Carboxylic Chlorides Research Articles

Novel urea‐based compounds as solid‐solid phase change materials: 1,3‐bisstearoylurea and 1,1,3,3‐tetrastearoylurea for thermal energy storage applications

1,3-Bisstearoylurea and 1,1,3,3-tetrastearoylurea were produced as solid-solid phase change materials (SS-PCMs) for potential solar thermal energy storage (TES) applications via condensation of urea with the respective amount of carboxyl chloride (stearoyl chloride). Both 1,3-bisstearoylurea and 1,1,3,3-tetrastearoylurea were characterized by Fourier-transform infrared (FT-IR), 1H nuclear magnetic resonance, differential scanning calorimetry (DSC), and thermogravimetric (TG) analysis techniques. 1,3-Bisstearoylurea and 1,1,3,3-tetrastearoylurea had considerable melting/crystallization enthalpy. The reason for crystallization was structural symmetry and flexibility of long alkyl groups there. Di and tetra alkyl groups made it possible to discuss the structure-property relationship for organic PCMs. Besides, the compounds were characterized through DSC and FT-IR spectroscopy before and after thermal cycling to determine their thermal reliability. Solid-solid phase change enthalpies of them for melting and crystallization were found 95.86 and −87.6 Jg−1 for 1,3-bisstearoylurea, respectively and 27.7 and −25.8 Jg−1 for 1,1,3.3-tetrastearoylurea, respectively. Thermal conductivity was studied to increase by simply expanded graphite addition. The thermal endurance limits of 1,3-bisstearoylurea and 1,1,3,3-tetrastearoylurea compounds were studied using TG analysis.

Copper-Catalyzed Decarboxylative Cross-Coupling of Carboxylic Acids and Arylcarbamoyl Chlorides

Copper-Catalyzed Decarboxylative Cross-Coupling of Carboxylic Acids and Arylcarbamoyl Chlorides

Quadruplex stable isotope derivatization strategy for the determination of panaxadiol and panaxatriol in foodstuffs and medicinal materials using ultra high performance liquid chromatography tandem mass spectrometry

This work proposed a novel strategy based on quadruplex stable isotope derivatization for sensitive, accurate, speedy and green determination of panaxadiol (PD) and panaxatriol (PT). This strategy integrated with ultrasound-assisted dispersive liquid-liquid microextraction, microwave-assisted derivatization, and magnetic graphene oxide dispersive solid phase extraction as efficient sample pretreatment techniques, coupling with ultra-high performance liquid chromatography tandem mass spectrometry detection in multiple reaction monitoring mode for the analytical purpose of high-throughput, sensitivity, selectivity, green and accuracy. Quadruplex mass spectrometry sensitizing derivatization reagents, 3-N-(D0-/D3-methyl-, and D0-/D5-ethyl-)-2′-carboxyl chloride rhodamine 6 G, were designed, synthesized and applied for the high-throughput derivatization of hydroxyl‑containing PD and PT for the first time. The analogue derivatives of PD and PT standards using 3-N-propyl-2′-carboxyl chloride rhodamine 6 G as derivatization reagent were employed as the internal standards for the mass spectrometry quantitation to minimize matrix effect. All rhodamine 6 G derivatives of PD and PT were easily and selectively adsorbed by magnetic graphene oxide for efficient magnetic dispersive solid phase extraction before injection. Parameters of (micro-) extractions, derivatization and liquid chromatography-mass spectrometry conditions were all optimized in details. Method validation results consisting of linearity, accuracy, precision, repeatability, matrix effect, stability and limits of detection (LODs, 0.02 ng/mL for PD and 0.03 ng/mL for PT) were determined. The analytical performance of this method benefited from efficient integration of suitable sample pretreatment techniques and characteristic structure of rhodamine 6 G with four mass tags in derivatization reagents. The developed and validated method has been applied to the quantitation of PD and PT for the quality assessment of related foodstuffs and traditional Chinese medicinal materials.

