Synthesis of new liquid crystalline diglycidyl ethers.

The phenolic Schiff bases I-VI were synthesized by condensation reactions between various diamines, namely o-dianisidine, o-tolidine and ethylenediamine with vanillin or p-hydroxybenzaldehyde and subsequent reactions between these phenolic Schiff bases and epichlorohydrin to produce new diglycidyl ethers Ia-VIa. The structures of these compounds were confirmed by CHN, FT-IR, (1)H-NMR, and (13)C-NMR spectroscopy. Their thermotropic liquid crystalline behavior was studied using differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). All the diglycidyl ethers prepared exhibit nematic mesophases, except for Va and VIa, which did not show any transition mesophases, but simply flow to liquids.

A structural study of epoxidized natural rubber (ENR-50) and its cyclic dithiocarbonate derivative using NMR spectroscopy techniques.

A structural study of epoxidized natural rubber (ENR-50) and its cyclic dithiocarbonate derivative was carried out using NMR spectroscopy techniques. The overlapping (1)H-NMR signals of ENR-50 at δ 1.56, 1.68-1.70, 2.06, 2.15-2.17 ppm were successfully assigned. In this work, the <(13)C-NMR chemical shift assignments of ENR-50 were consistent to the previously reported work. A cyclic dithiocarbonate derivative of ENR-50 was synthesized from the reaction of purified ENR-50 with carbon disulfide (CS(2)), in the presence of 4-dimethylaminopyridine (DMAP) as catalyst at reflux temperature. The cyclic dithiocarbonate formation involved the epoxide ring opening of the ENR-50. This was followed by insertion of the C-S moiety of CS(2) at the oxygen attached to the quaternary carbon and methine carbon of epoxidized isoprene unit, respectively. The bands due to the C=S and C-O were clearly observed in the FTIR spectrum while the (1)H-NMR spectrum of the derivative revealed the peak attributed to the methylene protons had split. The (13)C-NMR spectrum of the derivative further indicates two new carbon peaks arising from the >C=S and quaternary carbon of cyclic dithiocarbonate. All other (1)H- and (13)C-NMR chemical shifts of the derivative remain unchanged with respect to the ENR-50.

Synthesis of new azo compounds based on N-(4-hydroxypheneyl)maleimide and N-(4-methylpheneyl)maleimide.

Maleic anhydride was reacted with p-aminophenol and p-toluidine in the presence of di-phosphorus pentoxide (P2O5) as a catalyst to produce two compounds: N-(4-hydroxy-phenyl)maleimide (I) and N-(4-methylphenyl)maleimide (II). The new azo compounds I(a-c) and II(a-c) were prepared by the reaction of I and II with three different aromatic amines, namely aniline, p-aminophenol and p-toluidine. The structures of these compounds were confirmed by CHN, FT-IR, ¹H-NMR, ¹³C-NMR, mass spectrum and UV/Vis spectroscopy.

Synthesis and liquid crystalline properties of new diols containing azomethine groups.

A series of new mesogenic azomethine diols were successfully synthesized by condensation reactions between various chloroalkanols and N,N'-bis(4-hydroxy)-benzylidene-o-toluidine (1). The structures of these compounds were confirmed by CHN, FT-IR, (1)H-NMR, and (13)C-NMR spectrophotometer. Their thermotropic liquid crystalline behavior was studied using differential scanning calorimetry (DSC) and polarizing optical microscope (POM). 4,4'-di(4-Hydroxybutoxy)-N-benzylidine-o-tolidine (2a) does not exhibit liquid crystalline properties. A nematic texture was observed for mesogenic diols 2b, and 2d, whereas the diol 2c exhibits a smectic mesophase. The increase of terminal alkyl chain in these mesogenic diols leads to a decrease in the transition temperature.

A second monoclinic polymorph of 3ß-chloro-cholest-5-ene.

The title compound, C(27)H(45)Cl, is a second monoclinic polymorph which crystallizes in the space group P2(1) with four crystallographically independent mol-ecules in the asymmetric unit. The structure was previously reported [Bernal et al. (1940 ▶). Philos. Trans. R. Soc. London Ser. B, 239, 135-182; Vani & Vijayan (1979 ▶). Mol. Cryst. Liq. Cryst.51, 253-264], also in the space group P2(1), but with two unique mol-ecules in the asymmetric unit. As in the previously reported structures, rings A and C in the mol-ecule adopt chair conformations with half-chair conformations for rings B and D. The ring junctions B-C and C-D are trans, whereas the junction A-B is quasi-trans. In the crystal structure, mol-ecules are arranged in a head-to-tail fashion along a and are stacked along the b axis.

