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El chilhuacle (Capsicum annuum L.) es uno de los chiles más populares en Oaxaca. Sin embargo, se desconocer el manejo y la poscosecha de los frutos afecta directamente el rendimiento y la calidad del fruto. Con la finalidad de evaluar diferentes soluciones nutritivas para cada etapa fenológica, se establecieron tres experimentos en el campo experimental de la Facultad de Ciencias Agropecuarias de la Universidad Autónoma del Estado de Morelos. En la etapa vegetativa se evaluaron tres concentraciones de NO3-, en la etapa reproductiva nueve relaciones NO3-:H2PO4-:SO42-, y en la etapa de fructificación nueve relaciones NO3-:K+. Los tratamientos fueron distribuidos en un diseño de bloques completamente al azar con cinco repeticiones y una planta por unidad experimental en contenedores de polietileno negro (15.14 L), un sistema de siembra tresbolillo (50 cm etapa vegetativa y 75 cm en la etapa reproductiva y fructificación), sistema de riego por goteo y grava de tezontle rojo como sustrato. Los resultados indicaron que las soluciones nutritivas produjeron significancia en la altura, diámetro de tallo, volumen de raíz, materia seca de tallo y planta completa 14 meq L-1 de NO3- en la etapa vegetativa; redujo el aborto floral e incrementó el número de botones por planta con 10:0.75:9.25 meq L-1 de NO3-:H2PO4-:SO42- durante la etapa reproductiva y en fruto, la relación 14:9 meq L-1 de NO3-:K+ favoreció al incrementar significativamente el diámetro ecuatorial, peso de materia fresca y seca de fruto.

Kinetically controlled cyclocondensation of stereoisomeric and ring-chain tautomeric mixture of (±)-hydroxylactone 1 and 0.5 equiv of (R)-phenylglycinol provided tricyclic oxazoloisoindolone lactam (3R,5aS,9aR,9bS)-2a, a versatile intermediate for further stereocontrolled transformations to access enantiopure cis-fused octahydroisoindolones. An extension of this methodology was successfully applied to the synthesis of the 5,6-dihydroxy derivative (3aR,5R,6S,7aS)-17.

An expedient synthetic entry to cis-4-hydroxyphosphonic and cis-4-hydroxyphosphinic analogs of cis-4-hydroxypipecolic acid is presented in this paper. The main feature of this methodology is the highly regioselective addition of silyl phosphites or phosphonites to cyclic 1-benzyloxycarbonyl enaminones. Interestingly, the hydride reduction of the resulting 2-phospho-4-oxopiperidine proceeds with high diastereofacial preference using NaBH

Kinetically controlled cyclocondensation of stereoisomeric and ring-chain tautomeric mixture of (±)-hydroxylactone

Two new strategies for the efficient synthesis of racemic 1,2,3,4-tetrahydroisoquinoline-3-phosphonic acid (TicP) (±)-2 have been developed. The first strategy involves the electron-transfer reduction of the easily obtained α,β-dehydro phosphonophenylalanine followed by a Pictet–Spengler cyclization. The second strategy involves a radical decarboxylation–phosphorylation reaction on 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid (Tic). In both strategies, the highly electrophilic N-acyliminium ion is formed as a key intermediate, and the target compound is obtained in good yield using mild reaction conditions and readily available starting materials, complementing existing methodologies and contributing to the easy accessibility of (±)-2 for further research., This work was supported by Consejo Nacional de Ciencia y Tecnología (CONACYT) through projects 286614 and 256985, and Gobierno de Aragon-FEDER (Grupo Aminoacidos y Peptidos E19-17R; FEDER 2014-2020 “Construyendo Europa desde Aragon”).

We report the first stereoselective synthesis of (2R,3aR,7aR)- and (2S,3aS,7aS)-octahydroindole-2-phosphonic acid 2 (OicP derivatives). The key points are the highly diastereoselective synthesis of cis-fused bicyclic (3aR,7aR)- and (3aS,7aS)-pyrrolidin-2-ones 4 through a dynamic kinetic resolution of racemic γ-keto acid (±)-5 with (R)- and (S)-phenylglycinol via Meyers' bicyclic lactams, and the highly diastereoselective addition of trimethyl phosphite to the N-acyliminium ions 3 obtained from 4.

We report here a practical and efficient synthesis of diethyl 1,2,3,4-tetrahydroisoquinoline-3-phosphonate derivatives. The target compounds were prepared in good yield using a Pictet-Spengler reaction involving α-amino phosphonates that were easily obtained. We have paid special attention to the synthesis of (R)- and (S)-1,2,3,4-tetrahydroisoquinoline-3-phosphonic acid (Tic) 2a, a conformationally constrained analogue of phosphophenylalanine Phe. The procedure is based on the preparation of racemic phosphophenylalanine (Phe) diethyl ester followed by chiral chromatographic separation and subsequent Pictet-Spengler chemistry., The authors thank Consejo Nacional de Ciencia y Tecnología (CONACYT) for financial support through projects 181816 and 248868, the Ministerio de Ciencia e Innovación – FEDER (grant CTQ2010-17436), and the Gobierno de Aragón-FSE (research group E40).

