A straightforward route to obtain 13C1-labeled clenbuterol

González-Antuña, Ana; Lavandera, Iván; Rodríguez-González, Pablo; Rodríguez, Jorge; Alonso, J. Ignacio García; Gotor, Vicente

doi:10.1016/j.tet.2011.05.118

Cited by 11 publications

(6 citation statements)

References 29 publications

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“…En este sentido, merece la pena focalizar los esfuerzos de conservación en estas seis especies. Así, se propone la inclusión de estos ditíscidos en futuros análisis de conservación, los cuales incrementarán los listados nacionales de especies amenazadas existentes (i.e., Amaro, 2012;González-Alonso, Rodríguez Schettino, Rodríguez, Mancina, & Ramos García, 2012). Además, también se propone su inclusión en la Lista Roja de la UICN bajo la categoría de "Vulnerable", ya que al menos, cumplen con los criterios B1+2ab (i, ii, iii) de la UICN (IUCN, 2012), ya que se caracterizan por presentar poblaciones muy localizadas (tanto en extensión de la presencia como en área de ocurrencia), y con una disminución estimada tanto del rango de distribución como de la calidad del hábitat.…”

Section: Discussionunclassified

Vulnerabilidad de las especies de Dytiscidae (Coleoptera) en Cuba

Megna

Sánchez‐Fernández

García

et al. 2018

RBT

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Vulnerability of Dytiscidae species (Coleoptera) in Cuba. Cuba has one of the richest diving beetles species diversity in the Caribbean islands. However, Cuban Dytiscidae remain scarcely studied, and there is need to identify those species and habitats that urgently require effective conservation actions. Here we aim to identify the threatened taxa of the family Dytiscidae in Cuba according to their degree of vulnerability. For that, we compiled distributional data on the Cuban fauna, including data from literature, collections and own samplings carried out between the period 2000 and 2014. In addition, the vulnerability of the species was evaluated using a methodology that combines six criteria regarding both species and habitat attributes. This analysis of vulnerability was completed to 50 (94 %) out of 53 Cuban species. Five species (9 %) were identified as highly vulnerable, 20 (38 %) moderately and 25 (48 %) as having low conservation status. The five most threatened species were Laccodytes cobrinae, Laccophilus alariei, Copelatus barbouri, C. darlingtoni, and Desmopachria glabella. These species are endemic to Cuba and characterized by highly localized populations and low abundance as well as high habitat specificity. Thus, we propose the inclusion of these five species in both the red list of Cuban fauna and the IUCN Red List (under the category of “Vulnerable”). In addition, not all areas where these species were found belong to the National System of Protected Areas of Cuba. Thus, we suggest the inclusion of the Laguna Base Julio A. Mella and the North of Imías, and to develop effective management measures to prevent the alteration of these aquatic ecosystems. Rev. Biol. Trop. 66(2): 709-721. Epub 2018 June 01. Key words:

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Section: Discussionunclassified

Vulnerabilidad de las especies de Dytiscidae (Coleoptera) en Cuba

Megna

Sánchez‐Fernández

García

et al. 2018

RBT

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“…All 13 C 1 ‐labelled β 2 ‐agonists except clenbuterol were provided in pure solid form by ISC‐Science. Clenbuterol 13 C 1 was synthesised in our laboratory as described elsewhere . All compounds have the carbon‐13 label in the benzylic position.…”

Section: Methodsmentioning

confidence: 99%

Determination of the enrichment of isotopically labelled molecules by mass spectrometry

2014

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A general method for the determination of the enrichment of isotopically labelled molecules by mass spectrometry (MS) is described. In contrast to other published procedures, the method described here takes into account and corrects for measurement errors such as the contribution at M - 1 due to loss of hydrogen or lack of spectral resolution and provides an uncertainty value for the determined enrichment. The general procedure requires the following steps: (1) evaluation of linearity in the mass spectrometer by injecting the natural abundance compound at different concentration levels, (2) determination of the purity of the mass cluster using the natural abundance analogue, (3) calculation of the theoretical isotope composition of the labelled compound using different tentative isotope enrichments, (4) calculation of 'convoluted' isotope distributions for the labelled compound taking into account the purity of the mass cluster determined with the natural abundance analogue and (5) comparison of the isotope distributions measured for the labelled compound with those calculated for different isotope enrichments using linear regression. The method was applied to a series of commercially available (13)C- and (2)H-labelled compounds and to a suite of singly (13)C-labelled β2-agonist prepared in-house both by gas chromatography (GC)-MS, GC-tandem MS (MS/MS) and liquid chromatography-MS/MS with satisfactory results. It was observed that the main uncertainty source for the isotope enrichment was the uncertainty in the purity of the measured cluster as determined with the natural abundance compound.

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“…Racemic clenbuterol has been synthesised through the incorporation of carbon monoxide in aryl iodides [15], while racemic 13 C-labeled clenbuterol has been synthesised from acetanilide [16]. Enantiopure (R)-1-(4-amino-3,5-dichlorophenyl)-2-bromoethan-1-ol, a precursor for (R)-clenbuterol, has been synthesized through an asymmetric reduction of the parent ketone, catalysed by an alcohol dehydrogenase from Rhodococcus erythropolis.…”

Section: Introductionmentioning

confidence: 99%

Chemoenzymatic Synthesis of Synthons as Precursors for Enantiopure Clenbuterol and Other β2-Agonists

et al. 2018

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Clenbuterol is a β2-agonist used in the veterinary treatment of asthma in several countries. The drug is listed on the World Antidoping Agency’s prohibited list due to its effect on increased protein synthesis in the body. However, racemic clenbuterol has recently been shown to reduce the risk of Parkinson’s disease. In order to reveal which one (or both) of the enantiomers that cause this effect, pure enantiomers need to be separately studied. (R)-1-(4-Amino-3,5-dichlorophenyl)-2-bromoethan-1-ol has been synthesised in 93% enantiomeric excess (ee) by asymmetric reduction of the corresponding ketone catalysed by a ketoreductase and nicotinamide adenine dinucleotide phosphate (NADPH) as the cofactor in dimethyl sulfoxide (DMSO). (S)-N-(2,6-Dichloro-4-(1-hydroxyethyl)phenyl)acetamide has been synthesised in >98% ee by the same system. Both synthons are potential precursors for clenbuterol enantiomers.

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A straightforward route to obtain 13C1-labeled clenbuterol

Cited by 11 publications

References 29 publications

Vulnerabilidad de las especies de Dytiscidae (Coleoptera) en Cuba

Vulnerabilidad de las especies de Dytiscidae (Coleoptera) en Cuba

Determination of the enrichment of isotopically labelled molecules by mass spectrometry

Chemoenzymatic Synthesis of Synthons as Precursors for Enantiopure Clenbuterol and Other β2-Agonists

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