The Carbamoylation of the 3-Hydroxymethyl Group of 7α-Methoxy-7β-(5-d-aminoadipamido)-3-hydroxymethylceph-3-em-4-carboxylic Acid (Desacetyl-7α-methoxycephalosporin C) by Homogenates of Streptomyces clavuligerus

1977 ◽  
Vol 5 (4) ◽  
pp. 1026-1029 ◽  
Author(s):  
STEPHEN J. BREWER ◽  
TERENCE T. BOYLE ◽  
MICHAEL K. TURNER
Keyword(s):  
Carboxylic Acid ◽  
Streptomyces Clavuligerus ◽  
Hydroxymethyl Group

scholarly journals The oxygenation of [3-methyl-3H]desacetoxycephalosporin C [7β-(5-d-aminadipamido)-3-methylceph-3-em-4-carboxylic acid] to [3-hydroxymethyl-3H]desacetylcephalosporin C by 2-oxoglutarate-linked dioxygenases from Acremonium chrysogenum and Streptomyces clavuligerus

1978 ◽  
Vol 173 (3) ◽  
pp. 839-850 ◽  
Author(s):  
M K Turner ◽  
J E Farthing ◽  
S J Brewer
Keyword(s):  
Carboxylic Acid ◽  
Deae Cellulose ◽  
Streptomyces Clavuligerus ◽  
Reducing Agents ◽  
Side Chain ◽  
Acremonium Chrysogenum ◽  
Hydroxymethyl Group ◽  
Methyl Group ◽  
Full Activity

Cell-free extracts of Acremonium chrysogenum and Streptomyces clavuligerus oxidize the 3-methyl group of desacetoxycephalosporin C to a 3-hydroxymethyl group. The enzyme responsible for this reaction in these organisms was purified 20- and 30-fold respectively by chromatography on DEAE-cellulose. The enzymes, which were assayed with [3-methyl-3H]desacetoxycephalosporin C as substrate, have the properties expected of 2-oxoglutarate-linked dioxygenases. They require 2-oxoglutarate, Fe2+ cations and a mixture of reducing agents (dithiothreitol and ascorbate) for full activity. The enzyme from A. chrysogenum, but not that S. clavuligerus, is activated about 10-fold when it is preincubated with a reaction mixture from which either desacetoxycephalosporin C or 2-oxoglutarate is omitted. Fe2+ cations seem to play a key role in this activation. Both enzymes seem highly specific for cephalosporins with the natural 7beta-(5-D-aminoadipamido) side chain and are likely to be responsible for the oxidation of the 3-methylcephem nucleus in vivo.

scholarly journals An adenosine triphosphate-dependent carbamoylphosphate-3-hydroxymethylcephem O-carbamoyltransferase from Streptomyces clavuligerus

1980 ◽  
Vol 185 (3) ◽  
pp. 555-564 ◽  
Author(s):  
S J Brewer ◽  
P M Taylor ◽  
M K Turner
Keyword(s):  
Carboxylic Acid ◽  
Oxygen Atom ◽  
Deae Cellulose ◽  
Streptomyces Clavuligerus ◽  
Wide Range ◽  
Nucleoside Triphosphates ◽  
Phosphate Anions ◽  
Beta 2 ◽  
Methylene Group ◽  
Carbamoyl Group

Cell-free supernatants from cells of Streptomyces clavuligerus (N.R.R.L. 3585), which are actively synthesizing cephamycin C, transfer a carbamoyl group from carbamoylphosphate to a 3-hydroxymethylceph-3-em-4-carboxylic acid nucleus to form a 3-carbamoyloxymethylcephem. This reaction was stimulated by nucleoside triphosphates and by a mixture of Mn2+ and Mg2+ cations. The enzyme responsible was purified 40-fold by batch absorption onto DEAE-cellulose and hydroxyapatite. The purified O-carbamoyltransferase is most active at pH 6.8. It is stabilized by phosphate anions, but is inhibited by PPi anions, (NH4)2SO4 or NaCl. The enzyme is stimulated by ATP, but it is not known whether this nucleotide acts as an effector or as a substrate. Some activity is observed with dATP, but two other analogues of ATP, in which a methylene group replaced the oxygen atom between the alpha- and beta- or the beta- and gamma-phosphorus atoms, inhibit the action of ATP itself. The enzyme synthesizes a wide range of 3-carbamoyloxymethylcephems. The structure of some of these products, for example that of cefuroxime (3-carbamoyloxymethyl-7 beta-[2-(fur-2-yl)-2-syn-methoxyiminoacetamido]ceph-3-em-4-carboxylic acid), was confirmed by their proton-n.m.r. spectra.

