Synthesis and characterization of Sant-75 derivatives as Hedgehog-pathway inhibitors

• Chao Che,
• Song Li,
• Bo Yang,
• Shengchang Xin,
• Zhixiong Yu,
• Taofeng Shao,
• Chuanye Tao,
• Shuo Lin and
• Zhen Yang

Beilstein J. Org. Chem. 2012, 8, 841–849, doi:10.3762/bjoc.8.94

• the presence of catalytic NaOMe, followed by treatment with NH4Cl. Then, condensation of 13 with acetylacetaldehyde dimethyl acetal in 1,4-dioxane afforded 6-methyl-2-(4-pyridinyl)pyrimidine 14 in 62% yield [47]. Consequent allylic oxidation of 14 with selenium dioxide gave 11e in moderate yield

Synthesis of functionalized macrocyclic derivatives of trioxabicyclo[3.3.0]nonadiene

• Sabine Leber,
• Gert Kollenz and
• Curt Wentrup

Beilstein J. Org. Chem. 2012, 8, 738–743, doi:10.3762/bjoc.8.83

• the bisdioxine-derived macrocycles. Okazaki and co-workers designed bowl-shaped [8] and lantern-shaped [9] molecules containing a functionalized aryl group, which allowed the preparation of, among other things, stable simple enols [8] and a variety of unusual sulfur [9], selenium [10][11] and

Synthesis and oxidation of some azole-containing thioethers

• Andrei S. Potapov,
• Nina P. Chernova,
• Vladimir D. Ogorodnikov,
• Tatiana V. Petrenko and
• Andrei I. Khlebnikov

Beilstein J. Org. Chem. 2011, 7, 1526–1532, doi:10.3762/bjoc.7.179

• . Selenium dioxide-catalyzed oxidation of benzotriazole thioether by H2O2, however, proceeds selectively and yields sulfoxide only. Keywords: azole; oxidation; sulfone; sulfoxide; thioether; Introduction Compounds comprising two pyrazole moieties linked by an aliphatic spacer act as bidentate chelating

•  1, entry 4). It is evident that hydrogen peroxide alone is not an effective oxidant for thioether 5, therefore other oxidizing systems should be evaluated. Selenium(IV) oxide was reported to be an efficient catalyst in a thioether oxidation reaction promoted by H2O2 [17]. However, the performance of

• sulfone can be selectively isolated by varying the oxidation conditions. Sulfone can be prepared by the addition of an excess of H2O2 in acetic acid at elevated temperature, while sulfoxide is selectively formed upon the addition of H2O2 and selenium dioxide in methanol. Experimental General methods

A novel high-yield synthesis of aminoacyl p-nitroanilines and aminoacyl 7-amino-4-methylcoumarins: Important synthons for the synthesis of chromogenic/fluorogenic protease substrates

• Xinghua Wu,
• Yu Chen,
• Herve Aloysius and
• Longqin Hu

Beilstein J. Org. Chem. 2011, 7, 1030–1035, doi:10.3762/bjoc.7.117

• reach completion. After the completion of selenocarboxylation as monitored by LC-MS, a solution of azide in THF was added by syringe or cannulation. The reaction started immediately with the precipitation of gray selenium and the formation of nitrogen gas, and was complete within 2 h at room temperature

• isopropanol solution of sodium hydrogenselenide [22]. To a suspension of selenium (40 mg, 0.5 mmol) in deaerated isopropanol (5 mL) was added sodium borohydride (24 mg, 0.6 mmol) in one portion at room temperature. The mixture was stirred under a nitrogen atmosphere to provide a colorless solution of NaHSe in

• isopropanol, which was ready to be used. Preparation of an aqueous solution of sodium hydrogenselenide [22]. To a suspension of selenium (40 mg, 0.5 mmol) in deaerated distilled water (5 mL) was added sodium borohydride (40 mg, 1.0 mmol) in one portion at 5 °C. The mixture was vigorously stirred under a

