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Diels–alder reactions of alkyl 2H-azirine-3-carboxylates with furans
Alves, M. José; Azoia, Nuno G.; Bickley, Jamie F.; Fortes, A. Gil; Gilchrist, Thomas L.; Mendonça, RicardoMethyl 2-(2,6-dichlorophenyl)-2H-azirine-3-carboxylate 1 and furan give the aziridine 2 by a Diels–Alder cycloaddition reaction. The hydrolysis of compound 2 leads to a dihydrofuranol 11 by cleavage of a C–N bond. X-Ray crystal structures of compounds 2 and 11 have been determined. Compound 2 reacts with alcohols in a similar way to give 2-alkoxy-2,5-dihydrofurans as mixtures of cis and trans isomers. The struc...
Synthesis of 2-halo-2H-azirines from phosphorus ylides
Melo, Teresa M. V. D. Pinho e; Gonsalves, António M. D'A. Rocha; Lopes, Cláudia S. J.; Gilchrist, Thomas L.[alpha]-Oxophosphonium ylides (3a-3e) react with N-chlorosuccinimide and N-bromosuccinimide in the presence of azidotrimethylsilane giving the corresponding haloazidoalkenes (4a-4g) with elimination of triphenylphosphine oxide. These compounds were completely converted to the 2H-azirines 5a-5g on heating in heptane. ; http://www.sciencedirect.com/science/article/B6THS-3VXSK6D-3T/1/9eb19b08a4875f23803d57d6eca...
Azabicyclo[3.2.0]heptan-7-ones (carbapenams) from pyrrole
Gilchrist, Thomas L.; Lemos, A.; Ottaway, Carol J.The azabicyclo[3.2.0]heptan-7-ones 4, 10, 16 and 24 have been prepared from pyrrole. The same general approach has been used for all these derivatives; namely, substitution of pyrrole at the 2- and 5-carbon atoms, catalytic hydrogenation to produce pyrrolidine-2-acetic acid derivatives, and cyclisation using tris(1,3-dihydro-2-oxobenzoxazol-3-yl)phosphine oxide 6. The catalytic hydrogenation of 2,5-disubstitute...
Reaction of pyrroles with ethyl 2-nitroso- and 2-azo-propenoates, and with ethy...
Gilchrist, Thomas L.; Lemos, A.The reaction of ethyl 2-nitrosopropenoate 2a with 1 -methylpyrrole, 2.5-dimethylpyrrole and 2.5- diphenylpyrrole has been investigated. In every case the products result from highly regioselective attack at C-2 of the pyrrole by the electrophile. The azopropenoate esters 2b and 2c react similarly with pyrroles, to the extent that even 1 -(triisopropylsilyl)pyrrole is attacked exclusively at the 2-position by th...
Reactions of azoalkenes derived from hydrazones of ethyl bromopyruvate with ele...
Clarke, S; Gilchrist, Thomas L.; Lemos, A.; G. Roberts, TonyThree hydrazones of ethyl bromopyruvate, the dinitrophenylhydrazone 2a, the toluene-4-sulphonylhydrazone 2b and the t-butoxycarbonylhydrazone 2c, have been reacted with a series of nucleophilic alkenes and heterocycles in the presence of sodium carbonate. Azoalkenes 3 are presumed as intermediates and adducts have been isolated. The azoalkenes derived from hydrazones 2a and 2c are found to be useful electrophil...
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