共查询到20条相似文献,搜索用时 15 毫秒
1.
Eiichi Masumoto Hiroshi Maruoka Fumi Okabe Sho Nishida Ryoko Tomita Toshihiro Fujioka Kenji Yamagata 《Journal of heterocyclic chemistry》2012,49(4):893-899
A novel synthetic route to 4‐pyridazineacetic acids 10 – 12 has been achieved by the ring‐expansion reaction of N‐cyanomethylated 3‐pyrazoline‐4‐acetic acids 7 – 9 . 1H‐Pyrazole‐4‐acetic acids 1 – 3 were reacted with iodoacetonitrile in the presence of triethylamine in refluxing acetonitrile to give the corresponding C‐cyanomethylated 1H‐pyrazole‐4‐acetic acids 4 – 6 as major products together with N‐cyanomethylated 3‐pyrazoline‐4‐acetic acids 7 and 8 as minor products. On the other hand, reactions of 1 and 3 with chloroacetonitrile in the presence of triethylamine in refluxing chloroform afforded the corresponding N‐cyanomethylated 3‐pyrazoline‐4‐acetic acids 7 and 9 as major products. Thermal treatment of 7 – 9 with sodium hydride in N,N‐dimethylformamide caused ring expansion to yield the corresponding 4‐pyridazineacetic acids 10 – 12 . 相似文献
2.
Yu. M. Yutilov Kh. Ya. Lopatinskaya N. N. Smolyar S. V. Gres’ko 《Russian Journal of Organic Chemistry》2005,41(3):450-454
Halogenation of 2-unsubstituted and 2-methylimidazo[4,5-b]pyridines and their N-methyl derivatives with bromine and chlorine in acetic acid takes different pathways, depending on the acetic acid concentration. The bromination in 50% aqueous acetic acid gives only 6-bromoimidazo[4,5-b]pyridines; bromination and chlorination of 2-unsubstituted imidazo[4,5-b]pyridines in glacial acetic acid leads to 5,6-dibromo(dichloro)imidazo[4,5-b]pyridin-2-ones, and bromination of 2-methylimidazo[4,5-b]pyridines in glacial acetic acid involves both the pyridine ring and the 2-methyl group to afford the corresponding 6-bromo-2-tribromomethylimidazo[4,5-b]pyridines.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 3, 2005, pp. 457–461.Original Russian Text Copyright © 2005 by Yutilov, Lopatinskaya, Smolyar, Gres’ko. 相似文献
3.
de Castro Heizir F. Napoleão Diovana A. S. Oliveira Pedro C. 《Applied biochemistry and biotechnology》1998,(1):667-675
Several reports exist in the literature citing the decrease in conversion rates of organic-phase catalytic synthesis reactions
when acetic acid is present as a reaction component. This inhibition is thought to result from damage to either the hydration
layer-protein interaction or the overall enzyme structure. In this work, the inhibitory effect of acetic acid on lipase enzyme
activity was ameliorated by conducting syntheses under acetic acid-limiting conditions in a fed-batch system, resulting in
higher product yields. Periodic additions of acetic acid at levels of 40 mM or less gave maximum yields of 65% conversion for the reaction of citronellol and acetic acid to form citronellyl acetate.
The enzyme used was a fungal lipase fromMucor miehei, and was immobilized on macroporous synthetic resin (a Novo lipozyme Novo Nordisk, Denmark). These results represent a fourfold
improvement over batch runs reported in the literature for direct esterification of terpene alcohol with acetic acid using
lipozyme as a catalytic agent. 相似文献
4.
Mohandas Devaki V. Whelan Douglas R. Panchal Chandra J. 《Applied biochemistry and biotechnology》1995,(1):307-318
Mutants resistant to comparatively high levels of acetic acid were isolated from the xylose-fermenting yeastsCandida shehatae andPichia stipitis by adapting these cultures to increasing concentrations of acetic acid grown in shake-flask cultures. These mutants were
tested for their ability to ferment xylose in presence of high acetic acid concentrations, in acid hydrolysates of wood, and
in hardwood spent sulfite liquor, and compared with their wild-type counterparts and between themselves. TheP. stipitis mutant exhibited faster fermentation times, better tolerance to acid hydrolysates, and tolerance to lower pH. 相似文献
5.
