Reactions of glycidyl derivatives with ambident nucleophiles; part 2: amino acid derivatives

• Gerald Dyker,
• Andreas Thöne and
• Gerald Henkel

Beilstein J. Org. Chem. 2007, 3, No. 28, doi:10.1186/1860-5397-3-28

• achieved the annulation reaction of amino acid derivatives with glycidyl compounds as functionalized C3 building blocks in combination with a cobalt-catalyzed addition of anilines to the epoxide functionality. This rather selective transition-metal catalysed step builds up the alcohol and the amino

Allylsilanes in the synthesis of three to seven membered rings: the silylcuprate strategy

• Asunción Barbero,
• Francisco J. Pulido and
• M. Carmen Sañudo

Beilstein J. Org. Chem. 2007, 3, No. 16, doi:10.1186/1860-5397-3-16

• (Scheme 9). As shown in Scheme 9, the strategy employed allows the selective formation or 1- or 3-substituted derivatives, where the coupling of a C2 acetylenic synthon and a C2 epoxide synthon provides a new and useful [2+2] annulation strategy for the preparation of the strained cyclobutene ring. The

• vinylmagnesium bromide followed by Swern oxidation lead to enones 48. Lewis acid catalysed cyclization of 48 gives methylenecycloheptanones 49 in high yield (Scheme 11). [25] Consequently, oxoallylsilanes 47 can be considered as useful precursors for cycloheptane annulation. Moreover, the presence of an

Microwave assisted synthesis of triazoloquinazolinones and benzimidazoquinazolinones

• Aboul-Fetouh E. Mourad,
• Ashraf A. Aly,
• Hassan H. Farag and
• Eman A. Beshr

Beilstein J. Org. Chem. 2007, 3, No. 11, doi:10.1186/1860-5397-3-11

• ] anticancer, [5] anti-inflammatory, [6] anticonvulsant, [7] and antiproliferative activities as well as inhibitory effects for thymidylate synthase and poly-(ADP-ribose) polymerase (PARP). [8] An interesting method for quinazoline synthesis involved [5+1] annulation during the reaction of β-dicarbonyl

New modification of the Perkow reaction: halocarboxylate anions as leaving groups in 3-acyloxyquinoline- 2,4(1H,3H)-dione compounds

• Oldřich Paleta,
• Karel Pomeisl,
• Stanislav Kafka,
• Antonín Klásek and
• Vladislav Kubelka

Beilstein J. Org. Chem. 2005, 1, No. 17, doi:10.1186/1860-5397-1-17

• the corresponding 4-ethoxyquinolin-2(1H)-one. In both reactions, the fluorocarboxylate anion acts as the first observed leaving group. This observation restricts the application of the intramolecular Horner-Wadsworth-Emmons synthesis to modify quinoline-2,4(1H,3H)-diones by the annulation of

• fluorinated but-2-enolide rings. The 3-alkyl-3-hydroxyquinoline-2,4(1H,3H)-dione metabolites of Pseudomonas species exhibit antibiotic or lipoxygenase inhibitor activity[1] that may be modified by the introduction of an annulated pharmacophoric but-2-enolide ring. [2] The annulation was successfully carried

• reaction. Conversely, the 3-acetoxyquinoline-2,4(1H,3H)-diones bearing acetoxy group react via a different pathway. The annulation resulting in the formation of the targeted product 10 was successfully carried out[3] by the intramolecular Wittig synthesis using the bromoacetyl derivative of the starting 3

Synthesis of highly substituted allenylsilanes by alkylidenation of silylketenes

• Stephen P. Marsden and
• Pascal C. Ducept

Beilstein J. Org. Chem. 2005, 1, No. 5, doi:10.1186/1860-5397-1-5

• -carbon partners in [3+2] annulation reactions. Thus, reaction with aldehydes,[7] imines/iminiums,[7][8] enones [9][10][11] and nitrosyl cations [12] leads to dihydrofurans, dihydropyrroles, cyclopentenes and isoxazoles respectively.[13] In most cases the silicon is retained in the final product and can