- Aminodienylesters. I: The cycloaddition reactions of tert- aminodienylester with α,β-unsaturated carbonyl compounds, styrenes, and quinones
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Methyl 5-(N,N-dimethylamino)-2,4-pentadienoate (tert-aminodienylester 1) was synthesized by condensation of methyl crotonate (2) with N,N,N',N'- tetramethylenediamine (3). The reactivity of 1 was investigated with methyl propiolate (4), dimethyl 2-butynedionate (5), dimethyl maleate (6), dimethyl fumarate (7), 2-buten-4-olide (8), 2-cyclohexenone (9), styrene (10), trans- β-nitrostyrene (11), 1,4-benzoquinone (19), methyl 1,4-naphthoquinone-5- carboxylate (21), 1,4-naphthoquinone (24), juglone (26), 5-methoxy-1,4- naphthoquinone (28), naphthazarin (31), and naphthazarin dimethyl ether (33). In addition, 5-(N,N-dimethylamino)-2,4-pentadienenitrile (tert-aminodienyl- nitrile 37) was synthesized by condensation of crotononitrile (36) with 3. The reactivity of 37 was investigated with dimethyl 2-butynedionate (5), and 2-cyclohexenone (9).
- Koike, Takeshi,Tanabe, Mituharu,Takeuchi, Naoki,Tobinaga, Seisho
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p. 243 - 248
(2007/10/03)
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- INTERACTION OF 5-AZIDO-1,2,3-BENZENETRICARBOXYLIC ACID WITH THE MITOCHONDRIAL TRICARBOXYLATE CARRIER
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5-azido-1,2,3-benzenetricarboxylic acid (5-N3-BTA), a new derivative of 1,2,3-benzenetricarboxylic acid (BTA) has been synthesised in satisfactory overall yields (25percent).This azido compound inhibits the transport of citrate either in mitochondria or in reconstituted partially purified tricarboxylate carrier, both in the dark and upon irradiation.However, the inhibition is nearly completely supressed after washing the mitochondria, indicating that upon irradiation 5-N3-BTA does not form a covalent bond with the citrate-binding site of the tricarboxylate transport system.
- Capassso, Renato,Randazzo, Giacomino,Stipani, Italo,Zara, Vincenzo,Palmieri, Ferdinando
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p. 449 - 452
(2007/10/02)
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- Syntheses of Highly Substituted Benzenes via Diels-Alder Reactions with 2H-Pyran-2-ones
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The 2H-pyran-2-ones (α-pyrones) 1 react as dienes in Diels-Alder reactions with acetylene derivatives.The primarely formed cycloadducts immediately aromatize to benzenes by CO2 elimination.Thus, methyl acetylenedicarboxylate (2a) gives dimethyl phthalates 3, and methyl acetylenediphosphonate (2b) gives dimethyl 1,2-phenylenediphosphonates 8.The reactions of 1-(dimethylamino)-1-methoxyethene (9) with 1 regioselectively produce N,N-dimethylanilines 10 and isomeric homophthalate derivatives 12.Naphthoquinones 14 could be generated from 1,4-benzoquinone (13) and 1 in the presence of acetic anhydride and Pd/C.Hydroxy-2H-pyran-2-ones 4 react via their trimethylsilyl ether 6 analogously with 2a to give dimethyl (trimethylsiloxy)phthalates 7 which are easily converted to phenols 5 by acid-catalyzed hydrolysis.
- Ziegler, Thomas,Layh, Marcus,Effenberger, Franz
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p. 1347 - 1356
(2007/10/02)
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- COBALT CARBONYL-CATALYZED POLYCARBONYLATION OF ARYL HALIDES IN NaOMe/MeOH UNDER PHOTOSTIMULATION
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Cobalt carbonyl-catalyzed polycarbonylation of polychlorobenzenes could be easily achieved in NaOMe/MeOH under photostimulation, Moreover, under the present conditions, the carbonylation at ortho position (to another halogen atom or carboxyl group) proceeds in high selectivity ( >84percent ).
