Botrylactone: new interest in an old moleculedreview of its absolute configuration and related compounds

The absolute configuration of botrylactone, a unique compound with an interesting polyketide lactone skeleton with two oxirane bridges previously isolated from Botrytis cinerea and described as a powerful antibiotic, has been reviewed on the basis of sign of the optical rotation, NOE experiments and NMR method. The isolation of 7-deoxybotrylactone and 5-hydroxy-7-(4-hydroxydec-2(3)-enoyl) botrylactone enables us to characterize an intriguing new family of compounds with this interesting polyketide skeleton. A common biosynthetic origin with botcinin derivatives is proposed

Degraded limonoids: biologically active limonoid fragments re-enhancing interest in Meliaceae and Rutaceae sources

Phytochemical studies on the roots, twigs and leaves of Meliaceae and Rutaceae family plants have revealed the presence of non-complex terpenes derived from limonoid fragmentation. The occurrence and chemical structure of these degraded limonoids isolated from 1930 to March 2022 are reported in this review. Particular attention is given to the degradation levels in these compounds and their absolute configuration to discover presumable deconstruction pathways from more complex limonoids. Plausible intermediates have been postulated for most of them that would explain their origin from limonoids. The total or semi-synthesis of the most isolated degraded limonoids or analogues remains undescribed. This review focuses on the bioactivity of these fragmented limonoids and their synthesized analogues. Based on pharmacological and agrochemical studies, degraded limonoids appear to be excellent structural leads to consider for the total or semi-synthesis of more potent derivatives with the aim of discovering new hits and clarifying their modes of action

Relación entre el color de epidermis y algunas características de calidad en frutos de aguacate 'Hass’.

Mexico is the main 'Hass' avocado exporter in the world. More than 300,0001 are exported every year. The United States of America, Japan, the European Union, and Canada are the main importer countries. Recently, 'Hass'avocado shipments to Canada containing fruit with skin blackening have been rejected since this characteristic is associated with low pulp firmness and short shelf life. The objective of this study was to determine the relationship between skin color of 'Hass' avocado fruit with quality characteristics. Fruit varying in black skin color (from 0 to 100%, categories 1 to 5) were collected from two different packinghouses in Michoacán, Mexico. Treatments were arranged in a split-plot design with five replications. Significant differences were detected between packinghouses for weight, length, skin color ('a', ‘b’, chroma and hue) and pulp firmness but not for width, dry matter content or the Avocado Maturity Index (AMI). As color skin category increased towards more blackened fruit, AMI value increased, firmness decreased but dry matter content did not change. These results provide evidence that fruit skin blackening is not associated with lower fruit quality, but it did lower pulp firmness at fruit packing.México es el principal exportador de aguacate 'Hass' en el mundo con más de 300,000 t anuales. Los principales importadores son Estados Unidos de América, Japón, la Unión Europea y Canadá. Recientemente, embarques de aguacate 'Hass' que contenían frutos con ennegrecimiento de la epidermis fueron rechazados por el mercado canadiense, ya que esta característica se asocia con baja firmeza de pulpa y corta vida de anaquel. El objetivo de este estudio fue determinar la relación entre el color de la epidermis de frutos de aguacate 'Hass' con algunas características de calidad. En dos empacadoras de Michoacán, México, se tomaron muestras de frutos con diferentes porcentajes de color negro en la epidermis (de 0 a 100%; categorías 1 a 5). A cada fruto se le midió el color externo [luminosidad (L), 'a', 'b', croma y ángulo de tono], firmeza de pulpa,contenido de materia seca y el índice de maduración. Se empleó un diseño de parcelas divididas con cinco repeticiones. Se detectaron diferencias significativas entre empacadoras para peso, largo, color de cascara ('a', b', croma y hue) así como para firmeza de pulpa pero no para ancho, contenido de materia seca ni el índice de maduración. Se observó que conforme el color de categoría se incrementó hacia frutos más obscuros, los valores del índice de madurez se incrementaron, la firmeza disminuyó pero el contenido de materia seca no varió. Estos resultados proveen evidencia de que el obscurecimiento de la cascara no está asociado con la baja calidad de los frutos, aunque sí con la disminución de la firmeza de pulpa al momento del empacado

