Diene Condensation of Cyclopentadiene with Dienophiles of Allylacetylene Series

Veliev, M. G.; Chalabieva, A. Z.; Shatirova, M. I.; Akperova, E. G.

doi:10.1023/b:rujo.0000003159.15212.50

Cited by 6 publications

(4 citation statements)

References 2 publications

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“…These results are in accordance with the experimental observation that cyclopentadiene 1 (CPD) is more reactive than cyclohexadiene 9 in Diels-Alder reactions with strained cyclic dienophiles and 2-substituted allylacetylenes, 35 as well as with results of previously reported calculations for reactions of 1 and 9 with ethylene. 36,37 Earlier, Henry et al 38 ascribed this result to difference in distances in 1,4-diene reactive sites. In other words, in reactions with 9 the degree of orbital overlap between reacting sites in the transition structure is smaller than in case of 1 and consequently the contribution of the donor-acceptor interaction to the reaction barrier is smaller.…”

Section: Resultsmentioning

confidence: 99%

Computational study on reactivity of cyclic organometallic dienes containing silicon, germanium and tin

Margetić

Eckert‐Maksić

2006

New J. Chem.

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Section: Resultsmentioning

confidence: 99%

Computational study on reactivity of cyclic organometallic dienes containing silicon, germanium and tin

Margetić

Eckert‐Maksić

2006

New J. Chem.

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“…Of particular interest are acetylenic esters of norbornenecarboxylic acid. On the one hand, they have valuable properties themselves; on the other hand, they are promising as synthetic precursors of diverse valuable compounds owing to the combination of reactive norbornene and acetylenic fragments [4].The synthesis of propargyl norbornenecarboxylate by esterification of norbornenecarboxylic acid with propargyl alcohol in the presence of Brønsted acid catalysts was described in [5]. However, the yield (30%) and purity (88%) of the target product were poor.…”

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confidence: 99%

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Synthesis and corrosion-protective properties of acetylenic esters of bicyclo[2.2.1]hept-5-ene-2-carboxylic acid

Mamedov

2004

Russ J Appl Chem

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A procedure was developed for preparing acetylenic esters of bicyclo[2.2.1]hept-5-ene-2-carboxylic acid. The structures of the compounds were confirmed by IR and 1 H NMR spectroscopy. The Kovats indices of the compounds were determined, and their boiling points were estimated by gas3liquid chromatography. The protective properties of the esters against acid corrosion of steel were studied.Norbornene derivatives exhibit various useful properties. Thanks to their rigid framework structure, these compounds with fixed substituents are promising models for studying structure3property relationships [1]. Some norbornene derivatives exhibit analgetic, antiseptic, and antiphlogistic properties [2,3]. Of particular interest are acetylenic esters of norbornenecarboxylic acid. On the one hand, they have valuable properties themselves; on the other hand, they are promising as synthetic precursors of diverse valuable compounds owing to the combination of reactive norbornene and acetylenic fragments [4].The synthesis of propargyl norbornenecarboxylate by esterification of norbornenecarboxylic acid with propargyl alcohol in the presence of Brønsted acid catalysts was described in [5]. However, the yield (30%) and purity (88%) of the target product were poor.Proceeding with studies concerned with synthesis of acetylenic esters of norbornenecarboxylic acids [6 38], we developed a convenient synthetic route to these compounds and examined their protective properties against acid corrosion of metals. The compounds were prepared by reactions of bicyclo[2.2.1]hept-5-ene-2-carboxylic acid chloride I with acetylenic alcohols II!IV: II!IV I V !VIIwhere R 1 = R 2 = H (II, V); R 1 = Me, R 2 = H (III, VI); R 1 = Me, R 2 = CH=CH 2 (IV, VII).The reaction with primary alcohol II occurs at room temperature with heat liberation and is complete in 0.5 h. With tertiary alcohols III and IV, the reaction is less facile, and the corresponding esters VI and VII were obtained by heating at 80oC for 5 h. The yield of the target products was 90 396%.The structure of esters V3VII was confirmed by independent synthesis. First, we prepared acetylenic acrylates IX!XI by a reaction of acryloyl chloride with acetylenic alcohols II3IV. This was followed by the Diels3Alder addition of cyclopentadiene VII to acrylates IX!XI to obtain compounds V3VII:; CO 2 ÄCÄCÄCÄR 2 6 V!VII , Ä Ä g g g g R 1 R 1 + K S Q ? IX!XI VIII (2)where R 1 = R 2 = H (IX); R 1 = Me, R 2 = H (X); R 1 = Me, R 2 = CH=CH 2 (XI).The constants of compounds IV3VII prepared by both procedures are identical; they are listed in Table 1. The compositions and structures of the compounds were also confirmed by elemental analysis and by IR (Table 1) and 1 H NMR spectroscopy. The IR spectra of V3VII contain the stretching vibration bands (cm !1 ) of C=O (1730 31740), C3O (122531240) and C=C (2160 32165) groups. The band at 3290 cm !1 in the spectrum of V is characteristic of the =C3H bond. The stereoisomers of V and VII have similar IR spectra, with the absorption bands of the double bond in the norbornen...

