Identification (GC and GC-MS) of unsaturated acetates in Elasmopalpus lignosellus and their biological activity (GC-EAD and EAG)

Two insect colonies of Elasmopalpus lignosellus were reared in our laboratory, the first being initiated from pupae obtained from a cornfield in the region of Sete Lagoas, Minas Gerais and the second from a cornfield in the region of Goiania, Goiás. From the two colonies, two extracts were prepared from the pheromone glands of virgin E. lignosellus females. The extract obtained from the first colony was designated as extract 1 while the extract obtained from the second colony was designated as extract 2. Extract 1 was analyzed by gas chromatography-mass spectrometry (GC-MS) with (Z)-9-hexadecenyl acetate [(Z)-9-HDA] and (Z)-11-hexadecenyl acetate [(Z)-11-HDA] being identified and confirmed by the formation of DMDS derivatives. In addition, a third acetate, which could be either (E)-8-hexadecenyl acetate [(E)-8-HDA] or (E)-9-hexadecenyl acetate [(E)-9-HDA] was detected by GC-MS. Extract 2 was analyzed by gas chromatography (GC) and gas chromatography-electroannetography (GC-EAD) revealing the presence of (Z)-11-HDA and (Z)-9-TDA. In addition, the same compounds elicited a response with the E. lignosellus male antenna obtained from the second insect colony. Electroantennography (EAG) screening with the male E. lignosellus antenna (obtained from the second insect colony) was conducted with the 23 possible tetradecenyl acetates (TDA) and 22 hexadecenyl acetates (HDA) as standards. Out of the 23 TDA isomers evaluated, only (Z)-9-TDA elicited a response and out of the 22 HDA [(Z) and (E) isomers gamma2 to delta13] evaluated only (Z)-11-HDA elicited a response. The acetate compositions of two extracts obtained from insects originating from the two states (Minas Gerais and Goiás) of Brazil were different from one another as well as from that obtained from insects in Tifton, GA, USA. The bioactivity data (GC-EAD) of the extract 2 differed from those reported for the Tifton, GA, USA population. These data suggest polymorphism in relation to the insect populations found in Brazil and in the USA. The possibility of the existence of an E. lignosellus sub-species cannot be ruled out.     

Highly efficient deprotection of phenolic tetrahydropyranyl and methoxymethyl ethers and sequel cyclization to indanones using Sn(IV)Cl4 catalyst

Sn(IV)Cl₄ catalyst provided a rapid and efficient deprotection method for the phenolic THP and MOM ethers and sequel intramolecular Friedel–Crafts alkylation reaction of THP and MOM protected chalcone epoxides under mild conditions. The reaction took 2–3 min to give the products in excellent yield (90–98%) at 0 °C without affecting the other functional groups.     

Liquid Crystal Polymers: Overview of Characteristics and Applications in Communication and Biomedical Technologies

Russian Journal of Applied Chemistry - Liquid crystals polymers (LCPs) are aromatic polymers with unique properties which enable their usage in various applications. LCPs are herein discussed, in...     

p-Sulfonic acid calix[n]arenes as homogeneous and recyclable organocatalysts for esterification reactions

Esterification yields were significantly improved using calix[n]arenes catalysts under simple conditions. p-Sulfonic acid calix[4]arene and p-sulfonic acid calix[6]arene were powerful organocatalysts in several esterification reactions, which showed activity comparable or even superior to other well-established acids catalysts, such as, sulfuric acid, p-toluenesulfonic acid, and p-hydroxybezenesulfonic acid described in the literature.     

Peristaltic activity in blood flow of Casson nanoliquid with irreversibility aspects in vertical non-uniform channel

Due to the illuminating function of nanoliquids in several technological and medicinal domains, particularly in liquid transport processes known as peristalsis, inquisitive researchers have investigated the flow of peristaltic nanofluids. Consequently, the current study investigates the entropy production and magnetic influence on the peristaltic transport of heat and mass transport of Casson nanofluid in a non-uniform channel under convective circumstances. Utilizing the perturbation approach, fields of concentration, temperature, and velocity are derived from non-linear coupled partial differential equations (PDE). Entropy generation studies have been done. In addition, the influence of associated factors via specific physical terms, including the Sherwood number, the skin-friction coefficient, and the Nusselt number, for both Casson and Newtonian liquids, as well as the trapping phenomena, is visually examined.     

