Seletividade divergente de nucleófilos em iminas e y-lactonas derivadas de 2,4-O benzilideno D-eritrose

Dissertação de mestrado em Química MedicinalNeste trabalho começaram por ser sintetizadas, a D-eritrose e uma δ-lactona α,β insaturada seguindo metodologias conhecidas. Os dois reagentes foram usados na síntese de pirrolidinas polihidroxiladas N-substituídas em configuração D e L. O trabalho está dividido em três partes. As duas primeiras partes envolvem reações de D eritrose e a terceira parte com a δ-lactona. Na primeira parte é obtido um éster por reação de Wittig entre o acetato de metilo de trifenilfosforalideno e a D-eritrose, em meio ácido, sendo aferidas as condições reacionais que permitiam a síntese mais seletiva do isómero geométrico cis. A combinação do solvente diclorometano com temperaturas baixas permitiu um melhoramento da síntese do isómero cis. Na segunda parte do trabalho, foram obtidas três iminas a partir da D-eritrose, em meio anidro com a piperonilamina, com a 4-(fluoro)benzilamina e com a 4-(cloro)benzilamina. Foram estudadas as reatividades e seletividades em reações de adição nucleofílica para dois nucleófilos, o tert-butil((1-metoxivinil)oxi)dimetilsilano e o cianeto de trimetilsilano. O aducto que incorpora o grupo acetato de metilo foi tratado com ácido clorídrico, originando a mistura de pirrolidinas que, após adição de hidróxido de potássio permitiu a obtenção de (3S,4R)-3,4-dihidroxi-L-homoprolinas N-substituídas puras. Na terceira parte foi utilizada a δ-lactona α,β-insaturada proveniente da D-eritrose, sendo obtida uma β aminoamida por reação com a piperonilamina. A β-aminoamida, na presença de ácido clorídrico gerou a amino-y-lactona que sofreu bromação no álcool primário levando à formação da amino-y-lactona bromada. Por reação com a trietilamina em metanol obteve-se a pirrolidina portadora da função éster, que, ao adicionar ácido trifluoroacético, permitiu obter uma (3S,4R)-3,4 dihidroxi-D-homoprolina.In this work, D-erythrose and an α,β-unsaturated δ-lactone began to be synthesized following known methodologies. Both reagents were used in the synthesis of N-substituted polyhydroxylated homoprolines with D and L configurations. This work is divided into three parts. In the first two parts D-erythrose is involved in the reactions developed, in the third part the erythrosyl δ-lactone is the starting material. In the first part, a methyl α,β-unsaturated ester was coupled to the erythrose unit by Wittig reaction between triphenylphosphoralidene methyl acetate and D-erythrose. The process is catalysed by acid. By modifying the reaction’s conditions the selectivity of the reaction was pushed towards the cis geometric isomer. The combination of the dichloromethane as the solvent, with low temperatures allowed an important improvement of the cis isomer vs trans isomer. In the second part of the work, three imines were obtained from D-erythrose, in anhydrous medium with piperonylamine, 4-(fluoro)benzylamine, and 4-(chloro)benzylamine. The reactivity/selectivity of the formed imines to nucleophile additions was studied for two nucleophiles: tert-butyl((1 methoxyvinyl)oxy)dimethylsilane and trimethylsilyl cyanide. Adducts incorporating the methyl acetate group are single products. Those adducts were treated with concentrated hydrochloric acid, resulting in a mixture of two pyrrolidines which upon addition of potassium hydroxide evolve to one of them: the (3S,4R)-3,4-dihydroxy-N-substituted-L-homoprolines. Reaction with trimethylsilyl cyanide gave different ratio of R/S adducts. In the third part of the work the α,β unsaturated δ-lactone was reacted with a piperonylamine giving an β-aminoamide. In the presence of hydrochloric acid the β-aminoamide generated an amino-y-lactone, which underwent bromination in the primary alcohol leading to the formation of the brominated amino-y-lactone. Reaction with triethylamine in methanol gave the ester-functional pyrrolidine which, upon addition of trifluoroacetic acid afforded a (3S,4R)-3,4-dihydroxy-D-homoproline

