Treatment of 2-(6-(2-methoxyethyl)pyridyl) carboxylates with alkyl iodides in the presence of zinc dust and a catalytic amount of NiCl2 in DMF at 50 °C affords unsymmetrical ketones in good yields by a one-pot procedure.

Inclusion complex formation of beclomethasone dipropionate (BMDP) with gamma-cyclodextrin (gamma-CyD) in water and in solid state was assessed by solubility analysis and X-ray diffractometry. The solid complex of BMDP with gamma-CyD in a molar ratio of 1:2 was prepared and its in-vitro release behaviour was investigated using an ointment release simulator. The release of BMDP from hydrophilic ointment was significantly improved by the gamma-CyD complexation. Permeation and uptake studies indicated that the enhanced release of BMDP from the ointment may be due to the faster dissolution and the lower binding affinity of the complex in the ointment base. The vasoconstrictor activity of BMDP in man was found to be increased by gamma-CyD complexation, suggesting an improvement in the percutaneous absorption of BMDP.

ABSTRACT:As an extension of our previous study on cellulose-cuprammonium system, 1 an attempt was made to clarify the structure of cellulose---cuprammonium complex in the solid-liquid coexisting system by applying the fact that dissolution of cellulose into cuprammonium solution depends strongly on OH -concentration in the system. Electro-conductivity measurements on aqueous (aq) cuprammonium complex revealed that the complex existed as dissociated type at C0 " (OH concentration for aq solution) < 0.3 mo11-1 and as undissociated type at C0 H > 0.5.Absorption reaction of aq cuprammonium complex on solid cellulose was also dependent on C 0 H, revealing that the reaction order of OH-ion for the solid-liquid absorption reaction is unity and O for the system with C 0 u less than 0.3 moll-1 and for the system with C0 H > 0.5 moll-1 , respectively. Meanwhile, the reaction order of copper to cellulose was found unity regardless the C 0 H value. The latter fact might deny the random reaction of 3 OH groups in glucopyranose unit with copper ion and suggests indirectly the regio-selective complex formation of cuprammine and OH groups at C2 and C 3 as previously proved. It was found that even if the molar ratio of copper ion in aq cuprammine complex to solid cellulose is more than unity, copper absorbed on solid cellulose is at most 0.65 mo! mol-1 . This value is quite near to that evaluated for the cellulose dissolved in cuprammonium solution. Using the above results a tentative new cellulose dissolving process is proposed, in which the less amount of copper and NH3 are employed, compared with those used for conventional process.KEY WORDS Cuprammonium Cellulose / Hydroxyl Ion / Electroconductivity / Glucopyranose / Cupric Ion / Absorption Reaction / In the previous study 1 we carried out analysis on cellulose and regio-selective cellulose derivative dissolved in cuprammonium solution by ultraviolet (UV) and circular dichroism (CD) spectrometries, revealing that 1) copper selectively coordinates to hydroxyl groups at C 2 and C 3 positions of glucopyranose units in cellulose giving a cellulose---cuprammonium complex with charge transfer (CT) excitation around 300 nm, 2) the CT excitation relates to negative Cotton effect for cellulose with degree of polymerization (DP) more than 3, 3) the origin of the Cotton effect might be related to <5 chelate conformation of cellulose---cuprammonium complex, and 4) intensity of CT absorption levels off when molar ratio of copper to glucopyranose unit of cellulose (Cu/Cell) in the solution exceeds 0.6----0.7, predicting the existence of some chemical equiriblium state (and saturated states) between cellulose, cuprammonium complex and cellulose---cuprammonium complex in the solution. The above results mostly support the idea proposed by Reeves 2 that cellulose---cuprammonium complex is a salt of cuprammonium complex cation and diol anion at C 2 and C 3 positions on glucopyranose ring but differs from his prediction that Cu/Cell ratio is unity 1123

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ABSTRACT:An attempt was made to clarify the supermolecular structure of regenerated celluloses recovered from the copper-absorbing cclluloses, which were prepared by treating solid cellulose with aqueous (aq) cuprammonium hydroxide (CAH) solutions having different hydroxyl ion content (C011). X-Ray diffraction and CPIMAS 13 C NMR analyses carried out on the regenerated cellulose samples revealed that the samples had a wide variation of supermolecular structures depending on the C 011 : (1) The CAH solutions with C011 < 0.174 moll-1 brought about the increase in crystallinity, crystalline size and intramolecular hydrogen bond formation, and (2) the CAH solutions with C011 > 0.479 moll-1 tend to give the reverse results. Circular dichroism (CD) spectra for the cellulose films treated by two kinds cuprammonium solutions with Coil< 0.174 and C011 > 0.479 revealed that cuprammonium ions orderly coordinate to C2 and C3 hydroxyl groups of glucopyranose units of cellulose in only amorphous region in the case of Coil< 0.174 and the CAH with C011 > 0.479 penetrates into even a part of crystalline region of cellulose and causes a ligand exchange from ammonia to hydroxyl groups to give a non-dissociated complex form of cellulose having certain random cross-linking by copper atom. Thus, we concluded that the difference in the complex form of the copper-absorbing cellulose influences considerably the super-molecular structure of the regenerated celluloses.