Fibrinolytic Activity of Cerebro-Spinal Fluid and the Development of Artificial Cerebral Haematomas in Dogs

1969 ◽  
Vol 21 (02) ◽  
pp. 294-303 ◽  
Author(s):  
H Mihara ◽  
T Fujii ◽  
S Okamoto
Keyword(s):  
Cerebrospinal Fluid ◽  
Carboxylic Acid ◽  
Fibrinolytic Activity ◽  
Clinical Implications ◽  
Trans Form ◽  
Plate Method ◽  
Blood Samples ◽  
Fibrin Plate ◽  
The Brain

SummaryBlood was injected into the brains of dogs to produce artificial haematomas, and paraffin injected to produce intracerebral paraffin masses. Cerebrospinal fluid (CSF) and peripheral blood samples were withdrawn at regular intervals and their fibrinolytic activities estimated by the fibrin plate method. Trans-form aminomethylcyclohexane-carboxylic acid (t-AMCHA) was administered to some individuals. Genera] relationships were found between changes in CSF fibrinolytic activity, area of tissue damage and survival time. t-AMCHA was clearly beneficial to those animals given a programme of administration. Tissue activator was extracted from the brain tissue after death or sacrifice for haematoma examination. The possible role of tissue activator in relation to haematoma development, and clinical implications of the results, are discussed.

Stereospecific, Palladium-catalyzed C(sp3)–H Alkenylation and Alkynylation of a Proline Derivative Enabled by 8-Aminoquinoline as a Directing Group

2020 ◽  
Author(s):  
Aleksandra Balliu ◽  
Aaltje Roelofje Femmigje Strijker ◽  
Michael Oschmann ◽  
Monireh Pourghasemi Lati ◽  
Oscar Verho
Keyword(s):  
Carboxylic Acid ◽  
Building Blocks ◽  
Wide Range ◽  
Palladium Catalyzed ◽  
Directing Group ◽  
High Yields ◽  
Vinyl Iodides ◽  
Initial Results

<p>In this preprint, we present our initial results concerning a stereospecific Pd-catalyzed protocol for the C3 alkenylation and alkynylation of a proline derivative carrying the well utilized 8‑aminoquinoline directing group. Efficient C–H alkenylation was achieved with a wide range of vinyl iodides bearing different aliphatic, aromatic and heteroaromatic substituents, to furnish the corresponding C3 alkenylated products in good to high yields. In addition, we were able show that this protocol can also be used to install an alkynyl group into the pyrrolidine scaffold, when a TIPS-protected alkynyl bromide was used as the reaction partner. Furthermore, two different methods for the removal of the 8-aminoquinoline auxiliary are reported, which can enable access to both <i>cis</i>- and <i>trans</i>-configured carboxylic acid building blocks from the C–H alkenylation products.</p>

Ketones from Nickel-Catalyzed Decarboxylative, Non-Symmetric Cross-Electrophile Coupling of Carboxylic Acid Esters

2019 ◽  
Author(s):  
Jiang Wang ◽  
Brian P. Cary ◽  
Peyton Beyer ◽  
Samuel H. Gellman ◽  
Daniel Weix
Keyword(s):  
Carboxylic Acid ◽  
Solid Support ◽  
Reaction Conditions ◽  
Decarboxylative Coupling ◽  
New Strategy ◽  
The Cross ◽  
Acyl Donors ◽  
Acid Esters

A new strategy for the synthesis of ketones is presented based upon the decarboxylative coupling of N-hydroxyphthalimide (NHP) esters with S-2-pyridyl thioesters. The reactions are selective for the cross-coupled product because NHP esters act as radical donors and the thioesters act as acyl donors. The reaction conditions are general and mild, with over 40 examples presented, including larger fragments and the 20-mer peptide Exendin(9-39) on solid support.

Harnessing Applied Potential: The Anti-Markovnikov Hydrocarboxylation of Substituted Olefins

2019 ◽  
Author(s):  
Anas Alkayal ◽  
Volodymyr Tabas ◽  
Andrei V. Malkov ◽  
Benjamin Buckley
Keyword(s):  
Carboxylic Acid ◽  
Applied Potential ◽  
Markovnikov Addition

<div>The construction of carboxylic acid compounds in a selective fashion, from low value materials such as alkenes remains a long-standing challenge to synthetic chemists. In particular, anti-Markovnikov addition to styrenes are underdeveloped. Herein we report a new electrosynthetic approach to the selective hydrocarboxylation of substituted alkenes.</div>

Harnessing Applied Potential: The Anti-Markovnikov Hydrocarboxylation of Substituted Olefins

2019 ◽  
Author(s):  
Anas Alkayal ◽  
Volodymyr Tabas ◽  
Andrei V. Malkov ◽  
Benjamin Buckley
Keyword(s):  
Carboxylic Acid ◽  
Applied Potential ◽  
Markovnikov Addition

<div>The construction of carboxylic acid compounds in a selective fashion, from low value materials such as alkenes remains a long-standing challenge to synthetic chemists. In particular, anti-Markovnikov addition to styrenes are underdeveloped. Herein we report a new electrosynthetic approach to the selective hydrocarboxylation of substituted alkenes.</div>

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