Photocatalytic Transformation of Biomass and Biomass Derived Compounds-Application to Organic Synthesis.

Biomass and biomass-derived compounds have become an important alternative feedstock for chemical industry. They may replace fossil feedstocks such as mineral oil and related platform chemicals. These compounds may also be transformed conveniently into new innovative products for the medicinal or the agrochemical domain. The production of cosmetics or surfactants as well as materials for different applications are examples for other domains where new platform chemicals obtained from biomass can be used. Photochemical and especially photocatalytic reactions have recently been recognized as being important tools of organic chemistry as they make compounds or compound families available that cannot be or are difficultly synthesized with conventional methods of organic synthesis. The present review gives a short overview with selected examples on photocatalytic reactions of biopolymers, carbohydrates, fatty acids and some biomass-derived platform chemicals such as furans or levoglucosenone. In this article, the focus is on application to organic synthesis.

Amiodarona: fortalezas y debilidades / Amiodarone strengths and weaknesses

Prescritos en la práctica clínica por su eficacia. En su inicio se utilizó para tratar la angina de pecho. hoy día es usado para el tratamiento de cualquier forma de taquicardia. Objetivo: Reconocer la prescripción de la Amiodarona y sus efectos adversos. Métodos: Se realizó una revisión descriptiva en las bases de datos de Lilacs donde se encontraron 18 artículos y en PubMed/Medline (Mesh) 206 artículos, de los cuales se le aplicaron los criterios de inclusión a 51 artículos. Conclusiones: La amiodarona es uno de los antiarrítmicos más utilizados para el tratamiento de las arritmias, su variedad de efectos adversos y toxicidad es conocida, por tanto, los pacientes en tratamiento ameritan un minucioso monitoreo(AU)

Introduction: Amiodarone is one of the most prescribed antiarrhythmic drugs in clinical practice due to its efficacy. Initially it was used to treat angina pectoris, however, today it is used to treat any form of tachycardia. Objective: To identify the prescription of amiodarone and its adverse effects. Methods: A descriptive review was carried out in Lilacs databases where 18 articles were found and in PubMed/Medline (Mesh) 206 articles were retrieved. The inclusion criteria were applied to 51 articles. Conclusions: Amiodarone is one of the most widely used antiarrhythmic drugs for the treatment of arrhythmias, its variety of adverse effects and toxicity is known, therefore, patients undergoing treatment justify careful monitoring(AU)

Studies on The Application of The Paternò-Büchi Reaction to The Synthesis of Novel Fluorinated Scaffolds.

In the context of new scaffolds obtained by photochemical reactions, Paternò-Büchi reactions between heteroaromatic, trifluoromethylphenyl ketone and electron rich alkenes to give oxetanes are described. A comprehensive study has then been carried out on the reaction of aromatic ketones with fluorinated alkenes. Depending on the substitution pattern at the oxetane ring, a metathesis reaction is described as a minor side process to give mono fluorinated alkenes. Overall, this last reaction corresponds to a photo-Wittig reaction and yield amid isosteres. In order to explain the uncommon regioselectivity of the Paternò-Büchi reaction with these alkenes, electrostatic-potential derived charges (ESP) have been determined. In a second computational study, the relative stabilities of the typical 1,4-diradical intermediates of the Paternò-Büchi reaction have been determined. The results well explain the regioselectivity. Further transformations of the oxetanes or previous functionalization of the fluoroalkenes open perspectives for oxetanes as core structures for biologically active compounds.

Palladium-Catalyzed Regioselective Allylic Oxidation of Amorphadiene, a Precursor of Artemisinin.

A regioselective Pd-catalyzed allylic oxidation of amorphadiene, a key precursor to the antimalarial drug artemisinin, is described. Amorphadiene can be obtained in high yields by fermentation, but it is currently treated as a waste in the industrial semisynthetic artemisinin process. The catalytic step described here is a substitute for the P450 enzymes involved in the artemisinin biosynthesis and opens up new opportunities to supplement a critical step in the current semisynthetic route and increase the potential of the fermentation process.

Photochemical Hydrothiolation of Amorphadiene and Formal Synthesis of Artemisinin via a Pummerer Rearrangement.

