72867-60-8Relevant academic research and scientific papers
New Studies on [2 + 3] Cycloadditions of Thermally Generated N-Isopropyl- and N-(4-Methoxyphenyl)-Substituted Azomethine Ylides
Urbaniak, Katarzyna,Szymanski, Radoslaw,Romanski, Jaroslaw,Mloston, Grzegorz,Domagala, Malgorzata,Linden, Anthony,Heimgartner, Heinz
, p. 496 - 510 (2007/10/03)
The thermal reaction of 1-substituted 2,3-diphenylaziridines 2 with thiobenzophenone (6a) and 9H-fluorene-9-thione (6b) led to the corresponding 1,3-thiazolidines (Scheme 2). Whereas the cis-disubstituted aziridines and 6a yielded only trans-2,4,5,5-tetraphenyl-1,3-thiazolidines of type 7, the analogous reaction with 6b gave a mixture of trans- and cis-2,4-diphenyl-1,3-thiazolidines 7 and 8. During chromatography on SiO 2, the trans-configured spiro[9H-fluorene-9,5′ -[1,3]thiazolidines] 7c and 7d isomerized to the cis-isomers. The substituent at N(1) of the aziridine influences the reaction rate significantly, i.e., the more sterically demanding the substituent the slower the reaction. The reaction of cis-2,3-diphenylaziridines 2 with dimethyl azodicarboxylate (9) and dimethyl acetylenedicarboxylate (11) gave the trans-cycloadducts 10 and 12, respectively (Schemes 3 and 4). In the latter case, a partial dehydrogenation led to the corresponding pyrroles. Two stereoisomeric cycloadducts, 15 and 16, with a trans-relationship of the Ph groups were obtained from the reaction with dimethyl fumarate (14; Scheme 5); with dimethyl maleate (17), the expected cycloadduct 18 together with the 2,3-dihydropyrrole 19 was obtained (Scheme 6). The structures of the cycloadducts 7b, 8a, 15b, and 16b were established by X-ray crystallography.
Synthetic Uses of Open-Chain Analogues of Reissert Compounds
McEwen, William E.,Grossi, Anthony V.,MacDonald, Russell J.,Stamegna, Andrew P.
, p. 1301 - 1308 (2007/10/02)
Open-chain analogues, 2, of Reissert compounds are readily obtained by reaction of cyanohydrins with primary amines, the resulting aminonitriles, 1, then being acylated.Hydrofluoroborate salts, 3, of 2 are prepared by reaction with fluoroboric acid in glacial acetic acid.The salts, 3, undergo 1,3-dipolar addition reactions with reactive alkynes to give substituted pyrroles and with ethyl acrylate to give a different type of substituted pyrrole, the initial step in this instance being a Diels-Alder reaction.The open-chain Reissert analogues 2 also undergo base-catalyzed reactions, such as alkylation to provide compounds 22, which, in turn, undergo cleavage reactions in ethanolic alkali to give ketones 23.A conjugate addition reaction of the anion 18 to methyl acrylate to give, after some subsequent steps, a substituted pyrrole, 9, has also been demonstrated. α-Anilino ketones 27 result when the anion 18 is caused to react with aldehydes, the initial reaction mixtures being subjected to subsequent alkaline hydrolysis.Finally, N-benzyl Reissert analogues have been found to give desoxybenzoins plus benzonitriles on treatment with sodium hydride in tetrahydrofuran.
