Electrophilic Reactions of 2- and 4-Vinylpyridines

Doering, W. E.; Weil, Ruth Alice N.

doi:10.1021/ja01202a063

Cited by 72 publications

(45 citation statements)

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“…The racemic mixture of diastereomeric alcohols 36 a was resolved with d-dibenzoyltartaric acid and the required 3R,4S enantiomer was transformed into the related acetates 36 b by a BF 3 ·Et 2 O catalyzed acetylation. Finally, construction of the quinuclidine ring proceeded by conjugate addition of the piperidine nitrogen atom to vinylquinoline intermediate 44 b (see Scheme 13), [149] which was formed in situ by elimination of the acetate to yield a mixture of the previously known desoxyquinine and desoxyquinidine in a ratio of 57:43 (Scheme 12).…”

Section: Angewandte Chemiementioning

confidence: 99%

The Quest for Quinine: Those Who Won the Battles and Those Who Won the War

2005

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For a long time, the synthesis of quinine constituted an elusive target. In 2004, which marked the 60th anniversary of the publication of the approach used by Woodward and Doering to synthesize quinine, two new stereocontrolled total syntheses of the natural product were accomplished. Together with the well-publicized first stereocontrolled total synthesis of quinine by Stork in 2001, these publications evidence the revival of interest of organic chemists in the synthesis of this compound, once considered a miracle drug. The recently disclosed syntheses of quinine also testify in a remarkable manner the huge progress made by organic synthesis during the last three decades since the first series of partially controlled syntheses of quinine by the group of Uskokovic. Following an account of the historical importance of quinine as an antimalarial drug and a brief description of the experiments which contributed to its isolation and structural elucidation, the first reconstructions of quinine and the total syntheses of the natural product are discussed.

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Section: Angewandte Chemiementioning

confidence: 99%

The Quest for Quinine: Those Who Won the Battles and Those Who Won the War

2005

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“…show yields in percentages): 2-vinylfuran (20)[8] ,2-vinylbenzofuran (80 [9], 58[10]), 2-vinyldibenzofuran (70 [9], 63[8]), 4-vinyldibenzofuran ( 39.7) [ll], 2-vinylthiophene (74) [8,12], 3-vinylthiophene (55-60) [13], 2-vinyl-5-chlorothiophene (72) [14], 2-vinyl-5-bromothiophene (34) [14], 2-vinyl-2,5-dichlorothiophene (64) [14] , 2-vinyl-3,4,5-trichlorothiophene (70) [14], 2-vinylbenzothiophene (50) [15,16], 4-vinyldibenzothiophene (42) [ll] , 2-vinylselenophene (76)(77)(78)(79)(80) [17], 3-vinylpyridine [18] (37[19], 6.5 [20]), 3-vinyl-5-bromopyridine (67) [21], 3-vinylpiperazine (11.6)[18], 2-vinylphenoxanthin (79) [16], 5,6-dihydro-2,6-dimethyl-3-vinyl-2H-pyran [22] . B.…”

Section: Preparation Of Vinyl Heterocyclic Compoundsmentioning

confidence: 99%

“…1-Vinylpyrrolidone (48)(49)(50)(51)(52)(53)(54)(55)(56) [40], 9-vinylcarbazole [41], 9-vinyl-1,2,3,4-tetrahydrocarbazole [41] , 2-vinylthiophene (50) [42], 2-vinyl-5-chlorothiophene (47) [42], 2-vinyl-5-bromothiophene (21.8) [42], 3-vinylpyridine (38 [20], 18-20[18 J , 41-43 [43]), 4-vinylpyridine (85) [44], 3-vinyl-4-methylpyridinium salt (50) [45], 4-vinylquinoline [46], 2-vinylpiperazine (20) [37], 4-vinylpiperidine (35) [37], N-vinyl-1,2,4-triazole [499], 1-and 2-vinyltetrazole (20.1) [47], 2-vinylbenzimidazole [48], 5(6)-vinylbenzimidazole [49]. Downloaded by [] at 04: 14 27 December 2014 D. Pyrolysis of Acyloxyethyl Derivatives CyCH(OCOR)CH, -CyCH=CH, + RCOOH CyCH,CH,OCOR -CyCH=CH, + RCOOH In general, the reactions are performed at 400" to 600°C, in the l-Vinylsuccinimide (85-90) [50,51], 1-vinylphthalimide (85-90) [50-presence of A1,03 catalyst.…”