Titanium carbenoid-mediated cyclopropanation of allylic alcohols: selectivity and mechanism

A new method for the chemo- and stereoselective conversion of allylic alcohols into the corresponding cyclopropane derivatives has been developed. The cyclopropanation reaction was carried out with an unprecedented titanium carbenoid generated in situ from Nugent’s reagent, manganese and methylene diiodide. The reaction involving the participation of an allylic hydroxyl group, proceeded with conservation of the alkene geometry and in a high diastereomeric excess. The scope, limitations and mechanism of this metal-catalysed reaction are discussed

Fast HPLC analysis of omeprazole, 5-hydroxyomeprazole and omeprazole sulfone in liquid culture medium using a monolithic column for application in biotransformation studies with fungi

A fast liquid chromatography method was developed and validated for the simultaneous determination of omeprazole (OMZ), 5-hydroxyomeprazole (5-HOMZ) and omeprazole sulphone (OMZ SUL) in liquid culture medium for application in biotransformation studies employing phytopathogenic and endophytic fungi. The separation was achieved using a monolithic Chromolith Fast gradient RP 18 endcapped column, using a mobile phase consisting of 0.15% (v/v) trifluoroacetid acid (TFA) in water (solvent A) and 0.15% (v/v) TFA in acetonitrile (solvent B), under linear gradient of 5 to 90% of B in 1 min, flow rate of 1.0 mL min-1, temperature at 30 ºC and detection at 220 nm. Sample preparation was performed by liquid-liquid extraction, with recoveries in the range of 62.3 to 76.6% for all analytes. The method was linear in the range of 0.2 to 10.0 µg mL-1 (r &#8805; 0.995). The values for intra- and inter-day precision (% coefficient of variation) and accuracy (% relative error) were < 15% for all analytes. The validated method was used to evaluate OMZ biotransformation to their mammalian metabolites by selected fungi. In general, the phytopathogenic fungi studied were more efficient to biotransform OMZ. The sulfonation reaction was more prevalent for all studied fungi.Um método rápido por cromatografia líquida foi desenvolvido para a determinação simultânea de omeprazol (OMZ), 5-hidroxiomeprazol (5-HOMZ) e omeprazol sulfona (OMZ SUL) em meio de cultura líquido, para aplicação em estudos de biotransformação empregando fungos fitopatogênicos e endofíticos. A separação foi realizada empregando uma coluna monolítica Chromolith Fast gradient RP 18 com a fase móvel constituída por ácido trifluoroacético (TFA) 0,15% (v/v) em água (solvente A) e TFA 0,15% (v/v) em acetonitrila (solvente B). Foi empregado um gradiente linear de 5 a 90% de B em 1 minuto, vazão de 1,0 mL min-1, temperatura de 30 ºC e detecção em 220 nm. A extração líquido-líquido foi empregada na preparação das amostras, com recuperações na faixa de 62,3-76,6% para todos os analitos. O método foi linear na faixa de 0,2-10,0 µg mL-1 (r &#8805; 0,995). Os valores de precisão e exatidão intra- e inter-dias (coeficiente de variação e erro relativo) foram inferiores a 15% para todos os analitos. O método validado foi utilizado para avaliar a biotransformação do OMZ em seus principais metabólitos humanos pelos fungos selecionados. Em geral, os fungos fitopatogênicos foram mais eficientes para biotransformar o OMZ. A reação de sulfonação foi mais prevalente em todos os fungos estudadosFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Diastereoselective and enantioselective preparation of nor-mevaldic acid surrogates through desymmetrisation methodology. Enantioselective synthesis of (+) and (-) nor-mevalonic lactones

