Diethyl 4‐(2,5‐di­methoxy­phenyl)‐2,6‐di­methyl‐1,4‐di­hydro­pyridine‐3,5‐di­carboxyl­ate,conformational change with solvent of crystallization

The title compound, C₂₁H₂₇NO₆, has been crystallized from ethanol containing nitro­benzene and shows the phenyl ring, B, in an ap conformation. This structure may be compared with that of the mol­ecule crystallized from ethanol alone, in which the B ring is seen in an sp conformation. The isolation of this rotamer has implications for the understanding of the docking of calcium beta‐blocking di­hydro­pyridine mol­ecules with their receptor site.     

Synthesis of aminomethyl and amino analogs of 5-benzylacyclouridine and 5-benzyloxybenzylacyclouridine

Amino analogs of BAU (5-benzylacyclouridine) and BBAU (5-benzyloxybenzylacyclouridine) and their 2′-hydroxymethyl derivatives were synthesized for evaluation as inhibitors of uridine phosphorylase and hence potential cancer chemotherapeutic agents. Both aminomethyl analogs were found to be potent inhibitors of this enzyme and good potentiators of the anti-tumor action of FUdR.     

Synthesis of a novel amphiphilic GdPCTA-[12] derivative as a potential micellar MRI contrast agent

A novel amphiphilic contrast agent, a GdPCTA-[12] derivative containing a dodecyl chain as lipophilic moiety, has been prepared. A convergent synthetic route from commercially available diethylene triamine and 3-hydroxypyridine is described. The target amphiphilic gadolinium complex was obtained in nine steps in 22% overall yield. Physicochemical properties and relaxivity measurements of this new contrast agent are described.     

Fourier transform Raman and DFT study of three annulated oligothiophenes with different molecular shapes.

Herein, we study the conjugation properties of three different thienoacenes, each of which has three or four fused thiophene rings, by means of Fourier transform Raman spectroscopy. The B3LYP/6-31G** vibrational analysis of all of the collected spectroscopic data evidences that the selective enhancement of a limited number of Raman scatterings is related to the occurrence in the three thienoacenes of a vibronic coupling between the lowest unoccupied frontier molecular orbital (LUMO) and some Raman-active skeletal nu(C==C) stretching modes of 1600-1300 cm(-1).     

Abraham Model Expressions for Describing Water-to-Diethylene Glycol and Gas-to-Diethylene Glycol Solute Transfer Processes at 298.15 K

A gas chromatographic headspace analysis method was used to experimentally determine gas-to-liquid partition coefficients and infinite dilution activity dilution for 14 different aliphatic and cyclic hydrocarbons (alkanes, cycloalkanes, alkenes, alkynes), eight different aromatic compounds (benzene, alkylbenzenes, halobenzenes), five different chloroalkanes (dichloromethane, trichloromethane, 1-chlorobutane, 1,2-dichloropropane, isopropylbromide), tetrahydrofuran, butyl acetate, and acetonitrile dissolved in diethylene glycol at 298.15 K. Solubilities were also measured at 298.15 K for 31 crystalline nonelectrolyte organic solutes including several polycyclic aromatic hydrocarbons and substituted benzoic acid derivatives. The experimental results of the headspace chromatographic and spectroscopic solubility measurements were converted to gas-to-diethylene glycol and water-to-diethylene glycol partition coefficients, and molar solubility ratios using standard thermodynamic relationships. Expressions were derived for solute transfer into diethylene glycol from the calculated partition coefficients and solubility ratios. Mathematical correlations based on the Abraham model describe the observed partition coefficient and solubility data to within 0.14 log₁₀ units (or less).     

Effectiveness of Photodynamic Therapy in Elimination of HPV‐16 and HPV‐18 Associated with CIN I in Mexican Women

This study aimed to determine the effectiveness of photodynamic therapy (PDT), using δ‐aminolevulinic acid (5‐ALA), in the elimination of premalignant cervical lesions in Mexican patients with human papillomavirus (HPV) infection and/or cervical intraepithelial neoplasia (CIN). Thirty women diagnosed with CIN I and/or positive for HPV participated in the study. Topical 6% 5‐ALA in gel form was applied to the uterine cervix; after 4 h, the lesion area was irradiated with a light dose of 200 J cm^?2 at 635 nm. This procedure was performed three times at 48‐h intervals. Clinical follow‐up was performed at 3, 6, and 12 months after the initial PDT administration, by colposcopy, cervical cytology, histopathological analysis, polymerase chain reaction, and hybrid capture. Of HPV‐infected patients without evidence of CIN I, 80% cleared the infection, while HPV associated with CIN I was eliminated in 83% of patients (P < 0.05). At 12 months, CIN I had regressed in 57% of patients, although this response was not statistically significant. PDT using 6% 5‐ALA is concluded to be effective in eliminating HPV infection associated or not with CIN I.     

Synthesis and characterization of surrogate nuclear explosion debris: urban glass matrix

Journal of Radioanalytical and Nuclear Chemistry - We report a study of a fast radiochemical method to determine the activity of 131I via the radiochemical recovery obtained with a 129I tracer....     

Ecionines A and B, two new cytotoxic pyridoacridine alkaloids from the Australian marine sponge, Ecionemia geodides

Chemical investigations of the Australian marine sponge Ecionemia geodides resulted in the isolation of two new pyridoacridine alkaloids, ecionines A (1) and B (2), along with the previously isolated marine natural products, biemnadin (3) and meridine (4). Compounds 1 and 2 both contain an imine moiety, which is rare for the pyridoacridine structure class. The chemical structures of 1 and 2 were determined by extensive 1D and 2D NMR and MS data analyses. All compounds were tested against a panel of human bladder cancer cell lines, the increasingly metastatic TSU-Pr1 series (TSU-Pr1, TSU-Pr1-B1 and TSU-Pr1-B2) and the superficial bladder cancer cell line 5637. Ecionine A (1) displayed cytotoxicity against all cell lines, with IC₅₀ values ranging from 3 to 7 μM. This is the first report of chemistry from the sponge genus Ecionemia.     

Diastereoselective synthesis of substituted prolines via 5-endo-trig cyclisations of aza-[2,3]-Wittig sigmatropic rearrangement products

The major diastereoisomers of aza-[2,3]-Wittig sigmatropic rearrangement products from α-amino acid derivatives are susceptible to a rare nucleophilic 5-endo-trig cyclisations of an amine onto a non-conjugated vinylsilane in high yield and complete diastereocontrol. Five examples are presented, with cyclisation yields between 35 and 87%. A rationale for the stereoselectivity of the cyclisation is forwarded based upon the steric control factors that have been documented for the aza-[2,3]-Wittig sigmatropic rearrangement. A discussion of the mechanism in the context of the reaction conditions is also presented. Oxidation of the silyl group to a hydroxyl group and complete removal were demonstrated for synthetic utility.