The Synthesis and Reactions of Novel Pyrazole Derivatives by 4-phenylcarbonyl-5-phenyl-2,3-dihydro-2,3-furandione Reacted with Some Hydrazones

We report some novel pyrazole derivatives taking 4-phenylcarbonyl-5-phenyl-2,3-dihydro-2,3-furandione, 1. For this, 4-phenylcarbonyl-5-phenyl-2,3-dihydro-2,3-furandione, 1 was reacted with benzaldehyde(2- or 4-fluorophenyl)hydrazone to give 4-benzoyl-1-(2- or 4-fluorophenyl)-5-phenyl-1H-pyrazole-3-carboxylic acid 2a,b. Pyrazol derivative containing 2-fluorophenyl group 2a was converted into carboxylic chloride derivative 3a by thionyl chloride and then the compound 4a was obtained from reaction ammonia with compound 3a. In the next step, 4-benzoyl-1-(2-fluorophenyl)-5-phenyl-1H-pyrazole-3-carboxylic acid 2a was reacted with MeOH/H2SO4, EtOH/H2SO4, 2-nitrophenylhydrazine and 3-nitrophenylydrazine to give 5a,b and 6a,b pyrazol derivatives, respectively. The structures regarding all compounds synthesized were determined by the IR, NMR and elemental analysis method.

Synthesis of Enantiomerically Pure β‐Hydroxy Ketones via β‐Keto Weinreb Amides by a Condensation/Asymmetric‐Hydrogenation/Acylation Sequence

An established route to enantiomerically pure β‐hydroxy ketones proceeds through the asymmetric hydrogenation of β‐keto esters, an ester/amide exchange, and the use of the resulting β‐hydroxy amide for the acylation of an organometallic compound. We shortened this route by showing that β‐keto Weinreb amides are hydrogenated with up to 99 % ee in the presence of [Me2NH2]+{[RuCl(S)‐BINAP]2(µ‐Cl)3}– (0.5 mol‐%) at room temp./5 bar. These Weinreb amides were prepared by seemingly obvious yet unprecedented condensations of lithiated N‐methoxy‐N‐methylacetamide with carboxylic chlorides (51–87 % yield). The resulting β‐hydroxy Weinreb amides were used for the acylation of organolithium and Grignard reagents. They thus gave enantiomerically pure β‐hydroxy ketones (28 examples). A selection of these compounds gave anti‐1,3‐diols after another C=O bond hydrogenation, or syn‐1,3‐diols by a Narasaka–Prasad reduction.

ChemInform Abstract: Organocatalysis Approach to Trifluoromethylation with Fluoroform.

AbstractA new method for the trifluoromethylation of aldehydes, ketones, carboxylic chlorides, and carboxylic esters in the presence of PTBU is described.

A Chiral Pool Strategy for the Synthesis of Enantiopure Hydroxymethyl‐Substituted Pyridine Derivatives

AbstractA simple procedure for the synthesis of enantiopure hydroxymethyl‐substituted pyridine derivatives is presented. The developed method is based on TMSOTf‐promoted cyclocondensations of β‐ketoenamides, leading to differently substituted 4‐hydroxypyridine/4‐pyridone derivatives. The required β‐ketoenamides were prepared by acylation ofeasily available enamino ketones with suitably protected enantiopure carboxylic chlorides. Most of the experiments were performed withD‐mandelic acid as starting material. It has been shown that all steps occur essentially without racemisation. Several of the prepared 4‐pyridone derivatives were transformed into the corresponding pyrid‐4‐yl nonaflates and subjected to a series of palladium‐catalysed transformations, such as Suzuki, Heck or Sonogashira reactions. In addition, regioselective side‐chain functionalisation of unsymmetrically 2,6‐disubstituted pyridine derivatives was accomplished by application of Boekelheide rearrangements of the corresponding pyridineN‐oxides. The presented methods allow a flexible, rapid and scalable approach to highly substituted, enantiopure pyridine derivatives.

O-acyl derivatives of cyclopentanone and cycloheptanone oximes

By acylation of cyclopentanone and cycloheptanone oximes with carboxylic acids anhydrides or chlorides new esters were obtained of cyclopentanone and cycloheptanone oximes and their spectral characteristics were investigated.

