The reaction of dimethyl acetylenedicarboxylate with OH-acid such as 2-naphthol in the presence of trimethyl or triphenyl phosphite under solvent-free conditions produce oxaphosphaphenanthrene derivatives in good yields. Also, the reaction of dimethyl acetylenedicarboxylate and trimethyl phosphite in the presence of 1-naphthol leads to succinate derivatives in excellent yields. Using triethyl p...

Recently, the attention of researchers has been drawn toward the synthesis of chitosan derivatives and their nanoparticles with enhanced antimicrobial activities. In this study, chitosan derivatives with different azides and alkyne groups were synthesized using click chemistry, and these were further transformed into nanoparticles by using the ionotropic gelation method. A series of chitosan de...

The present study is imported to solve two critical problems we face in our daily life which are microbial pollution and colon cancer. One pot green synthesis of a water soluble polyelectrolyte complex (PEC) between cationic polysaccharide as N,N,N-trimethyl chitosan chloride (TMC) and anionic polymer as poly (acrylic acid) (PAA) in presence of silver nanoparticles to yield (TMC/PAA/Ag) nanocom...

Chitosan (1) was reacted with phenylisothiocyanate in 5% AcOH/H2O to give N-phenylthiocarbamoyl chitosan (2) with a degree of substitution (DS) of N-phenylthiocarbamoyl groups of 0.86 in 87.1% yield. The following acylation of compound 2 with hexanoyl chloride in the presence of pyridine afforded 3,6-di-O-2,3-hexanoyl chitosan isothiocyanate (4a) with a DS of the isothiocyanate groups of 0.70 i...

In the title compound, C(14)H(22)O(4) (systematic name: 9-hy-droxy-1,5,5-trimethyl-1,8-epidi-oxy-spiro-[5.5]decan-2-one), which was isolated from the fermentation broth of Steccherinum ochraceum, the two six-membered rings adopt chair conformations and are bridged by a peroxide group. The hy-droxy H atom forms a three-centre cyclic inter-molecular O-H⋯(O,O') hydrogen-bonding inter-action with a...

Polymethylated Flavonols, Identification, Enzymatic Synthesis, O-Methyltransferase, Chrysosplenium americanum, Saxifragaceae The major flavonoid constituents of Chrysosplenium americanum (Saxifragaceae) were identi­ fied by UV-, NMRand mass spectroscopy and the analysis of their hydrolytic products. They consisted of two 2'-0-/?-D-glucosides of partially methylated 2'-hydroxyquercetin and four ...

We have previously demonstrated that chitosan derivative N-octyl-O-sulfate chitosan (NOSC), which presents important pharmacological properties, can suspend single walled carbon nanotubes (SWNTs) up to 20 times more effectively than other chitosan derivatives in an aqueous environment. In an attempt to further investigate the impact of different molecular weights of chitosan to the solubilizati...

In this work, antioxidant hydrogels were prepared by the construction of an interpenetrating chitosan network and functionalization with gallic acid. The poly(2-hydroxyethyl methacrylate) p(HEMA)-based hydrogels were first synthesized and subsequently surface-modified with an interpenetrating polymer network (IPN) structure prepared with methacrylamide chitosan via free radical polymerization. ...

The hydro-thermal reaction of benzene-1,4-dicarboxylic acid and 4,4'-trimethyl-ene dipiperidine leads to the formation of the title compound, C(13)H(28)N(2) (2+)·C(8)H(4)O(4) (2-). The anion is located on a center of inversion whereas the cation is positioned on a twofold rotation axis. In the crystal structure, the anions and cations are linked by N-H⋯O and N-H⋯(O,O) hydrogen bonds.