Addition Of Dimethyl Acetylenedicarboxylate Research Articles

SYNTHESIS AND MOLECULAR STRUCTURE OF 2,3,4,5-TETRAHYDRO-1 H -3-BENZAZEPINE DERIVATIVES AND DIMETHYL 4-CYANO-2,3,6,7-TETRAHYDRO-1 H -3-BENZAZONINE-5,6-DICARBOXYLATE

A study was carried out on the direction of 1,2,3,4-tetrahydroisoquinolinium quaternary salt rearrangements by the action of base with or without dimethyl acetylenedicarboxylate. These quaternary salts containing a methylene group at the nitrogen atom, are converted in the presence of base through intermediate N -ylides into the Stevens rearrangement products, namely, tetrahydro-3-benzazepines. Upon the addition of dimethyl acetylenedicarboxylate as an electrophilic trap, this diester adds at the carbanion site of the ylide with subsequent recyclization of the piperidine fragment to give a 2-benzazonine derivative with an unusual 4,5-positioning of the olefin bond in the nine-membered heterocycle. An X-ray structural analysis established the molecular structures of 2-cyano-3-methyl-2,3,4,5-tetrahydro-1 H -3-benzazepine and dimethyl 4-cyano-2,3,6,7-tetrahydro-1 H -3-benzazonine-5,6-dicarboxylate. Authors: A. T. Soldatenkov, S. A. Soldatova, J. A. Mamyrbekova-Bekro, G. S. Gimranova, A. V. Malkova, K. B. Polyanskii, N. M. Kolyadina, and V. N. Khrustalev English Translation in Chemistry of Heterocyclic Compounds, 2012, 48 (9), pp 1332-1339 http://link.springer.com/article/10.1007/s10593-012-1141-9

Synthesis and molecular structure of 2,3,4,5-tetrahydro-1H-3-benzazepine derivatives and dimethyl 4-cyano-2,3,6,7-tetrahydro-1H-3-benzazonine-5,6-dicarboxylate

A study was carried out on the direction of 1,2,3,4-tetrahydroisoquinolinium quaternary salt rearrangements by the action of base with or without dimethyl acetylenedicarboxylate. These quaternary salts containing a methylene group at the nitrogen atom, are converted in the presence of base through intermediate N-ylides into the Stevens rearrangement products, namely, tetrahydro-3-benzazepines. Upon the addition of dimethyl acetylenedicarboxylate as an electrophilic trap, this diester adds at the carbanion site of the ylide with subsequent recyclization of the piperidine fragment to give a 2-benzazonine derivative with an unusual 4,5-positioning of the olefin bond in the nine-membered heterocycle. An X-ray structural analysis established the molecular structures of 2-cyano-3-methyl-2,3,4,5-tetrahydro-1H-3-benzazepine and dimethyl 4-cyano-2,3,6,7-tetrahydro-1H-3-benzazo-nine-5,6-dicarboxylate.

Synthesis of Thiadiazine and Triazino[3,4-b]thiadiazine Derivatives

The addition of dimethyl acetylenedicarboxylate (DMAD) to dithizon afforded dimethyl-trans-5,6-dihydro-4-phenyl-2-phenylhydrazino-1,3,4-thiadiazin-5,6-dicarboxylate (2) and dimethyl-2-methoxycarbonylmethylene-4,8-diphenyl-1,2,4-triazino[3,4-b]-1,3,4-thiadiazin-3-one-6,7-dicarboxylate (3).

Synthesis of some trisubstituted thiazolidin-4-ones

The addition of dimethyl acetylenedicarboxylate (DMAD) to thiocarbohydrazide and aldehyde dithiocarbohydrazones afforded new substituted thiazolidines.

Zirconocene‐Mediated Intermolecular Coupling of Si‐tethered Diynes with Alkynes, Ketones, Aldehydes, and Isocyanates by means of Novel Skeletal Rearrangement of Zirconacyclobutene–Silacyclobutene and Zirconacyclohexadiene–Silacyclobutene Fused‐Ring Intermediates

