Microwave-induced synthesis of new optically active and soluble polyamides containing pendent 4-(2-phthalimidiylpropanoylamino)benzoylamino-groups

A rapid microwave-induced synthesis of polyamides–containing amino acid moieties

5-(2-(9,10-Dihydro-9,10-ethanoanthracene-11,12-dicarboximido)propanoylamino)isophthalic acid as a novel aromatic dicarboxylic acid monomer was prepared in four steps. In the first step, cis-9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxylic acid anhydride was reacted with l-alanine in acetic acid solution and the resulting imide acid was obtained in high yield. In the second step, treatment of this imide acid with excess thionyl chloride gave acid chloride in good yield. In the last step, this acid chloride was reacted with 5-aminoisophthalic acid to provide novel bulky chiral aromatic dicarboxylic acid. The direct polycondensation reactions of this diacid with several aromatic diamines were carried out under microwave irradiation. In order to compare this technique with classical heating, the polymerization reactions were also performed under solution polycondensation conditions. The polymerization reactions occurred rapidly under microwave conditions and produced a series of novel optically active polyamides (PAs)–containing pendent 9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboximido)propanoylamino group, with good yields and moderate inherent viscosities of 0.27–0.47 dL g−1. The resulting new PAs showed good solubility and are readily soluble in organic solvents. PAs were thermally stable, with 10% weight loss recorded at 411°C and 450°C under nitrogen atmosphere and char yields at 800°C higher than 44% and glass transition temperature above 163°C.

Controlled radical polymerization of an acrylamide containing L-alanine moiety via ATRP

Homopolymerization of an optically active acrylamide having an amino acid moiety in the side chain, N-acryloyl-L-alanine (AAla) was carried out via atom transfer radical polymerization (ATRP) at room temperature using 2-hydroxyethyl-2'-methyl-2'-bromopropionate (HMB) or sodium-4-(bromomethyl)benzoate (SBB) as initiator in pure water, methanol/water mixture and pure methanol solvents. The polymerization reaction resulted in the optically active biocompatible amino acid-based homopolymer in good yield with narrow molecular weight distribution. The number average molecular weight increased with conversion and polydispersity was low. The structure and molecular weight of synthesized polymer were characterized by (1)H NMR, FT-IR spectroscopic techniques and size-exclusion chromatography.

Highly efficient microwave-assisted synthesis of photoactive polyamides bearing 5-(3-acetoxynaphthoylamino)benzamide moieties

A novel aromatic dicarboxylic acid monomer, 5-[4-(3-acetoxynaphthoylamino)benzoylamino]isophthalic acid, was prepared in five steps. The direct polycondensation of this dicarboxylic acid with several aromatic diamines was performed under microwave irradiation and conventional heating in the presence of triphenyl phosphite/pyridine/ N-methyl-2-pyrrolidone/calcium chloride. The polymerization reactions were effectively preceded, and the resulting novel photoactive polyamides (PAs) were obtained in high yields and moderate inherent viscosities in the range of 0.32–0.58 dL g−1. Thermogravimetric analysis results showed that polymers were thermally stable, 10% weight loss temperatures were in excess of 430°C and 488°C, and char yields at 800°C under nitrogen atmosphere were higher than 62%. The resulting polymers exhibited ultraviolet–visible absorption bands at 268 and 312 nm in N,N-dimethylformamide (DMF) solution. Their photoluminescence in DMF solution demonstrated fluorescence emission bands maxima around 367 and 429 nm for all of the PAs.

Synthesis, characterization and in vitro antimicrobial and biodegradability study of pseudo-poly(amino acid)s derived from N,N'-(pyromellitoyl)-bis-L-tyrosine dimethyl ester as a chiral bioactive diphenolic monomer

In this investigation N,N'-(pyromellitoyl)-bis-L-tyrosine dimethyl ester (7) as a chiral bioactive diphenolic monomer was prepared in three steps. The aim of this work was to obtain novel optically and biologically active pseudo-poly(amino acid)s (PAA)s that are more soluble in common organic solvents while maintaining their high thermal stability. Thus, several new, highly soluble, thermally stable, optically active and biodegradable PAAs containing different amino acid moieties in the main chain were prepared with moderate molecular weights via direct polycondensation using tosyl chloride, pyridine and N,N'-dimethylformamide as a condensing agent. The resulting novel polymers were characterized with FT-IR, (1)H-NMR, elemental and thermogravimetric analysis techniques. In addition, in vitro toxicity and biodegradability behavior of the diphenolic monomer 7, different synthetic diacids (3a-3e) and obtained PAAs, which were investigated in culture media, showed that the synthesized compounds and polymers derived from them are biologically active and biodegradable under a natural environment.