A new access to artemisinin is reported based on a selective photochemical hydrothiolation of amorphadiene, a waste product of the industrial semisynthetic route. This study highlights the discovery of two distinctive activation pathways under solvent-free conditions or using a photocatalyst promoting H-abstraction. Subsequently, a chemoselective oxidation of the resulting photochemically generated thioether, followed by a Pummerer rearrangement, affords dihydroartemisinic aldehyde, a key intermediate in the synthesis of artemisinin.

Infarto agudo de miocardio en cuatro hospitales de atención secundaria en Cuba en la era COVID-19 / Acute myocardial infarction in four secondary care hospitals in Cuba in the COVID-19 era

RESUMEN Introducción: Las características clínico-epidemiológicas en el diagnóstico, evolución y tratamiento de los pacientes con infarto agudo de miocardio en la era COVID-19 dependen de varios factores. Objetivos: Precisar el comportamiento de algunas variables clínico-epidemiológicas en la atención y tratamiento de los pacientes con infarto agudo de miocardio en el curso de la COVID-19. Método: Se realizó un estudio observacional en cuatro hospitales de atención secundaria en Cuba. Se utilizaron las siguientes variables: número de ingresos por infartos, mortalidad hospitalaria, tiempo de demora mayor de 4 horas desde el inicio de los síntomas y la llegada a la primera asistencia médica y el porcentaje de trombólisis. Se definieron dos grupos, los ingresados entre el 1 de marzo al 30 de septiembre de 2019 (Grupo I) y los ingresados en igual período pero del 2020 (Grupo II). Las comparaciones entre ambos grupos se realizaron utilizando el test de Chi cuadrado. Resultados: Existió una disminución de 53 ingresos por infarto agudo de miocardio en Las Tunas (112 vs. 159, p<0.05), con un incremento del número de ingresos en el Hospital Enrique Cabrera en los pacientes del grupo II (98 vs. 68, p<0.05). Se incrementó el número de fallecidos y la mortalidad hospitalaria en el grupo II en todos los centros con relación al grupo I. En la mayoría de los centros se incrementó la demora desde el inicio de los síntomas y la llegada al lugar de la primera asistencia médica. El porciento de trombólisis fue superior al 50% en la mayoría de los centros en el grupo II. Conclusiones: Las características de la COVID-19 pueden modificar aspectos clínicos y epidemiológicos en la atención y tratamiento de los pacientes con infarto agudo de miocardio.

ABSTRACT Introduction: The clinico-epidemiological characteristics in the diagnosis, evolution and treatment of patients with acute myocardial infarction in the COVID-19 era depend on several factors. Objectives: To determine the behavior of some clinico-epidemiological variables in the management of patients with acute myocardial infarction during de COVID-19 pandemic. Methods: An observational study was carried out in four secondary care hospitals in Cuba. The following variables were used: number of admission due to acute myocardial infarction, hospital mortality, delay longer than four hours from the beginning of the symptoms to the arrival to the first medical assistance, and thrombolysis percentage. Two groups were defined, those admitted from March 1st to September 30th, 2019 (Group I) and those admitted in the same period, but from 2020 (Group II). Comparisons between both groups were made using the chi square test. Results: There was a decrease of 53 admissions due to acute myocardial infarction in Las Tunas (112 vs. 159; p<0.05), with an increase in the number of admissions in the Hospital Enrique Cabrera in patients from Group II (98 vs. 68; p<0.05). The number of deaths and hospital mortality in Group II increased in all the centers in relation to Group I. In most of the hospitals there was an increase of the time elapsed from the beginning of the symptoms to the arrival to the first medical assistance. Thrombolysis percentage in Group II was higher than 50% in most of the centers. Conclusions: The characteristics of COVID-19 may modify the clinical and epidemiological aspects in the management of patients with acute myocardial infarction.

Crystallization-Induced Diastereoisomer Transformation of Dihydroartemisinic Aldehyde with the Betti Base.

Artemisinin is an important drug to fight malaria. It is produced either by extraction or via a semisynthetic route involving enzyme engineering. A key intermediate to produce artemisinin by the enzymatic route is dihydroartemisinic aldehyde (DHAAl). However, control of the absolute configuration of the stereocenter α to the aldehyde is highly challenging. Herein we report a protocol that allows the diastereomeric enrichment of a mixture of (11R)/(11S)-DHAAl to the desired (11R)-DHAAl by utilizing a crystallization-induced diastereomer transformation induced by the Betti base. In addition, the Betti base can be quantitatively recovered and reused after the reaction.