Bis(alkynyl)silanes react with low valent zirconocene species to afford zirconacyclobutene intermediates. These in situ generated reactive organometallic intermediates can react with alkynes, ketones, aldehydes, and isocyanates by means of a novel skeletal rearrangement. When a zirconacyclobutene intermediate was treated with an alkyne, an alpha-alkynylsilyl zirconacyclopentadiene was formed. Addition of dimethyl acetylenedicarboxylate (DMAD) and CuCl resulted in one-pot formation of an alkynylsilyl-benzene derivative from three different alkynes. At a higher temperature, the alpha-alkynylsilylzirconacyclopentadiene was transformed by means of an intramolecular skeletal rearrangement to a zirconacyclohexadiene-silacyclobutene fused-ring compound, which reacted with DMAD in the presence of CuCl affording the same alkynylsilyl-benzene derivative. When treated with a ketone, an aldehdye, or an isocyanate, the zirconocyclobutene intermediate also underwent the above-mentioned skeletal rearrangement, generating zirconocene-mediated cross-coupling products.

Heteroatom influence on the pi-facial selectivity of Diels-Alder cycloadditions to 1-oxa-4-thia-6-vinylspiro[4.5]dec-6-ene, 3-methoxy-3-methyl-2-vinylcyclohexene, and 3-methoxy-2-vinylcyclohexene.

The facial selectivities of the Diels-Alder cycloadditions of several dienophiles to the title substrates were studied. The observed selectivities are interpreted as a consequence of the relative steric interactions offered by the substituents. The addition of dimethylacetylene dicarboxylate (DMAD) is influenced by the electrostatic repulsion arising from the interaction of an electron pair orbital on the acetal oxygen and the orthogonal pi-orbital of the acetylene unit in DMAD in the syn-to-oxygen addition of the latter. This repulsion is offset on coordination of Li+ to the said oxygen electron pair orbital, and the addition thus proceeds syn to oxygen. The enhanced and accelerated syn-to-oxygen addition in lithium perchlorate in nitromethane is interpreted as a consequence of the coordination of Li+ to both the acetal oxygen and a heteroatom in the dienophile that brings them in close proximity to facilitate a reaction. The Li+-oxygen combination, however, also exerts some steric effect that results in reduced syn-to-oxygen addition of dienophiles having large substituents such as N-phenylmaleimide.

A SIMPLE AND EFFICIENT METHOD FOR THE UNUSUAL REGIOSELECTIVE SYNTHESIS OF THIAZOLOPYRIMIDINES

The addition of dimethyl acetylenedicarboxylate (DMAD)to 2-thio-uracils 1 afforded in good yield cycloadducts which were characterized to be new thiazolo [2,3-b] pyrimidines.

Reaction of Dimethyl Acetylene-Dicarobxylate With Triazinone

The addition of dimethyl acetylenedicarboxylate (DMAD) to 6-menthy-1, 2,4-triazlne-3(2H)thione-5(4H)-one afforded 2-methoxylcarboxy-7-methyl-1,3-thiazino[3,2-b][1,2,4]triazine-4,8-dione.

Bis‐ through Tetrakis‐Adducts of C60 by Reversible Tether‐Directed Remote Functionalization and systematic investigation of the changes in fullerene properties as a function of degree, pattern, and nature of functionalization

