52900-70-6Relevant academic research and scientific papers
Ortho-palladation of (Z)-2-Aryl-4-Arylidene-5(4H)-oxazolones. structure and functionalization
Roiban, Gheorghe-Doru,Serrano, Elena,Soler, Tatiana,Contel, Maria,Grosu, Ion,Cativiela, Carlos,Urriolabeitia, Esteban P.
experimental part, p. 1428 - 1435 (2010/05/01)
Ortho-palladated complexes of (Z)-2-aryl-4-arylidene-5(4H)-oxazolones have been prepared through oxidative addition. The reaction of (Z)-2-phenyl-4-(2- bromobenzylidene)-5(4H)-oxazolone (4) with Pd2(dba)3 · CHCl3 gives the six-membered cyclopalladated dinuclear complex [Pd(μ-Br)(o-C6H4CH=CNC(O)OCPh)]2 (7). The reaction of 7 with PPh3 gives dinuclear 9, which incorporates one phosphine per Pd atom through cleavage of the Pd-N bond, and preserves the bromide bridging system. However, reaction with PPh2Me gives mononuclear 8, which incorporates two phosphines as a results of the cleavage of the μ-Br system and N displacement. In contrast, the reaction of 7 with pyridine gives complex 12 due to simple cleavage of the Br bridge, leaving the N-bonding intact. Therefore, three different reaction pathways have been characterized. The reactivity of the Pd-C bond in 7 has also been examined, and functionalized oxazolones can be obtained. The reaction of 7 with PhI(OAc)2 in acetic acid gives the starting oxazolone C 6H4-2-Br-CH=CNC(O)OCPh (4), through the presumed oxidation of the Pd center and C-Br bond formation by reductive coupling. In contrast, the reaction of the acetate dlmer 14 with PhI(OAc)2 in acetic acid gives C 6H4-2-OAcCH=CNC(O)OCPh (20) through C-O coupling. When treatment of 7 with PhI(OAc)2 is performed in MeOH or EtOH, the oxazolones C6H4-2-OR-CH=CNC(O)OCPh (R = Me (18), Et (19)) are obtained. The reaction of 7 with CO in alcohols ROH gives cleanly the oxazolones C6H4-2-CO2RCH=CNC(O)OCPh (R = Me (21), iPr (22)) through CO migratory insertion into the Pd-C bond and further nucleophilic attack of the RO-fragment.
Montmorillonite K-10 mediated Erlenmeyer synthesis of 4-arylmethylene-2- phenyl-5(4H)-oxazolones
Karade,Shirodkar,Dhoot,Waghmare
, p. 46 - 47 (2007/10/03)
Aromatic aldehydes and hippuric acid in acetic anhydride undergoes classical Erlenmeyer synthesis in the presence of a catalytic amount of Montmorillonite K-10 to afford the corresponding azlactones in excellent yields with high selectivity. The azlactone
Efficient and chemoselective conversion of aryl aldehydes to their azalactones catalysed by Bi(III) salts under solvent free conditions
Khodaei, Mohammad Mehdi,Khosropour, Ahmad Reza,Jomor, Saied Jabar Hoseini
, p. 638 - 641 (2007/10/03)
Bi(NO3)3.5H2O, Bi(TFA)3 and Bi(OTf)3 were found to be highly powerful and practical catalysts for the synthesis of azalactones under solvent free conditions with excellent yields. In addition, high ch
