Silica gel and microwave-promoted synthesis of dihydropyrrolizines and tetrahydroindolizines from enaminones

• Robin Klintworth,
• Garreth L. Morgans,
• Stefania M. Scalzullo,
• Charles B. de Koning,
• Willem A. L. van Otterlo and
• Joseph P. Michael

Beilstein J. Org. Chem. 2021, 17, 2543–2552, doi:10.3762/bjoc.17.170

• initial formation of the requisite enaminones (from 18 and 3-bromo-1,1,1-trifluoropropan-2-one or ethyl bromopyruvate, respectively) failed. Following up on reactions with these and other synthetically intriguing substituents will require a different method for making the necessary enaminones. Our success

Conjugated nitrosoalkenes as Michael acceptors in carbon–carbon bond forming reactions: a review and perspective

• Yaroslav D. Boyko,
• Valentin S. Dorokhov,
• Alexey Yu. Sukhorukov and
• Sema L. Ioffe

Beilstein J. Org. Chem. 2017, 13, 2214–2234, doi:10.3762/bjoc.13.220

• displayed more potent activities than the parent natural product (Scheme 26) [63]. In their synthesis, 5-bromo-1H-indole was converted to the corresponding functionalized oxime 73 upon the action of ethyl bromopyruvate oxime in the presence of Na2CO3 in 60% yield. The adduct was transformed into carboxylic

• tryptamine derivatives. Thus, reduction of adducts 68 derived from ethyl bromopyruvate oxime and indoles can be considered as a simple and convenient method for the preparation of substituted tryptophanes 75 as shown in Scheme 27 [64]. This synthetic scheme has found several applications in medicinal

• Ottenheijm in the total synthesis of an analogue of the tryptophan-containing natural alkaloid neoechinulin B (indole 77) [67][68] (Scheme 28). At the initial stage, N-methylindole was alkylated with ethyl bromopyruvate oxime and sodium carbonate to give adduct 78, which was then transformed into N

Synthesis of the heterocyclic core of the D-series GE2270

• Christophe Berini,
• Thibaut Martin,
• Pierrik Lassalas,
• Francis Marsais,
• Christine Baudequin and
• Christophe Hoarau

Beilstein J. Org. Chem. 2017, 13, 1407–1412, doi:10.3762/bjoc.13.137

• , THF/H2O (2:1), rt, 14 h, 93%. e) (i) 8, Bis(pinacolato)diboron, Pd(OAc)2 (5 mol %), CyJohnPhos (20 mol %), KOAc, dioxane, 1 h; (ii) K3PO4, dioxane/H2O (4:1), 110 °C, 14 h, 82–99%. f) Lawesson’s reagent, CH2Cl2, 40 °C, 12 h, 91–94%. g) Ethyl bromopyruvate, CaCO3, THF/EtOH (1:1), 60 °C, 24 h. Synthesis

A one-pot catalyst-free synthesis of functionalized pyrrolo[1,2-a]quinoxaline derivatives from benzene-1,2-diamine, acetylenedicarboxylates and ethyl bromopyruvate

• Mohammad Piltan,
• Loghman Moradi,
• Golaleh Abasi and
• Seyed Amir Zarei

Beilstein J. Org. Chem. 2013, 9, 510–515, doi:10.3762/bjoc.9.55

• -diaminobenzene, dialkyl acetylenedicarboxylates, and ethyl bromopyruvate forms pyrrolo[1,2-a]quinoxaline derivatives in good yields. Ethylenediamine also reacts under similar conditions to produce new pyrrolo[1,2-a]pyrazine derivatives. Keywords: acetylenedicarboxylates; benzene-1,2-diamine; ethyl bromopyruvate

• -diaminobenzenes 1 with dialkyl acetylenedicarboxylates 2a–c in the presence of ethyl bromopyruvate (3) was performed in acetonitrile under reflux over 12 hours. The 1H and 13C NMR spectra of the crude products clearly indicated the formation of polysubstituted pyrrolo[1,2-a]quinoxaline derivatives 4a–h in 88–93

• react with ethyl bromopyruvate (3) to generate the intermediate 6. This intermediate undergoes a series of cyclization and elimination reactions to generate the product 4a. We then investigated the reaction between ethylenediamine (8) and activated acetylenic compounds in the presence of ethyl

Synthesis and enzymatic evaluation of 2- and 4-aminothiazole- based inhibitors of neuronal nitric oxide synthase

• Graham R. Lawton,
• Haitao Ji,
• Pavel Martásek,
• Linda J. Roman and
• Richard B. Silverman

Beilstein J. Org. Chem. 2009, 5, No. 28, doi:10.3762/bjoc.5.28

• in Scheme 4. Treatment of acetonitrile with LDA followed by addition of epoxide 5 gave trans-alcohol 24 [14]. The nitrile group was converted to a thioamide using ammonium sulfide [15]. The thioamide was condensed with either ethyl bromopyruvate or an epoxide (30) [16]. Condensation produces an