AbstractBy the tether‐directed remote functionalization method, a series of bis‐ to hexakis‐adducts of C60, i.e., 1–7 (Fig. 1), had previously been prepared with high regioselectivity. An efficient method for the removal of the tether‐reactive‐group conjugate was now developed and its utility demonstrated in the regioselective synthesis of bis‐ to tetrakis(methano)fullerenes ( = di‐ to tetracyclopropafullerenes‐C60‐Ih) 9–11 starting from 4, 5, and 7, respectively (Schemes 2, 4, and 5). This versatile protocol consists of a 1O2 ene reaction with the two cyclohexene rings in the starting materials, reduction of the formed mixture of isomeric allylic hydroperoxides to the corresponding alcohols, acid‐promoted elimination of H2O to cyclohexa‐1,3‐dienes, Diels‐Alder addition of dimethyl acetylenedicarboxylate, retro‐Diels‐Alder addition, and, ultimately, transesterification. In the series 9–11, all methano moieties are attached along an equatorial belt of the fullerene. Starting from C2v‐symmetrical tetrakis‐adduct 15, transesterification with dodecan‐1‐ol or octan‐1‐ol yielded the octaesters 16 and 17, respectively, as noncrystalline fullerene derivatives (Scheme 3). The X‐ray crystal structure of a CHCl3 solvate of 11 (Fig. 3) showed that the residual conjugated π‐chromophore of the C‐sphere is reduced to two tetrabenzopyracylene substructures connected by four biphenyl‐type bonds (Fig. 5). In the eight six‐membered rings surrounding the two pyracylene (= cyclopent[fg]acenaphthylene) moieties, 6–6 and 6–5 bond‐length alteration (0.05 Å) was reduced by ca. 0.01 Å as compared to the free C60 skeleton (0.06 Å) (Fig. 4). The crystal packing (Fig. 6) revealed short contacts between Cl‐atoms of the solvent molecule and sp2‐ and sp3‐C‐atoms of the C‐sphere, as well as short contacts between Cl‐atoms and O‐atoms of the EtOOC groups attached to the methano moieties of 11. The physical properties and chemical reactivity of compounds 1‐11 were comprehensively investigated as a function of degree and pattern of addition and the nature of the addends. Methods applied to this study were UV/VIS (Figs. 7–11), IR, and NMR spectroscopy (Table 2), cyclic (CV) and steady‐state (SSV) voltammetry (Table 1), calculations of the energies of the lowest uunoccupied mmolecular orbitals (LUMOs) and electron affinities (Figs. 12 and 13), and evaluation of chemical reactivity in competition experiments. It was found that the properties of the fullerene derivatives were not only affected by the degree and pattern of addition but also, in a remarkable way, by the nature of the addends (methano vs. but‐2‐ene‐1, 4‐diyl) anellated to the C‐sphere. Attachment of multiple thano moieties along an equatorial belt as in the series 8–11 induces only a small perturbation of the original fullerene π‐chromophore. In general, with increasing attenuation of the conjugated fullerene π‐chromophore, the optical (HOMO‐LUMO) gap in the UV/VIS spectrum is shifted to higher energy, the number of reversible one‐electron reductions decreases, and the first reduction potential becomes increasingly negative, the computed LUMO energy increases and the electron affinity decreases, and the reactivity of the fullerene towards nucleophiles and carbenes and as dienophile in cycloadditions decreases.

Synthesis of 4-phosphazenyl-2,3-dihydropyrrol-2-ones and 5-phosphazenyl-2-pyridones from β-[(N-acyl)phosphazenyl]enamines and dimethyl acetylenedicarboxylate

4-Phosphazenyl-2,3-dihydropyrrol-2-ones and 5-phosphazenyl-2-pyridones are obtained by addition of dimethyl acetylenedicarboxylate to [(N-acyl)phosphazenyl]enamines. In refluxing dichloromethane the reaction affords exclusively 2,3-dihydropyrrol-2-ones, while in toluene at 110 °C a mixture of 2-pyridones and 2,3-dihydropyrrol-2-ones is formed. They are easily separated by fractional recrystallization. The structures of all new compounds have been unequivocally assigned based on two-dimensional 1H,13C correlation and steady-state nuclear Overhauser enhancement experiments. For 2-pyridones the absolute sign of 4JPH has been determined.

Preparation and structure of cycloalkane‐condensed [1,3]thiazino[3,2‐a] pyrimidinones

AbstractIsocyanate salts prepared from cis‐2‐amino‐1‐cyclopentane‐ and ‐hexane‐carboxylate and the corresponding trans‐cyclohexane and ‐cyclohexene derivates with KSCN were cyclized to cycloalkane/ene‐condensed 2‐thioxo‐4‐pyrimidinones, which were transformed to tricyclic 1,3‐thiazino[3,2‐a]pyrimidinones by addition of dimethyl acetylenedicarboxylate. The stereo structures of the new compounds were established by IR and 1H and 13C NMR spectroscopy, making use of the signal multiplicities in the proton‐coupled carbon spectra.

Synthesis and structure determination of products from addition of dimethyl acetylenedicarboxylate to 2,3-dihydro-2-thioxoquinazolin-4(1H)-one. X-Ray molecular structure of the dimethyl esters of 1,2-dihydro-5-oxo-5H-thiazolo[3,2-a]quinazoline-1,2-dicarboxylic, 2,3-dihydro-5-oxo-5H-thiazolo[2,3-b]quinazoline-2,3-dicarboxylic, and 5-oxo-5H-thiazolo[2,3-b]quinazoline-2,3-dicarboxylic acids

The addition of dimethyl acetylenedicarboxylate to 2,3-dihydro-2-thioxoquinazolin-4(1H)-one afforded four main cycloadducts, the structures of which were unequivocally solved by 13C n.m.r. spectroscopy and confirmed by X-ray crystallographic analysis. The products were identified as dimethyl 1,2-dihydro-5-oxo-5H-thiazolo[3,2-a]quinazoline-1,2-dicarboxylate, dimethyl 2,3-dihydro-5-oxo-5H-thiazolo[2,3-b]quinazoline-2,3-dicarboxylate, dimethyl 5-oxo-5H-thiazolo[2,3-b]quinazoline-2,3-dicarboxylate, and tetramethyl 2,2′-(1″,2″,3″,4″-tetrahydro-4-oxo-2-thioxoquinazoline-1″,3″-diyl)difumarate.

