In this thesis, mechanistic and synthetic studies on transformations of Hphosphonates into DNA analogues containing P-S or P-C bonds are described. Configurational stability of dinucleoside H-phosphonates and the stereochemical course of their sulfurisation in the presence of 1,8diazabicyclo[5.4.0]undec-7-ene (DBU) were investigated. In light of these studies, the reported stereoselective sulfu...

The cooperative catalysis of CpRu(PPh3)2(CH3CN)PF6 (1b) and DBU enables chemoselective nucleophilic activation of acetonitrile in the presence of base-sensitive aldehydes 2 to afford corresponding beta-hydroxynitriles in good yield.

A series of 2-amino-4-(nitroalkyl)-4H-chromene-3-carbonitriles were synthesized by an efficient multicomponent reaction in aqueous media using DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) as a catalyst at room temperature. Mild condition, environment friendly procedure and excellent yields are the main advantages of this procedure. The cytotoxic activity of target compounds were evaluated against t...

Depending on the catalyst used, N-methylation of indole with dimethylcarbonate (DMC)—an environmentally friendly alkylation agent—yields different products. With 1,4-diazabicyclo[2.2.2]octane (DABCO), reaction forms only N-methylated indole, but 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), both and N-methoxycarbonylated are formed. Using direct ESI(+)-MS monitoring to collect actual snapshots chan...

Growing attention in developing new N-heterocyclic carbene (NHC)-mediated reactions involving homoenolate intermediates has prompted our interest in exploring the mechanistic details of the related reactions. In this work, we carried out a detailed theoretical study for the NHC-catalyzed annulation reaction of cinnamaldehyde (A) and benzodi(enone) (B) in the presence of 1,8-diazabicyclo[5.4.0]u...

Treatment of aculeximycin with 2% 1,8-diazabicyclo[5,4,0]undecene-7 (DBU)-methanol yielded three products, aculexitriose, pseudoaglycones I and II. The structural elucidation of aculexitriose was carried out by spectral analyses (MS, NMR (1H-1H 2D NMR spectroscopy, nuclear Overhauser effect] and chemical degradations of aculexitriose and its derivatives. The structure of aculexitriose was estab...

An efficient, metal free approach to highly substituted 2-pyrrolines by DBU-catalyzed tandem additions (a formal [3+2] cycloaddition) of electron-deficient 1,3-conjugated enynes and 2-aminomalonates under mild conditions was developed.

A route to prepare the cyanoethyl-phosphoramidite monomer of O4-alkylthymine and a method for the routine solid-phase synthesis of oligodeoxynucleotides containing O4-alkylthymine are described. This method has been used to make DNA sequences up to 48 bases in length. The amino function of the adenine and guanine in the sequence were protected with the phenoxyacetyl group, and that of cytosine ...

A series of cellulose-based fluorescent materials are prepared under relative mild conditions by use the DMSO/1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)/CO2 system to utilize as coating pigments. Through observation 365 nm UV light, exhibit good fluorescence response and bright color. Furthermore, due limitation molecular skeleton cellulose, intrinsic aggregation caused quenching phenomenon commo...

A single-step catalytic ring expansion approach from 4-oxoazetidine-2-carbaldehydes to enantiopure succinimides has been achieved by the use of a base (DBU) and a thiazolium salt precatalyst.