Ho Sik Kim Eun Ah Kim Geuk Jeong Yong Tae Park Young Seuk Hong Yoshihisa Okamoto Yoshihisa Kurasawa 《Journal of heterocyclic chemistry》1998,35(2):445-450
The reaction of 6-chloro-2-(1-methylhydrazino)quinoxaline 4-oxide 8 with acetic anhydride resulted in the intramolecular cyclization to give 8-chloro-2,4-dimethyl-4H-1,3,4-oxadiazino[5,6-b]quinoxaline 7a , while the reaction of compound 8 with acetic anhydride/pyridine or acetic anhydride/acetic acid afforded 3-(2,2-diacetyl-1-memymydrazmo)-7-chloro-2-oxo-1,2-dihydroquinoxaline 9 , effecting no intramolecular cyclization. The reaction of 2-(2-acetyl-1-methylhydrazino)-6-chloroquinoxaline 4-oxide 10a or 6-chloro-2-(1-methyl-2-trifluoroacetylhydrazino)quinoxaline 4-oxide 10b with phosphoryl chloride provided compound 7a or 8-chloro-4-memyl-2-trifluoromethyl-4H-1,3,4-oxadiazino[5,6-b]quinoxaline 7b , respectively. The reaction of compound 7b with phosphorus pentasulfide gave 7-chloro-3-(1-methyl-2-trifluoroacetylhydrazino)-2-thioxo-1,2-dihydroquinoxaline 11 , whose dehydration with sulfuric acid in acetic acid afforded 8-chloro-4-methyl-2-trifluoromemyl-4H-1,3,4-thiadiazino[5,6-b]quinoxaline 12 . 相似文献
6.
A Divergent Synthesis of Spiropyrazole Derivatives Containing Iminolactone and/or Cyclic Imide Moiety
下载免费PDF全文
![点击此处可从《Journal of heterocyclic chemistry》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Eiichi Masumoto Hiroshi Maruoka Fumi Okabe Toshihiro Fujioka Kenji Yamagata 《Journal of heterocyclic chemistry》2015,52(1):48-53
An approach to spiropyrazole derivatives containing iminolactone and/or cyclic imide moiety starting from 1H‐pyrazole‐4‐acetic acid derivative is described. Hydrolysis of C‐cyanomethylated 1H‐pyrazole‐4‐acetic acid methyl ester ( 1 ), which was easily prepared from 1H‐pyrazole‐4‐acetic acid derivative by a C‐cyanomethylation, led to the C‐cyanomethylated 1H‐pyrazole‐4‐acetic acid ( 2 ). Compound 2 was reacted with ethanol in the presence of tin(IV) chloride in refluxing chloroform to give the key intermediate ethyl imidate ( 3 ). Sodium hydride‐assisted lactonization of 3 in N,N‐dimethylformamide afforded the spiropyrazole derivative containing iminolactone moiety ( 4 ). On the other hand, thermal treatment of 3 with sodium acetate in the absence of solvent caused another intramolecular cyclization to yield the spiropyrazole derivative containing cyclic imide moiety ( 6 ). 相似文献
7.
E. V. Tatarnikova V. V. Sizov A. V. Aleksandrov I. V. Tselinskii 《Russian Journal of Organic Chemistry》2009,45(10):1523-1527
N-Nitrobenzimidazol-2-ones readily undergo rearrangement to C-nitro derivatives on heating in various solvents (ethyl acetate, butyl acetate, acetonitrile, acetone, dioxane, o-dichlorobenzene, anisole, acetic acid). This rearrangement was used to develop a procedure for the synthesis of 4,5,6,7-tetranitro-1,3-dihydrobenzimidazol-2-one
in high yield (90–96%) by nitration of 1,3-dihydrobenzimidazol-2-one, as well as of 5,6-dinitro- and 4,5,6-trinitro-1,3-dihydrobenzimidazol-2-ones,
with a small excess of concentrated nitric acid in a mixture with acetic anhydride and acetic acid at 50–60°C. 相似文献
8.
The 6-(2-nitrostyryl)-2H-pyran-2-ones 1 were reduced with hydrogen over Pd/C at room temperature and atmospheric pressure giving the 2-benzoylamino-4-(1,2,3,4-tetrahydro-2-quinolinylidene-2-pentenedioic acid derivatives 2 which were converted, without isolation, into the 5,6-dihydro-1H-benzo[c]quinolizin-1-ones 4 in refluxing acetic anhydride. When α-aminoacids 2 were treated with acetic anhydride at room temperature oxazolones 3 were isolated, while by heating quinolizines 4 were found. Compounds 3 were transformed into 4 in refluxing acetic acid or anhydride. 相似文献
9.