Synthesis and characterisation of some new 2,6-disubstituted thiazolo-[3,2-b][1,2,4]triazine-3,7-diones

The addition of dimethyl acetylenedicarboxylate to 3-thioxo-1,2,4-triazin-5-ones afforded in good yield cycloadducts which were characterised by i.r., mass, and 1H and 13C n.m.r. spectroscopy. On the basis of their 13C chemical shifts and C,H coupling constant measurements the products were identified as 6-substituted (Z)-2-(methoxycarbonylmethylene)thiazolo[3,2-b][1,2,4]triazine-3,7-diones.

Diels-Alder additions of dimethyl acetylenedicarboxylate to sterically hindered cyclohexa-2,4-dienones. Formation and X-ray structure analysis of stereoisomeric bicyclo[2.2.2]octadienones

The Diels-Alder addition of dimethyl acetylenedicarboxylate to sterically hindered 2,4-cyclohexadienones (spiro-quinol ethers) gives rise to stereoisomeric bicyclo[2.2.2]octadienones. The structures of three of these have been elucidated by single-crystal X-ray diffraction methods and their 1H n.m.r. and electronic absorption spectral properties are reported.

Reactions of 5,6,7,8-tetrahalogeno-1,4-dihydronaphthalen-1,4-imines with dimethyl acetylenedicarboxylate

Isomeric 1 : 1 adducts obtained from tetrachlorobenzyne and N-t-butylpyrrole are a naphthalen-1,4-imine and a benzo[3,4]cyclobuta[1,2-b]pyrrole derivative. The former (5) decomposes thermally by a retro-Diels–Alder reaction to give an isoindole (17), which forms another naphthalen-1,4-imine (6) by addition of dimethyl acetylenedicarboxylate. 5,6,7,8-Tetrafluoro-1,4-dihydro-1,4-methyliminonaphthalene (1) reacts with the acetylene ester to give two simple naphthalene derivatives, a benz[g]indole (18) and a benzo[de]quinoline (26). Adducts are obtained from 5,6,7,8-tetrachloro-1,4-dihydro-1,4-methyliminonaphthalene (2) with benzyne, dibenzoylacetylene, and dimethyl acetylenedicarboxylate. Unusually large long-range H–F and C–F nuclear spin interactions are observed for two fluorinated benz[g]indole derivatives (18) and (22).

ChemInform Abstract: SYNTHESIS AND ANTILEUKEMIC ACTIVITY OF 5‐SUBSTITUTED 2,3‐DIHYDRO‐6,7‐BIS(HYDROXYMETHYL)‐1H‐PYRROLIZINE DIESTERS

AbstractAus Prolin entstehen mit entsprechenden Säurechloriden die Substitutionsprodukte (I), die mit Acetanhydrid zu den Zwischenstufen (II) reagieren.

Cycloaddition reactions. Thermal addition of dimethyl acetylenedicarboxylate to 1-methoxyindene

The cycloaddition of 1-methoxyindene 2 to dimethyl acetylenedicarboxylate to form a fused cyclobutene system 3 is discussed. Photochemical ring enlargement of 3 leads to a benzocycloheptatriene system 5 while reduction yields a dihydro derivative 4. Saponification of 3 followed by photochemical ring expansion yields the diacid 7 which is subsequently hydrolyzed and decarboxylated to ketoacid 8.

Cycloaddition reactions. Addition of dimethyl acetylenedicarboxylate to 1-dimethylaminoindene

The cycloaddition of 1-dimethylaminoindene (2) to dimethyl acetylenedicarboxylate to form a fused cyclobutene system 3 is discussed. Compound 3 underwent two modes of ring opening to yield either the indene–maleate system 4 or the benzocycloheptatriene system 5 depending on reaction conditions. The synthesis of a number of multifunctional benzotropones from 5 is discussed.