Cyclization of ortho-(alk-2-enyl)anilines under the action of iodine

The reaction of ortho-(cyclohex-2-enyl)aniline with I₂ in nonpolar and polar solvents affords predominantly 1-iodohexahydrocarbazole and azatricyclotridecatriene, respectively. Under analogous conditions, 4-methyl-2-(1-methylbut-2-en-1-yl)aniline undergoes cyclization to form exclusively products with quinoline structures regardless of the solvent used.     

Synthesis of 1-iodo-1,2,3,4,4a,9a-hexahydrocarbazoles and their isomerization into 3-iodo-2,4-propano-1,2,3,4-tetrahydroquinolines

The reactions of 2-(cyclohex-2-enyl)-4,5-difluoroaniline or N-methyl-2-(cyclohex-2-enyl)aniline with I₂ in CCl₄ in the presence of NaHCO₃ give 1-iodo-1,2,3,4,4a,9a-hexahydrocarbazoles, which isomerize in MeCN into the corresponding 3-iodo-2,4-propano-1,2,3,4-tetrahydroquinolines in quantitative yields.     

Synthesis of 3-substituted cyclopenta[b]indoles

When reacting with I₂, 2-(cyclopent-2-enyl)anilines undergo cyclization into 3-iodo-1,2,3,3a,4,8b-hexahydrocyclopenta[b]indoles in high yields. The minor reaction products were 3,5- or 3,7-diiodoindolines. Ammonolysis of 3-iodo-5-methyl-1,2,3,3a,4,8b-hexahydro-cyclopenta[b]indole or itsN-chloroacetyl derivative results in 3-amino-5-methyl-1,2,3,3a,48b-hexahydro- and 5-methyl-1,3a,4,8b-tetrahydrocyclopenta[b]indoles. Published inIzvestiya Akademii Nauk. Seriya Khimischeskaya, No. 10, pp. 1789–1793, October, 2000.     

Reactions of N- and C-Alkenylanilines: III. Synthesis and Cyclization of Substituted 2-(1-Methyl-2-butenyl)anilines

Reactions of substituted 2-(1-methyl-2-butenyl)anilines with iodine result in cyclization and formation of 3-iodo-1,2,3,4-tetrahydroquinolines; N-methylsulfonyl-2-(1-methyl-2-butenyl)anilines give rise exclusively to the corresponding 2-(1-iodoethyl)-3-methyl-2,3-dihydroindoles.     

Preparation of 4,4a,9,9a-tetrahydrocarbazoles and 1,3a,4,8b-tetra-hydrocyclopenta[b]indoles

Halocyclization of mesylates or tosylates of 2-(cycloalk-2-en-1-yl)anilines gives N-methanesulfonyl-or N-toluenesulfonyl-1-halo-1,2,3,4,4a,9a-hexahydrocarbazoles, heating of which in DMF at 160°C or in piperidine at 110°C leads to 4,4a,9,9a-tetrahydro-3H-carbazoles. Heating N-methanesulfonyl-1-iodo-1,2,3,3a,4,8b-hexahydrocyclopenta[b]indole in DMF at 180—200°C gives 1,3a,4,9b-tetrahydrocyclopenta[b]indole, while in the presence of an ortho-methyl substituent the dehydroiodination reaction proceeds in piperidine at 110°C in high yield. The effect of the nature of the ortho substituent of N-methyl-1-iodo-1,2,3,3a,4,8b-hexahydrocyclopenta[b]indole on the conformational equilibrium of the cyclopentane ring has been established by ¹H NMR spectroscopy. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1184–1190, August, 2006.     

Reaction of 1,6-dioxaspiro[2.5]octane with nucleophiles

The reaction of 1,6-dioxaspiro[2,5]octane with methanol, phenols, thiols, thiocyanic and 2,4-dichlorophenoxyacetic acids, sodium sulfite, and thiourea occurs with fission of the oxirane ring in accordance with the Krasuskii rule.Bashkir State University, Ufa 450074. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1061–1064, August, 1997.     

Synthesis of Alkenyl Derivatives of Difluoro-, Trifluoro,and Nitroanilines

N-Alkenyl derivatives of di- and trifluoroanilines were prepared by their reaction with 2-chloro-3-pentene. Their transformations under conditions of the Claisen rearrangement were studied. C-Alkenylnitroanilines were prepared by reaction of piperylene with o- and p-nitroanilines in the presence of AlCl₃.     

Reactions of N- and C-Alkenylanilines: V. Synthesis of Iodo-Substituted Heterocycles from o-Cycloalkenylanilines and Their Transformations

Iodination of N-isopropyl- and N-benzyl-2-(2-cyclohexenyl)anilines gave the corresponding 1-iodo-hexahydrocarbazoles which underwent quantitative isomerization into 3-iodo-2,4-propano-1,2,3,4-tetrahydro-quinolines. Nucleophilic substitution in 1-iodohexahydrocarbazoles and 3-iodo-2,4-propano-1,2,3,3a,4,8b-hexahydrocyclopenta[b]indole was studied. N-Allylation of the latter via reaction with allyl bromide is accompanied by replacement of the iodine atom by bromine.     

Reactions of N- and C-Alkenylanilines: II. Halocyclization of 2-(2-Cycloalkenyl)anilines

The reaction of 2-(2-cyclopentenyl)anilines with I₂ in the presence of NaHCO₃ results in formation of 3-iodocyclopenta[b]indoles in high yields. Under similar conditions 2-(2-cyclohexenyl)anilines give rise to cyclization products whose structure depends on the solvent and substituents in the aromatic ring and on the nitrogen atom.