Methyl Acetylenedicarboxylate Research Articles

Study of the Hydroamination Reaction of Methyl Acetylenedicarboxylate with Aromatic Amines and its Heterocyclization Products

AbstractHere we describe the reaction of dimethyl acetylenedicarboxylate with aniline, N‐ethylaniline or diphenylamine. The diasteromeric enamines obtained in each case are inequivocally characterized by 1H‐ and 13C‐NMR spectra and computational methods. The heterocyclization reaction of each isolated diasteromeric enamines, leads to different products depending on the reaction conditions and the stereoelectronic characteristics of the substrate. Thus, we were able to obtain 1‐phenyl‐2‐methoxycarbonyl‐4‐quinolinone, and to find a new route for obtaining 1‐phenyl‐3‐oxo‐1,3‐dihydro‐2‐indoliliden‐acetic acid derivatives.

Bis(pyridylimino)isoindolato (BPI) Osmium Complexes: Structural Chemistry and Reactivity

A series of osmium complexes with monoanionic, meridionally coordinating 1,3-bis(2-pyridylimino)isoindolates (BPI) as spectator ligands has been synthesized. Reaction of the dichlorido metal precursor [OsCl2(PPh3)3] with the lithiated BPI ligand transfer reagent gave the chlorido complex [(tBu-BPIMe)Os(PPh3)2Cl] (2) which, in turn, was reacted with lithium triethylborohydride to yield the hydrido complex [(tBu-BPIMe)Os(PPh3)2H] (3). Treatment of complex 2 with thallium hexafluorophosphate under a nitrogen pressure afforded the cationic dinitrogen complex [(tBu-BPIMe)Os(PPh3)2(N2)]PF6 (4), which contains an end-on coordinated dinitrogen molecule trans to the isoindolato nitrogen atom. To synthesize the alkynyl complex [(tBu-BPIMe)Os(PPh3)2(C≡CPh)] (5), the chlorido complex 2 was treated with lithium phenylacetylide. Complex 5 was subsequently converted quantitatively by addition of one or two equivalents of HBF4 to the vinylidene complex [(tBu-BPIMe)Os(PPh3)2(═C═CHPh)]BF4 (6), and the cationic species [(H-tBu-BPIMe)Os(PPh3)2(═C═CHPh)](BF4)2 (7), respectively; the latter being formed via protonation of one imine nitrogen atom of the BPI ligand. Upon stirring, a toluene solution of the chlorido complex 2 with benzyl potassium, the four-membered metallacycle [(tBu-BPIMe)Os(PPh3)(o-C6H4PPh2)] (8) was obtained, which reacted with molecular hydrogen and phenyl acetylene to give the hydrido complex 3 and the acetylide complex 5, respectively. Stirring of 8 with methyl acetylenedicarboxylate (DMAD) yielded [(tBu-BPIMe)Os(DMAD)(o-C6H4PPh2)] (9), while treatment with carbon monoxide gave the acyl complex [(tBu-BPIMe)Os(o–C(O)-C6H4PPh2)(CO)] (10) by an insertion of CO into the osmium carbon bond.

ChemInform Abstract: Synthesis of Pyrrolidine and Tetrahydroazonine Derivatives from N‐[Bis(ethoxycarbonyl)methyl]tetrahydropyridinium Bromide and Methyl Acetylenedicarboxylate.

AbstractThe base‐mediated reaction of acetylenedicarboxylate (II) with tetrahydropyridinium salt (I) affords predominantly pyrrolidine (III) or azonine (IV) depending on the reaction temperature.

Synthesis of pyrrolidine and tetrahydroazonine derivatives from N-[bis(ethoxycarbonyl)methyl]tetrahydropyridinium bromide and methyl acetylenedicarboxylate

The reaction of N-methyl-N-(diethoxycarbonyl)methyltetrahydropyridinium bromide with dimethyl acetylenedicarboxylate in the presence of triethylamine at room temperature afforded 1,2-dimethyl 1-ethyl 2-[(3-vinyl-1-methyl-3-phenyl-2-ethoxycarbonyl)pyrrolidin-2-yl]-ethene-1,1,2-tricarboxylate in 25% yield. Its structure was proved by XRD analysis. At cooling to −20°C the pyrrolidine yield signifi cantly decreased and 3,4-dimethyl 2,2-diethyl 1-methyl-7-phenyl-1,5,8,9-tetrahydro-2H-azonine-2,2,3,4-tetratcarboxylate was obtained in 31% yield.

