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121.
A. V. Vasilyev N. P. Solov'eva N. Ya. Podhaluzina A. Yu. Tolmachev V. F. Traven 《Chemistry of Heterocyclic Compounds》2003,39(4):534-538
Fries rearrangement of 7-acetoxy-4-methylquinolin-2-one and subsequent condensation of the 6-acetyl-7-hydroxy-4-methylquinolin-2-one obtained with -chloro ketones gives a series of furo[3,2-g]quinolin-7-ones. 相似文献
122.
5-Amino-4-cyano-8-isobutyl-7-isopropyl-6-thiocarbamoyl-2-azabicyclo[2.2.2]oct-5-en-3-thione was synthesized by the condensation of isovaleryl aldehyde with cyanothioacetamide. The structure of the product was established by X-ray crystallography. 相似文献
123.
1,1‐Diamino‐2,2‐dinitroethylene (FOX‐7), one of the most well‐known energetic materials, has attracted broad attention around the world. To extend the chemistry of FOX‐7, we present here a series of energetic salts based on 3‐dinitromethyl‐[1,2,4]triazine, which is prepared from FOX‐7. All these salts were fully characterized using 1H NMR, 13C NMR, IR, and elemental analysis. In addition, the potassium salt ( 2 ), ammonium salt ( 5 ), and guanidinium salt ( 7 ) were further confirmed by single‐crystal X‐ray diffraction. Extensive hydrogen bonds were observed in these salts. The salts exhibit moderate densities varying from 1.63 to 1.76 g · cm–3. All the compounds possess good thermal stability with decomposition temperatures from 118 to 267 °C. The detonation performance for salts were calculated by using EXPLO 5, their detonation velocities are in the range from 6807 to 8614 m · s–1 and detonation pressures fall between 18.8 to 31.6 GPa. All the salts exhibit very low mechanical sensitivity, which indicates their potential application as insensitive energetic materials. 相似文献
124.
Abhaysingh Bhadoriya Priyanka A. Shah Pranav S. Shrivastav Kirtikumar D. Bharwad Puran Singhal 《Biomedical chromatography : BMC》2019,33(8)
A high‐throughput and sensitive ultra‐performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) method has been developed for the determination of terbinafine in human plasma. The method employed liquid–liquid extraction of terbinafine and terbinafine‐d7 (used as internal standard) from 100 μL human plasma with ethyl acetate–n‐hexane (80:20, v/v) solvent mixture. Chromatography was performed on a BEH C18 (50 × 2.1 mm, 1.7 μm) column using acetonitrile–8.0 mm ammonium formate, pH 3.5 (85:15, v/v) under isocratic elution. For quantitative analysis, MS/MS ion transitions were monitored at m/z 292.2/141.1 and m/z 299.1/148.2 for terbinafine and terbinafine‐d7, respectively, using electrospray ionization in the positive mode. The method was validated according to regulatory guidance for selectivity, sensitivity, linearity, recovery, matrix effect, stability, dilution reliability and ruggedness with acceptable accuracy and precision. The method shows good linearity over the tested concentration range from 1.00 to 2000 ng/mL (r2 ≥ 0.9984). The intra‐batch and inter‐batch precision (CV) was 1.8–3.2 and 2.1–4.5%, respectively. The method was successfully applied to a bioequivalence study with 250 mg terbinafine in 32 healthy subjects. The major advantage of this method includes higher sensitivity, small plasma volume for processing and a short analysis time. 相似文献
125.
The relative enthalpies of melts in the system KF - K2NbF7 were measured by drop-calorimetry at the temperatures 1058, 1140 and 1208 K as a function of composition. Heat capacities
of melted mixtures and enthalpies of mixing were determined using the experimental data. The molar heat capacity of melts
diverges slightly from additivity. The molar enthalpy of mixing of melts shows small negative deviation from ideality which
decreases with decreasing temperature. The thermal effect at mixing was assigned predominantly to association reactions producing
more complex fluoroniobate anions.
相似文献
126.
A Minor New Flavone from Scutellaria baicalensis Georgi 总被引:1,自引:0,他引:1
A new flavone,6,2′-dihydroxy-5,7,8,6′-tetramethoxyflavone,was isolated from the roots of Scutellaria baicalensis. Its structure was established on the basis of spectral evidences. 相似文献
127.