Solvent-Controlled Photoinduced Electron Transfer between Porphyrin and Carbon Nanotubes

beta-Cyclodextrin (beta-CD)-modified multiwalled carbon nanotubes (MWCNTs) were successfully prepared by reaction of surface-bound carboxylic chloride groups of MWCNTs with aminoethyleneamino-deoxy-beta-CD (ENCD) and comprehensively characterized by FTIR, Raman, and X-ray photoelectron spectroscopy and thermogravimetric and differential thermal analysis. The beta-CD-modified MWCNTs (ENCD-MWCNTs) are highly water-soluble, with a solubility of ca. 9.0 mg x mL(-1). Furthermore, the photoinduced electron transfer (PET) process between tetrakis(4-carboxyphenyl)porphyrin (TCPP) and ENCD-MWCNTs was investigated by means of fluorescence, fluorescence decay, transient absorption spectroscopy, and cyclic voltammetry. Obvious quenching processes were observed upon addition of both MWCNT-COOH and ENCD-MWCNTs to the aqueous solutions of TCPP, indicating that the PET process between TCPP and carbon nanotubes takes place upon irradiation. When 1-adamantane acetic acid was added to the aqueous solutions of TCPP/MWCNT-COOH and TCPP/ENCD-MWCNTs, respectively, the former fluorescence remains, while the latter fluorescence recovers. On the contrary, the fluorescence intensity of TCPP in the DMF solution was hardly decreased upon addition of ENCD-MWCNTs, whereas its fluorescence was quenched in the presence of MWCNT-COOH. The observations indicate that the CD cavities play a vital role on the control of the PET process.

Studies of the Mechanism of a Single-Crystal-to-Single-Crystal Reversible Dehydration of a Copper Carboxylate Framework

The open-framework copper carboxylate chloride [Cu7Cl2(THFTC)2(OH)4(H2O)2](H2O)4 (THFTC = tetrahydrofuran-2,3,4,5-tetracarboxylate) was synthesized hydrothermally and was characterized structurally and magnetically. The centrosymmetric three-dimensional framework has channels filled with water. Single crystals kept under vacuum at different temperatures (room temperature, 65 °C, and 105 °C) remain single while the structure is dehydrated in steps accompanied by distortions of the framework and repositioning of the water molecules and chlorine atoms. The dehydrated compounds are acentric and have two distinct channels with different inner environments. These single-crystal-to-single-crystal transformations are reversible evidenced by the structural studies of the dehydrated single crystals after exposure to humid air. Magnetic measurements showed antiferromagnetic coupling between the Cu2+ ions. Homometallic ferrimagnetism is observed below Tc of 2.4 and 3.4 K for the as-synthesized and the dehydrated samp...

Synthesis and antiinflammatory activity of substituted (2-oxochromen-3-yl)benzamides

The title compounds were synthesized by condensing 3-aminocoumarin with substituted aromatic acid chlorides. The acid chlorides were prepared from different substituted aromatic carboxylic acids and thionyl chloride. The structures of the compounds were confirmed by IR, NMR spectral data and elemental analysis. The title compounds were found to possess significant anti-inflammatory and analgesic activities.

Selective Attachment of Functionalized Carbon Nanotubes on Templates Fabricated by AFM and Nanosphere Lithography

We have investigated a selective attachment of functionalized single-walled carbon nanotubes (SWNTs) on templates. Our efforts have been concentrated on both functionalization of carbon nanotubes and their binding onto templates such as Si-wafer and gold. The alignment of SWNTs was performed by modifying the SWNTs with carboxylic acid, carboxylic chloride and alkyl thiol groups. Functionalized SWNTs were selectively immobilized through the formation of amide bonds using a coupling reagent onto prepatterned nanostructures by a self-assembly method. The characterization of chemically attached carbon nanotubes has been investigated using various surface characterization tools like AFM, TEM, SEM, and FT-IR.