Synthesis of the First Example of a Tetrahydroindeno[2,1‐c]azonine System by the Reaction of 2,3‐Dihydro‐1H‐indeno[2,1‐c]pyridinium Methylide with Methyl Acetylenedicarboxylate.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Synthesis of the first example of a tetrahydroindeno[2,1-c]azonine system by the reaction of 2,3-dihydro-1H-indeno[2,1-c]pyridyinium methylide with methyl acetylene dicarboxylate

N-Ethoxycarbonylmethylides of 1,2,3,6-tetrahydropyridines undergo a variety of reactions, the direction of which depends on the nature of the substituents on the heterocycle. Six-membered heterocycles may decyclize into pentadienamines [1], recyclize with constriction of the ring to derivatives of pyrrolidine [2], or recyclization with expansion of a seven-membered azacycle [3]. When the anhydrobase is generated in the presence of methyl acetylenedicarboxylate (MADC) the latter readily reacts with the carbanion center to give addition products [4] or products of cyclization of the indolizine type [5-7]. However when a solution of an equimolar mixture of MADC, 2-methoxycarbonylmethyl-2-methyl9-phenyl-2,3-dihydro-1H-indeno[2,1-c]pyridinium bromide (1) and triethylamine in methylene chloride was kept at ~20°C for 3 h the indenoazonine 2 was unexpectedly formed and was isolated in 47% yield by column chromatography.

Diels-Alder Reactions of Pyrimidine o-Quinodimethanes: Stereochemistry and Applications to the Synthesis of Tetrahydro- and Quinazoline Derivatives

The Diels-Alder reactions of the ortho-quinodimethane (o-QDM) thermally generated from 2,4- diphenylciclobutapyrimidine with the dienophiles diethyl maleate, diethyl fumarate and dimethyl acetylenedicarboxylate have been investigated. The reaction afforded 5,6,7,8-tetrahydroquinazoline and quinazoline derivatives. While diethyl maleate formed a mixture of cis- and trans-adducts, diethyl fumarate gave only the trans-adduct. The reaction with methyl acetylenedicarboxylate formed a mixture of 5,8- dihydroquinazoline and quinazoline derivatives. Keywords: Pyrimidine ortho-quinodimethanes, diels-alder reaction, tetrahydroquinazolines, quinazolines

Chemical reactions of 4,5,6,7-tetrahydro-4,5,7-trimethylpyrrolo[3,2-c]pyridine and its 2-formyl derivative

N-Alkyl substituted tetrahydropyrrolo[3,2-c]pyridines have been obtained by alkylation of 4,5,6,7-tetrahydro-4,-5, 7-trimethylpyrrolo[3,2-c]pyridine and its 2-formyl derivative chloroalkyldimethylamines, acrylonitrile, methyl acetylenedicarboxylate and dichloroethane. 2-Formyl substituted tetrahydropyrrolo[3,2-c]pyridine has been reduced with sodium borohydride and condensed with monoethanolamine and hydroxylamine. The stereochemistry of the products has been studied by 1H NMR spectroscopy.

Synthesis of Salviolone, a Cytotoxic Benzotropolonoid Bisnorditerpene from Salvia miltiorrhiza

Abstract The structure of salviolone was unequivocally confirmed by synthesis in six steps starting from 3,3-dimethyl-2-vinylcyclohexene and methyl acetylenedicarboxylate.

Étude cinétique de l'ouverture thermique de la liaison C—C d'aziridines et d'époxydes dipôles-1,3 potentiels: I. Méthode d'étude expérimentale