Transperineal intraprostatic injection of botulinum neurotoxin A vs transurethral resection of prostate for management of lower urinary tract symptoms secondary to benign prostate hyperplasia: A prospective randomised study.

Objectives: To evaluate transperineal intraprostatic injection of botulinum neurotoxin A (BoNT-A) in patients with lower urinary tract symptoms (LUTS) secondary to benign prostate hyperplasia (BPH) who failed to respond to 6-month medical treatment compared with transurethral resection of the prostate (TURP). Patients and methods: In all, 92 men were divided into TURP and BoNT-A groups after being evaluated using the International Prostate Symptom Score (IPSS) and five-item version of the International Index of Erectile Function, estimation of serum total prostate-specific antigen (tPSA), ultrasonographic estimation of prostatic volume (PV), and uroflowmetry determination of voiding volume (VV), maximum urinary flow rate (Qmax) and post-void residual urine volume (PVR). BoNT-A (200 U diluted in 3 mL saline) was injected, using a 22-G spinal needle under transrectal ultrasonography guidance, with 1-mL in each lobe. Patients were assessed 3-monthly for 12 months. Results: The IPSS significantly decreased in all patients with a non-significant difference between the groups. The mean VV and Qmax increased, whilst PVR, PV and serum tPSA significantly decreased. Patients who showed deterioration at 12 months were re-evaluated and underwent TURP. BoNT-A injection significantly maintained erectile function compared with TURP. Conclusion: Intraprostatic BoNT-A injection reduced PV with subsequent increases in VV and Qmax, and decreases in PVR and serum tPSA level. Intraprostatic BoNT-A injection allowed surgery sparing in >70% and preserved erectile function in 91.3% of patients. Abbreviations: BoNT-A: botulinum neurotoxin A; HRQOL: health-related quality of life; IIEF-5: five-item version of the International Index of Erectile Function; PV: prostatic volume; PVR: post-void residual urine volume; Qmax: maximum urinary flow rate; tPSA: total PSA; VV: voided volume.

New polyurethane nanocomposites based on soya oil.

New polyurethane (PU) nanocomposites were prepared from a dispersion of 0 - 5% montmorillonite (MMT) clay with isocyanate and soya oil polyol that was synthesized via transesterification of triglycerides to reduce petroleum dependence. FT-IR spectra indicate the presence of hydrogen bonding between nanoclay and the polymer matrix, whereas the exfoliated structure of clay layers was confirmed by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Optical microscopy, mechanical and thermal analyses were done to investigate significant improvement of the nanocomposites. The results showed PU-3% nanoclay (NC) showed optimum results in mechanical properties such as tensile and flexural strength but the lowest in impact strength.

Structure-property studies of thermoplastic and thermosetting polyurethanes using palm and soya oils-based polyols.

Palm and soya oils were converted to monoglycerides via transesterification of triglycerides with glycerol by one step process to produce renewable polyols. Thermoplastic polyurethanes (TPPUs) were prepared from the reaction of the monoglycerides which act as polyol with 4,4'-methylenediphenyldiisocyanate (MDI) whereas, thermosetting polyurethanes (TSPUs) were prepared from the reaction of glycerol, MDI and monoglycerides in one pot. Characterization of the polyurethanes was carried out by FT-IR, (1)H NMR, and iodine value and sol-gel fraction. The TSPUs showed good thermal properties compared to TPPUs as well as TSPUs exhibits good properties in pencil hardness and adhesion, however poorer in flexural and impact strength compared to TPPUs. The higher percentage of cross linked fraction, the higher degree of cross linking occurred, which is due to the higher number of double bond presents in the TSPUs. These were reflected in iodine value test as the highest iodine value of the soya-based thermosetting polyurethanes confirmed the highest degree of cross linking. Polyurethanes based on soya oil showed better properties compared to palm oil. This study is a breakthrough development of polyurethane resins using palm and soya oils as one of the raw materials.