Sustainable synthesis of L-phenylalanine derivatives in continuous flow by immobilized phenylalanine ammonia lyase

The application of phenyl ammonia lyases for the amination of a variety of cinnamic acids has been shown to be a cost-efficient method to produce a variety of phenylalanine analogues. Nonetheless, as many other biocatalytic tools, the process intensification, especially due to the high equivalents of ammonia needed, and the cost-efficiency of the catalyst production and use have been key points to further prove their usefulness. Here, we investigated the use of previously characterized PALs (AvPAL and PbPAL) for the amination of a series of substituted cinnamic acids. To enhance the process scalability and the reusability of the catalyst, we investigated the use of covalent immobilization onto commercially available supports, creating a heterogeneous catalyst with good recovered activity (50%) and excellent stability. The immobilized enzyme was also incorporated in continuous flow for the synthesis of 3-methoxy-phenyl alanine and 4-nitro-phenylalanine, which allowed for shorter reaction times (20 mins of contact time) and excellent conversions (88 ± 4% and 89 ± 5%) respectively, which could be maintained over extended periods of time, up to 24h. This work exemplifies the advantages that the combination of enzyme catalysis with flow technologies can have not only in the reaction kinetics, but also in the productivity, catalyst reusability and downstream processing

An original phylogenetic approach identified mitochondrial haplogroup T1a1 as inversely associated with breast cancer risk in BRCA2 mutation carriers

Introduction: Individuals carrying pathogenic mutations in the BRCA1 and BRCA2 genes have a high lifetime risk of breast cancer. BRCA1 and BRCA2 are involved in DNA double-strand break repair, DNA alterations that can be caused by exposure to reactive oxygen species, a main source of which are mitochondria. Mitochondrial genome variations affect electron transport chain efficiency and reactive oxygen species production. Individuals with different mitochondrial haplogroups differ in their metabolism and sensitivity to oxidative stress. Variability in mitochondrial genetic background can alter reactive oxygen species production, leading to cancer risk. In the present study, we tested the hypothesis that mitochondrial haplogroups modify breast cancer risk in BRCA1/2 mutation carriers. Methods: We genotyped 22,214 (11,421 affected, 10,793 unaffected) mutation carriers belonging to the Consortium of Investigators of Modifiers of BRCA1/2 for 129 mitochondrial polymorphisms using the iCOGS array. Haplogroup inference and association detection were performed using a phylogenetic approach. ALTree was applied to explore the reference mitochondrial evolutionary tree and detect subclades enriched in affected or unaffected individuals. Results: We discovered that subclade T1a1 was depleted in affected BRCA2 mutation carriers compared with the rest of clade T (hazard ratio (HR) = 0.55; 95% confidence interval (CI), 0.34 to 0.88; P = 0.01). Compared with the most frequent haplogroup in the general population (that is, H and T clades), the T1a1 haplogroup has a HR of 0.62 (95% CI, 0.40 to 0.95; P = 0.03). We also identified three potential susceptibility loci, including G13708A/rs28359178, which has demonstrated an inverse association with familial breast cancer risk. Conclusions: This study illustrates how original approaches such as the phylogeny-based method we used can empower classical molecular epidemiological studies aimed at identifying association or risk modification effects.Peer reviewe

Genome-Wide Association Study in BRCA1 Mutation Carriers Identifies Novel Loci Associated with Breast and Ovarian Cancer Risk

BRCA1-associated breast and ovarian cancer risks can be modified by common genetic variants. To identify further cancer risk-modifying loci, we performed a multi-stage GWAS of 11,705 BRCA1 carriers (of whom 5,920 were diagnosed with breast and 1,839 were diagnosed with ovarian cancer), with a further replication in an additional sample of 2,646 BRCA1 carriers. We identified a novel breast cancer risk modifier locus at 1q32 for BRCA1 carriers (rs2290854, P = 2.7×10-8, HR = 1.14, 95% CI: 1.09-1.20). In addition, we identified two novel ovarian cancer risk modifier loci: 17q21.31 (rs17631303, P = 1.4×10-8, HR = 1.27, 95% CI: 1.17-1.38) and 4q32.3 (rs4691139, P = 3.4×10-8, HR = 1.20, 95% CI: 1.17-1.38). The 4q32.3 locus was not associated with ovarian cancer risk in the general population or BRCA2 carriers, suggesting a BRCA1-specific associat

A scalable and safe continuous flow procedure for in-line generation of Diazomethane and its precursor MNU

Diazomethane is a valuable C1-building block for organic synthesis but very difficult to handle and its use for scale-up is still a challenge with regard to safety. Herein we present a simple and robust continuous flow setup, that allows a safe on-demand generation of diazomethane with a productivity of 110 mmol/h. The developed two-step process starts from non-hazardous N-methylurea, generates and consumes N-methyl-N-nitrosourea (MNU) and diazomethane in-line, thus enabling a safe and convenient scale-up to multi-gram scale in a conventional synthesis laboratory