The thermolysis of the 2-cyanoaziridines (1), 2-alkoxycarbonylaziridines (2), 2-arylaziridines (3), and 2,2-dicyano-3-aryloxiranes (4) leads to a rupture of the carbon –carbon bond yielding an azomethine ylide and the ylide of a carbonyl. The reaction of these ylides of azomethine with methyl acetylene dicarboxylate (MADC) leads to the formation of a 3-pyroline, which is transformed, according to the substituants, to a 2-pyrroline or to pyrrole. The addition of the ylides of carbonyl leads to the formation of dihydrofurans. Through the kinetic treatment of the addition of these heterocyclic compounds (1 to 4) to MADC, it is possible to determine the rate constants for the opening of the C—C bond (k1). In the case of the aziridines 1, the rates have been determined by ir while hplc has been used in the other cases. Relative to the heterocyclic compounds, the order of the experimental rate constants (kex) is always equal to one. In the cases of theN-cyclohexyl-2-cyano-3-alkylaziridines and of the N-cyclohexyl-2-carbomethoxy-3-phenylaziridine, kex varies with the concentration of MADC and this implies that the rate constants for the cycloaddition of the ylide of azomethine and its reclosing to give aziridine are similar. In the other cases, kex is independent of the concentration of MADC and this implies that the heterocyclic compounds are slowly transformed into 1,3-dipoles, followed by a rapid cycloaddition, [Formula: see text]. [Journal translation]

Comportement non aromatique d'azoles-I : Etude de la reaction des pyrazoles n-substitues avec les esters acetyleniques

The only known example of the Diels-Alder reaction involving a pyrazole ring was described by Abjean in 1974. The reaction of methyl acetylenedicarboxylate with the 1-phenylpyrazole -BF 3 complexes gives, according to Abjean, 15 the N-anilinopyridinium fluoroborate. X-ray crystal structure determination of both compounds shows that the first is a pyrazolium fluoroborate and not a complex and the second is the Michael addition product of pyrazole with the acetylenic ester.

The π‐Anisotropy of the Double Bond of a syn‐11‐Oxasesquinorbornene Derivative.. Stereoselectivity of the Diels–Alder additions of (2‐norborneno)[c]furan. Crystal structure of 11‐oxa‐endo‐tetracyclo[6.2.1.13,6.02,7]‐dodec‐2(7)‐ene‐9,10‐exo‐dicarboxylic anhydride

AbstractThe reaction of (2‐norborneno)[c]furan (4) with maleic anhydride gave 11‐oxa‐endo‐tetracyclo[6.2.1.13,6.02,7]dodec‐2(7)‐ene‐9,10‐exo‐dicarboxylic anhydride (5) and, with methyl acetylenedicarboxylate, methyl 11‐oxa‐endo‐tetracyclo [6.2.1.13,6.02,7]dodeca‐2(7),9‐diene‐9,10‐dicarboxylate (7). The syn‐11‐oxa‐sesquinorbornenes 5 and 7 could be equilibrated with their cycloaddents. They are at least 2 kcal/mol more stable than the corresponding anti‐sesquinorbornenes 6 and 8. The structure of 7 was deduced from its spectral data, by epoxidation with air or a peracid to give the exo‐epoxide 13 and by catalytic hydrogenation to give 14. The structure of 5 was established by single‐crystal X‐ray diffraction. A dihedral angle of 163° was measured between the C(1,2,7,8) and C(2,3,6,7) planes in 5. This important deviation from planarity for the C(2,7) double bond is attributed to (π, ω)‐repulsive interactions that make the π‐electron density of 2‐norbornene and 7‐oxa‐2‐norbornene derivatives preferentially polarized toward the exo‐face. This finding is discussed in relation with the relative stability of the syn‐ and anti‐ 11‐oxasesquinorbornenes and with the endo‐stereoselectivity of the cycloadditions of the norbornenofuran 4.

Hypotheses sur la formation par pyrolyse du premier intermediaire a silicium digonal

The synthesis of 2,8-dimethyl 3,9-dichloro 6-sila[5.5] spiro undecatetra 2.4,8,10-ene is described. The thermal decomposition of the adduct formed by the reaction of this product with methyl acetylene dicarboxylate is studied. From the characterization of the copyrolysis products, two possible mechanisms are proposed which imply the formation of digonal silicon such as 2-silaallene and 2-silaketene.

Benzofurazan N-oxides as synthetic precursors. Part 2. Conversion of benzofurazan N-oxides into 2H-benzimidazoles and some unusual reactions of 2H-benzimidazoles

Benzofurazan N-oxides react with primary nitroalkanes to give 1-hydroxybenzimidazole 3-oxides; with secondary nitroalkanes, red 2,2-dialkyl-2H-benzimidazole 1,3-dioxides are formed. The 2H-benzimidazole oxides react as bis-1,3-dipolar nitrones with acetylenic dipolarophiles (methyl acetylenedicarboxylate and benzyne) but undergo a complex series of redox reactions with tetracyanoethylene giving purple quinonoid dicyanomethylene derivatives, also formed by the action of the malononitrile anion. O-Alkylation of the 2H-benzimidazole oxides occurs with methyl fluorosulphate, and irradiation results in rearrangement to O-2-nitrophenylhydroxylamine derivatives.

