Juan I. Sarmiento-Sánchez

Synthesis of 1H-benzoxazine-2,4-diones from heterocyclic anhydrides: evaluation of antioxidant and antimicrobial activities

A facile one-step synthesis of 1H-benzoxazine-2,4-diones from heterocyclic anhydrides and TMSA was described. This paper determines their antimicrobial activity against nine human bacterial pathogens by the broth microdilution method; antioxidant activity by DPPH• inactivation and a ferric-reducing power assay; and toxicity by a brine shrimp, Artemia salina, assay. The 1H-benzoxazine-2,4-dione yields were in the range of 57 to 98%. The novel compound 1H-pyrazino[2,3-][1,3]oxazine-2,4-dione 4c showed the highest antioxidant capacity (DPPH 35.4% and FRAP 0.063 µmol TEs/µmol).

Synthesis of 1,3-dihydro-2H-benzimidazol-2-ones (microreview)

This microreview covers data regarding the synthesis of 1,3-dihydro-2H-benzimidazol-2-ones published during the last five years. The synthetic routes to benzimidazolones can be classified into several types: cyclocarbonylation of 1,2-diaminobenzenes, transformation of benzimidazolium salts, synthesis from arylureas, a Curtius reaction of anthranilic acids or phthalic anhydrides, and other pathways.

Antioxidant activity and antimicrobial evaluation of 1-benzyl-1,2,3-triazole

Este articulo reporta las actividades biologicas de 1-bencil-1,2,3-triazoles: antibacteriana por el metodo de microdilucion en caldo, antioxidante por el metodo de inactivacion del DPPH (2,2-difenil-1-picrilhidrazil•) y la toxicidad en el ensayo de artemia (Artemia salina). El compuesto 1-(1-bencil-1H-1,2,3-triazol-4-il) ciclopentanol (50 µg/mL a 200 µg/mL) presento inhibicion selectiva y moderada contra el crecimiento de Staphylococcus aureus 3, mientras que el mismo efecto se registro para el 3-(1-bencil-1H-1,2,3-triazol-4-il)-1-propanol contra E. coli AO11, E. coli AO15 y Salmonella enterica serovar Typhi. Los compuestos 5g-i mostraron la mas alta inactivacion del DPPH•. Los compuestos sinteticos 1,2,3-triazoles evaluados se clasificaron en el intervalo de moderadamente toxico a no toxico. Asi, basados en la informacion publicada actualmente, estos podrian ser una fuente de compuestos con actividades biologicas de importancia para la salud humana

Synthesis and Antioxidant Evaluation of Enantiomerically Pure Bis-(1,2,3-triazolylmethyl)amino Esters from Modified α-Amino Acids

The efforts for synthesis of enantiomerically pure bis-(1,2,3-triazolylmethyl)amino esters 6 are reported in good yields from an in situ generated α-azidomethyl ketone. Optimum experimental conditions were established for preparation of α-halomethyl ketones 10 and α-N,N-dipropargylamino esters 11, all derived from α-amino acids. The starting materials reacted under conventional click chemistry conditions, revealing a specific reactivity of bromomethyl ketones over chloromethyl ketones. The antioxidant activity of compounds 6 was assayed by DPPH method. The compound 6c with an IC50 of 75.57 ± 1.74 μg mL−1 was the most active. Technically, this methodology allows the preparation of a combinatorial library of analogues with different structural characteristics depending on the nature of the modified α-amino acids employed in the synthesis.

1-Benzyl-4-(naphthalen-1-yl)-1H-1,2,3-triazole.

In the title compound, C19H15N3, the benzyl group is almost perpendicular to the triazole ring [dihedral angle = 80.64 (8)°], while the napthyl group makes an angle of 30.27 (12)° with the plane of the triazole ring. This conformation is different from the 1-benzyl-4-phenyl-1H-1,2,3-triazole analogue, which has the benzyl ring system at an angle of 87.94° and the phenyl group at an angle of 3.35° to the plane of the triazole ring.

Synthesis of quinazolin-4(3H)-ones, an update (microreview)

This microreview covers the newest methods for the synthesis of quinazolin-4(3H)-ones published between 2017 and 2018. The synthetic methods primarily involve the use of a metal catalyst. However, few metal-free synthetic pathways are also addressed.

Open image in new window Synthetic approaches involving cyclic acetal groups for the design of biodegradable and biocompatible polymers (microreview)

This microreview addresses relevant data of current studies involving the exploitation of cyclic acetals in the design of degradable synthetic polymers. Two approaches are presented: polymerization of cyclic acetal units and formation of cyclic acetal units after the polymerization. This microreview contains data from the few fundamental references and literature published in the period from 2007 to 2018.

Microwave-assisted synthesis of benzoxazinediones under solvent-free conditions

ABSTRACT Benzoxazinediones exhibit potential as versatile synthons in the synthesis of wide variety of heterocyclic compounds with biological activity. In this work, an efficient and eco-friendly one-step synthesis of benzoxazine-2,4-diones from phthalic anhydrides derivatives and trimethylsilyl azide using the microwave technique was developed and compared with conventional heating. Microwave irradiation plays a critical role in driving the reaction and providing access to products and/or regioisomers not available from conventional heating. Thus, the regioselectivity of the reaction may be modulated by the irradiation time. Depending on the method employed the benzoxazinediones were isolated with yields in the range of 30–90%. GRAPHICAL ABSTRACT