141 research outputs found
The Rocky Road to a Digital Lab
The pharmaceutical industry has begun incorporating continuous manufacturing technology in synthetic routes toward active pharmaceutical ingredients (APIs). The development of smart manufacturing routes can be accelerated by utilizing digitalization, process analytical technology (PAT), and data-rich experimentation from an early stage. Here, we present the key aspects of implementing automated flow chemistry reactor platforms with real-time process analytics. Based on our experiences in this field, we aim to highlight the potential of these platforms to conduct self-optimization, automated reaction model building, dynamic experiments and to implement advanced process control strategie
Flow Technology for Telescoped Generation, Lithiation and Electrophilic (C3) Functionalization of Highly Strained 1-Azabicyclo[1.1.0]butanes
Strained compounds are privileged moieties in modern synthesis. In this context, 1-azabicyclo[1.1.0]butanes are appealing structural motifs that can be employed as click reagents or precursors to azetidines. We herein report the first telescoped continuous flow protocol for the generation, lithiation, and electrophilic trapping of 1-azabicyclo[1.1.0]butanes. The flow method allows for exquisite control of the reaction parameters, and the process operates at higher temperatures and safer conditions with respect to batch mode. The efficiency of this intramolecular cyclization/C3-lithiation/electrophilic quenching flow sequence is documented with more than 20 examples
Can electromagnetic fields influence the structure and enzymatic digest of proteins? A critical evaluation of microwave-assisted proteomics protocols
AbstractThis study reevaluates the putative advantages of microwave-assisted tryptic digests compared to conventionally heated protocols performed at the same temperature. An initial investigation of enzyme stability in a temperature range of 37–80°C demonstrated that trypsin activity declines sharply at temperatures above 60°C, regardless if microwave dielectric heating or conventional heating is employed. Tryptic digests of three proteins of different size (bovine serum albumin, cytochrome c and β-casein) were thus performed at 37°C and 50°C using both microwave and conventional heating applying accurate internal fiber-optic probe reaction temperature measurements. The impact of the heating method on protein degradation and peptide fragment generation was analyzed by SDS-PAGE and MALDI-TOF-MS. Time-dependent tryptic digestion of the three proteins and subsequent analysis of the corresponding cleavage products by MALDI-TOF provided virtually identical results for both microwave and conventional heating. In addition, the impact of electromagnetic field strength on the tertiary structure of trypsin and BSA was evaluated by molecular mechanics calculations. These simulations revealed that the applied field in a typical laboratory microwave reactor is 3–4 orders of magnitude too low to induce conformational changes in proteins or enzymes
Novel pyrazole inhibitors for discrimination between receptor-operated and store-operated Ca2+ entry
On the chemistry of stable alpha-oxoketenes
This short review describes the preparation and chemistry of sterically stabilized α-oxoketenes, which can be isolated and handled as true neat compounds. Their reactions with dienophiles afford [4+2] - as well as [2+2] cycloadducts depending on their ability to adopt that conformation suitable for each type of cycloaddition reactions. Addition of nucleophiles leads either to dipivaloylacetic acid derivatives as expected products or to the rare molecular skeleton of mono-or bifunctionalized bridged bisdioxines, which exhibit axial chirality. The bifunctionalized derivatives may serve as novel spacer units in several macrocyclic systems
Anthropogenic reaction parameters - the missing link between chemical intuition and the available chemical space
How do skilled synthetic chemists develop
such a good intuitive expertise
?
Why can we
only access such a small amount of the available chemical space
—
both in terms of the
re
actions used and the chemical scaffolds we make?
We argue here that these
seemingly
unrelated
questions
have a common root and
are strongly
interdependent
.
We performed a
comprehensive analysis of organic reaction parameters dating back to 1771 and discove
red
that
there are several
anthropogenic
factors
that limit the
reaction parameters and thus the
scop
e of synthetic
chemistry.
Nevertheless,
many of the anthropogenic limitations such as
the
narrow parameter space and the opportunity of the rapid and clear
feedback on the progress of
reactions appear to be crucial for the acquisition of valid and reliable chemical intuition.
In
parallel, however, all of these
same
factors represent limitations
for the
exploration of
available chemistry space and
we argue
th
at these
are thus at least partly responsible for
limited access to new chemistries. We advocate, therefore, that the present
anthropogenic
boundaries can be expanded by a more conscious expl
oration of “off
-
road” chemistry that
would also
extend the intuit
ive knowledge of trained chemists
Evidence-Based Annotation of the Malaria Parasite's Genome Using Comparative Expression Profiling
A fundamental problem in systems biology and whole genome sequence analysis is how to infer functions for the many uncharacterized proteins that are identified, whether they are conserved across organisms of different phyla or are phylum-specific. This problem is especially acute in pathogens, such as malaria parasites, where genetic and biochemical investigations are likely to be more difficult. Here we perform comparative expression analysis on Plasmodium parasite life cycle data derived from P. falciparum blood, sporozoite, zygote and ookinete stages, and P. yoelii mosquito oocyst and salivary gland sporozoites, blood and liver stages and show that type II fatty acid biosynthesis genes are upregulated in liver and insect stages relative to asexual blood stages. We also show that some universally uncharacterized genes with orthologs in Plasmodium species, Saccharomyces cerevisiae and humans show coordinated transcription patterns in large collections of human and yeast expression data and that the function of the uncharacterized genes can sometimes be predicted based on the expression patterns across these diverse organisms. We also use a comprehensive and unbiased literature mining method to predict which uncharacterized parasite-specific genes are likely to have roles in processes such as gliding motility, host-cell interactions, sporozoite stage, or rhoptry function. These analyses, together with protein-protein interaction data, provide probabilistic models that predict the function of 926 uncharacterized malaria genes and also suggest that malaria parasites may provide a simple model system for the study of some human processes. These data also provide a foundation for further studies of transcriptional regulation in malaria parasites
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