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Rapid synthesis of 4-ethyloctanoic acid by means of microwave irradiation is described. Diethyl malonate reacted with 2-ethyl-1-bromohexane in the presence of sodium ethoxide to give diethyl (2-ethylhexyl)malonate (1b). 1b was saponified in the solution of ethanol and potassium hydroxide and then acidified to form (2-ethylhexyl)propanedioic acid (1...
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... Compared to traditional heating methods, microwave heating could expand the reaction range as well as shorten the reaction time from a few days or hours to a few minutes. Thus, when applied in fields of organic synthesis, pharmaceutical chemistry, and high-throughput chemistry, microwave heating shows greater advantage than traditional heating methods [30][31][32][33]. ...
Owing to the significant biological activities, quinazoline derivatives have drawn more and more attention in the synthesis and bioactivities research. This chapter summarizes the recent advances in the investigations of synthesis and biological activities of quinazoline derivatives. According to the main method the authors adopted in their research design, those synthetic methods include microwave assisted reaction, ultrasound-promoted reaction, metal-mediated reaction, water reaction, and phase-transfer catalysis reaction. The biological activities of the synthesized quinazoline derivatives are also discussed.
... Scheme 1 Synthesis of derivatives 3 by cascade imino-Diels-Alder reaction.thesis, pharmaceutical chemistry and high-throughput chemistry, microwave heating shows greater advantage than traditional heating methods[28][29][30][31]. Luo et al. reported the first microwave-assisted synthesis of new quinazoline derivates containing αaminophosphonate[32]. ...
Owing to the significant biological activities, quinazoline derivatives have drawn more and more attention in the synthesis and bioactivities research. This review summarizes the recent advances in the synthesis and biological activities investigations of quinazoline derivatives. According to the main method the authors adopted in their research design, those synthetic methods were divided into five main classifications, including Aza-reaction, Microwave-assisted reaction, Metal-mediated reaction, Ultrasound-promoted reaction and Phase-transfer catalysis reaction. The biological activities of the synthesized quinazoline derivatives also are discussed.
... However, it requires long reaction times, poor yield, and the sensitive nature of 4-chloroquinazoline, accompanied by a complicated route to access the desired product through the classic mode, has motivated us to investigate alternative methodologies [16]. Microwave heating has been developed as a possible alternative to conventional heating with the potential to emerge as the preferred heating mode in organic synthesis17181920. In this perspective, microwave heating has an edge over the traditional method both in medicinal and high-throughput chemistry applications because it can offer an expanded reaction range and diminished reaction times from several hours or days down to minutes. ...
This study describes the simple synthesis of new (quinazolin-4-ylamino) methylphosphonates via microwave irradiation. Substituted-2-aminobenzonitrile reacted with 1,1-dimethoxy-N,N-dimethylmethanamine at a reflux condition to obtain N'-(substituted-2-cyanophenyl)-N,N-dimethylformamidine (1). The subsequent reaction of this intermediate product with α-aminophosphonate (2) in a solution containing glacial acetic acid in 2-propanol through microwave irradiation resulted in the formation of (quinazolin-4-ylamino)methyl-phosphonate derivatives 3a to 3x, which were unequivocally characterized by the spectral data and elemental analysis. The influence of the reaction conditions on the yield of 3a was investigated to optimize the synthetic conditions. The relative optimal conditions for the synthesis of 3a include a 1:1 molar ratio of N'-(2-cyanophenyl)-N,N-dimethylformamidine to diethyl amino(phenyl)methylphosphonate and a 4:1 volume ratio of isopropanol to HOAc in the solvent mixture, at a reaction temperature of 150 °C, with a microwave power of 100 W and a corresponding pressure of 150 psi for 20 min in the microwave synthesizer. The yield of 3a was approximately 79%, whereas those of 3b to 3x were approximately 77% to 86%. Some of the synthesized compounds displayed weak to good anti-Tobacco mosaic virus (TMV) activity.
To characterize the key odorants in ripe Capparis spinosa L. fruit (RCF) and to investigate changes in the odorants after storage, volatiles were captured by both solid-phase microextraction and solvent extraction combined with solvent-assisted flavor evaporation; a total of 22 aroma-active regions were detected in the isolates by gas chromatography–olfactometry. Of 19 odor-active compounds identified positively, 13 odorants were found in RCF for the first time; their flavor dilution factors ranging from 1 to 512 were measured by an aroma extract dilution assay. Eleven odorants were determined as the key odorants by stable isotope dilution analysis, odor activity value (OAV) calculation, and recombination experiments. To further investigate the changes in odorants after storage, their concentrations and OAVs were determined. The results showed that the number of key odorants did not change before and after storage, but the concentrations of octanoic acid, sotolon, and 3-methylbutanoic acid increased markedly.