Alkene selenenylation: A comprehensive analysis of relative reactivities, stereochemistry and asymmetric induction, and their comparisons with sulfenylation

• Vadim A. Soloshonok and
• Donna J. Nelson

Beilstein J. Org. Chem. 2011, 7, 744–758, doi:10.3762/bjoc.7.85

• straightforward and general methods for the preparation of the corresponding selenium derivatives, which are useful intermediates in organic synthesis, often with interesting biological applications [4][5]. Thus, organoselenium compounds are reported to have antitumor [6][7][8], antimicrobial [7][8], antiviral [7

• ][8], and anti-oxidant [9][10] properties. It is interesting to note that the current applications of organoselenium derivatives have outpaced those of conventional inorganic selenium compounds [6][7][8][9][10]. This potential in biological applications [11] of organoselenium compounds is enhanced by

• reactivity of organoselenium compounds, it is expected that chiral selenium containing derivatives could be synthetically useful as chiral auxiliaries or intermediates for the development of a novel asymmetric methodology platform [15][16][17][18]. Furthermore, compared with sulfur analogs [44], chiral

Metathesis access to monocyclic iminocyclitol-based therapeutic agents

• Ileana Dragutan,
• Valerian Dragutan,
• Carmen Mitan,
• Hermanus C.M. Vosloo,
• Lionel Delaude and
• Albert Demonceau

Beilstein J. Org. Chem. 2011, 7, 699–716, doi:10.3762/bjoc.7.81

• , separation of the diastereomers by flash chromatography was possible, affording the pure tetrahydropyridine derivative trans-133 in 74% yield. Successive epoxidations on enantiopure trans-133 and then 134, followed each time by regioselective epoxide opening (with a selenium–boron complex and water

The allylic chalcogen effect in olefin metathesis

• Yuya A. Lin and
• Benjamin G. Davis

Beilstein J. Org. Chem. 2010, 6, 1219–1228, doi:10.3762/bjoc.6.140

• their effects appear to be a general phenomenon in metathesis chemistry. In this review, we collect these reports and discuss the activating effect of allylic chalcogens, such as oxygen, sulfur and selenium, as well as their relative reactivity in olefin metathesis. The applications of the allylic

• allyl sulfide with combined CM yields of 73% (CM and self-metathesis) and 45% (CM only, no self-metathesis observed), respectively (Scheme 11b) [38]. This further improvement in reactivity may be attributed to the increased softness of selenium which makes the coordination to ruthenium even more

• favorable than the sulfur in allyl sulfides. While, as a single example, Kotetsu and co-workers have synthesized selenium-containing bicyclic β-lactams via RCM of an allyl selenide derivative, enhanced reactivity was unnoticed [39]. With a better understanding of the allylic chalcogen effect, olefin

Intramolecular hydroxycarbene C–H-insertion: The curious case of (o-methoxyphenyl)hydroxycarbene

• Dennis Gerbig,
• David Ley,
• Hans Peter Reisenauer and
• Peter R. Schreiner

Beilstein J. Org. Chem. 2010, 6, 1061–1069, doi:10.3762/bjoc.6.121

• , was added 3.33 g (30.0 mmol) of selenium dioxide. The mixture was stirred at 80 °C for 4 h. After filtration, concentration of the solution gave a brown oil that was dissolved in 5% sodium hydroxide solution and washed three times with small portions of diethyl ether. The aqueous layer was acidified

Aromatic and heterocyclic perfluoroalkyl sulfides. Methods of preparation

• Vladimir N. Boiko

Beilstein J. Org. Chem. 2010, 6, 880–921, doi:10.3762/bjoc.6.88

Mitomycins syntheses: a recent update

• Jean-Christophe Andrez

Beilstein J. Org. Chem. 2009, 5, No. 33, doi:10.3762/bjoc.5.33