hepatopancreas. It is noteworthy that the toxin burden shifted towards the mantle from gill, muscle and gonad at the 17th day. Moreover, variability of PSTs was measured, and was associated with changes in each environmental factor. Hence, this study primarily illustrates the combined effects of SST and TAA on PSTs toxicity, showing that increasing environmental temperature is of benefit to lower PSTs toxicity with rapid elimination rates.

scholarly journals The complexities of insulin allergy: a case and approach

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Babak Aberumand ◽  
Samira Jeimy
Keyword(s):  
Skin Testing ◽  
Emergency Department Visits ◽  
Good Effect ◽  
First Episode ◽  
Similar Reaction ◽  
Hypersensitivity Reactions ◽  
Epinephrine Administration ◽  
Insulin Allergy ◽  
Recombinant Insulin ◽  
Insulin Dependent

Abstract Background Insulin hypersensitivity is rare, but challenging for individuals with diabetes. The prevalence of insulin allergy has decreased since the introduction of human recombinant insulin preparations. Hypersensitivity reactions range from injection site erythema and swelling, to anaphylaxis. While some reactions are to excipients (zinc, protamine, metacresol), many are to recombinant insulin itself. We present a case of type 1 hypersensitivity to various preparations of insulin in a patient with insulin-dependent type 2 diabetes mellitus (T2DM). Case presentation A 61-year-old woman with a 30-year history of insulin-dependent T2DM was referred for evaluation of reactions to insulin. She had two episodes over 5-months; both required Emergency Department visits and epinephrine administration. The first episode entailed a burning sensation of the extremities and nausea, immediately after injecting NovoRapid® insulin. The second event entailed a similar reaction but this time there was also angioedema of the upper airway with difficulty breathing and hypotension, immediately after injecting Levemir® and NovoRapid®, and taking metformin. There were no cofactors such as exercise, infectious illness, or NSAIDs use. Skin testing was performed with metformin, Lantus®, Humalog®, NovoRapid®, glulisine, insulin regular, NPH, Levemir® and the excipient protamine, as per published testing concentrations. Metacresol was not tested as its use was restricted by the hospital pharmacy. Insulin preparations with and without metacresol were included in testing however. A clinic staff served as a negative control. The patent had negative testing with protamine, but sensitization to all insulin preparations. Metformin skin testing and challenge along with latex IgE were negative. Subsequently, she underwent intentional weight loss of 70 lb, and was started on oral hypoglycemics with good effect. Conclusions Our case highlights the importance of diagnosing insulin allergy through a detailed history and focused testing. Therapeutic strategies include avoidance and insulin alternatives, alternate insulin preparations, or desensitization. In severe recurrent hypersensitivity reactions, Omalizumab or pancreatic transplantation have been effective.

Considerazioni e Ricerche genetistiche sul Problema degli omoinnesti

1963 ◽  
Vol 12 (2) ◽  
pp. 97-116
Author(s):  
Luigi Gedda ◽  
Ezio Gentileschi ◽  
Giorgio Gentileschi
Keyword(s):  
Lymph Nodes ◽  
Inbred Line ◽  
Skin Graft ◽  
Inbred Mice ◽  
Subsequent Stage ◽  
Subsequent Reaction ◽  
Regional Lymph Nodes ◽  
Skin Homograft ◽  
Lymphoreticular Tissue ◽  
Mz Twins

SUMMARYThe Authors describe the results obtained by their studies concerning the reaction of histocompatibility to homografts, the origin of parvicellular infiltration and regional lymphonodular modifications due to a skin graft.The acceptance or reject of a homograft in rabbit twins makes it possible to establish the presence of MZ twins. As for the parvicellular infiltration, noticed in the case of kidney homografts, according to the researches of the Authors, who have depressed the graft by means of irradiation, it may be assumed that it is originated either from the graft, or from the host.The study of regional lymph-nodes in the skin homograft in rabbit shows an evident proliferation of the lymphoreticular tissue starting in the very early days, when the graft is viable; in a subsequent stage corresponding to the graft's elimination there is a clear prevalence of plasmocytary elements in the lymphatic cords.The homograft in mice of the inbred line C57BL6shows the graft's acceptance by tissural reactions equivalent to the ones of the autograft.The homograft from random mouse on inbred mice shows the absence of a histiocytary lymphonodular reaction of the epithelioid type, which may be observed sometimes in the reaction to the allogenic homograft in the rabbit; it would be then a subsequent reaction not related to histocompatibility phenomena.

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