Synthesis of 3,5-dioxoalkanoates, 3,5-dioxopimelates and 2,4-dioxoadipates by acylation of 1,3-bis-silyl enol ethers

3,5-Dioxoalkanoates, 3,5-dioxopimelates and 2,4-dioxoadipates were prepared by acylation of 1,3-bis-silyl enol ethers with carboxylic chlorides, methyl 3-chloro-3-oxopropanoate and ethyl 2-chloro-2-oxoacetate, respectively.

Microwave-Assisted Facile and Convenient Synthesis of Imidazolines.

The 2-substituted imidazolines are of considerable importance because their derivatives exhibit a wide variety of biological activities, including antihypercholesterolemic, antiinflammatory, antidiabetic and antihypertensive. These compounds are also used as intermediates and catalysts in synthetic chemistry. Several methods for the synthesis of 2-imidazolines from carboxylic acids, esters, nitriles, orthoesters, hydroximoyl chlorides, hydroxy amides, and mono-, or disubstituted chlorodicyanovinyl benzene have been reported previously. However, some of these methods suffer from disadvantages such as long reaction times, low yields of the products, difficulty in preparation of starting materials and tedious workup. Therefore, there is still a scope to find potential methods for this transformation. In recent years organic reactions assisted by microwave irradiation have gained special attention. The chief features of the microwave reactions are the enhanced selectivity, much improved reaction rates, milder reaction conditions and formation of cleaner products. In this paper we wish to report an efficient and convenient method for the synthesis of 2-imidazolines from nitriles and ethylenediamine in the presence of sulfur under microwave irradiation (Scheme 1). Typically, benzonitrile (1a), ethylenediamine and sulfur were mixed and irradiated for 2.5 min in a domestic microwave oven (operating at 720 W). The reaction mixture was allowed to reach to room temperature, then cold water was added and the mixture was extracted with chloroform. Removal of the solvent and recrystallization of the crude product from cyclohexane gave the corresponding 2imidazoline (2a) in 97% yield. The effect of microwave irradiation power in this reaction was also investigated. The results show that the highest yield of compound 2a is obtained at a power of 720 W (Table 1). At this power, the temperature of the reaction vessel after the irradiation was measured to be ~130 °C. Under the same reaction conditions, a variety of nitriles are cleanly and rapidly converted to their corresponding 2-imidazolines in 96-99% yields within 1.211 min (Table 2). The conventional thermal reactions were also performed for this transformation in the absence of microwave energy. The experimental results show that the yields of the products are relatively lower under this condition and the reaction times are longer, specially in the cases of 1b, 1h and 1j. In order to show the general applicability of this method, the reaction of benzonirtile was performed on a 100 mmole scale. The result (95% yield, 2.5 min) was comparable to that obtained by the small scale experiment. In order to show the effect of sulfur, a mixture of benzonitrile (1a) and ethylenediamine was irradiated in the absence of sulfur. Under this condition, the reaction did not proceed at all and benzonitrile remained intact in the reaction mixture. The exact mechanism of the reaction is not clear at this time. However, a plausible explanation is that sulfur reacts with nitrile to produce thioamide. Thioamide reacts with ethylenediamine, which upon elimination of hydrogen sulfide and ammonia, produces 2-imidazoline. Evolution of hydrogen sulfide is a certification of the above statement. In conclusion, a simple and efficient procedure for the synthesis of 2-imidazolines has been explored. Mild reaction conditions, absence of solvent, shorter reaction time, easy and quick isolation of the products and excellent yields are main advantages of this procedure which make this method an attractive and useful contribution to the present methodologies.

