- Exocyclic-endocyclic n-acyliminium ion equilibration via an intramolecular α-thioamidoalkylation in the synthesis of fused N,S-heterocyclic systems: Some new parameters
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The reactivity of N-[aryl(or alkyl)thio(oxo or seleno)alkylamidals 6 bearing the N-(CH2)n-X-(CH2)m-Ar functionality towards neat TFA has been examined. Substrates of type 6 give, together with the products 11, 17, 19, and
- Hucher, Nicolas,Pesquet, Anthony,Netchitailo, Pierre,Daich, Adam
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p. 2758 - 2770
(2007/10/03)
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- Access to the new isoindolo[1,3]benzothiazocinones via the combination of N-acyliminium chemistry and friedel-crafts type π-cyclization
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New racemic and chiral [4,2]- and [3,5]benzothiazocines (4) and (5) in the isoindolinone series were synthesized easily in few steps based on the combination of N-acyliminium chemistry and π-cationic cyclization of acylium ions. The chemoselectivity observed during these processes, particularly in the reduction, the thioalkylation and the cyclization stages, were also discussed.
- Cul, Armelle,Daich, Adam,Decroix, Bernard,Sanz, Gerard,Van Hijfte, Luc
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- π-aromatic and sulfur nucleophilic partners in cationic π-cyclizations: Intramolecular amidoalkylation and thioamidoalkylation cyclization via ω-carbinol lactams
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NaBH4 reduction of imides 1 and 6a,b,c followed by a π-cyclization of the resultant N-acyliminium ions, generated in trifluoroacetic acid conditions, afforded two positional isomers, isoindolobenzothiazolinones 4 and 8, respectively. These ring closures proceeded via an intramolecular α-amidoalkylation with the classical α-aromatic or the atypical sulfur atom as an internal nucleophile. A ready access to the related six-membered N,S-heterocyclic compounds such as isoindolobenzothiazinones 20a and 21a is also described. During this reaction, we have shown that ω-carbinol lactam precursor 14a led to endocyclic and exocyclic N-acyliminium ions 18a and 19a in equilibrium via the cyclic aza-sulfonium ion A. The latter furnished the expected products 20a and 21a in good yields. Similarly, different ω-carbinol lactams 14b-e substituted at C-angular position afforded the corresponding isoindolobenzothiazinones 20b-e and 21b-e bearing an angular alkyl, aralkyl, or aryl group. In the case of methyl 14b and benzyl 14e groups, an additional amount of the dehydration products 16b and 31 was isolated. These results indicate that the isomerization-π-cyclization takes place via the cleavage of the thioether linkage in acidic medium.
- Hucher,Decroix,Daich
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p. 4695 - 4703
(2007/10/03)
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- Formation of new 5,11b-bridged isoindolo[2,1-b]isoquinolinones alkaloids through a tandem Pummerer/ π-cationic cyclization
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(formula presented) The tandem Pummerer/π-aromatic cyclization of α-acyliminium ion, leading efficiently in "one pot" to thioepoxyareno-bridged isoindoloisoquinolinone incorporating the arylthio group, has been demonstrated for the first time. During this
- Hucher, Nicolas,Daich, Adam,Decroix, Bernard
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p. 1201 - 1204
(2007/10/03)
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- Substituted phthalimides for regulating the growth of plants
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Certain substituted phthalimides have been found to be effective in regulating the growth of corn plants.
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