In this work, the combined use of p-sulfonic acid-calix[n]arene and microwave energy to hydrolyze the 1,3-dioxolane ketal of isatin was evaluated with excellent results. This is the first time that p-sulfonic acid-calix[n]arene has been used as the catalyst in a ketal hydrolysis reaction and the deprotection of the ketone carbonyl of isatin is reported. The presence of 2.5 mol% of p-sulfonic acid-calix[4,6]arene at 160 ºC resulted in over 96% conversion of this ketal in 10 min, with the additional advantage of using water as a solvent. This catalytic system (aqueous phase containing p-sulfonic acid-calix[4]arene) was reused for five consecutive cycles, with a conversion above 96% maintained. This reusable system is not practicable using p-toluenesulfonic acid and p-hydroxybenzenesulfonic acid as catalysts since both are extracted to the organic phase with the reaction product. The hydrolysis of 1,3-dioxolane ketal of isatins with different substituents (CH3, I, Br, Cl, F, NO2) in the aromatic ring was also evaluated. The protecting group of 5-methyl-isatin was removed with 73% conversion using 2.5 mol% of p-sulfonic acid-calix[4]arene at 160 ºC for 5 min. In contrast, the ketal of 5-nitro-isatin reached 80% conversion using the same conditions after 40 min.

The crescent number of scientific articles published per year shows that research on biodiesel continues to play an important role to support the growing demand for this biofuel. The second edition of Biodiesel: An Overview presents the worldwide research in the last 15 years. Microalgae biomass is the most studied raw material alternative in this period and several studies have been carried out to develop basic heterogeneous catalysts for biodiesel production. Concerning to production technologies, supercritical conditions and intensification process have been extensively investigated. The development of new antioxidants additives has focused mainly on biomass-derived formulations and there are few studies on biocide candidates. In terms of pollutant emissions, in general, the studies showed that the addition of biodiesel generates lower concentrations of polycyclic aromatic hydrocarbons (PAH), CO and n-alkanes pollutants, but carbonyl compounds, major ions and NOx are emitted in a higher concentration compared to pure diesel.

Novel isatinspirooxazine derivatives were designed and synthesized as potential anti-proliferative agents. The new compounds were obtained from aldol condensation reactions between isatin and 3-(hydroxyimino)butan-2-one in the presence of an organic base in order to generate an aldol adduct, followed by cyclization in trifluoroacetic acid, providing the desired isatinspirooxazines in 30 to 80% yield. All the synthesized compounds, including the starting material and the synthetic intermediates, were tested for in vitro anti-proliferative activity against cell lines MCF-7 and MDA-MB231 (breast cancer) and A549 (lung cancer), highlighting the compound 4-methyl,5'-methyl-spiro[(5-aza-4-eno-3-one-cyclohexane)-1,3'-(1H-indol-one)] with an IC50 (half maximal inhibitory concentration) = 0.34 µM, more potent than the reference drug, doxorubicin (IC50 = 1.88 µM), in breast cancer line MDA-MB231.

In this study, whole cells of marine-derived fungi were used to reduce isatin (1H-indole-2,3-dione) to dioxindole (3-hydroxyindolin-2-one) for 7 days at 32 °C. The screening showed that several strains could reduce isatin and produce the enantioenriched dioxindole. The best conversions were obtained by Cladosporium sp. CBMAI 1237 and Westerdykella sp. CBMAI 1679, however, the best enantiomeric excess was obtained only by Aspergillus sydowii CBMAI 935 (66% ee). In conclusion, marine-derived fungi show potential for asymmetric and chemoselective reduction of isatin (1H-indole-2,3-dione).

This short report describes the preparation of twelve isatin derivatives, 5'-(4-alkyl/aryl-1H-1,2,3-triazoles), using 5-azido-spiro[1,3-dioxolane-2,3'-indol]-2'(1'H)-one in the presence of various alkynes under acidic conditions and ultrasound irradiation. Compared with conventional methods, yields increased to 78-98%, and reaction times decreased to 5 min. Besides time and energy saving, there was no need for purification of the product by column chromatography on silica gel, generating less waste and spent solvent.