Synthese, Struktur und Reaktivität von funktionalisierten Stibanidokomplexen des Eisens und Rutheniums [(η5-C5Me5)(CO)2MSbR1R2] (M = Fe, Ru; R1, R2 = SiMe3, C(O)tBu, C(O)Ph, C(O)-1 Ad)

Bei der Reaktion äquimolarer Mengen an [(η5-C5Me5)(CO)2RuSb(SiMe3)2] (1 b) mit Carbonsäurechloriden RC(O)Cl (R = tBu, Ph, 1-Adamantyl) werden die Acyl(trimethylsilyl)stibanido-Komplexe [(η5-C5Me5) · (CO)2RuSb{C(O)R}(SiMe3)] 2 b (R = tBu), 4 b (R = Ph) und 6 b (R = 1-Ad) erhalten. Die Umsetzung von 1 b mit zwei Äquivalenten Pivaloylchlorid oder Benzoylchlorid liefert die Diacylstibanido-Komplexe [(η5-C5Me5)(CO)2Ru–Sb{C(O)R}2] (3 b, 5 b). Analog hierzu wird der Eisenkomplex [(η5-C5Me5)(CO)2FeSb(SiMe3)2] (1 a) von überschüssigem Säurechlorid in die entsprechenden Diacylstibanido-Komplexe 3 a (R = tBu), 5 a (R = Ph) und 7 a (R = 1-Ad) übergeführt. Die Reaktion äquimolarer Mengen 1 a mit RC(O)Cl führte lediglich zu Gemischen aus Mono- und Diacylstibanido-Komplexen neben unumgesetzten 1 a. Oxalylchlorid reagiert mit zwei Äquivalenten 1 a quantitativ zu [{(η5-C5Me5)(CO)2FeSb(SiMe3)C(O)}2] (8). Die Molekülstrukturen von 1 a, 2 b und 5 b wurden durch Röntgenstrukturanalysen bestimmt. Synthesis, Structure, and Reactivity of Functionalized Stibanido Complexes of Iron and Ruthenium [(η5-C5Me5)(CO)2MSbR1R2] (M = Fe, Ru; R1, R2 = SiMe3, C(O)tBu, C(O)Ph, C(O)-1 Ad) The reaction of equimolar amounts of [(η5-C5Me5)(CO)2RuSb(SiMe3)2] (1 b) and the carboxylic chlorides RC(O)Cl (R = tBu, Ph, 1-adamantyl) afforded the acyl(trimethylsilyl)stibanido complexes [(η5-C5Me5)(CO)2RuSb · {C(O)R}(SiMe3)] 2 b (R = tBu), 4 b (R = Ph), and 6 b (R = 1-Ad). The treatment of 1 b with two molar equivalents of pivaloyl chloride and benzoyl chloride led to the diacylstibanido complexes [(η5-C5Me5)(CO)2RuSb{C(O)R}2] (3 b, 5 b). Analogously, the iron complex [(η5-C5Me5)(CO)2FeSb · (SiMe3)2] (1 a) is converted into the corresponding diacylstibanido complexes 3 a (R = tBu), 5 a (R = Ph) and 7 a (R = 1-Ad) by an excess of acid chloride. The treatment of 1 a with equimolar amounts of RC(O)Cl gave inseparable mixtures of starting material and the monoacyl- and diacyl stibanido complexes. Oxalyl chloride reacted quantitatively with two equivalents of 1 a to give complex [{(η5-C5Me5) · (CO)2FeSb(SiMe3)C(O)}2] (8). The molecular structures of 1 a, 2 b and 5 b were elucidated by single crystal X-ray analyses.

“Bridgehead Nitrogen Heterocycles: Synthesis and Reactions of S-Triazolothiadiazinyl and S-Triazolothiadiazo-Lylquinoxalines”

The reaction of 3(4-amino-5-mercapto-1,2,4-triazol-3′-yl)quinoxalin-2(1H)-one 4 with phenacyl bromide, 2,3-dichloroquinoxaline, benzoine, chloroacetic acid, and α-chloroacetonitrile to give triazolothiadiazino derivatives 5–10. Reaction of 4 with phenyl isothiocyanate, aromatic aldehydes, formic acid, aromatic carboxylic acid, benzoyl chloride, and carbon disulphide gave triazolothiadiazino derivatives 11–17.