Section: Of Halogenoethyl Derivativesmentioning

confidence: 99%

Preparation and Polymerization of Vinyl Heterocyclic Compounds

Takemoto

1970

Journal of Macromolecular Science, Part C: Polymer Reviews

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“…22 As has been widely known, the electronegative nitrogen imposes the electron deficiency on the a-and g-positions of pyridine, and the electron deficiency can be extended to a double bond conjugated in the a-and g-positions but impossible in the b-position due to the resonance interactions of the double bonds. 13,18,23 Therefore, a plausible mechanism is proposed for the lactonization (Scheme 3, In the present work, we combined ketene dithioacetal group and tetronic acid ring in the same molecules, which makes compounds 3 having the potential to become highly valuable organic intermediates. It is reported by some researchers that the selective 1,4-reduction of a-oxo ketene-S,S-acetals has been achieved in Mg/MeOH or Zn/ HOAc systems.…”

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confidence: 95%

“…Doering et al gave an example of oxa-pyridylethylation of 2-vinylpyridine with ethanol catalyzed by sodium ethoxide. 13 The reaction was carried out under strongly basic condition and its yield was very low (20%). Their attempts, together with that from other research groups, to develop oxa-pyridylethylation under acidic conditions were unsuccessful.…”

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confidence: 99%

A Facile and Efficient Synthesis of 3,5-Disubstituted Tetronic Acids in Aqueous Media Involving Acid-Catalyzed Intramolecular Oxa-Pyridylethylation

Bi¹,

Li²,

Sun³

et al. 2004

Synlett

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A facile and efficient one-pot synthesis of 3-[bis(alkylthio/alkylamino)methylene]-5-(pyridyl/quinoylmethyl) furan-2,4(3H,5H)-diones 3 and 10, based on a sequential aldol condensation and lactonization reaction between a-oxo ketene-S,S-acetals 1 and pyridine/qinoline-carboxaldehydes 2 in aqueous media, has been developed. A mechanism involving an acid-catalyzed intramolecular oxa-pyridylethylation reaction is proposed for the formation of the lactone ring.Tetronic acid derivatives (TADs), e.g. vitamin C and penicillic acid, have attracted much attention for their presence in many natural products along with a large array of useful biological and pharmacological activities. 1,2 To date, extensive work has been reported on the synthetic methodology for this kind of compounds and their practical applications. Generally, TADs can be principally synthesized either by the modification of the pre-constructed core scaffold of a TAD 3 or through the construction of 3-oxo-g-lactone ring from appropriately substituted open chain precursors. 4 Nevertheless, to match the increasingly scientific and practical demands for TADs, it is still of continued interest and great importance to explore novel and efficient synthetic approaches for such compounds. On the other hand, a-oxo ketene-S,S-acetals are emerging as a kind of versatile intermediate 5 in the construction of heterocyclic 6 and carbocyclic 7 compounds over the last several decades. Pak and co-workers reported the aldol condensation of a-oxo ketene-S,S-acetals 1 with aryl aldehydes which was followed by ester hydrolysis and decarboxylation to give alkenoyl ketene dithoacetals 4. 8 In our previous work, 9,10 we found that halodecarboxylation could further take place after the aldol condensation of aoxo ketene-S,S-acetals 1 with some aryl aldehydes. As a part of further investigation of this kind of a-oxo ketene-S,S-acetals, we here wish to report a novel synthetic method for 3,5-disubstituted TADs 3 involving tandem aldol condensation and acid-catalyzed lactonization reaction of a-oxo ketene-S,S-acetals 1 with the selected heteroaryl aldehydes, as well as the further transformation to TADs 10 by the displacement reaction with various amines. Scheme 1 Reagents and conditions: (i) NaOH, EtOH-H 2 O (2:1, v/v), r.t., 0.5-1.0 h; (ii) HCl aq (1 N), r.t., 0.5-2.0 h.The initial study was performed on the aldol condensation between a-oxo ketene-S,S-acetal 1a (n = 1) and 4-pyridinecarboxaldehyde 2a in the presence of NaOH according to the procedure described in literature (Scheme 1). 8 The only product was obtained from the resulting reaction mixture in excellent yield and identified as 3-(1,3-dithiolan-2-ylidene)-5-(pyridin-4-ylmethyl)furan-2, 4(3H,5H)-dione (3a) on the basis of its elemental analysis, 1 H NMR and 13 C NMR spectra and single crystal X-ray analysis. The product is thus a tetronic acid derivative instead of an alkenoyl ketene dithioacetal 4.In an attempt to extend the scope of this novel reaction, aoxo ketene-S,S-acetal 1b and some other aryl aldehydes were selec...

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Electrophilic Reactions of 2- and 4-Vinylpyridines

Cited by 72 publications

References 0 publications

The Quest for Quinine: Those Who Won the Battles and Those Who Won the War

The Quest for Quinine: Those Who Won the Battles and Those Who Won the War

Preparation and Polymerization of Vinyl Heterocyclic Compounds

A Facile and Efficient Synthesis of 3,5-Disubstituted Tetronic Acids in Aqueous Media Involving Acid-Catalyzed Intramolecular Oxa-Pyridylethylation

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