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1.
The first mass spectra of pyrrolo [2, 3-b] pyrazine and some of its derivatives and of pyrazino [2, 3-b] indole are reported and compared with those of related compounds. Differences between the spectra of some aryl substituted derivatives are described and discussed.  相似文献   

2.
On treatment with higher diazoalkanes, 2,4,6/3,5-penta-acetoxy-cyclohexanone (penta-O-acetyl-myo-inosose-2 or -scyllo-inosose) afforded by ring expansion all-trans-penta-acetoxy-C-alkyl-cycloheptanones, which by deacylation were converted to hemiacetals. The reactions with diazoalkanes of the penta-acetoxy-inosose in the presence of aluminium chloride and of the free inosose in water solution have also been studied. The structure, the configuration, and, in some cases, the conformation of the new compounds have been established and some of their reactions have been investigated. The mechanisms of formation of the ring expansion products and of the concomitant spiro-epoxides have been discussed.  相似文献   

3.
Enthalpies and temperatures of fusion or transition for four substituted dipeptides (Nacetylamides of glycyl-L-alanine (NAGAA),L-alanyl-L-alanine (NAA2A),L-prolyl-glycine (NAPGA) andL-leucyl-L-proline monohydrate (NALPA·H2O)) were determined by differential scanning calorimetry and the entropies of fusion derived. The results obtained have been compared with those of the corresponding substituted aminoacids and some of their racemic crystalline mixtures. The enthalpies and entropies of fusion of some substituted aminoacids have been redetermined. The results are discussed in comparison with crystal structural data, which has been reported in the literature or determined recently by some of the authors. Rationalization of the fusion parameters was attempted mainly on the basis of the number of intramolecular hydrogen bonds and the packing densities in the crystals.This work was carried out with the financial support from the Italian C.N.R. (Rome) and from the Ministry of University and Scientific and Technological Research.  相似文献   

4.
The reaction of some 2-aminobenzothiazoles and 2-aminothiazoles with ethyl 3-bromo-4-oxopentanoate was investigated with the aim to obtain the corresponding imidazo[2,1-b]benzothiazole and imidazo[2,1-b]-thiazole derivatives, respectively. In some cases, two unexpected side products were obtained together with the required compound and their structures were elucidated: e.g., 2-aminobenzothiazole reacted with ethyl 3-bromo-4-oxopentanoate to give ethyl 2-methylimidazo[2,1-b]benzothiazole-3-acetate together with ethyl imi-dazo[2,1-b]benzothiazole-2-propionate and ethyl 3-(benzothiazol-2-yl)amino-4-oxopentanoate.  相似文献   

5.
The mass spectrometric behaviour of twenty saturated heterocyclic compounds with a 1,3-oxazin-4-one moiety fused with cis or trans anellation to a cycloalkane ring (C5-C8) was studied. The roles of the C-2 and N-3 substituent(s) were found to be characteristic, while the size of the cycloalkane ring seemed to be unimportant. Some fragmentation processes involving breakdown of the oxazinone ring of the cis or trans isomers displayed significant stereoselectivity. A striking new decomposition process involving significant chlorine elimination from the molecular ion of some 2-p-chlorophenyl derivatives was observed and was studied in some detail.  相似文献   

6.
Dehydrochlorination of tert-chlorine-telechelic polyisobutylene with potassium tert-butoxide in refluxing tetrahydrofuran is quantitative after 22 h, but results in ca. 3% endo olefin chain ends which are not reactive in some subsequent functionalization reactions. The formation of these undesired structures is most likely due to simultaneous thermally induced HCl loss. Lower temperatures and longer reaction times led to exclusive formation of external double bonds in some cases but to incomplete dehydrochlorination.  相似文献   

7.
2-o-Chlorophenyl-2H-naphtho[1,2-d]v-triazole-4,5-quinone condenses with semicarbazide and some of its derivatives at the 4 position and the products cyclize into the corresponding 1,2,4-triazines. Reactions of these triazines with some reagents are described.  相似文献   

8.
The direct sulfonylation of 4,5‐dichloropyridazin‐3‐ones with some benzenesulfonyl chlorides in the presence of base in tetrahydrofuran gave only the corresponding N‐sulfonylated product. The reaction of 2‐benzenesulfonyl‐4,5‐dichloropyridazin‐3‐ones with some aliphatic amines under neutral conditions afforded 5‐alkylamino‐2‐benzenesulfonyl‐4‐chloropyridazin‐3‐ones and/or the corresponding N‐alkyl‐benzenesulfonamides.  相似文献   