Diazomethane and Flow Chemistry: Filling a Gap in Pharma R&D

A scale-up of hazardous reactions in batch requires extensive safety investigations which can cause massive delays for the scale-up process of pharmaceutical intermediates and active molecules. Continuous flow chemistry as an enabling technology nowadays has proven that it can help to reduce the safety hazards thus bringing back neglected chemistries into synthesis laboratories where in the past quite often the application of those reactions was avoided. One of those hazardous but very useful reagents is diazomethane which is a valuable C1-building block for organic synthesis. A safe handling of diazomethane on larger scale in a batch reactor is almost impossible but the hazards of preparing and reacting diazomethane however can be minimized significantly under continuous flow conditions. Recently, we developed a simple and robust continuous flow process for a safe on-demand generation of diazomethane and its precursor N-methyl-N-nitrosourea (MNU). The developed two-step process starts from non-hazardous N-methylurea, generates and consumes N-methyl-N-nitrosourea (MNU) and diazomethane in-line and enables a safe and convenient scale-up to multi-gram scale in a conventional synthesis laboratory

Scale-up in microwave-accelerated organic synthesis.

Microwave-assisted organic chemistry has received strong exposure in the literature over the last decade, and nowadays more and more research chemists are successfully applying microwave technology to organic reactions on a small scale. However, the efficient application of this technology to cover the specific needs of larger-scale preparations, e.g., in a kilo lab, remains to be shown. We therefore initiated a study to investigate the scalability of microwave technology. Two different microwave systems designed for large-scale operation were evaluated in order to characterize strengths and weaknesses of each instrument with regard to scale-up. Special focus was directed on temperature/pressure limits, handling of suspensions, ability to rapidly heat and cool, robustness, and overall processing time. Based on the results of this study, a batch microwave reactor with a reaction volume of approximately 1.1 1 was purchased and installed in the kilo lab. Several reactions have been performed successfully on a 50- to 100-g scale in our laboratory, showing that a scale-up from a 15 ml scale to a 1-1 scale is feasible. In general, a significant reduction of reaction time was achievable, in some cases yields and selectivity were also improved. Nevertheless, a major weakness of the available systems is the limited vessel size, which is, in most cases, far below a suitable reaction volume required for work in a kilo lab

OePNV in der Marktwirtschaft: ein Ordnungsentwurf mit kritischer Wuerdigung der juengsten Reformen

Available from Bibliothek des Instituts fuer Weltwirtschaft, ZBW, D-21400 Kiel C 204427 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Spatial representations in local field potential activity of primate anterior intraparietal cortex (AIP)

The execution of reach-to-grasp movements in order to interact with our environment is an important subset of the human movement repertoire. To coordinate such goal-directed movements, information about the relative spatial position of target and effector (in this case the hand) has to be continuously integrated and processed. Recently, we reported the existence of spatial representations in spiking-activity of the cortical fronto-parietal grasp network (Lehmann & Scherberger 2013), and in particular in the anterior intraparietal cortex (AIP). To further investigate the nature of these spatial representations, we explored in two rhesus monkeys (Macaca mulatta) how different frequency bands of the local field potential (LFP) in AIP are modulated by grip type, target position, and gaze position, during the planning and execution of reach-to-grasp movements. We systematically varied grasp type, spatial target, and gaze position and found that both spatial and grasp information were encoded in a variety of frequency bands (1–13Hz, 13–30Hz, 30–60Hz, and 60–100Hz, respectively). Whereas the representation of grasp type strongly increased towards and during movement execution, spatial information was represented throughout the task. Both spatial and grasp type representations could be readily decoded from all frequency bands. The fact that grasp type and spatial (reach) information was found not only in spiking activity, but also in various LFP frequency bands of AIP, might significantly contribute to the development of LFP-based neural interfaces for the control of upper limb prostheses

From Lab Scale to Kilolab Scale using a Multimode Batch Microwave Reactor

An evaluation of a new bench-top microwave batch reactor that uses a single 1 L reaction vessel is presented. Several microwave-assisted organic reactions have been scaled-up, including Newman Kwart and Diels-Alder reactions, Pd-catalyzed cross-couplings, heterocycle synthesis, aromatic substitution and a Knoevenagel condensation. A range of different solvents (high and low microwave absorbing), varying reaction times (4 s up to 2 h) and temperatures (120 °C to 250 °C) have been explored in these investigations. For all studied transformations it was possible to perform a direct scale-up (up to 720 mL applied volume) without changing the previously optimized reaction conditions achieved in a laboratory scale single-mode microwave instrument (2-20 mL processing volume), obtaining similar isolated product yields. A scalability up to 360 fold, when moving from 3 mmol up to 1.08 mol, was demonstrated and isolated product yields up to 300 g (2.5 mol scale) in a single run could be accomplished, providing the potential for a kilogram output per day by performing multiple sequential runs

Scale-up of Organic Reactions in a Pharmaceutical Kilo-Lab Using a Commercial Microwave Reactor

A range of pharmaceutically relevant reactions were investigated for scale-up in a kilo-lab environment using a commercial batch microwave reactor. Typical scale-up issues are discussed, taking into account the specific limitations of microwave heating in large scale experiments. Examples for scale-up from 15 mL to 1 L are presented and demonstrate that the synthesis of compounds on greater than 100 g scale is feasible in one batch. Reaction times are significantly reduced and the productivity of our scale-up laboratory is enhanced. Production rates of 0.5 – 1 kg per day have been achieved using microwave technology. The article concludes with a brief discussion of advantages and disadvantages of this type of batch microwave reactor