Jin-Nam Kim Jong-Sok Choo Young-Jung Wee Jong-Sun Yun Hwa-Won Ryu 《Applied biochemistry and biotechnology》2005,123(1-3):861-869
A new acetic acid-producing microorganism, Acetobacter sp. RKY4, was isolated from Korean traditional persimmon vinegar, and we optimized the culture medium for acetic acid production
from ethanol using the newly isolated Acetobacter sp. RKY4. The optimized culture medium for acetic acid production using this microorganism was found to be 40 g/L ethanol,
10 g/L glycerol, 10 g/L corn steep liquor, 0.5 g/L MgSO4·7H2O, and 1.0 g/L (NH4H2PO4. Acetobacter sp. RKY4 produced 47.1 g/L of acetic acid after 48 h of fermentation in a 250 mL Erlenmeyer flask containing 50 mL of the
optimized medium. 相似文献
10.
The dissociation constant of acetic acid in N-methylpropionamide (NMP) has been determined at 11 temperatures from 5 to 55°C by measurement of the electromotive force of cells without liquid junction containing hydrogen gas electrodes and silver-silver chloride electrodes. The pK at 25°C was found to be 7.995 (molal scale) as compared with 4.756 in water; thus, acetic acid is much weaker in NMP than in water despite the higher dielectric constant of the nonaqueous solvent (176 as compared with 78.3 at 25°C). The standard changes of enthalpy and entropy for the dissociation of acetic acid were calculated from the temperature coefficient of pK, and thermodynamic functions for the transfer dissociation process were obtained. The weakness of acetic acid in NMP is discussed in terms of electrostatic effects and solute-solvent interactions. 相似文献
11.
George Bobowski 《Journal of heterocyclic chemistry》1983,20(1):183-187
The treatment of N-[2-(1H-indol-3-yl)ethyl]alkanamide, 1 (1), with phosphorus oxychloride under controlled conditions gave l-alkyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-ol, 2 . The reaction of 2 with acetic anhydride or with methyl isocyanate at room temperature resulted in the formation of amido carbinol 3 and urea carbinol 7, respectively. The former was transformed into amido ester 4 by boiling acetic anhydride. When the reaction of 3 with acetic anhydride was carried out in the presence of excess triethylamine at 105°, C-N bond cleavage of the tetrahydropyridine ring took place with concurrent bis(N-acetylation) to give the enol ester derivative 5 . The structures of all compounds are consistent with chemical and spectral evidence. 相似文献
12.
Inhibition of microbial xylitol production by acetic acid and its relation with fermentative parameters 总被引:5,自引:0,他引:5
Precipitated sugarcane bagasse hemicellulosic hydrolysate containing acetic acid was fermented by Candida guilliermondii FTI 20037 under different operational conditions (pH 4.0 and 7.0, three aeration rates). At pH 7.0 and k
L
a of 10 (0.75 vvm) and 22.5/h (3.0 vvm) the acetic acid had not been consumed until the end of the fermentations, whereas at
the same pH and k
L
a of 35/h (4.5 vvm) the acid was rapidly consumed and acetic acid inhibition was not important. On the other hand, fermentations
at an initial pH of 4.0 and k
L
a of 22.5 and 35/h required less time for the acid uptake than fermentations at k
L
a of 10/h. The acetic acid assimilation by the yeast indicates the ability of this strain to ferment in partially detoxified
medium, making possible the utilization of the sugarcane bagasse hydrolysate in this bioprocess. The effects on xylitol yield
and production are reported. 相似文献
13.
Milan a
i Mladen Trkovnik Frane a
i Elizabeta Has‐Schn 《Journal of heterocyclic chemistry》2006,43(2):261-266
14.
By employing deuterium substitution and metastable ion defocusing methods, it has been determined that 1-acetoxytetralin undergoes a highly regiospecific (>98%) 1,4-elimenation of acetic acid. The mechanism closely parallels that for loss of water from 1-tetralol in terms of specificity. However, unlike the water loss, which shows a significant kinetic isotope effect (KH/KD = 2.0) and a large release of translational energy (270 meV), the expulsion of acetic acid occurs without an isotope effect and with release of only 10 meV of kinetic energy. Competitive with acetic acid loss is the elimination of ketene which has been shown to occur by a 4-centered transition state. The 2-acetoxytetralin exhibits the more traditional 1,2-elimination of acetic acid which contrasts with a 1,3-elemination of water for the corresponding alcohol. 相似文献
15.