9.
Regioselectivity of glycoside containing cis‐diol esterification with fatty acid using dibutyltin dimethoxide as stannylating agent was probed, the results showed the equatorial position of cis‐diol has some advantage of being acylated, although the orientation of adjacent groups could affected the regioselectivity. The glycoside fatty acid esters were regioselectively synthesized on optimized condition with this stannyl method, the biological tests against bacterial as Staphylococcus aureus and Salmonella agona were carried out with these fatty acid esters, the testing results showed that glycoside esters with 12 or 14 carbon long chain fatty acid have some obvious inhibition against Staphylococcus aureus.  相似文献   

10.
Efficient and convenient synthesis of coumarin derivatives was accomplished via reactions of 2-(1-(2-oxo-2H-chromen-3-yl)ethylidene)hydrazinecarbothioamide with some carbon electrophiles, e.g. maleic anhydride, dimethyl acetylenedicarboxylate, 1,2-dichloroethane, 3′-nitro-w-bromoacetophenone, N-(4-acetylphenyl)-2-chloroacetamide, ethyl cyanoacetate/3-chlorobenzaldehyde and acetylacetone to construct some N-heterocycles such as thiazolidine, thiazole, pyrimidine and pyrazolone derivatives. The structures of all synthesized products were substantiated from their analytical and spectral data. The antioxidant activities of the synthesized compounds were examined.  相似文献   

11.
Anthranilic diamides have been proven to be a class of efficacious and safe insecticides targeting ryanodine receptors (RyRs) during the last decade. In order to develop innovative scaffolds with high insecticidal activity, two series of N‐pyridylpyrazole derivatives containing N‐(tert‐butyl)benzohydrazide substructures were designed and synthesized. Their insecticidal activities against oriental armyworm (Mythimna separata) and diamondback moth (Plutella xylostella) were evaluated. Preliminary bioassay results revealed that some of the new compounds exhibited good insecticidal activity against the oriental armyworm and diamondback moth. The mode of action of these compounds were verified using calcium‐imaging technique and the results showed that some new compounds could effectively modulate the insect cytosolic Ca2+ level, and break the cellular calcium homeostasis, indicating some of these compounds were potent activators of the RyRs.  相似文献   

12.
Reactions of 3-[2-(morpholin-4-yl)vinyl]-1H-indole ( 1 ), the 1,2-dihydro-9H-carbazole 2 , as well as the 3-(tetrahydropyridin-4-yl)-1H-indoles 3a and 3b with some carbo- and heterodienophiles are described. The scope and limitations of the synthetic utility of these amino- (or homoamino)-functionalized 3-vinyl-1H-indoles are reported and some MO calculations for the qualitative prediction of their reactivities are presented. The reactions gave rise to substitution products, redox products, Diels-Alder adducts, ene adducts, and Michael-type adducts (Schemes 2 and 3).  相似文献   

13.
Exact solution of Schr?dinger equation for the pseudoharmonic potential is obtained for an arbitrary angular momentum. The energy eigenvalues and corresponding eigenfunctions are calculated by Nikiforov–Uvarov method. Wavefunctions are expressed in terms of Jacobi polynomials. The energy eigenvalues are calculated numerically for some values of ℓ and n with n ≤ 5 for some diatomic molecules.   相似文献   

14.
The reaction of ethyl‐3‐mercaptoquinoxaline‐2‐carboxylate with phenacyl bromide, ethyl chloroacetate, chloroacetonitrile or chloroacetone furnished the corresponding 3‐hydroxy thieno[2,3‐b]quinoxaline. 2‐Cyano‐3‐hydroxythieno[2,3‐b]quinoxaline and 2‐acetyl‐3‐hydroxythieno[2,3‐b]quinoxa line were employed as precursors in the synthesis of some novel furo[2′,3′:4,5]thieno[2,3‐b]quinoxaline, pyrano[2′,3′:4,5]thieno[2,3‐b]quinoxaline and other heterocyclic systems fused with thieno[2,3‐b]quinoxalines. The antibacterial and antifungal activities of some the synthesised compounds were studied.  相似文献   