- Kazimura, Tsugunori,Kudo, Kiyoshi,Mori, Sadayuki,Sugita, Nobuyuki
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p. 851 - 854
(2007/10/02)
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- REACTION OF 3a,4-DIHYDROPHTHALIDES WITH ACETYLENIC DIENOPHILES
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The tricycloocta-2,5-diene-4,7-carbolactones, the initially-formed Diels-Alder adducts from 3a,4-dihydrophthalides and acetylenic dienophiles, were so strained that they underwent the retro-Diels-Alder reaction to afford the benzene derivatives in good yields.
- Noguchi, Michihiko,Kakimoto, Shinji,Kajigaeshi, Shoji
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p. 665 - 668
(2007/10/02)
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- ALKOXY-5 PENTADIENOATES: ETUDE DE LEUR REACTIVITE DANS LA REACTION DE DIELS ET ALDER SOUS HAUTE PRESSION
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High pressure Diels-Alder reaction of 5-alkoxy pentadienoates 1 (ambident dienes) with some dienophiles is described.High regio and endo-stereoselectivity in such process is observed.
- Revial, Gilbert,Blanchard, Mireille,d'Angelo, Jean
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p. 899 - 902
(2007/10/02)
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- 2-Addition of Pyrroles to Dimethyl Acetylenedicarboxylate: Michael-Type Adducts and Diels-Alder Products
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Pyrroles 1 having an open 2-position react with dimethyl acetylenedicarboxylate (DMAD) in the presence of a source of active hydrogen, usually provided in the present cases by their own NH groups (if present) or by sufficient acetic acid, to give 1:1 Michael-type adducts at the 2-position (dimethyl 2-pyrrolyl-2-butenedioates), usually as both the Z (3) and E (4) isomers. Analogy with the data obtained permits assignment of stereochemistry to several other 1:1 adducts previously reported, including 3g and 4g from 2,3-dimethylpyrrole (1g) and 3h from 2,3,4-trimethylpyrrole (1h). On the basis of NMR and mass spectral data, the 2:1 adduct of 1f and DMAD (a coproduct of 3f and 4f) is reassigned the structure dimethyl 2,2-bis(3,5-dimethyl-2-pyrrolyl)butanedioate (9). Formation of 3 and 4 is usually competitive with Diels-Alder reactions in which the pyrrole acts as a diene. The Diels-Alder reaction tends to be relatively favored in the absence of weak acids such as acetic acid and at higher temperatures than in refluxing ether. The initial 1:1 Diels-Alder adducts (5) are unstable and were not isolated. They tend to react by one of four pathways: (1) they revert to 3 and 4; (2) they react further with DMAD, giving 1:2 adducts of type 6 (tetramethyl 3a,7a-dihydroindole-2,3,3a,4-tetracarboxylates); (3) at higher temperatures (63-160 deg C) they undergo retro-Diels-Alder cleavage, giving the corresponding dimethyl N-substituted pyrrole-3,4-dicarboxylates (7); (4) they eliminate the bridging nitrogen to give dimethyl 4-substituted phthalates (14) or to give (via 5 and 7 and a further Diels-Alder reaction of 7 with DMAD) tetramethyl benzene-1,2,4,5-tetracarboxylate (24) from 1p and 1q. The 1:2 adducts of type 6 undergo further Diels-Alder reaction at their diene system with DMAD to give as coproducts trimethyl 5-substituted benzene-1,2,3-tricarboxylates (16) and trimethyl 1-substituted pyrrole-2,3,4-tricarboxylates (17, similar to 7). In a few instances the 2-vinylpyrroles 3 and/or 4 were observed to act as dienes in a Diels-Alder synthesis of indoles.
- Noland, Wayland E.,Lee, Chang Kiu
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p. 4573 - 4582
(2007/10/02)
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