Silvia E. Asías Ana M. Bruno Diego A. Dominici Mariela Bollini Carlos H. Gaozza 《Journal of heterocyclic chemistry》2003,40(1):107-112
In order to find new antimalarial drugs, an exploration about the chemical properties of the starting compounds 3‐amino‐6‐chloro‐4‐phenyl‐1H‐quinolin‐2‐one ( 1 ) and 3‐amino‐4‐methyl‐1H‐quinolin‐2‐one ( 2 ) was developed. Acylation with acyl chloride, sulfonyl chloride and acetic anhydride were carried out. Despite a previous report [2], when acetyl chloride or acetic anhydride were assayed on 1 , only the diacetyl derivative 7 was obtained. When this compound was heated at reflux temperature in a mixture of acetic acid and acetic anhydride, it was transformed in the oxazoloquinoline 8 . Further reactions of the acyl derivatives with diazomethane afforded 1‐methylated compounds. Compound 2 gave the imine 16 by condensation with 4‐nitrobenzaldehyde. 相似文献
16.
Bis(3-(arylthiomethyl)benzaldehydes), linked to aliphatic spacers via ethers, were prepared and used as key synthons for the bis(2-phenyloxazol-5(4H)-ones) via their reaction with benzoylglycine in acetic anhydride in the presence of fused sodium acetate at 100°C for 6 hours. Bis(oxazol-5(4H)-ones) were reacted with the appropriate aromatic or heterocyclic amines in glacial acetic acid in the presence of fused sodium acetate at 100°C for 24 hours to afford a novel series of bis(2-phenylimidazol-4-ones) and their related hybrids with benzo[d]thiazole and pyrimidine-2,4(1H,3H)-dione. Moreover, bis(oxazol-5(4H)-ones) reacted with (4-aminobenzoyl)glycine to afford bis[(4-(5-oxo-1H-imidazol-1-yl)benzoyl)glycine] derivatives followed by their reaction with anisaldehyde in acetic anhydride containing fused sodium acetate at 100°C for 12 hours to afford bis(5-oxo-1H-imidazol-1-yloxazol-5(4H)-one) hybrids. Furthermore, bis(3-(arylthiomethyl)benzaldehydes) were reacted with 2,2′-(terephthaloylbis(azanediyl))diacetic acid in acetic anhydride containing fused sodium acetate at 100°C for 12 hours to give benzo-fused macrocycles containing oxazolone subunits which reacted with appropriate aromatic amines in DMF and glacial acetic acid containing fused sodium acetate at 100°C for 24 hours to give benzo-fused macrocycles containing imidazolone subunits. 相似文献
17.
It was shown that ethyl 2-nitroacetoacetate is a synthetic precursor of ethoxycarbonylnitrile oxide as well as of isoxazole- and isoxazoline-3-carboxylic acids and their esters. The elimination of acetic acid from ethyl 2-nitroacetoacetate occurs in a mixture of acetic acid and acetic anhydride in the presence of strong mineral acids,e.g., H2SO4, at room temperature and gives isoxazolines in yields of up to 85–91 %.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 103–105, January, 1994. 相似文献
18.
[(1-Amino-6-hydroxy-2(1H)-pyrimidinylidene)hydrazone]butanedioic acid dimethyl esters 3 , formed from 3-amino-2-hydrazino-4(3H)-pyrimidinones and dimethyl acetylenedicarboxylate in acetic acid at room temperature, underwent a facile, thermal rearrangement to 1-amino-2,6-dihydro-2,6-dioxo-1H-pyrimido-[1,2-b]-[1,2,4]triazine-3-acetic acid methyl esters 6 in hot acetic acid. 相似文献
19.
Snjeana Antoli Biserka Koji‐Prodi Volker Magnus 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(8):1026-1027
The structural characterization of 1H‐pyrrolo[2,3‐b]pyridine‐3‐acetic acid (alternative name: 7‐azaindole‐3‐acetic acid), C9H8N2O2, reveals similar molecular geometry, i.e. with the side chain perpendicular to the 7‐azaindole ring, to that of the natural plant growth hormone indole‐3‐acetic acid (auxin) and its alkylated and halogenated derivatives. 相似文献
20.
Iron(II) in acetic acid medium and the presence of pyrophosphate is used as a new reductimetric reagent and utilised for the spectrophotometric titration of microgram quantities of six oxazine dyes. All these dyes are rapidly and quantitatively reduced to their colourless leuco-bases in a 2-electron reduction with iron(II), provided the medium contains 1 or 3M acetic acid (depending on the dye) and at least 0.1M pyrophosphate. The redox potentials of the iron(III)/iron(II) couple at different pyrophosphate and acetic acid concentrations have been measured and a method for purification of some of the commercially impure oxazine dyes is suggested. 相似文献