Selectivities in 1,2,3-triazolide displacements of halides and additions to alkynes

4,5-Dicarbomethoxy-1,2,3-triazolide or 4-phenyl-1,2,3-triazolide displace chloride from ethyl chloroacetate or β-chloropropionate to give both 1-N and 2-N alkylated products. Our highest 2-N to 1-N selectivity was ca 5/1 and was found with the base triethylamine in DMF. The same triazolides and others add to alkynes, e.g. ethyl propiolate, methyl acetylenedicarboxylate, phenylpropiolaldehyde, ethyl phenylpropiolate, etc, to give Michael adducts at the 2-N position exclusively. Here the usual preference holds, i.e., the anti adduct is favored, but anti to syn isomerization usually sets in. On the basis of the available data for nucleophilic substitutions and additions, a limited directioselectivity pattern emerges for H-1,2,3-triazoles ( T) and their anions ( T −): neutral T almost invariably leads with 1-N; T t-- usually adds to unsaturates at 2-N; unsubstituted, 4-substituted and 4,5-disubstituted T − attack organic halides at both 1-N and 2-N. Compared to phenyl, 2-triazolyl exerts a greater deshielding effect on proton chemical shifts; these and other patterns in the PMR spectra of the Michael adducts are discussed. CNDO calculations indicate that the 1-H is more stable than the 2-H-1,2,3-triazole and that in both neutral triazole and in triazolide, the 1-nitrogen position should lead nucleophilic attacks-this directioselectivity prediction is only partly (and probably fortuitously) correct.

Epoxydes α,α-disubstitues par des groupements electroattracteurs—VI : Cycloadditions dipolaires-1,3 des ylures de carbonyle avec l'acetylene dicarboxylate, le fumarate et le maleate de methyle. Etude de la stereochimie des produits obtenus

gem-Dicyano epoxides were prepared by the reaction of sodium hypochlorite on the corresponding dicyano-olefins. Thermolysis of these epoxides yields carbonyl-ylids which give 1,3-dipolar cycloaddition with methyl-acetylene dicarboxylate, methyl fumarate, or methyl maleate. Each dipolarophile, maleate or fumarate, reacts in a supra-facial manner with the carbonyl ylid, and gives rise to two tetrahydrofurans the stereochemistry of which is established by NMR. Secondary orbital interactions of reactants explain the stereochemistry of the preponderant tetrahydrofuran.

Benzothiazinones by addition of o‐Mercaptobenzamides to acetylene esters

AbstractThe condensation of o‐mercaptobenzamides with methyl acetylenedicarboxylate or methyl propiolate occurs with trans addition of the SH to the alkyne linkage. The resulting vinyl sulfide adducts can be ring closed to 1,3‐benzothiazin‐4‐ones in excellent yield.

Addition reactions of heterocyclic compounds. Part XXVI. Dimethyl acetylenedicarboxylate with imidazoles and benzimidazoles

Methyl acetylenedicarboxylate with 2- and 4-methylimidazole gave 2- and 4-methyl-1-(1,2-dimethoxycarbonyl-vinyl)imidazoles. The major products from 1,2-dimethyl- and 1-ethyl-2-methyl-benzimidazoles were azepino-[1,2-a]benzimidazoles, but 2-ethyl-1-methyl- and 1-methyl-benzimidazole gave pyrido[1,2-a]benzimidazoles. Benzimidazole gave, according to the conditions, two 2,3-dihydro-1,3-di-(1,2-dimethoxycarbonylvinyl)-2-methoxybenzimidazoles, a pyrido[1,2-a]benzimidazole, or dimethyl αβ-dibenzimidazol-1-ylsuccinate.

Unusual adducts of methyl acetylenedicarboxylate and olefins

Unusual adducts of methyl acetylenedicarboxylate and olefins

The reaction between pyridazine and maleic anhydride

Addition of pyridazine to two moles of maleic anhydride yields a product (III) analogous to the adducts of methyl acetylenedicarboxylate with pyridine and its derivatives.