- Indium-mediated one-pot synthesis of benzoxazoles or oxazoles from 2-nitrophenols or 1-aryl-2-nitroethanones
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One-pot reduction-triggered heterocyclizations from 2-nitrophenols to benzoxazoles and from 1-aryl-2-nitroethanones to oxazoles were investigated. In the presence of indium/AcOH in benzene at reflux, 2-nitrophenols and R-C(OMe)3 (R=H, Me, Ph) produced excellent yields of corresponding benzoxazoles within an hour. Similarly, 1-aryl-2-nitroethanones and Ph-C(OMe)3 in the presence of indium/AcOH in acetonitrile transformed into the corresponding oxazoles with good yields.
- Lee, Jung June,Kim, Jihye,Jun, Young Moo,Lee, Byung Min,Kim, Byeong Hyo
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scheme or table
p. 8821 - 8831
(2009/12/26)
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- Diarylimidoylcyanides, an attractive class of intermediate: Novel synthesis of α-anilino-β-nitroenamines, N, N′- Disubstituted amidines and substituted phenyl glyoxate
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The first report of the use of diarylimidoyl cyanides for the synthesis of α-anilino-β-nitrostyrenes, benzamides, and glyoxalic esters is presented, and the advantage of this class of intermediate over diarylimidoyl chlorides is discussed. Copyright Taylor & Francis Group, LLC.
- Roychowdhury, Abhijit,Kumar, Versha V.,Bhaduri
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p. 715 - 727
(2007/10/03)
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- 115. 1,3-Dipole mit Zentralem S-Atom aus der Umsetzung von Aziden mit Thiocarbonyl-Verbindungen: Eine unerwartete MeS-Wanderung im Abfangprodukt eines 'Thiocarbonyl-aminids' mit Dithiobenzoesaeure-methylester
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Reaction of PhN3 with O-methyl thiobenzoate (11a) and thioacetate (11c) as well as with the dithio esters 11b, d at 80 deg C yields the corresponding imidates and thioimidates 12 (Scheme 3).The formation of 12 is rationalized by a 1,3-dipolar cycloaddition of the azide and the C=S group followed by successive elimination of N2 and S.In the three-component reaction of 11b, PhN3, and the sterically crowded thioketone 1a, 1,2,4-trithiolane 13a and 1,4,2-dithiazolidine 3a are formed in addition to 12b (Scheme 4).The heterocycles 13 and 3a are trapping products of 1a and 'thiocarbonyl-aminide' 5a and 'thiocarbonyl-amidine' 2a (Ar= Ph), respectively (Scheme 6).These 1,3-dipoles are formed as reactive intermediates.Surprisingly, in the presence of catalytic amounts of acids, the major product is the (methyldithio)cyclobutyl thioimidate of type 14 (Scheme 5), formed by an acid-catalyzed MeS migration in dithiazolidine 17.A reaction mechanism is proposed in Scheme 7.
- Mloston, Grzegorz,Romanski, Jaroslaw,Linden, Anthony,Heimgartner, Heinz
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p. 1499 - 1510
(2007/10/02)
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- Metathesis and diaziridination reactions of (CO)5W = C(OMe)-p-XC6H4 with cis-azobenzene. Electronic and solvent effects
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The reaction of cis-azobenzene with a series of para substituted phenyl carbenes (CO)5W=C(OMe)p-XC6H4 (X = H, OMe, CF3) was carried out in both noncoordinating and coordinating solvents. The stability and reactivity of the initially formed zwitterionic species (CO)5WNPhNPhC(OMe)(p-XC6H4) depended on the substituent X. In noncoordinating solvents, the unsubstituted zwittenonic species (CO)5WNPhNPhC(OMe)C6H5 was converted into an isomeric zwitterionic intermediate and a 2,4-diazametallacycle. Both isomeric zwitterions and the 2,4-diazametallacycle ultimately decomposed to yield the metathesis product PhN=C(OMe)Ph. The mechanism of 2,4-diazametallacycle formation was shown to involve the intermediacy of a coordinated diazindine in which the metal subsequently inserts into the N-N bond. When the unsubstituted zwittenon was decomposed in CH3CN, the coordinated diaziridine was displaced by solvent, inhibiting formation of the 2,4-diazametallacycle.
- Maxey, Claudia Tata,Sleiman, Hanadi F.,Massey, Scott T.,White, Lisa McElwee
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p. 5153 - 5160
(2007/10/02)
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- Mechanisms of Nucleophilic Attack at Carbon-Nitrogen Double Bonds. The Reaction of Aryl N-Arylbenzimidates with Methoxide Ion
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Rate data for the reaction of three series of aryl N-arylbenzimidates with methoxide ion at 303 K are presented.Linear Hammett plots were obtained for each series.Solvent isotope effects have also been measured.The results are interpreted in terms of rate-determining formation of a tetrahedral intermediate, irrespective of the nature of the substituent.
- Rowe, Jeffrey E.
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p. 1259 - 1262
(2007/10/02)
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- Cycloaddition of Diphenylcyclopropenone with Carboximidate, Carboximidamide, and Carboximidothioate
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The reaction of diphenylcyclopropenone with R1N=C(R2)X (2) (R1, R2=alkyl, aryl, X=MeO, EtO, MeS, or Me2N) gave 2-pyrrolin-4-one (3) in good yield.The less reactive carboximidothioate (2, R1=4-MeC6H4, R2=Ph, X=MeS) yielded isomeric 3-pyrrolin-2-one together with 3.
- Yoshida, Hiroshi,Sogame, Shingo,Bando, Shoichi,Nakajima, Shosuke,Ogata, Tsuyoshi,Matsumoto, Kiyoshi
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p. 3849 - 3850
(2007/10/02)
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- OXIDATIVE BENZOIN REACTIONS
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A one-pot synthesis (yields over 50percent) of methyl and ethyl esters from aldehydes (and the corresponding alcohol), using aromatic nitrocompounds as oxidizing agents under the catalytic action of cyanide ion or of a conjugate base of a thiazolium ion, is described.A variety of by-products (α-hydroxybenzylidenaniline (16), α-methoxybenzylidenaniline (21), α-cyanobenzylidenaniline (27), N1-hydroxy-N1,N2-diphenylbenzamidine (28), and others) have been identified.
- Castells, J.,Pujol, F.,Llitjos, H.,Moreno-Manas, M.
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p. 337 - 346
(2007/10/02)
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