Annelated Pyridines Research Articles

A New Way to 2,3,4-Trisubstituted Benzo[h]quinolines: Synthesis, Consecutive Reactions and Cellular Activities †.

The reaction of mercaptoacetic acid esters with pentachloro-2-nitro-1,3-butadiene provides the appropriate precursors for the synthesis of 2,3,4-trisubstituted benzo[h]quinolines. These heterocycles are easily accessible via a single-step reaction with naphthalen-1-amine or anthracen-1-amine as the precursor. Due to the steric bulk and high electron density ring, the ring closure of benzo[h]quinolines takes place exclusively. Such highly substituted annelated pyridine systems can be modified in subsequent, selective reactions to build up new N-heterocycles with promising microbiological properties. The antibacterial and antiproliferative assays against four mammalian cell lines demonstrate that some of the sulfur-substituted benzo[h]quinoline analogs display potent phenotypic bioactivities in the single-digit micromolar range.

Generation and trapping of non-aromatic cycloimines via diazotization/dediazotization of N-amino cyclic amines: theoretical and experimental results

A theoretical investigation of the model diazotization/dediazotization of N-aminopiperidine and N-aminomorpholine at the DFT (B3LYP/6-31+G(d)) level indicated that the corresponding cycloimines can be generated transiently, which can be trapped with dimethyl acetylenedicarboxylate (DMAD) to form a 1,4-dipole followed by cycloaddition of the latter with a second molecule of DMAD to give the corresponding pyrido-annelated products. All steps have low activation free energy barriers and are thermodynamically favoured. Based on the theoretical results, we carried out successfully diazotization of N-amino cyclic amines, namely N-aminopiperidine, 4-aminomorpholine and 1-amino-4-methylpiperazine with tert.-butyl nitrite followed by dediazotization to generate transiently the corresponding cycloimines, which could be trapped with dimethyl acetylenedicarboxylate. to afford new annelated pyridine derivatives, namely tetramethyl 9H-5,6,7,8-tetrahydroquinolizine-1,2,3,4-tetracarboxylate, tetramethyl 5,6,8,9-tetrahydropyrido[2,1-c][1,4]oxazine-1,2,3,4-tetracarboxylate and tetramethyl 9H-5,6,7,8-tetrahydro-7-methylpyrido[1,2-a]pyrazine-1,2,3,4-tetracarboxylate which were duly characterized.

Vapor Phase Synthesis of Annelated Pyridines over Metal Modified Zeolite Beta

Vapor phase synthesis of annelated pyridines from cyclic ketones, aldehydes and ammonia was carried out over various zeolite molecular sieves like Hβ, HZSM-5 (240), HZSM-5 (40), HY, HX, HMCM-41 and Mordenite. The preliminary screening of catalyst clearly shows that Hβ catalyst was found to be more active for the vapor phase synthesis of annelated pyridines. Hβ was further modified with transition metals like Fe, Cu, Pb, Mo, Zn, Ni, Co, Ce, W and Sn to get higher yields.

ChemInform Abstract: Intramolecular Diels-Alder Reactions of Pyrimidines and a Computational Study Toward Their Structure and Reactivity.

The syuntheses of 2-(prop-2-ynyloxy)carbonylpyrimidine (1), 5-(prop-2-ynyloxy)carbonylpyrimidine (2), 5-phenyl-22-(1-prop-2-ynylpyrryl)pyrimidine (8), 5-phenyl-2-2-(1-prop-2-ynylpysrrolidinyl)pyrimidine (9) and 2-2-(prop-2-ynyloxy)phenyl-4,6-R 2 -5-R 1 -pyrimidine (R 1 = H, Cl, Ph; R 2 = H, Me) (14a-d) are described.Upon heating, the compounds 1, 9, and 14 undergo an intramolecular Diels-Alder reaction and a subsequent retro Diels-Alder reaction to yield the annelated pyridines 15, 16, and 17, respectively

Liquid phase synthesis of annelated pyridines over molecular sieve catalyst

Simple and selective single step synthesis of substituted octahydrophenanthridines and annelated pyridines was achieved using simple cyclic ketones, aliphatic aldehydes and ammonia over zeolites as catalyst under high pressure (autogeneous pressure) conditions with high yields and high conversions for the first time. The catalyst was inexpensive, environmentally friendly and could be reused many times without significant loss of activity.

A facile synthesis of annelated pyridines from β-formyl enamides under microwave irradiation

The condensation of β-formyl enamides with cyanomethylenes under microwave irradiation is catalysed by basic alumina to afford fused pyridines in excellent yields.