The evaluation of the antibacterial capacity of tea tree functionalized microcapsules in textiles

The textile industry develops products that go beyond aesthetic concerns. Manufacturers functionalize these new textile products to provide them with new technical properties, to meet and even exceed user needs. The technical properties are diverse, from ultraviolet protection to antimicrobial or self-cleaning properties. The growth of microorganisms on textiles can result in unpleasant odors, stains or even accelerate the wear and tear of textile products. Microcapsules may contain natural or synthetic components in their core, capable of providing the desired properties to textiles (Figure 1). In addition, a shell protects the core and its design allows a gradual release of the main component. In this work, microcapsules were dyed to prevent the appearance of stains. This research tested the antibacterial capacity of microcapsules functionalized with tea tree essential oil on polyester fabric (PES). The fabric was tested with dyed and undyed microcapsules to ensure no dye interference. This research evaluates antibacterial capacity using the following standard bacteria: Staphylococcus aureus and Escherichia coli

Functionalization of woven fabrics for antimicrobial capability using microcapsules with essential oils

[Excerpt] The functionalization of textiles covers multiple objectives, such as the allocation of perfumes, antimicrobials, some drugs, phase change materials. Among these goals, the antimicrobial capability ensures that microorganisms do not thrive on textiles (Fig. 1), allowing users to use these products safer in different scenarios. This research evaluates the antimicrobial capacity of cotton fabrics through the application of microcapsules containing essential oils.The authors are grateful to the Agência Nacional de Inovação for the funding of the Project 4NoPressure - POCI-01-0247- FEDER-039869 and ARCHKNIT POCI-01-0247-FEDER-03973, co-funded by the European Regional Development Fund (ERDF), through the Operational Programme for Competitiveness and Internationalisation (COMPETE 2020), under the PORTUGAL 2020 Partnership Agreement

Development of a plasma activated multifunctional polyester fabric using zinc oxide nanoparticles and citronella oil microcapsules

Apresentação efetuada na 21th World Textile Conference - AUTEX 2022, em Lodz, Poland, 2022This work was funded by ERDF through the COP and FCT projects: UID/CTM/00264/2021, PLASMAMED PTDC/CTM TEX/28295/2017, ARCHKNIT POCI-01-0247-FEDER-039733, FATORST+ POCI-01-0247-ERDF-047124, MEDCOR PTDC/CTM-TEX/1213/2020, 4NoPressure POCI-01-0247-FEDER-039869 financed by FEDER through POCI under the “Portugal 2020” programme, and the Ph.D. scholarship SFRH/BD/137668/2018

Development of a plasma activated multifunctional polyester fabric using zinc oxide nanoparticles and citronella oil microcapsules

There is a high demand for the development of textiles possessing multifunctional properties for outdoor, protective and health care applications. The coating of polyester (PES) textiles with metal nanoparticles and essential oils may act in a synergistic mode to obtain materials with improved antimicrobial and UV-protection properties. However, the lack of functional groups onto PES structure makes the adhesion of particles a difficult task. In this work, PES fabric was activated by dielectric barrier discharge (DBD) plasma treatment, and functionalized with zinc oxide nanoparticles (ZnO NPs) and poly (methyl methacrylate) (PMMA)-citronella microcapsules by dip-coating