In this paper, we report the synthesis of a new series of α-aminophosphonates derivatives based in an efficient three-component reaction. All compounds prepared showed significant anti-inflammatory activity, being the compounds 1a, 1c, 1d, 1f, 2b and 2c the most promising ones, in terms of maximal efficacy (over 95%), potency (ED50 range between 0.7 and 10.1 mg/ear) and relative potency (range from 0.04 to 0.67). Compounds 1a, 1c, 1d and 1f significantly decrease the number of neutrophils (range from 46.7 to 63.0%) and monocytes (18.9–34.1%) in blood samples from the orbital sinus. Additionally, QSAR model revealed that the spherical molecular shape and the location of the HOMO on the phenyl ring improves the anti-inflammatory activity of the compounds. The values of R2, Q2, s and F statistical parameters and the QUIK, asymptotic Q2 and Overfitting rules validate the descriptive and predictive ability of the QSAR model. Altogether these results suggest that these new α-aminophosphonates are potential agents for the treatment of inflammation.

Practical and convenient method for the synthesis of novel phosphonopeptides 8a-h and 10a-f incorporating the quaternary α-aminophosphonate 6 is reported. The target compounds were prepared in moderate to good yield based on the preparation of the quaternary α-aminophosphonate 6 followed by the formation of the α-bromoamide 7 and subsequent nucleophilic substitution reaction with several amines or by peptide bond formation with several amino acids and with the quaternary α-aminophosphonate 6, using isobutyl chloroformate as activating agent under racemization-free condition.

The alkylation reaction of diethyl N-(diphenylmethylene)aminomethylphosphonate (6) with alkyl dihalides under phase-transfer catalysis followed by hydrolysis of the benzophenone imine moiety and subsequent cyclization provides a simple and convenient method for the synthesis of known and new cyclic α-aminophosphonates 1–5 in moderate to good yields.

Optically active α-aminoalkylphosphonic acids 1 are structural analogues of α-amino acids 2, obtained by isosteric substitution of the planar and less bulky carboxylic acid (CO2H) by a tetrahedral phosphonic acid functionality (PO3H2). Several α-aminoalkylphosphonic acids and derivatives have been isolated from natural sources, either as free amino acids or as constituents of more complex molecules. These classes of compounds are currently attracting interest in organic and medicinal chemistry, as well as in agriculture, due to their important biological and pharmacological properties. Additionally, the α-aminophosphonates have been used as key synthetic intermediates for the preparation of more complex compounds1b, and as organocatalysts., We gratefully acknowledge CONACyT of Mexico (grant 181816), Ministerio de Economía y Competitividad (grant CTQ2013-40855-R), and Gobierno de Aragón -FSE (research group E40).

Shikimic acid (SA) pathway is the common route used by bacteria, plants, fungi, algae, and certain Apicomplexa parasites for the biosynthesis of aromatic amino acids and other secondary metabolites. As this essential pathway is absent in mammals designing inhibitors against implied enzymes may lead to the development of antimicrobial and herbicidal agents harmless to humans. Shikimate dehydrogenase (SDH) is the fourth enzyme of the SA pathway. In this contribution, a series of SA amide derivatives were synthesised and evaluated for in vitro SDH inhibition and antibacterial activity against Escherichia coli. All tested compounds showed to be mixed type inhibitors; diamide derivatives displayed more inhibitory activity than synthesised monoamides. Among the evaluated compounds, molecules called 4a and 4b were the most active derivatives with IC50 588 and 589 µM, respectively. Molecular modelling studies suggested two different binding modes of monoamide and diamide derivatives to the SDH enzyme of E. coli.

The authors are thankful for financial support by the Mexican Consejo Nacional de Ciencia y Tecnologia (CONACYT) for financial support via project 181816, by the Spanish Ministerio de Ciencia e Innovacion (MICINN), FEDER (grant number CTQ2010- 17436) and by the Gobierno de Aragon-FSE (research group E40). J. L. V.-C. also thank CONACYT for graduate scholarships.

The most important and available references have been collected in this review to prove the versatility of stereoselective synthesis of acyclic α,α-disubstituted α-amino acids from amino acids template equivalents., The authors gratefully acknowledge financial support from CONACYT (projects 286614 and 256985), and Gobierno de Aragon-FEDER (Grupo Aminoacidos y Peptidos E19-17R; FEDER 2014–2020 ″Construyendo Europa desde Aragon").