REACTIONS WITH CYANOTHIOACETAMIDE AND ITS DERIVATIVES: SYNTHESIS AND CHARACTERIZATION OF SEVERAL NEW PYRIDINE AND ANNELATED PYRIDINE DERIVATIVES

Abstract Several new pyridines and annelated pyridines were synthesised via the reactions of some pyridinethiones with a variety of activated halogenomethyl containing reagents and hydrazines. Structures were established on the basis of elemental analysis and spectral data.

Die Synthese von Azaisomeren des Triesters von PQQ: 3H‐Pyrrolo[3,2‐f]‐, 1H‐Pyrrolo[3,2‐h]‐ und 7H‐Pyrrolo[2,3‐h]chinolinchinon‐Derivate

The Synthesis of Azaisomers of the Triester of PQQ: 3H‐Pyrrolo[3,2‐f]‐, 1H‐Pyrrolo[3,2‐h]‐, and 7H‐Pyrrolo[2,3‐h]quinolinequinone DerivativesWe describe here the synthesis of the title compounds 3–5, starting from highly substituted aminoindoles. The annelated pyridine rings were built up in each case with dimethyl 4‐oxoglutaconate according to Corey's procedure. All three o‐quinone derivatives 3–5 are stable compounds, comparable to PQQ‐triester. The azaisomers vary in biological activity from practically inactive to strong inhibition of the α‐amidating enzyme or the ornithin decarboxylase.

REACTIONS WITH CYANOTHIOACETAMIDE DERIVATIVES: SYNTHESIS AND REACTIONS OF SOME PYRAZOLO[3,4-b]PYRIDINE DERIVATIVES

Abstract The ylidene derivatives of cyanothioacetamide 1a–d reacted with ethyl acetoacetate to give the pyridinethiol derivatives 2a–d. Compounds 2a–d were used as starting material for the synthesis of several heterocyclic compounds. Reactions with hydrazine hydrate, ethyl iodide, methyl chloroacetate and α-chloro ethyl acetoacetate gave the pyridine and annelated pyridine derivatives 5a–d, 6a–d, 7a, 8b–d, and 12a–d, respectively. Compounds 7a, 8b–d and 12a–d reacted with hydrazine hydrate to yield the annelated pyridines 10a–d and 15a–d, respectively.

Selective catalytic hydrogenation of the pyridine ring in arylpyridines and condensed pyridine systems (review)

Data are summarized concerning selective hydrogenation of the pyridine ring in arylpyridines, including those containing silicon, and in annelated pyridines. An effective catalyst, rhenium heptasulfide, has been found, which makes it possible to reduce the pyridine ring without affecting the benzene rings.

Intramolecular Diels-Alder reactions of pyrimidines and a computational study toward their structure and reactivity

The syuntheses of 2-(prop-2-ynyloxy)carbonylpyrimidine (1), 5-(prop-2-ynyloxy)carbonylpyrimidine (2), 5-phenyl-22-(1-prop-2-ynylpyrryl)pyrimidine (8), 5-phenyl-2-2-(1-prop-2-ynylpysrrolidinyl)pyrimidine (9) and 2-2-(prop-2-ynyloxy)phenyl-4,6-R 2 -5-R 1 -pyrimidine (R 1 = H, Cl, Ph; R 2 = H, Me) (14a-d) are described.Upon heating, the compounds 1, 9, and 14 undergo an intramolecular Diels-Alder reaction and a subsequent retro Diels-Alder reaction to yield the annelated pyridines 15, 16, and 17, respectively

A computational study towards the reactivity of 2-(2-ethynylphenyl-X-)pyrimidines in intramolecular Diels-Alder reactions.

The reactivity of 2-(2-trimethylsilylethynylphenyl-X-)pyrimidines towards intramolecular Diels-Alder reactions to give tricyclic annelated pyridines, decreases in the order X = CO > O > CH 2 > NH. A conformational study (MM calculations) and determination of the heat of activation (MNDO calculations) of their 2-(2-ethynylphenyl-X-)pyrimidine analogs showed that the order of reactivity is reflected by the probability of the molecules to be in a conformation which is able to react.