Nuclear magnetic resonance is a technique that is widely used for elucidating and characterizing organic substances. Organofluorine substances have applications in many areas from drugs to liquid crystals, but their NMR spectra are often challenging due to fluoride coupling with other nuclei. For this reason, NMR spectra of this class of substances are not commonly covered in undergraduate and graduate chemistry courses and related fields. Thus, the aim of this work was the presentation and discussion of 1H, 13C, and 19F NMR spectra of eleven organofluorine substances which, in the case of 1H and 13C nuclei, showed classic patterns of first-order coupling and the effects of the fluorine nucleus in different chemical and magnetic environments. In addition, the observation of long distance coupling constants was possible through the use of apodization functions in the processing of the spectra. It is expected that the examples presented herein can be utilized and discussed in undergraduate and graduate NMR spectroscopy disciplines and thus improve the teaching and future research of organofluorine compounds.

Este artigo descreve a preparação de uma série de 16 ácidos antranílicos, em rendimentos que variaram de 51 a 97%, através do tratamento de isatinas com NaOH e H2O2. Independentemente da natureza do substituinte no anel aromático, as reações se completaram em 15 min. a temperatura ambiente, ao passo que as isatinas contendo substituinte no átomo de nitrogênio requereram um tempo maior para completar a reação (45 min.), sob as mesmas condições.

This paper describes the preparation of a series of 16 anthranilic acids in yields ranging from 51 to 97%, by treating the isatins with NaOH and H2O2. Independently of the nature of the substituent on the aromatic ring, the reactions were complete in 15 min at room temperature, whereas those of isatins containing a substituent on the nitrogen atom required longer reaction time for completion (45 min) under the same reaction conditions.

A isatina é uma molécula pequena, versátil e de ampla aplicação farmacológica. Estas características fazem da isatina e de seus derivados uma fonte de estudos químicos e farmacológicos atraente para diversos grupos de pesquisa. Embora possua estrutura relativamente simples, é rica em possibilidades de transformações químicas. Este artigo apresenta um painel dos diversos trabalhos desenvolvidos por grupos brasileiros que envolvem modificações estruturais, ensaios biológicos e investigações de novos métodos para a síntese de isatinas.

Isatin is a small, versatile and widely applicable pharmacological molecule. These characteristics make isatin and its derivatives attractive to many research groups as resources for chemical and pharmacological studies. Although it has a relatively simple structure, isatin is a useful chemical scaffold for a variety of chemical transformations. This article discusses several studies performed by Brazilian groups, including investigations of its structural changes, biological assay designs and new methods for the synthesis of isatin.

As isatinas e os 1H-1,2,3-triazóis são duas classes de compostos com grande destaque na síntese orgânica e na química medicinal uma vez que são núcleos heterociclos com elevada reatividade, que permitem a obtenção de diversos compostos com importantes propriedades biológicas. Neste artigo, a síntese de novos 5`-(4-alquil/aril-1H-1,2,3-triazóis)-isatina via reação de cicloadição 1,3-dipolar catalisada por ácido acético é descrita.

Isatin and 1H-1,2,3-triazoles are two classes of compounds with great prominence in organic synthesis and medicinal chemistry as they are heterocycle nuclei with a high reactivity allowing to obtain several compounds with important biological properties. Herein, the synthesis of novel 5'-(4-alquil/aril-1H-1,2,3-triazole)-isatin via reaction of 1,3-dipolar cycloaddition catalyzed by acetic acid is reported.

Considering all the aspects of the principles of green chemistry, we present herein the addition reactions of amines to 1,4-naphthoquinone in water as solvent and also in solid phase. These reactions resulted in very colorful products that were easily monitored by thin layer chromatography and consequently easy to separate. Therefore, they are interesting experiments for experimental organic chemistry in the classrooms or in the laboratories.

