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• 109-89-7 diethylamine 
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• 35264-84-7 ZGly, triethylammonium salt 
• 16748-79-1 perfluorophenyl 2-(((benzyloxy)carbonyl)amino)acetate 

Relevant academic research and scientific papers

New branched macrocyclic ligand and its side-arm, two urea-based receptors for anions: Synthesis, binding studies and crystal structure

The synthesis and characterization of the two new hosting molecules for anions 4(N),10(N)-bis-[2-(4-nitrophenylureido)acetamido]-1,7-dimethyl-1,4,7,10- tetraazacyclododecane (L1) and 1-((diethylcarbamoyl)methyl)-3-(4-nitrophenyl) urea (L2) are reported. L1 is a branched tetraazamacrocycle bearing two p-nitrophenylureido groups as side-arms, whereas L2 has the same linear chain and binding moiety of L1 side-arm. The best synthetic routes for use in obtaining L1 were explored, affording the synthesis of the new intermediate 4, a versatile building block for further functionalized branched macrocyclic hosts. The binding properties of both ligands towards the halides series and acetate anions (G) were investigated by NMR and UV-Vis spectroscopy in a dimethyl sulfoxide-0.5% water solution. Both ligands interact with F-, Cl - and AcO- while Br- and I- did not. The NMR experiments proved that the binding occurs via H-bond to the ureido fragments. Fluoride anion is basic enough to deprotonate the ureido group of both ligands, thus preventing the determination of the addition constants to both ligands; this was instead possible for Cl- and AcO-. L1 forms G-L species of 1: 1 ([GL1]) and 2: 1 ([G2L1]) stoichiometry while L2 forms only the 1: 1 [GL2] species. The higher value of the formation constant of the [AcOL1]-vs. the [AcOL2]- species (log K = 5.5 vs. 2.8 for the reaction AcO- + L = AcOL-) suggested that both side-arms of L1 cooperate in binding acetate; this does not occur with Cl-. The results confirmed that this tetraaza-macrocyclic base acts as a preorganizing scaffold for side-arms when they are linked to it via an amide function. The crystal structure of L2·H2O is also reported. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.

Application of Predictive QSAR Models to Database Mining: Identification and Experimental Validation of Novel Anticonvulsant Compounds

We have developed a drug discovery strategy that employs variable selection quantitative structure-activity relationship (QSAR) models for chemical database mining. The approach starts with the development of rigorously validated QSAR models obtained with

Peptide Synthesis with Benzo- and Naphthosultones

6-Nitro- and 6,8-dinitronaphth-1,2-oxathiole S,S-dioxides (7b and 7c) have been prepared from the parent naphthosultone 7a and compared with 5-nitrobenz-3H-1,2-oxathiole S,S-dioxide (1b) as coupling reagents for peptide synthesis.Nucleophilic attack of a carboxylate salt on these strained five-membered sultones leads to activated esters 3 and 9 which rapidly react with amines (except in the case of 9c).The rate constant for the formation of ester 9b is higher than that of 3b.Amides or peptides are formed in slightly better yields with the naphthosultone 7b than with the benzosultone 1b.The naphthosultones are also preferred over the benzosultones from the point of view of amount of 5(4H)-oxazolone formation from N-benzoyl amino acids and the degree of racemization.However the rate of alkaline hydrolysis of 7b is slower than that of 1b.All these results may be rationalized by a better intramolecular acyl transfer reaction in the more rigid mixed anhydride intermediate 8b.There is no dependence on in the rate equation for aminolysis of esters 3b and 9b by benzylamine in THF, acetonitrile, or DMF and the aminolysis is probably anchimerically assisted by a neighbouring S=O group.Esters 3b are more selective acylating agents for primary amino groups in the presence of secondary ones than esters 9b and this observation is exploited in a synthesis of maytenine by selective acylation of spermidine.