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1.
Summary The synthesis of antamanide, retroantamanide, and perhydroantamanide has been effected. It has been shown that the inversion of the direction of acylation — the equilibrium interchange of the valine and alanine residues (retroantamanide) — lowers the stability of the complexes with sodium and potassium in ethanolic solutions, while the replacement of the phenyl groups by cyclohexyl groups has practically no effect on complex formation.M. M. Shemyakin Institute of the Chemistry of Natural Compounds, Academy of Sciences of the USSR. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 469–474, July–August, 1971.  相似文献   

2.
The Friedel—Crafts acylation of trimethylhydroquinone, 3,5-diethyl-2-hydroxyhydroquinone, and 3,5-diethyl-1,2,4-trimethoxybenzene with dichloromaleic or citraconic anhydride in an AlCl3—NaCl melt is accompanied by o-C-dealkylation to afford functionally substituted naphthazarins.  相似文献   

3.
The acylation of 1-hydroxyamino-2-hydroxyiminoethanes with -halo acid chlorides has given the products of N- and O-acylation at the hydroxyamino group. The action of bases on the products of N-acylation — N-(2-hydroxyiminoalkyl)-2-halohydroxamic acids — has given, depending on the conditions, 1-hydroxy-2-oxo-1,2,3,6- or -1,2,5,6-tetrahydropyrazine 4-oxides and 1,2-oxazetidin-3-ones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 115–120, January, 1984.  相似文献   

4.
Conclusions Acylation of alkenes with branching at the allylic carbon provides a preparative route to cyclic carboxonium salts. Such salts can be prepared by protonation of, -unsaturated ketones —the products of acylation of unbranched alkenes. We have examined the mechanism of acylation of acylium salts.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 397–408, February, 1978.  相似文献   

5.
The principal electrophilic substitution reactions involving the hydrogen atom of 4,5,6,7-dibenzindole — the Vilsmeier reaction, the Mannich reaction, diazo coupling, and acylation — were studied, and a qualitative comparison of its reactivities with indole and 4,5- and 6,7-benzindoles was made. It was established that 4,5,6,7-dibenzindole has the most clearly expressed electron-donor properties. The structures of the synthesized compounds were proved by data from the IR, UV, PMR, and mass spectra.See [1] for communication 17.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 366–370, March, 1979.  相似文献   

6.
The ring isomer of the corresponding acyl derivative — 5,9-dioxo-17a-hydroxy-9,10,11,16-17,17a-hexahydro-5H-dibenzo[d,e,h]phthalazino[2,3-a]cinnoline — was obtained by acylation of 1,2,3,4-tetrahydrophthalazine with anthraquinone-1-carboxylic acid chloride. Treatment of the product with thionyl chloride or hydrogen chloride gave the deeply colored 5,9-dioxo-9,10,11,16-tetrahydro-5H-dibenzo[d,e,h]phthalazino[2,3-a]cinnolinium chloride. The possibility of charge transfer between the chloride anion and the phthalazinium cation is examined as a reason for the deep coloration. This compound very readily undergoes hydrolytic oxidative cleavage at the C-N bond to give 2-(2-formylbenzyl)-3,7-dioxo-2,3-dihydro-7H-dibenzo[d,e,h]cinnoline.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1411–1415, October, 1977.  相似文献   

7.
An example of a more environmentally benign Friedel—Crafts acylation reaction constitutes the first step of a two step synthesis of p-anisic acid. The greener Friedel—Crafts acylation involves reaction, on acidic alumina in the absence of solvent, of anisole with a mixed anhydride derived from acetic acid and trifluoroacetic anhydride. The acylated anisole is then oxidized, employing the haloform reaction to produce p-anisic acid. Students identify the anisic acid isomer obtained through spectral analysis and/or melting-point determination and then infer the regioselectivity of the initial acylation. The experiment offers opportunities for instruction in the tenets of green chemistry and reinforcement of the theory of electrophilic aromatic substitution presented in lecture.  相似文献   

