Unprecedented Temperature-dependent Formation of 3- and 7-Methyl-3<i>H</i>-azepine Derivatives by the Reaction of <i>o</i>-Nitrotoluene with Tributylphosphine in Nucleophilic Media

Ulfa, Siti Mariyah; Okamoto, Hideki; Satake, Kyosuke

doi:10.1246/cl.2012.400

Cited by 8 publications

(5 citation statements)

References 39 publications

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“…This product often reported as by-product by the formation of singlet nitrene in the intermediate step of reaction. It is reported that the deoxygenation of nitro-derivatives compound is temperature-dependentreaction [13]. The theoretical calculation support an experimental results, since intramolecular insertion reaction of pyridylnitrene is considered to be suppressed by the lower HOMO (-9.932 eV) energy level of pyridine ring compared to that of benzene (-9.653 eV), then ring expansion product should be difficult to be obtained.…”

Section: Reaction Of Nitropyridine Derivatives With Bu 3 Psupporting

confidence: 65%

Shortcut Approach to 1,4-Diazepine from 3-Pyridylnitrene Intermedietes under Mild Condition

Ulfa

Okamoto

Satake

2014

J. Pure App. Chem. Res.

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The reaction of nitropyridine derivatives and tributylphosphine (Bu 3 P) with the existence of nucleophilic solvent gives ring expansion product as diazepines in medium yield. Reaction mechanism subjected the formation of phenylnitrene, followed by intramolecular electrophilic insertion reaction to pyridine ring and subsequent ring enlargement. The intermediate in the reaction confirmed by computational calculation using B3LYP/6-31G* level. The intramolecular insertion reaction of pyridylnitrene is considered suppressed by the low HOMO (-9.932 eV) energy level of pyridine ring compared to that of benzene (-9.653 eV), hence 1,4-diazepine is obtained when employed 3-nitro-2,6-lutidine as starting material. The formation of diazepines was confirmed by the analysis of 1 H NMR data. Separation of the product mixture using column chromatography on SiO 2 was carried out and found to give expected diazepine along with the reduction product.

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Section: Reaction Of Nitropyridine Derivatives With Bu 3 Psupporting

confidence: 65%

Shortcut Approach to 1,4-Diazepine from 3-Pyridylnitrene Intermedietes under Mild Condition

Ulfa

Okamoto

Satake

2014

J. Pure App. Chem. Res.

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“…Senyawa turunan azepina banyak digunakan sebagai bahan dasar produk farmasetikal dan kesehatan [1]. Sintesis senyawa ini telah banyak dipelajari baik secara eksperimental [2,3,4,13] maupun teoritis menggunakan perhitungan komputasi kimia [5,6]. Mekanisme reaksi sintesis yang telah dipublikasikan adalah melalui reaksi intramolekuler fenilnitrena sebagai senyawa intermediet menjadi benzoazirina dan…”

Section: Pendahuluanunclassified

Synthesis of 2-Methoxy-3H-Azepine Derived Compounds Through the Thermal Reaction between Alkylnitrobenzene and Tributylphosphine