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“…Raising the temperature to 1458 transformed the intermediate into the blue-fluorescent (l ¼ 366 nm) 8-pentadienyl-purine 17 that was isolated in a yield of 86%. It was debenzylated in 95% yield by treatment with in situ generated Me 3 SiBr, leading to the poorly soluble 8-(penta-1,3-dienyl)guanine (18) Deep green crystals of 10 were obtained in hexane/CHCl 3 at 48. Even at this low temperature, 10 was partially transformed into a yellow precipitate of 12, indicating the ease of the hetero-Diels -Alder cycloaddition.…”

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Diels–Alder Additions, Ene Reactions, and Condensations of 4‐(Acylamino)‐5‐nitrosopyrimidines – Synthesis of 8‐Substituted Guanines and of 6‐Substituted Pteridinones

Steinlin

Vasella

2008

Helvetica Chimica Acta

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Abstract4‐(Acylamino)‐5‐nitrosopyrimidines react either by a reductive condensation to provide 8‐substituted guanines, or by a Diels–Alder cycloaddition, or an ene reaction, to provide 6‐substituted pteridinones, depending on the nature of the acyl group and the reaction conditions. Experimental details are provided for the transformation of (acylamino)‐nitrosopyrimidines to 8‐substituted guanines, and the scope of the reaction is further demonstrated by transforming the trifluoro acetamide 25 to the 8‐(trifluoromethyl)guanine (27), and the N,N′‐bis(nitrosopyrimidinyl)‐dicarboxamide 29 to the (R,R)‐1,2‐di(guan‐8‐yl)ethane‐1,2‐diol (32). An intramolecular Diels–Alder reaction of the N‐sorbyl (=N‐hexa‐2,4‐dienoyl) nitrosopyrimidine 10, followed by a spontaneous elimination to cleave the N,O bond of the initial cycloaddition product provided the pteridinones 14 or 15, characterized by a (Z)‐ or (E)‐3‐hydroxyprop‐1‐enyl group at C(6). Treatment of 10 with Ph3P led to the C(8)‐penta‐1,3‐dienyl‐guanine 18. The ene reaction of the N‐crotonyl (=N‐but‐2‐enoyl) nitrosopyrimidine 19 provided the 6‐vinyl‐pteridinone 20a that dimerized readily to 21a, while treatment of 19 with Ph3P led in high yield to 8‐(prop‐1‐enyl)guanine (23). The structure of the dimer 21 was established by X‐ray analysis of its bis(N,N‐dimethylformamidine) derivative 21b. The crystal structure of the nitroso amide 10 is characterized by two molecules in the centrosymmetric unit cell. Intermolecular H‐bonds connect the amino group to the amide carbonyl and to N(1). The crystalline bis(purine) 30 forms a left‐handed helix with four molecules per turn and a pitch of 30.2 Å.

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Diene Condensation of Cyclopentadiene with Dienophiles of Allylacetylene Series

Cited by 6 publications

References 2 publications

Computational study on reactivity of cyclic organometallic dienes containing silicon, germanium and tin

Computational study on reactivity of cyclic organometallic dienes containing silicon, germanium and tin

Synthesis and corrosion-protective properties of acetylenic esters of bicyclo[2.2.1]hept-5-ene-2-carboxylic acid

Diels–Alder Additions, Ene Reactions, and Condensations of 4‐(Acylamino)‐5‐nitrosopyrimidines – Synthesis of 8‐Substituted Guanines and of 6‐Substituted Pteridinones

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