Enzymes are powerful tools in organic synthesis that are able to catalyse a wide variety of selective chemical transformations under mild and environmentally friendly conditions. Enzymes such as the lipases have also found applications in the synthesis and degradation of polymeric materials. However, the use of these natural catalysts in the synthesis and the post-synthetic modification of dend...

this study was conducted to determine polymorphism of gola-drb3 in nadushan goat using pcr-rflp. blood samples were randomly taken from 100 goats. dna was extracted from the blood samples using diatom dna prep kit. spectrophotometer and 1% agarose gel were used for determining its quantities and qualities. exon 2 of drb 3.2 gene encompassing 285 bp was amplified with heminested-pcr method in tw...

Objective: To evaluate color and surface gloss stability of bis-acryl resins resin composites, submitted to artificialstaining with cigarette smoke. Material Methods: Specimens each material were prepared (n=15). Two resincomposites (GrandioSO [RCG], Filtek Supreme [RCZ]) five (Luxatemp Star [BisLUX], Protemp4[BisPRO], Structor3 [BisSTR], Visalys Temp [BisVIS] Yprov [BisYPR]) tested. Initial wa...

A new N-protecting group, ethanesulfonylethoxycarbonyl (Esc), was designed to perform peptide synthesis in both aqueous and organic solvents. Esc-amino acids were prepared by the reaction of Esc-Cl and amino acids. Although Esc-Cl was a highly reactive reagent, it was not stable and decomposed during the purification procedure. A more stable reagent, ethanesulfonylethyl-4-nitrophenyl carbonate ...

Nearest-neighbor inductive effects are known to influence amide proton exchange. Here we show that longrange electrostatic interactions also have a significant effect on the rate of amide proton exchange. We have measured the effects of salt (NaC1) on the exchange rates of the neutral polypeptide poly(DL-alanine) (PDLA) and of the positively charged polymer poly(DL-lysine) (PDLL). Our results s...

Optically active poly(cis-5-methyl-L-proline) and poly(trans-5-methyl-L-proline) were synthesized from their respective N-carboxy-anhydrides (NCA). Analysis of the i.r., u.v., n.m.r., ORD, and CD spectra of the polymers showed that two different conformations of each polymer exist in the solid and in solution in appropriate solvents. Form I and form II of poly(trans-5-methylL-proline) were foun...

Abstract In this work, new bio-based copoly(ester amide)s were synthesized by a two-step melt polycondensation process, using 2,5-furanedicarboxylic acid dimethyl ester (DMFDC), 1,3-propanediol (PDO), and 1,3-diaminopropane (DAP), with different DAP content. The chemical structure of the obtained poly(trimethylene 2,5-furandicarboxylate)-co-poly(propylene furanamide) (PTF-co-PPAF) copolymers wa...