8.
The alkylation and acylation of 2,4-disubstituted 1,2-dihydro-4H-3,1-benzoxazines were used to obtain N-methyl and N-acetyl derivatives of these compounds for the first time.1H NMR was used to reveal several conformational features of these compounds relative to their donor—acceptor properties at positions 2, 3, and 4 of the heterocycle.Communication 11, see [2].Kuban State Technological University, 350072 Krasnodar. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 841–846, June, 1997.  相似文献   

9.
Tetra- and pentacyclic indole [2,3-c] pyrylium salts were obtained by acylation of 2-(3-indolyl) dimedone and 2- (1-ethyl-3-indolyl)indan-1,3-dione. The latter salts by the action of ammonia are converted to the corresponding -carbolines — derivatives of the natural alkaloid harman.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 363–366, March, 1985.  相似文献   

10.
This review concerns the cyclization of thiosemicarbazones and thiocarbhydrazones of carbonyl compounds leading to the title heterocycles. We examine the irreversible cyclization by the action of oxidizing agents or as the result of acylation or alkylation as well as the ring—chain tautomerism. The effect of the substitution and solvent on the equilibrium of the thiosemicarbazones with some of the possible heterocyclic tautomeric forms was examined. The usefulness of these data for predicting the results of their irreversible cyclization was discussed.Dedicated to Professor A. R. Katritzky on the occasion of his sixty-fifth birthday.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 991–1005, July, 1993.  相似文献   

11.
The action of guanidine on esters of chromone-2-carboxylic acids leads to the opening of the pyrone ring and to the formation of hydantoin derivatives — 2-imino-5-(2-hydroxybenzoylmethylene)tetrahydroimidazol-4-ones — in addition to other reaction products.Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 7, pp. 874–875, July, 1970.  相似文献   

12.
This work describes a novel approach for the synthesis of (−)-epigallocatechin gallate (EGCG) palmitate by a chemical-synthesis method, where the elevated stability of the EGCG derivative is achieved. Various parameters affecting the acylation process, such as the base, solvent, as well as the molar ratio of palmitoyl chloride, have been studied to optimize the acylation procedure. The optimized reaction condition was set as follows: EGCG/palmitoyl chloride/sodium acetate was under a molar ratio of 1:2:2, with acetone as the solvent, and the reaction temperature was 40 °C. Under the optimized condition, the yield reached 90.6%. The EGCG palmitate (PEGCG) was isolated and identified as 4′-O-palmitoyl EGCG. Moreover, the stability of PEGCG under different conditions was proved significantly superior to EGCG. Finally, PEGCG showed better inhibition towards α-amylase and α-glucosidase, which was 4.5 and 52 times of EGCG, respectively. Molecular docking simulations confirmed the in vitro assay results. This study set a novel and practical synthetic approach for the derivatization of EGCG, and suggest that PEGCG may act as an antidiabetic agent.  相似文献   

13.
Yuan  Ai-Hua  Lu  Lu-De  Shen  Xiao-Ping  Chen  Li-Zhuang  Yu  Kai-Bei 《Transition Metal Chemistry》2003,28(2):163-167
A cyanide-bridged FeIII–FeII mixed-valence assembly, [FeIII(salen)]2[FeII(CN)5NO] [salen = N,N-ethylenebis(salicylideneiminato)dianion], prepared by slow diffusion of an aqueous solution of Na2[Fe(CN)5NO] · 2H2O and a MeOH solution of [Fe(salen)NO3] in an H tube, has been characterized by X-ray structure analysis, i.r. spectra and magnetic measurements. The product assumes a two-dimensional network structure consisting of pillow-like octanuclear [—FeII—CN—FeIII—NC—]4 units with dimensions: FeII—C = 1.942(7) Å, C—N = 1.139(9) Å, FeIII—N = 2.173(6) Å, FeII—C—N = 178.0(6)°, FeIII—N—C = 163.4(6)°. The FeII—N—O bond angle is linear (180.0°). The variable temperature magnetic susceptibility, measured in the 4.8–300 K range, indicates the presence of a weak intralayer antiferromagnetic interaction and gives an FeIII–FeIII exchange integral of –0.033 cm–1.  相似文献   