α-Amino-H-phosphinic acids and derivatives are an important group of compounds of synthetic and pharmacological interest, and particular attention has been dedicated toward their stereoselective synthesis in recent years. While some of these compounds show activity by themselves, they are also valuable starting materials in the synthesis of phosphinic bioisosteres of natural peptides, where the hydrolyzable bond is substituted by a phosphinic functionality that mimics the transition state of peptide hydrolysis, thus acting as efficient enzyme­ inhibitors in which the molecular stereochemistry is demonstrated to be critical. This review summarizes the latest developments on the asymmetric synthesis of acyclic and phosphacyclic α-amino-H-phosphinic acids and derivatives following an order according to the strategy used; in addition, some implications in medicinal chemistry are disclosed., The authors gratefully acknowledge CONACYT (grant 181816, 248868) and PRODEP (project UAEMOR-PTC-379) of Mexico, Ministerio de Economía y Competitividad (grant CTQ2013-40855-R) and Gobierno de Aragón – FSE (research group E40) for their financial support.

The authors thank Consejo Nacional de Ciencia y Tecnologia (CONACYT) for financial support through projects 181816 and 248868, the Ministerio de Ciencia e Innovacion – FEDER (grant CTQ2010-17436), and the Gobierno de Aragon-FSE (research group E40).

The alkylation reaction of diethyl N-(diphenylmethylene)aminomethylphosphonate (6) with alkyl dihalides under phase-transfer catalysis followed by hydrolysis of the benzophenone imine moiety and subsequent cyclization provides a simple and convenient method for the synthesis of known and new cyclic α-aminophosphonates 1–5 in moderate to good yields.

This review describes the synthesis, biological interest and importance of the α-aminophosphonic acids analogs of the 20 proteinogenic α-amino acids. Special attention is devoted to those stereoselective procedures that allow the synthesis of the required compounds in enantiomerically pure form. © 2012 Bentham Science Publishers.

The first diastereoselective total synthesis of 5-substituted morpholine-3-phosphonic acids is reported. The principal feature of the synthesis is the introduction of a dimethyl phosphonate group into 5-substituted morpholin-3-ones. The procedure is based on the preparation of N -Boc-( S )-5-phenyl- and N -Boc-( S )-5-benzylmorpholin-3-one from l -phenylglycine and l -phenylalanine methyl esters, followed by the formation of the 3-methoxylated compounds and subsequent reaction with trimethyl phosphite in the presence of BF 3 ·OEt 2 . Diastereoselectivity in the formation of cis -disubstituted products is in agreement with the nucleophilic addition to other methoxylated derivatives.

The authors are thankful for financial support by the Mexican Consejo Nacional de Ciencia y Tecnologia (CONACYT) for financial support via project 181816, by the Spanish Ministerio de Ciencia e Innovacion (MICINN), FEDER (grant number CTQ2010- 17436) and by the Gobierno de Aragon-FSE (research group E40). J. L. V.-C. also thank CONACYT for graduate scholarships.

We gratefully acknowledge CONACyT of Mexico (grant 181816), Ministerio de Economia y Competitividad (grant CTQ2013-40855-R), and Gobierno de Aragon -FSE (research group E40).

Diastereoselective nucleophilic addition of trimethyl phosphite to an N-acyliminium intermediate derived from substrate (I) gives cyclic α-aminophosphonates.

A three-component reaction of o-formylbenzoic acid, primary amines and dimethyl phosphite constitutes an efficient synthesis of isoindolinone phosphonates, which readily undergo dephosphorylation with LiAlH4.

The one-pot three-component reaction of 2-formylbenzoic acid with (S)- and (R)-methylbenzylamine and dimethyl phosphite (Kabachnik-Fields reaction) proceeded in short reaction times under solvent and catalyst free-conditions to afford the corresponding (3R,1′S)- and (3S,1′R)-isoindolin-1-one-3- phosphonates 3, respectively, in good yield and with high diastereoselectivity (95:5 dr). The use of a solvent decreases the diastereoselectivity and slows the reaction rate. The reaction rate was also influenced by CO2H functionality through protonation of the imine intermediate. The absolute configuration at the new stereogenic center was determined by X-ray crystal analysis, and a mechanism was proposed to explain the high diastereoselectivity. © 2011 Elsevier Ltd. All rights reserved., The authors thank the CONACYT of Mexico, for their financial support via projects 62271 and J000.400/2009), Ministerio de Ciencia e Innovación (project CTQ2010-17436) and Consejo Superior de Investigaciones Científicas (project 2008MX0044. One of us, J.L.V.C. also thanks the CONACYT for a Graduate Scholarship.