It is commonly observed that the rate of enzymatic hydrolysis of solid cellulose substrates declines markedly with time. In
this work the mechanism behind the rate reduction was investigated using two dominant cellulases of Trichoderma reesei: exoglucanase Cel7A (formerly known as CBHI) and endoglucanase Cel7B (formerly EGI). Hydrolysis of steam-pretreated spruce
(SPS) was performed with Cel7A and Cel7B alone, and in reconstituted mixtures. Throughout the 48-h hydrolysis, soluble products,
hydrolysis rates, and enzyme adsorption to the substrate were measured. The hydrolysis rate for both enzymes decreases rapidly
with hydrolysis time. Both enzymes adsorbed rapidly to the substrate during hydrolysis. Cel7A and Cel7B cooperate synergistically,
and synergism was approximately constant during the SPS hydrolysis. Thermal instability of the enzymes and product inhibition
was not the main cause of reduced hydrolysis rates. Adding fresh substrate to substrate previously hydrolyzed for 24 h with
Cel7A slightly increased the hydrolysis of SPS; however, the rate increased even more by adding fresh Cel7A. This suggests
that enzymes become inactivated while adsorbed to the substrate and that unproductive binding is the main cause of hydrolysis
rate reduction. The strongest increase in hydrolysis rate was achieved by adding Cel7B. An improved model is proposed that
extends the standard endo-exo synergy model and explains the rapid decrease in hydrolysis rate. It appears that the processive
action of Cel7A becomes hindered by obstacles in the lignocellulose substrate. Obstacles created by disordered cellulose chains
can be removed by the endo activity of Cel7B, which explains some of the observed synergism between Cel7A and Cel7B. The improved
model is supported by adsorption studies during hydrolysis. 相似文献
128.
A new class of M(II)–Hg(II) (M=Cu(II), Co(II), Ni(II)) mixed-metal coordination polymers, Cu(2-pyrazinecarboxylate)2HgCl2 (4), [Co(2-pyrazinecarboxylate)2(HgCl2)2] · 0.61H2O (5) and [Ni(2-pyrazinecarboxylate)2(HgCl2)2] · 0.77H2O (6), have been prepared by self assembly of metal-containing building blocks, M(2-pyrazinecarboxylate)2 · (H2O)2(M=Cu(II), Co(II), Ni(II)), with HgCl2. Compounds 4–6 were characterized fully by IR, elemental analysis and single crystal X-ray diffraction. Compound 4 crystallized in the monoclinic space group C2/c, with a=17.916(5) Å, b=7.223(2) Å, c=13.335(4) Å, β=128.726(3)°, V=1346.2(6) Å3, Z=4. It contains alternating Hg(II) and Cu(II) metal centers that are cross-linked by 2-pyrazinecarboxylate spacers and chlorine co-ligands to generate a unique three-dimensional Hg(II)–Cu(II) mixed metal framework. Compound 5 crystallized in the triclinic space group P
, with a=6.3879(7) Å, b=6.6626(8) Å, c=13.2286(15) Å, α=96.339(2)°, β=91.590(2)°, γ=113.462(2)°, V=511.71(10) Å3, Z=1. Compound 6 also crystallized in the triclinic space group P
, with a=6.3543(8) Å, b=6.6194(8) Å, c=13.2801(16) Å, α=96.449(2)°, β=92.263(2)°, γ=113.541(2)°, V=506.67(11) Å3, Z=1. Compounds 5 and 6 are isostructural and in the solid state the Hg(II)M(II)Hg(II) units are connected by Hg2Cl2 linkages to produce a novel M(II)–Hg(II) (M=Co(II), Ni(II)) zigzag mixed-metal chain, in which a new type of M–M′–M′–M array was observed. The metal containing building blocks, M(2-pyrazinecarboxylate)2 · (H2O)2 (M=Cu(II), Co(II), Ni(II)), exhibit different connectivities to HgCl2 depending on the metal cation contained within them. 相似文献
129.
V. A. Yanchenko A. M. Demchenko M. O. Lozinskii 《Chemistry of Heterocyclic Compounds》2004,40(4):516-518
We propose a method for obtaining derivatives of 7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine by alkylation of 4-amino-5-methyl-4H-1,2,4-triazole-3-thiol by substituted -chloroacetanilides, followed by cyclization of the intermediate by phosphorus oxychloride. 相似文献
130.
Warren"s method, which has been proposed for the synthesis of -phenylthiodialkyl ketones, appeared to be inefficient for the preparation of their alkenyl alkyl analogs. The latter were prepared in good yields by alkenylation of alkyl phenylthiomethyl ketones with alkenyl bromides. 相似文献