One-pot three-component synthesis and photophysical characteristics of novel triene merocyanines

• Christian Muschelknautz,
• Robin Visse,
• Jan Nordmann and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2014, 10, 599–612, doi:10.3762/bjoc.10.51

• display broad absorption bands and computations suggest, that novel types of panchromatic absorbing bichromophores should be readily available by ligating the second chromophore via the electronically nonperturbing N-sulfonyl moiety. Synthetic, photophysical, and computational studies addressing

Gold-catalyzed intermolecular hydroamination of allenes with sulfonamides

• Chen Zhang,
• Shao-Qiao Zhang,
• Hua-Jun Cai and
• Dong-Mei Cui

Beilstein J. Org. Chem. 2013, 9, 1045–1050, doi:10.3762/bjoc.9.117

• ; hydroamination; N-sulfonyl; selectivity; sulfonamide; Introduction Hydroamination of an N–H bond across a C–C unsaturated bond represents one of the most effective and atom-economical methods to prepare amine derivatives [1][2][3][4][5]. In the case of using allenes, this reaction can lead to allylamines, which

Palladium-catalyzed C–N and C–O bond formation of N-substituted 4-bromo-7-azaindoles with amides, amines, amino acid esters and phenols

• Rajendra Surasani,
• Dipak Kalita,
• A. V. Dhanunjaya Rao and
• K. B. Chandrasekhar

Beilstein J. Org. Chem. 2012, 8, 2004–2018, doi:10.3762/bjoc.8.227

• without N-protection (1a, Table 2, entry 1). When the reaction was carried out with N-sulfonyl-protected 4-bromo-7-azaindole 1b only the desulfonated product (Table 2, entry 2) was obtained. It is worth mentioning that the N-sulfonyl protected 7-azaindole 1b was efficiently deprotected under basic

Approaches towards the synthesis of 5-aminopyrazoles

• Ranjana Aggarwal,
• Vinod Kumar,
• Rajiv Kumar and
• Shiv P. Singh

Beilstein J. Org. Chem. 2011, 7, 179–197, doi:10.3762/bjoc.7.25

• 20 on treatment with 5% HCl in ethanol underwent cyclization to afford 21. A novel solid phase synthesis of some 5-aminopyrazoles 24 and their N-acyl and N-sulfonyl derivatives has recently been reported by Watson et al. [38] via the resin supported β-ketonitriles 22 (Scheme 7). The resin supported

Diastereoselective functionalisation of benzo-annulated bicyclic sultams: Application for the synthesis of cis-2,4-diarylpyrrolidines

• Susan Kelleher,
• Pierre-Yves Quesne and
• Paul Evans

Beilstein J. Org. Chem. 2009, 5, No. 69, doi:10.3762/bjoc.5.69

• ). Functionalisation of the N-sulfonyl enamines 5a and 5b was subsequently studied with the ultimate aim of introducing substituents, in a stereoselective fashion, to the masked pyrrolidine ring. Thus, epoxidation of 5a and 5b (Scheme 3) using m-CPBA proceeded smoothly for both substrates and as hoped, occurred under

• hoped for alcohol 8. A similar outcome was observed under both Sakurai-type conditions and treatment with potassium cyanide. It seems probable that these failures reflect a combination of the inability of the N-lone pair to stabilise the developing α-carbocation (the resultant N-sulfonyl iminium ion

• the N-sulfonyl group and its ability to stabilise an α-carbocation, N-sulfonyl iminium ions have been implicated in many instances [18][19][21]. However, in this particular case, based on the conformation of the rigid bicyclic molecule, this mode of stabilisation is not feasible. An alternative

Pd/C- Mediated synthesis of indoles in water

• Mohosin Layek,
• Udaya Lakshmi,
• Dipak Kalita,
• Deepak K. Barange,
• Aminul Islam,
• K. Mukkanti and
• Manojit Pal

Beilstein J. Org. Chem. 2009, 5, No. 46, doi:10.3762/bjoc.5.46

• interest. Preparation of 2,5-disubstituted indole. Preparation of compound C. Pd/C-Catalyzed synthesis of 2,5-disubstituted N-sulfonyl-indoles in aqueous media.a Supporting Information Supporting Information File 78: Spectral data of 2-substituted indoles 3a–s. Acknowledgements The authors thank Dr. V