Ulfa

Okamoto

Satake

2015

Nat-B

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ABSTRAKReaksi fotolisis fenilazida telah banyak dilaporkan menghasilkan 3H-azepina, sedangkan metode reaksi termal dengan menggunakan turunan alkilnitrobenzena masih belum banyak diketahui. Sintesis senyawa baru turunan 2-metoksi-3H-azepina telah dilakukan dengan mereaksikan alkilnitrobenzena dan tributilphosphina (Bu3P) pada suhu 150°C selama 24 jam dalam pelarut metanol. Hasil analisis menunjukkan reaksi antara m-nitrobenzena menghasilkan dua isomer azepina yaitu 2-metoksi-6-metil-3H-azepina dan 2-metoksi-4-metil-3H-azepina sebanyak 61%. Reaksi 2,3-dimetilnitrobenzena dengan metode yang sama menghasilkan tiga isomer yaitu 2-metoksi-6,7-dimetil-3H-azepina; 2-metoksi-3,4-dimetil-3H-azepina dan 7-metoksi-5,6-dimetil-4H-azepina. Sedangkan reaksi antara 3,5-dimetilnitrobenzena hanya menghasilkan 2-metoksi-4,6-dimetil-3H-azepina sebanyak 42%. Reaksi antara 2,6-dimetilnitrobenzena tidak menunjukkan terbentuknya turunan 3H-azepina karena halangan sterik dari gugus metil pada posisi C2 dan C6. Elusidasi struktur dari semua senyawa baru turunan azepina yang disintesis telah dikonfirmasi menggunakan HETCOR.Kata kunci : azepina, siklisasi, reaksi intramolekular, fotolisis, tributilphosphina, nitrobenzena. ABSTRACTAlthough photolysis of phenyazide has been widely reported to give 3H-azepine, the thermal deoxygenation reaction of alkylnitrobenzene derived similar products hitherto unexplored. Novel synthesis of 2-methoxy-3H-azepine derivatives was carried out using alkylnitrobenzene with tributylphosphine (Bu3P) reacted at 150°C for 24 hours in the presence of methanol. Reaction of m-nitrobenzene with the above methods gave two isomers of 3H-azepine, namely, 2-methoxy-6-methyl-3H-azepine and 2-methoxy-4-methyl-3H-azepine in 61%. Reaction of 2,3-dimethylnitrobenzene with Bu3P afforded the three isomers, that is, 2-methoxy-6,7-dimethyl-3H-azepine; 2-methoxy-3,4-dimethyl-3H-azepine and 7-methoxy-5,6-dimethyl-4H-azepine. Reaction of 3,5-dimethylnitrobenzene gave the sole product of 2-methoxy-4,6-dimethyl-3H-azepine in 42%. In contrast, reaction of 2,6-dimethylnitrobenzene didn't give any product because the steric effect of methyl groups attached on C2 and C6. Structure elucidation of all novel products have confirmed by HETCOR.

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“…The ring closure of aryl nitrene can occur both clockwise and counterclockwise. [33][34][35] Therefore, as a result of the photoinitiated rearrangement of asymmetric aryl azides, both 3-and 7-substituted 1,2-didehydroazepines C and C' are formed. [36] Then, after the nucleophilic addition to the ketenimine fragment of intermediates C, 2,3-(3) and 2,7-disubstituted (3') azepines are formed (Scheme 2).…”

Section: Introductionmentioning

confidence: 99%

“…The ring closure of aryl nitrene can occur both clockwise and counterclockwise [33–35] . Therefore, as a result of the photoinitiated rearrangement of asymmetric aryl azides, both 3‐ and 7‐substituted 1,2‐didehydroazepines C and C’ are formed [36] .…”

Section: Introductionmentioning

confidence: 99%

Effects of the Solvent and the Nucleophile on the Photochemical Synthesis of Azepines

Giricheva,

Budruev

2024

ChemistrySelect

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The research focused on the photolysis of ortho‐ and para‐substituted aryl azides and the preparation of 2‐arylamino‐substituted azepines. The best results were achieved in 1,4‐dioxane for ortho‐substituted azides and in ethanol for para‐substituted azides, respectively. It was found that reactions with arylamines, which have electron‐donating groups, typically produce higher yields of heterocycles than those with electron‐withdrawing groups.

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Unprecedented Temperature-dependent Formation of 3- and 7-Methyl-3H-azepine Derivatives by the Reaction of o-Nitrotoluene with Tributylphosphine in Nucleophilic Media

Cited by 8 publications

References 39 publications

Shortcut Approach to 1,4-Diazepine from 3-Pyridylnitrene Intermedietes under Mild Condition

Shortcut Approach to 1,4-Diazepine from 3-Pyridylnitrene Intermedietes under Mild Condition

Synthesis of 2-Methoxy-3H-Azepine Derived Compounds Through the Thermal Reaction between Alkylnitrobenzene and Tributylphosphine

Effects of the Solvent and the Nucleophile on the Photochemical Synthesis of Azepines

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