Competitive cyclization of ethyl trifluoroacetoacetate and methyl ketones with 1,3-diamino-2-propanol into hydrogenated oxazolo- and pyrimido-condensed pyridones

• Svetlana O. Kushch,
• Marina V. Goryaeva,
• Yanina V. Burgart,
• Marina A. Ezhikova,
• Mikhail I. Kodess,
• Pavel A. Slepukhin,
• Alexandrina S. Volobueva,
• Vladimir V. Zarubaev and
• Victor I. Saloutin

Beilstein J. Org. Chem. 2025, 21, 2716–2729, doi:10.3762/bjoc.21.209

• for 3-polyfluoroalkyl-3-oxo esters containing an activated carbonyl group capable of adding α-methylene ketones. It is characterized by the cyclization at the 1,3-dicarbonyl fragment of 3-oxo ester and offers a possibility of using a variety of nucleophilic agents to form hydrogenated diastereomeric

• ethylenediamine [27] as well as with 2-(aminomethyl)aniline and 1,3-diaminopropane [28]. In addition, we have found another route for the three-component cyclization of 3-polyfluoroalkyl-3-oxo esters with α-methylene ketones involving mono- and dialkylamines, leading to 5-polyfluoroalkylaminocyclohexen-2-ones [29

• minor when heated in 1,4-dioxane (Scheme 3, Table 3). Previously, we proposed and experimentally confirmed an aldol mechanism underlying the three-component cyclization of polyfluoroalkyl-3-oxo esters with α-methylene ketones and amines in piperidone derivatives. According to this mechanism, the key

Continuous multistep synthesis of 2-(azidomethyl)oxazoles

• Thaís A. Rossa,
• Nícolas S. Suveges,
• Marcus M. Sá,
• David Cantillo and
• C. Oliver Kappe

Beilstein J. Org. Chem. 2018, 14, 506–514, doi:10.3762/bjoc.14.36

• preparation of oxazoles described in the literature. These include ring-closure reactions of diazocarbonyl compounds with amides or nitriles [16], α-haloketones and amides [17][18][19], cyanohydrins and aldehydes (Fischer synthesis) [20][21], or oxidative additions of α-methylene ketones to nitriles [22][23

Attempts to prepare an all-carbon indigoid system

• Şeref Yildizhan,
• Henning Hopf and
• Peter G. Jones

Beilstein J. Org. Chem. 2015, 11, 363–372, doi:10.3762/bjoc.11.42

• dimerized to 30, the conversion of this olefin to 14 failed. Keywords: α-methylene ketones; Cope rearrangement; cross-conjugation; indigo; McMurry coupling; Introduction Cross-conjugated organic molecules are defined as unsaturated systems containing two π-electron systems (or lone pairs) that are in

• -carbon analog of an indigoid dyestuff has failed so far. It is conceivable that unsubstituted α-methylene ketones such as 12 are too reactive to be isolated under the reaction conditions. On the other hand, if the methylene group is protected by two methyl groups, the corresponding ketone, 13, becomes

• omitted. From indigo to heteroindigo derivatives and all-carbon-indigo. Attempts to prepare the α-methylene ketones 12 and 13. Dimerization of 13 under McMurry conditions. Dimerization of indan-1-one (18) by a stepwise approach. Methylenation of 19 and bisalkylation of the product 23 with 1,2