14.
Reactions of VO(acac)2 with alkylene dithiophosphoric acids, POGOS2H, and of VOCl3 with the ammonium salts NH4(POGOS2) in 1:2 molar ratio gave the oxovanadium(IV) alkylene dithiophosphates, [VO(POGOS2)2], and monochloroxovanadium(V) alkylene dithiophosphates, [VOCl(POGOS2)2], respectively, where G = —CH2CMe2-CH2—, —CH2CEt2CH2—, —CHMeCH2CMe2— or —CMe2CMe2—. These complexes are green solids, soluble in common organic solvents and sensitive to moisture. They were characterized by elemental analysis, molecular weight and spectral studies including i.r. and n.m.r. (1H, 13C and 31P), which suggested bidentate bonding of the POGOS2 ligands to give a square pyramidal for the VIV complexes and an octahedral geometry for the VV complexes.  相似文献   

15.
The review surveys the data on the reactions of phosphorus and arsenic ylides with compounds containing E=X bonds (E = C, Si, Ge, or Sn; X = C or S), cyclic oligomers (R2ES)n (n = 2 or 3), and heavier analogs of carbenes. These reactions give rise to two new classes of heteroorganic betaines containing the (+)E15—C—E14—X(–) (I) and (+)E15—C—E14(–) (II) (E15 = P or As; E14 = Si, Ge, or Sn; X = C or S) structural fragments. Procedures for the synthesis of these compounds, their reactivities, the X-ray diffraction structures, and the electronic structures established by high-level quantum-chemical calculations are considered in detail. The carbon analogs of betaines of type I, viz., compounds bearing the (+)P—C—C—X(–) fragment (III), are also discussed. The latter were long considered as possible intermediates in the reactions of compounds containing the polar C=X bond (X = C, O, S, NR, etc.) with phosphorus ylides (classical Wittig and Corey—Chaykovsky reactions and related processes).  相似文献   

16.
Conductometric and high-frequency conductometric methods for the determination of the endpoint of catalytic titrations were developed. Titrations of sodium acetate were made in a mixture of acetic anhydride and acetic acid (7:3–11:3) which was 0.05–0.1 mol dm−3 in sodium perchlorate. Integral and derivative titration curves were recorded in both coulometric and volumetric titrations. Different acylation reactions, as well as dehydration of formic acid, were used as the indicator reactions. The optimal conditions of determination—choice of volume ratio of acetic anhydride to acetic acid, rate of the titrating reagent addition, concentration of sodium perchlorate, and concentration of several alcohols, water, and formic acid as components of the indicator reactions—were determined. Using the catalytic conductometric method, amounts of 0.04–11 mg of sodium acetate were determined with a relative standard deviation of less than 0.8 and 1.6% in volumetric and coulometric addition, respectively. Using the catalytic high-frequency conductometric method, amounts of 1–11 mg of sodium acetate were determined with relative standard deviation less than 0.5% (volumetrically) or less than 1.4% (coulometrically). The obtained results were compared with those of potentiometric and catalytic thermometric titrations.  相似文献   

17.
Summary Three new substances — tenuferin, tenuferinin, and tenuferidin — have been isolated from the roots ofFerula tenuisecta Eug. Kor. It has been shown that they are esters of an undescribed sesquiterpene alcohol — 8,10-dihydroxy-3,4-epoxyguaiane — and isovanillic, vanillic, and p-hydroxybenzoic acids, respectively.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodynkh Soedinenii, No. 1, pp. 70–75, January–February, 1978.  相似文献   