Benzyl 4-ethyloctanoate was synthesized by the reaction of 4-ethyloctanoyl chloride with benzyl alcohol, and its synthesis conditions were optimized. The yield of benzyl 4-ethyloctanoate was about 93%. Based on the synthesis of benzyl 4-ethyloctanoate, phenethyl 4-ethyloctanoate, phenylpropanol 4-ethyloctanoate and cinnamyl 4-ethyloctanoate were prepared. The odor evaluations indicate that these four new ester compounds have floral and sweet note. These ester compounds have relatively high molecular weights and can be used as fixing agent to prolong the fragrance compounds lifetime.
We describe a specific procedure for the synthesis of deuterium-labelled 2-(1-methylalkyl)succinate established via alkylation of diethyl malonate, Krapcho decarboxylation reaction with D2O and hydrolysis reaction. Two novel compounds, 2-[2H]-2-ethylsuccinic acid and 2-[2H]-2-(1-methylheptyl)succinic acid were prepared via this synthetic route and characterized by mass spectrometry and 1H NMR. The results showed that the 2-(1-methylalkyl)succinic acids were deuterated at the β-position, which is considered as an important reaction center in the anaerobic degradation of n-alkanes.
Anaerobic biodegradation of petroleum hydrocarbons has been reported to proceed predominantly via fumarate addition to yield substituted succinate metabolites. These metabolites, commonly regarded as signature biomarkers, are specific indicators of anaerobic hydrocarbon degradation by microbial activity. To the best of our knowledge, mass spectrometry information for 2-(1-methylalkyl) succinic acids, 2-arylsuccinic acids, 2-cycloalkylsuccinic acids and/or their derivatives is still incomplete, especially for the analysis of environmental samples. Here, a novel approach is proposed for the successful synthesis of five hydrocarbon-derived succinic acids. The characteristic fragments of 2-(1-methylalkyl)succinic acid diesters were investigated by four derivatization processes (methyl, ethyl, n-butyl and trimethylsilyl esterification), some of which are not available in official libraries. Under electron ionization mass spectrometry conditions, informative fragments of various molecular masses have been obtained. Results confirmed characteristic differences among the derivatization processes of the chemically synthesized compounds. In the case of 2-(cyclo)alkylsuccinate esters, four intermediate fragments were observed at m/z 114+14n, 118+28n, [M-(17+14n)]+ and [M-(59+14n)]+ (n = 1, 2 and 4 for methyl, ethyl and n-butyl ester). However, for silylation the abundant fragment ions are at m/z 262, 217, 172, 147, 73 and [M–15]+. These data provide information for the identification of hydrocarbon-derived succinic acids as anaerobic biodegradation intermediates in hydrocarbons-rich environments.
The influence of the side chain on the molecular organization and charge transport performance of diketopyrrolopyrrole-quaterthiophene copolymers (PDQTs) was studied. It was found that, by increasing the side chain length from 2-octyldodecyl (PDQT-20) to 2-decyltetradecyl (PDQT-24), the mobility increased from 2.10 cm2 V-1 s-1 up to 3.37 cm2 V-1 s-1 in organic thin film transistors (OTFTs). The increase was found to be due to the improved surface morphology, rather than the changes in crystallinity and [small pi]-[small pi] stacking distance. A new side chain substituent, 4-decylhexadecyl, was developed for studying the effects of the bifurcation point of the branched side chains in comparison with 2-octyldodecyl and 2-decyltetradecyl. The 4-decylhexadecyl substituted PDQT (PDQT-26) showed a surge in mobility up to 6.90 cm2 V-1 s-1. The remarkably enhanced charge transport performance observed for PDQT-26 was believed to originate from its much shorter [small pi]-[small pi] distance (3.68 A) than those of PDQT-20 (3.79 A) and PDQT-24 (3.86 A). The improvement was the result of a farther distance of the bifurcation point of 4-decylhexadecyl from the polymer backbone, which could effectively minimize the steric interference of the bulky side chain branches with the backbone to facilitate the co-facial [small pi]-[small pi] stacking.