Simple and condensed β-lactams. Part 33. AlCl3 catalyzed ring closures of some 3-aryloxy-4-oxoazetidine-2-carboxylic chlorides to 1H-chromeno[3,2-b]azete-2,8(2aH,8aH)-diones and some reactions of the products

Carboxylic chlorides 3a–3c, when treated with AlCl3, afforded the tricyclic compounds 17a–17c. NaBH4 reduction of 17a and 17b afforded compounds 11a and 11b. The latter and the related known compounds 4a, 5b, 6a and 7a were used for the preparation of various dihydrochromeno[3,2-b]azet-2(1H)-ones and of a 3,4-disubstituted chromane-2-carboxylic ester (26) of fixed stereochemistry. Catalytic reduction of 8-chloro compound 5b afforded compounds 10b and 25, the products of simple hydrodechlorination and of azetidinone ring cleavage with concomitant hydrodechlorination, respectively.

Reactions of ZrOCl 2 ·8H 2 O with carboxylic acids and thionyl chloride: crystal and molecular structures of K 4 [Zr(mal) 4 ]·2H 2 O and K 4 [Zr(dipic) 3 ] 2 ·13.5H 2 O

Reactions of ZrOCl2·8H2O in aqueous solution with a carboxylic acid in the presence of K2CO3 have been studied as a route to ZrIV-carboxylates. With malonic acid (HO2CCH2CO2H) (H2mal) the product has been identified as K4[Zr(mal)4]·2H2O (1) by X-ray crystallography. The individual eight-coordinate zirconium anions contain four bidentate (OO′) malonate anions with the metal geometry approximating to a square antiprism with each chelating ligand spanning the two square faces, Zr—O 2.091(3)–2.288(3) A. The four potassium cations feature irregular coordination spheres of oxygen atoms [from both H2O and (mal) ligand molecules] with a 7–9 coordination range. With 2,6-dicarboxypicolinic␣acid (HO2CC5NH3CO2H) (H2dipic) the product has been characterised as K4[Zr(dipic)3]2·13.5H2O (2) following X-ray diffraction studies. The structure consists of two [Zr(dipic)3]2- anions, four potassium cations and lattice solvate (H2O) molecules. Individual anions feature nine-coordinate zirconium in which each dipic ligand is terdentate, being bonded via one N (pyridine) and two O (carboxylate) atoms. The metal geometry approximates to tricapped trigonal prismatic with each nitrogen atom capping a regular face of four oxygen atoms, Zr—O, 2.216(6)–2.261(6) A; Zr—N, 2.343(8)–2.361(7) A. The potassium cations show similar environments to those observed in structure (1). Dehydration of ZrOCl2·8H2O using SOCl2 in the presence of an excess of THF effects removal of coordinated H2O molecules and hydroxy bridging groups to provide the anhydrous bis-adduct ZrCl4(thf)2 in good yield (72%).

Mercury(II) halide adducts of a dicarboxylate-like ligand: Crystal structures of polymeric mercury(II) complexes with 1,4-diazoniobicyclo[2.2.2]octane-1,4-diacetate

Three mercury(II) complexes containing double-betaine and halide ligands, [(HgCl2)2(L1)] n (1), [(HgBr2)2(L1)(H2O)2] n (2), and [2HgCl2(HL1)·Hg2Cl6] n (3) [L1=−O2CCH2N+(CH2CH2)3-N+H2CO2 −], have been prepared and shown to have polymeric structures by single-crystal X-ray analysis. Complex (1) exhibits an infinite zigzag chain in which each mercury(II) atom is coordinated by pairs of carboxylate oxygen atoms and chloride ligands in a distorted tetrahedral geometry. In complex (2), the mercury(II) atom is in an unusual square-planar coordination geometry, and weak mercury-ligand and hydrogen bonding extend the structural skeletons into a three-dimensional network. Complex (3) consists primarily of an assembly of HgCl2(HL1) moieties and [Hg2Cl6]− anions, and the mercury(II) atoms are in planar T-shaped and distorted tetrahedral coordination environments, respectively. The resulting three-dimensional network is based on the cross-linkage of nearly planar, wide ribbons running in thea direction.

ChemInform Abstract: Reaction of N‐Silylated Lactams with Carboxylic Chlorides of Higher Carboxylic Acids and Alkaline Hydrolysis of the N‐Acyllactams Obtained.

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