Intraoperative transfusion practices in Europe

Transfusion of allogeneic blood influences outcome after surgery. Despite widespread availability of transfusion guidelines, transfusion practices might vary among physicians, departments, hospitals and countries. Our aim was to determine the amount of packed red blood cells (pRBC) and blood products transfused intraoperatively, and to describe factors determining transfusion throughout Europe. We did a prospective observational cohort study enrolling 5803 patients in 126 European centres that received at least one pRBC unit intraoperatively, during a continuous three month period in 2013. The overall intraoperative transfusion rate was 1.8%; 59% of transfusions were at least partially initiated as a result of a physiological transfusion trigger- mostly because of hypotension (55.4%) and/or tachycardia (30.7%). Haemoglobin (Hb)- based transfusion trigger alone initiated only 8.5% of transfusions. The Hb concentration [mean (sd)] just before transfusion was 8.1 (1.7) g dl and increased to 9.8 (1.8) g dl after transfusion. The mean number of intraoperatively transfused pRBC units was 2.5 (2.7) units (median 2). Although European Society of Anaesthesiology transfusion guidelines are moderately implemented in Europe with respect to Hb threshold for transfusion (7-9 g dl), there is still an urgent need for further educational efforts that focus on the number of pRBC units to be transfused at this threshold

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved

Intraoperative transfusion practices in Europe

© 2016 The Author. Published by Oxford University Press on behalf of the British Journal of Anaesthesia.Background: Transfusion of allogeneic blood influences outcome after surgery. Despite widespread availability of transfusion guidelines, transfusion practices might vary among physicians, departments, hospitals and countries. Our aim was to determine the amount of packed red blood cells (pRBC) and blood products transfused intraoperatively, and to describe factors determining transfusion throughout Europe. Methods: We did a prospective observational cohort study enrolling 5803 patients in 126 European centres that received at least one pRBC unit intraoperatively, during a continuous three month period in 2013. Results: The overall intraoperative transfusion rate was 1.8%; 59% of transfusions were at least partially initiated as a result of a physiological transfusion trigger- mostly because of hypotension (55.4%) and/or tachycardia (30.7%). Haemoglobin (Hb)- based transfusion trigger alone initiated only 8.5% of transfusions. The Hb concentration [mean (sd)] just before transfusion was 8.1 (1.7) g dl-1 and increased to 9.8 (1.8) g dl-1 after transfusion. The mean number of intraoperatively transfused pRBC units was 2.5 (2.7) units (median 2). Conclusions: Although European Society of Anaesthesiology transfusion guidelines are moderately implemented in Europe with respect to Hb threshold for transfusion (7-9 g dl-1), there is still an urgent need for further educational efforts that focus on the number of pRBC units to be transfused at this threshold

Intraoperative transfusion practices and perioperative outcome in the European elderly: A secondary analysis of the observational ETPOS study

The demographic development suggests a dramatic growth in the number of elderly patients undergoing surgery in Europe. Most red blood cell transfusions (RBCT) are administered to older people, but little is known about perioperative transfusion practices in this population. In this secondary analysis of the prospective observational multicentre European Transfusion Practice and Outcome Study (ETPOS), we specifically evaluated intraoperative transfusion practices and the related outcomes of 3149 patients aged 65 years and older. Enrolled patients underwent elective surgery in 123 European hospitals, received at least one RBCT intraoperatively and were followed up for 30 days maximum. The mean haemoglobin value at the beginning of surgery was 108 (21) g/l, 84 (15) g/l before transfusion and 101 (16) g/l at the end of surgery. A median of 2 [1–2] units of RBCT were administered. Mostly, more than one transfusion trigger was present, with physiological triggers being preeminent. We revealed a descriptive association between each intraoperatively administered RBCT and mortality and discharge respectively, within the first 10 postoperative days but not thereafter. In our unadjusted model the hazard ratio (HR) for mortality was 1.11 (95% CI: 1.08–1.15) and the HR for discharge was 0.78 (95% CI: 0.74–0.83). After adjustment for several variables, such as age, preoperative haemoglobin and blood loss, the HR for mortality was 1.10 (95% CI: 1.05–1.15) and HR for discharge was 0.82 (95% CI: 0.78–0.87). Preoperative anaemia in European elderly surgical patients is undertreated. Various triggers seem to support the decision for RBCT. A closer monitoring of elderly patients receiving intraoperative RBCT for the first 10 postoperative days might be justifiable. Further research on the causal relationship between RBCT and outcomes and on optimal transfusion strategies in the elderly population is warranted. A thorough analysis of different time periods within the first 30 postoperative days is recommended