A isatina e seus derivados são conhecidos na literatura por possuírem uma diversidade de propriedades biológicas. O método de Sandmeyer é o mais utilizado para síntese de diferentes isatinas substituídas, geralmente com altos rendimentos. Apesar de eficiente, este método apresenta algumas limitações, tais como a formação de uma mistura de regioisômeros e baixos rendimentos dependendo do tipo e posição do substituinte presente no material de partida, a anilina. Para superar estas limitações, é preferível que alguns derivados de isatina sejam obtidos por métodos alternativos. Este artigo descreve a cloração de derivados da isatina empregando ácido tricloroisocianúrico [1,3,5-tricloro-1,3,5-triazina-2,4,6-(1H,3H,5H)-triona ou TCCA) em diferentes condições reacionais.

Isatin and its derivatives have been extensively reported in the literature as having range of potential pharmacological compounds. The Sandmeyer method is the most widely used for isatin synthesis and furnishes different substituted isatins, usually with high yields. Although efficient, the Sandmeyer route has certain limitations, such as the formation of a mixture of regiosiomers and low yields depending on the type and position of the substituent. Thus, overcome these limitations, it is preferable that some derivative isatins be obtained by alternative methods. This article has investigated the chlorination of isatin derivatives using trichloroisocyanuric acid [1,3,5-trichloro 1,3,5-triazine-2,4,6-(1H,3H,5H)-trione or TCCA] at different reaction conditions.

This article describes the preparation of 5-nitroisatin and of 5-chloroisatin from isonitrosoacetanilide in a single step, using readily available and inexpensive reagents. These reactions require around 90 minutes and may be carried out as an undergraduate experiment, providing an opportunity to discuss the electrophilic aromatic substitution mechanism, as well as spectroscopic techniques for product identification.

Uma metodologia rápida e eficiente foi desenvolvida para separação de isômeros de isatinas utilizando a técnica de cromatografia contracorrente de alta velocidade. Os isômeros de derivados de isatinas foram preparados segundo a metodologia de Sandmeyer e separados com o sistema de solventes hexano:acetato de etila:etanol:água 1:0,5:0,5:1 (v/v/v/v).

A rapid and efficient method, using high-speed counter-current chromatography (HSCCC) technique, was developed for the separation of isomeric isatin derivatives, prepared following the Sandmeyer route. The biphasic solvent system composed of hexane:ethyl acetate:ethanol:water 1:0.5:0.5:1 (v/v/v/v) was used for all separations.

Protein kinases are one of the largest protein families and they are responsible for regulation of a great number of signal transduction pathways in cells, through the phosphorylation of serine, threonine, or tyrosine residues. Deregulation of these enzymes is associated with several diseases including cancer, diabetes and inflammation. For this reason, specific inhibition of tyrosine or serine/threonine kinases may represent an interesting therapeutic approach. The most important types of protein kinases, their structural features and chemical inhibitors are discussed in this paper. Emphasis is given to the small-molecule drugs that target the ATP-binding sites of these enzymes.

Compostos oxindol-ferrocenos com potencial atividade anticâncer foram preparados a partir de reações de oxindóis substituídos e carboxaldeído-ferroceno na presença de KOH como catalisador. Os produtos foram caracterizados por dados espectroscópicos incluindo RMN de ¹H e 13C, infravermelho e espectrometria de massas. As configurações E e Z foram estabelecidas por experimentos de nOe ou NOESY.

A series of ferrocenyl oxindoles with potential anticancer activity were prepared from the reactions of substituted oxindoles and ferrocenylcarboxyaldehyde in the presence of KOH as catalyst. The products were characterized by spectral data including ¹H and 13C NMR, IR and mass spectrometry. The E and Z configurations were established by nOe or NOESY experiments.