Synthesis of amorpha-4,11-diene from dihydroartemisinic acid.

Amorphadiene is a natural product involved in the biosynthesis of the antimalarial drug artemisinin. A convenient four-step synthesis of amorphadiene, starting from commercially available dihydroartemisinic acid, is reported. The targeted molecule is isolated with an overall yield of 85% on a multi-gram scale in four steps with only one chromatography.

Factores relacionados con la muerte súbita en pacientes con infarto agudo de miocardio / Factors related to sudden death in patients with acute myocardial infarction

Introducción: La cardiopatía isquémica es una importante causa de muerte en Cuba y el mundo. Objetivo: Identificar factores que influyen en la muerte súbita (MS) cardíaca de pacientes con infarto agudo de miocardio (IAM). Método: Se realizó un estudio retrospectivo en el Cardiocentro del Hospital Hermanos Ameijeiras, desde enero/2007 a enero/2016. La muestra fue de 465 pacientes con diagnóstico de IAM, dividida en dos grupos, 79 fallecidos y 386 vivos. Se utilizaron medidas de resumen para variables cuanti y cualitativas. La comparación de proporciones se realizó con la prueba Chi-cuadrado. Resultados: En los pacientes con IAM se asociaron significativamente a MS: la hipertensión arterial (0,047), el hábito de fumar (p<0,001), la insuficiencia arterial periférica (p=0,002), la dislipidemia, las arritmias (p<0,001), la fracción de eyección del ventrículo izquierdo menor de 50 por ciento (p<0,001), su diámetro telediastólico aumentado (53,0/11,0; p<0,001), el IAM sin elevación del ST (p=0,013), la enfermedad de coronaria derecha (p=0,011) y tronco (p=0,030); así como los mayores niveles de creatinina (p=0,006). Conclusiones: Las variables clínicas que se asociaron a la aparición de MS cardíaca fueron: hipertensión arterial, hábito de fumar, insuficiencia arterial periférica, antecedentes patológicos familiares y dislipidemia. Las arritmias, la baja fracción de eyección y el diámetro telediastólico del ventrículo izquierdo aumentado, se relacionaron con la MS en el IAM, donde fue más frecuente el que no tuvo elevación del ST. La coronaria derecha y el tronco de la coronaria izquierda, así como los niveles elevados de creatinina, se asociaron a la MS de estos pacientes(AU)

A comparison of the ellipsoidal and voxelized dosimetric methodologies for internal, heterogeneous radionuclide sources.

Non-human biota dosimetry has historically relied on ellipsoidal dosimetric phantoms. In 2008, the International Commission on Radiological Protection (ICRP) presented a set of ellipsoidal models representative of wildlife, including dosimetric data for homogeneously distributed internal radionuclide sources. Such data makes it possible to quickly and easily estimate radiation dose rate. Voxelized modeling, first developed for use in human medical dosimetry, utilizes advanced imaging technologies to generate realistic and detailed dosimetric phantoms. Individual organs or tissues may be segmented and dosimetric data derived for each anatomic area of interest via Monte Carlo modeling. Recently, dosimetric data derived from voxelized models has become available for organisms similar to the ICRP's Reference Animals and Plants in 2008. However, if the existing ellipsoidal models are conservative, there may be little need to employ voxel models in regulatory assessments. At the same time, existing dosimetric techniques may be inadequate to resolve recent controversies surrounding the impact of ionizing radiation exposure on wildlife. This study quantifies the difference between voxel-calculated and ellipsoid-calculated dose rates for seven radionuclides assumed to be heterogeneously distributed: (14)C, (36)Cl, (60)Co, (90)Sr, (131)I, (134)Cs, (137)Cs, and (210)Po. Generally, the two methodologies agree within a factor of two to three. Finally, this paper compares the assumptions of each dosimetric system, the conditions under which each model best applies, and the implications that our results have for the ongoing dialog surrounding wildlife dosimetry.