18.
The Friedel–Crafts acylation of anisole (AN) with acetic anhydride (AA) and the Fries rearrangement of phenyl acetate in the liquid phase catalyzed by bulk and silica-supported heteropoly acids (HPA), mainly H3PW12O40 (PW), have been studied. In anisole acylation, PW exhibits very high activity, yielding up to 98% para and 2–4% ortho isomer of methoxyacetophenone (MOAP) at 90-110°C and an AN/AA molar ratio of 10–20. The reaction appears to be heterogeneously catalyzed; no contribution of homogeneous catalysis by HPA was observed. PW is almost 100 times more active than the zeolite H-Beta, which is in agreement with the higher acid strength of HPA. The PW catalyst is reusable, although gradual decline of activity was observed due to the coking of the catalyst. The acylation is inhibited by the product because of adsorption of MOAP on the catalyst surface. In contrast to anisole, the acylation of toluene with HPA is far less efficient than that with H-Beta. Evidence is provided that the activity of HPA in toluene acylation is inhibited by preferential adsorption of acetic anhydride on the catalyst. It is demonstrated that PW is a very efficient and reusable catalyst for the Fries rearrangement of phenyl acetate in homogeneous or heterogeneous liquid-phase systems at 100–150°C.  相似文献   

19.
The following tetracyclic ring systems and their derivatives have been synthesized for pharmacological investigations: Trimethylenethieno[2,3—d]dihydropyrrolo[1,2—a]pyrimidin-4-one and -4-thione (1 a, 5 a); Tetramethylenethieno[2,3—d]dihydropyrrolo[1,2—a]pyrimidin-4-one and -4-thione (1 b, 1 j, 5 b); Pentamethylenethieno[2,3—d]dihydropyrrolo[1,2—a]pyrimidin-4-one and-4-thione (1 c, 5 c); Trimethylenethieno[2,3—d]tetrahydropyrido[1,2—a]pyrimidin-4-one and -4-thione (1 d, 5 d); Tetramethylenethieno[2,3—d]tetrahydropyrido[1,2,—a]pyrimidin-4-one and -4-thione (1 e, 5 e); Pentamethylenethieno[2,3—d]tetrahydropyrido[1,2—a]pyrimidin-4-one and -4-thione (1 f, 5 f); Trimethylenethieno[2,3—d]tetrahydroazepino[1,2—a]pyrimidin-4-one and -4-thione (1 g, 5 g); Tetramethylenethieno[2,3—d]tetrahydroazepino[1,2—a]pyrimidin-4-on and -4-thione (1 h, 5 h); Pentamethylenethieno[2,3—d]tetrahydroazepino[1,2—a]pyrimidin-4-one and -4-thione (1 i, 5 i); Tentamethylenethieno[2,3—d]tetrahydroazepino[1,2—a]pyrimidin-4-one (7 b); Pentamethylenethieno-[2,3—d]tetrahydropyrido[1,2—a]pyrimidin-4-one (7 c).Compounds1 a–i were synthesized from 2-amino-3-ethoxycarbonyl-4,5-polymethylenethiophene2 a–c with the corresponding lactim ethers (3 a–c) in chlorobenzene in the presence of polyphosphoric acid (PPA). Compounds7 b and7 c were obtained in the reaction of -amino acid esters2 b and2 c with 2-bromopyridine (6). The thione derivatives (5 a–i) were prepared from compounds1 a–i with phosphorus(V) sulphide.Part 74:Szabó J, Fodor L, Szcs E, Bernáth G, Sohár P (1984) Pharmazie 39: 347.  相似文献   

20.
N-Acyl derivatives of imidazole-2-thione and its derivatives were obtained by the reaction of imidazole2-thione and its derivatives with aliphatic anhydrides and with benzoyl chloride in pyridine. The hydrochlorides of 1-methyl and 4 (5)-methyl-S benzoylimidazole-2-thione were obtained by the reaction of 1-methyl- and 4 (5)-methylimidazole-2-thione with benzoyl chloride in dry ethanol. The acylation of imidazole-2-thione and of some of its derivatives was investigated with the aid of their IR spectra, and the importance of the medium in the formation of N- and S -acyl derivatives was shown, as well as the possibility of the migration of substituants from the S — to the N atom under its influence.For part VI see [1].  相似文献   

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