Physicochemical Investigation of Some Thiobarbiturate Derivatives and Their Binding Study with Deoxyribonucleic Acid

Due to the gradual increase in genetic related disease worldwide, the synthesis, characterization and physicochemical investigation of medicinal compounds such as thiobarbiturates and their derivatives is a highly desired area of research. Keeping their importance as medicinal compounds in mind, herein we report the synthesis and physicochemical characterization of five selected thiobarbiturate samples namely (MKA20 MKA21, MKA22, MKA23, MKA24) by using various physicochemical techniques. All the selected thiobarbiturates and their derivatives were synthesized by the reaction of diethyl thiobarbituric acid with different aromatic aldehydes. The synthesized thiobarbiturates and their derivatives were analyzed by various electroanalytical techniques, which gave us valuable information about the nature of thiobarbiturates and their derivatives. Further, the preliminary interaction of these thiobarbiturate with Deoxyribonucleic acid in aqueous solution was also investigated by using Ultraviolet-Visible spectrometry. On the basis of various results obtained, it can be said that most of their properties and extent of interaction with Deoxyribonucleic acid are varying with changing the alkyl groups on one hand and the functional groups on the other hand.     

Direct Umpolung Morita–Baylis–Hillman like α‐Functionalization of Enones via Enolonium Species

Herein we report on the umpolung of Morita–Baylis–Hillman type intermediates and application to the α‐functionalization of enone C?H bonds. This reaction gives direct access to α‐chloro‐enones, 1,2‐diketones and α‐tosyloxy‐enones. The latter are important intermediates for cross‐coupling reaction and, to the best of our knowledge, cannot be made in a single step from enones in any other way. The proposed mechanism is supported by spectroscopic studies. The key initial step involves conjugate attack of an amine (DABCO or pyridine), likely assisted by hypervalent iodine acting as a Lewis acid leading to formation of an electrophilic β‐ammonium‐enolonium species. Nucleophilic attack by acetate, tosylate, or chloride anion is followed by base induced elimination of the ammonium species to give the noted products. Hydrolysis of α‐acetoxy‐enones lead to formation of 1,2‐diketones. The α‐tosyl‐enones participate in Negishi coupling reactions under standard conditions.     

Location of double bonds in diene and triene acetates by partial reduction followed by methylthiolation

Two random reduction procedures (NH2NH2/H2O2 and NH2NH2/O2) were compared and conditions optimized for the reduction of two synthetic pheromone compounds (9Z,11E)-9,11-tetradecadienyl acetate and (9Z,12E)-9,12-tetradecadienyl acetate on a 300 microg scale at 60 degrees C. The relative amounts of the four products (completely reduced acetate, unreacted diene acetate and two monoene acetates), characterized by gas chromatography (GC) from the reaction mixture, depended on the reaction conditions. The reduction was straightforward without any detectable undesired side products. The reaction yields were reproducible with both the reducing reagents. The optimized reduction conditions thus established were utilized to reduce seven synthetic compounds (four diene and three triene acetates) on a micro scale (5 microg). In all cases, expected compounds were identified by GC-MS. After reduction, two methods were used to locate the position of double bonds in the partially reduced compounds. In the first method, the products from the above seven compounds were isolated by extraction with hexane and reacted with dimethyl disulfide to give the DMDS adducts. In the second method ("one-pot"), the reduced compounds were not isolated but instead, the solvents were evaporated and the DMDS derivatives formed. In both cases, determination of the position of the double bonds was possible by GC-MS analyses. The complete procedure (reduction and DMDS derivative formation) could be carried out on a 100 ng scale. Although neither of the partial reduction methods offered significant advantages over the other, partial reduction with NH2NH2/H2O2 was more convenient and hence should be the method of choice, together with DMDS derivative formation to locate double bonds in pheromones. In addition, a new procedure is described using ND2ND2/H2O2 and DMDS derivative formation capable of distinguishing between the double bond positions in (Z)-9-tetradecenyl acetate and (9Z,12E)-9,12-tetradecadienyl acetate (1:1 mixture).