Solvent-free desymmetrisation of a meso-dialdehyde with chiral alcohols, led to preparation of 4- silyloxy-6-alkyloxytetrahydro-2H-pyran-2-one derivatives with a 96% de. This methodology, which yields the corresponding methyl nor-mevaldates with 99% ee, has been applied to the enantioselective synthesis of the ( )-(R) and (þ)-(S) nor-mevalonic acid lactones

Exploring mutasynthesis to increase structural diversity in the synthesis of highly oxygenated polyketide lactones

The enantioselective synthesis of (2R,3R,4E,8E)-3-hydroxy-2,4,8-trimethyldeca-4,8-dienolide (5) by ring-closing metathesis is described. This compound is an analogue of 3,4-dihydroxy-2,4,6,8-tetramethyldec- 8-enolide (4) which is a rare 11-membered lactone produced by the fungus, Botrytis cinerea. Mutasynthetic studies with compound 5 using two mutants of B. cinerea led to the isolation of four new highly oxygenated 11-membered lactones (11–14) in which compound 5 has been stereoselectively epoxidized and hydroxylated at sites that were not easily accessible by classical synthetic chemistry

The synthesis of 3-hydroxy-2,4,8-trimethyldec- 8-enolides and an approach to 3,4-dihydroxy- 2,4,6,8-tetramethyldec-8-enolide

The synthesis of several derivatives of 3-hydroxy-2,4,8-trimethyldec-8-enolide and attempts at the synthesis of 3,4-dihydroxy-2,4,6,8-tetramethyldec-8-enolide (1), a structure which has been assigned to a metabolite of the phytopathogenic fungus, Botrytis cinerea, gave products whose spectroscopic data had significant differences from those reported for the natural product 1. The rare 11-membered lactone rings were constructed by ring-closing metathesis reactions. The increase in conformational restrictions imposed by the substituents has a high influence on the stereochemistry of the ring-closing metathesis reaction and gives rise to a decrease in the yield for the synthesis of 11-membered lactones. The predominant alkene which was obtained was the (Z)-isomer. The observed spectroscopic differences between the synthesized lactones and the natural product and the spectroscopic data of its acetylated derivative 26a allowed us to revise the structure 1 to that of the γ-butyrolactone 26

The Asymmetric Total Synthesis of Cinbotolide: A Revision of the Original Structure

The structure 3,4-dihydroxy-2,4,6,8-tetramethyldec-8-enolide (1) was assigned to a metabolite of Botrytis cinerea, but the spectra of several synthetic analogues had significant differences from that of 1. Examination of the constituents of a B. cinerea mutant that overproduces polyketides gave sufficient quantities of 1, now named cinbotolide, for chemical transformations. These led to a revised γ-butyrolactone structure for the metabolite. This structure has been confirmed by an asymmetric total synthesis, which also established its absolute configuration

Phytotoxic Activity and Metabolism of Botrytis cinerea and Structure−Activity Relationships of Isocaryolane Derivatives

Research has been conducted on the biotransformation of (8S,9R)-isocaryolan- 9-ol (4a) and (1S,2S,5R,8S)-8 methylene-1,4,4-trimethyltricyclo[6.2.1.02,5]undecan-12-ol (5a) by the fungal phytopathogen Botrytis cinerea. The biotransformation of compound 4a yielded compounds 6−9, while the biotransformation of compound 5a yielded compounds 10−13. The activity of compounds 4a and 5a against B. cinerea has been evaluated. (8R,9R)- Isocaryolane-8,9-diol (6), a major metabolite of compound 4a, shows activity compared to its parent compound 4a, which is inactive. The effect of isocaryolanes 3, 4a, and 5a, together with their biotransformation products 6−8, 10, and 14−17, on the germination and radicle and shoot growth of Lactuca sativa (lettuce) has also been determined. Compounds 7−13 are described for the first time