Cycloaromatization ofα-oxoketene dithioacetals with lithioacetonitrile and lithiopropionitrile: a facile route to substituted and annelated pyridines

The enolacetals 2 obtained by 1,2-addition of lithioacetonitrile or lithioprop- ionitrile to α-Oxoketene dithioacetals 1 undergo intramolecular Ritter reaction accompanied with 1,3-MeS shift in the presence of phosphoric acid to afford a variety of substituted and annelated 2,6-bis(methylthio)pyridines 3 and 4 respectively in good yields. Cyclization of 2 in the presence of bromine and acetic acid yielded the corresponding 2-bromo-6- methylthio-4,5-substituted and annelated pyridines 9 in good yields. The bis(methylthio) groups in 3 could either be removed with Raney Nickel or replaced by methyl group in the presence of triphenylphosphine-Nickel chloride complex to afford the corresponding desulphurized (8) or methylated (15) pyridines in good yields. Attempted cyclization of enolacetals 2a, 2p and 2s in the presence of borontrifluoride etherate and methanol yielded only the dienes 14a-b and β-cyanomethyl-α,β -unsaturated ester 14c respectively.

Intramolecular cyclization reactions of pyrimidinium cations

N-alkylpyrimidinium cations carrying a dienophilic side-chain at the 2- or 5-position undergo intramolecular inverse electron demand Diels-Alder reactions into the corresponding annelated pyridine derivatives under considerably milder conditions than the corresponding neutral pyrimidines. Protonation of the pyrimidine ring also facilitates the intramolecular Diels-Alder reaction. Protonation of less activated pyrimidines leads, however, to products resulting from an intramolecular coplanar cycloamination reaction.

EPR study of arene-solvated cobalt clusters as catalysts in the co-cyclization of α,ω-diynes and nitriles

The thermal evolution of a Co-arene co-condensate, obtained by direct evaporation of both the metal and the organic substrate at −196°C, has been studied by EPR spectroscopy. On warming at −40°C, the solid matrix melts and the solution obtained has been shown to contain large and small metal clusters, a trimeric species being recognizable. At room temperature, a precipitate containing microcrystals and large clusters separates, while the presence of small and microclusters persists in solution. The reaction between 1,7-octadiyne and acetonitrile using the solution or the precipitate as precursor catalysts can provide completely different products, affording the annelated pyridine ( 1) or alkynyl pyridine derivatives ( 2). A mononuclear Co 0 species has been identified by EPR spectroscopy during the reaction affording 1, while the formation of 2, which occurs in the presence of microcrystals or large clusters, may be ascribed to a polynuclear catalyst. Transmission electron microscopy has been employed to evaluate the dimensions and distribution of the clusters.

Intramolecular Diels-Alder reactions of quaternary pyrazinium salts and protonated pyrazinium cations. Synthesis of annelated pyridinium salts and annelated pyridines.

Quaternization of alkynyl substituted pyrazines with triethyloxonium tetrafluoroborate in dichloromethane occurs exclusively at N-4 yielding 3-alkynyl-1-ethylpyrazinium salts, as shown by the 13C NMR data. Protonation of the same pyrazines with trifluoroacetic acid also occurs at N-4. The quaternary pyrazinium salts as well as the protonated pyrazines undergo an intramolecular Diels-Alder reaction under considerably milder conditions than the corresponding neutral pyrazines. The products of the reactions were [ c ]-annelated quaternary pyridinium salts and [ c ]-annelated protonated pyridinium cations, respectively.

Intramolecular Diels-Alder reactions of pyrimidines: Synthesis of tricyclic annelated pyridines.

2-(2-Trimethylsilylethynylphenyl-X)-pyrimidines ( 2, X= O, S, NAc, CH 2, CO) easily undergo intramolecular Diels-Alder reaction with inverse electron demand, to give tricyclic annelated pyridines in excellent yields. The synthesis of 2 and the cycloaddition reaction to give the tricyclic annelated pyridines is described.

Synthesis of annelated pyridines from 1,5-diketone equivalents using cupric acetate and ammonium acetate

Cupric acetate serves as a mild oxidant in the efficient synthesis of 1,2,3,4,5,6,7,8-octahydroacridines 2 and 7 from a 1,5-diketone ( 6) a ketoalcohol ( 1) or a 4H-pyran ( 5) using ammonium acetate in acetic acid.

Novel intramolecular Diels-Alder reactions of pyrimidines. Synthesis of heterocyclic annelated pyridines

Pyrimidines carrying a dienophilic side-chain at the 2 or 5 position undergo intramolecular Diels-Alder reactions to give heterocyclic annelated pyridines.

ChemInform Abstract: CARBOCYCLIC ANNELATED PYRIDINES

Chemischer InformationsdienstVolume 16, Issue 40 Reviews ChemInform Abstract: CARBOCYCLIC ANNELATED PYRIDINES R. P. THUMMEL, R. P. THUMMELSearch for more papers by this author R. P. THUMMEL, R. P. THUMMELSearch for more papers by this author First published: October 8, 1985 https://doi.org/10.1002/chin.198540361AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume16, Issue40October 8, 1985 RelatedInformation