15.
The rate constants for the esterification of some 3-, 4-, and 5-substituted thiophene-2-carboxylic acids with diazodiphenylmethane in methanol at 25° have been measured. The reactivity of some para- and ortho-substituted benzoic acids has also been determined. Logarithmic kinetic constants for ortho-, meta-, and para-like substituted thiophene-2-carboxylic acids furnish an excellent linear free energy relationship when plotted versus Δpka (β 0.89, r 0.989, C.L. > 99.9%, n 18, i 0.04), thus confirming the peculiar behaviour of five-membered ring derivatives. The correlation with σH values offers an additional proof of the hyper-ortho character of the 2,3-relation in thiophene derivatives. para- and ortho-Substituted benzoic acids show the usual behaviour of six-membered ring derivatives.  相似文献   

16.
The solid‐solid reactions of some electron‐donors with sulfanilic acid in the presence of solid sodium nitrite afford azo dyes by self‐catalyzed diazotization of sulfanilic acid (2) under solvent‐free conditions with moderate yields. Also the reactions of some electron‐donors with diazotization of o‐nitroaniline (5), m‐nitroaniline (6) and p‐nitroaniline (7) in the presence of solid sodium nitrite catalyzed by p‐toluenesulfonic acid (PTSA) afford azo dyes under solvent‐free conditions in good yields. This new method totally avoids the use of acids, alkalies, and toxic and/or expensive solvents in diazotization and diazo coupling reactions.  相似文献   

17.
The fundamental chemistry of pyridazines, the syntheses of substituted irnidazo[1,2-b]pyridazines (1) (and some related compounds) and the interaction of the products with central benzodiazepine receptors (CBR) and peripheral-type (mitochondrial) benzodiazepine receptors (PBR) are described. Some of these imidazo[1,2-b]pyridazines had high selective affinity for the central benzodiazepine receptors and others had high selectivity for the peripheral-type (mitochondrial) benzodiazepine receptors. The results of structure-activity studies and molecular modeling will be reported. In vivo tests of some compounds which interacted strongly with the central benzodiazepine receptors revealed reasonably potent anticonvulsant/anticonflict activity, and some of those which bind selectively to the peripheral-type (mitochondrial) benzodiazepine receptors are being examined as possible radiopharmaceuticals for imaging of tumors (and other disease states).  相似文献   

18.
The dissociation equilibrium constants of some is-α-phenyl-β-arylacrylic acids (Ar = 2-pyridyl, 3-pyridyl, 4-pyridyl, 1-naphthyl, 2-naphthyl, anthracen-9-yl) have been measured in 80% aqueous 2-methoxyethanol at 25°. The pKa values of these acids, together with those of p-substituted phenyl, 2-furyl, 2-thienyl and selenophen-2-yl derivatives, have been rationalized by an equation involving separate contributions of polar, conjugative and steric effects of heterocycles. The pKa values of some E-α-phenyl-β-alkylacrylic acids (alk = methyl; ethyl; n-propyl; i-propyl; n-butyl; i-butyl) are also reported.  相似文献   

19.
The photolysis of benzene or alcoholic solutions of N-acetyl-and N,N-diacetylbenzimidazolones gave mixtures of ortho- and para-rearrangements products accompanied to some extent with de-N-acylation. The different products have been identified by means of nmr, mass spectrometry and unambiguous synthesis.  相似文献   

20.
《合成通讯》2012,42(2):185-196
Abstract

A series of some pyrrolone derivatives were synthesized from the acid hydrazide, derived from a pyrazolyl-2(3H)-furanone, through treating with some carbonyl reagents such as 1-phenyl-3-(thiophen-2-yl)-1H-pyrazole-4-carbaldehyde, formic acid, lauroyl chloride, succinoyl chloride, propionic anhydride, as well as, ethoxymethylene malononitrile. All compounds were obtained in good yields and characterized by their microanalytical and spectral data. The synthesized products were evaluated for their in vitro antitumor activity against two human carcinoma cell lines (HCT-116 and MCF7) using doxorubicin as a reference drug by MTT assay. The results revealed that some compounds exhibited significant potency. Noteworthy, the N-propionyl hydrazide derivative was the most potent against both cell lines.  相似文献   

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