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PubMed1977

Preparation of spin-labeled opiates: morphine and codeine.

The preparation of 6-spin-labeled codeine and morphine is described. Treatment of either 6-chlorocodide or 8-bromocodide with 4-amino-2,2,6,6-tetramethylpiperidino-1-oxyl free radical in dimethylformamide afforded 6-spin-labeled codeine. Similar treatment of 6-chloromorphide afforded 6-spin-labeled morphine. Exclusive formation of the 6-isomer in these reactions is explained by halide-ion-catalyzed isomerization of the 6-halo opiate to the 8-halo isomer followed by a normal SN2' displacement of the halogen. Both spin-labeled compounds displayed weak in vivo analgesic activity and did not bind appreciably to receptors in brain homogenate.

Codeine↗
PubMed1979

Phenazines with two cationic side chains as potential antimalarials.

1,9-Phenazine-bis(dialkylaminocarboxamides) were prepared for screening as potential antimalarials. No significant activity against Plasmodium berghei was observed. The phenazine targets were prepared from 1,9-phenazinedicarboxylic acid by standard methods. The reaction between 1,9-phenazinedicarboxylic acid and thionyl chloride in the presence of dimethylformamide unexpectedly gave 4-chloro-1,9-phenazinedicarbonyl chloride.

Animals↗
PubMed1979

Prostaglandin prodrugs. II: New method for synthesizing prostaglandin C1-aliphatic esters.

A new method for synthesizing C1-aliphatic esters of dinoprost and dinoprostone without using hydroxyl protective groups is described. Reaction of the prostaglandin with an alkyl halide in the presence of the sterically hindered amine N,N-diisopropylethylamine proceeds smoothly to give C1-esters in various solvents at ambient or slightly elevated temperatures. Polar solvents were strongly catalytic, and even the hindered tert-butyl esters were synthesized by employing solvents such as dimethylformamide or dimethyl sulfoxide. Biological evaluation in the hamster antifertility assay showed that some esters maintained high bioactivity.

Animals↗
PubMed1979

Sarin transport across excised human skin II: Effect of solvent pretreatment on permeability.

The effect of pretreating callus membranes with dimethyl sulfoxide, dimethylacetamide, dimethylformamide, formamide, dioxane, or methyl orthoformate on sarin permeability was studied at three temperatures to determine the activation energy for transport. In addition, the effect of membrane pretreatment on permeability through callus membranes from either a sarin-carboxypolymethylene gel or a sarin-polymethyl methacrylate gel was studied.

Humans↗
PubMed1980

Synthesis of propranolol mustard as a possible lung-specific antitumor agent.

A nitrogen mustard analog of propranolol was synthesized as a potential lung-specific antitumor agent. Since dl-propranolol concentrates in lung tissue and beta-blocking activity resides only with the l-enantiomer, the d-modification could serve as a lung-directed carrier for a cytotoxic group. Reaction of 1-(1-naphthyloxy)-3-[bis(2-hydroxyethyl)amino]-2-propanol with thionyl chloride resulted in replacement of all three hydroxyl groups with chlorine. The necessary chlorination selectivity was achieved with p-toluenesulfonyl chloride in dimethylformamide solution to provide propranolol mustard, 1-(1-naphthyloxy)-3-[bis(2-chloroethyl)amino]-2-propanol. Both the trichloro compound and propranolol mustard showed reproducible activity against P-388 leukemia. Neither compound was active against the B16 tumor or Lewis lung carcinoma.

Animals↗
PubMed1980

Antileukemic activity of 2-bis(2-methylthio)vinyl-1-methylquinolinium iodides.

Reaction of 1-methylquinolinium-2-dithioacetic acid zwitterions with excess methyl iodide in dimethylformamide gave the corresponding bis(2-methylthio)vinyl derivatives. These compounds were more soluble in both aqueous and organic media than the dithioacetic acid zwitterions but showed comparable antileukemic activity in mice. Reaction with morpholine converted a bis(2-methylthio)vinyl derivative almost quantitatively to the 2-mono(methylthio)-2-morpholino derivative. Leukemia cell culture studies of the 6-methyl derivative showed no effect on cell cycle processes.

Animals↗
PubMed1984

Expanded solubility parameter approach. I: Naphthalene and benzoic acid in individual solvents.

An expanded solubility parameter system was tested in conjunction with the extended Hansen solubility approach and the UNIFAC method to calculate the solubilities of naphthalene and benzoic acid in polar and nonpolar solvents. The expanded parameter system is characterized by delta d for the dispersion force, delta p for dipolar forces, a basic or electron-donor parameter, delta b, and an acidic or electron-acceptor parameter delta a. The correlation between the calculated and observed solubilities of benzoic acid was increased by use of the four-parameter system. An indicator variable was required to bring the solubilities into line in strongly dipolar solvents such as N,N-dimethylformamide. For naphthalene, use of the four-parameter approach proved not to be an improvement over the three-parameter extended Hansen solubility approach. The UNIFAC method was not successful in calculating solubilities of benzoic acid in the 40 polar and nonpolar solvents. A triangular plot of the three Hansen parameters for benzoic acid, p-hydroxybenzoic acid, and methyl p-hydroxybenzoate illustrated the contributions of dispersion, dipolar, and Lewis acid-base (hydrogen bonding) interaction forces among the three benzoic acid compounds and the various classes of solvents. A multiple regression procedure for calculating the four partial solubility parameters of drug solutes was developed.

Benzoates↗
PubMed1987

Interlaboratory comparison of analytical methods for residual ethylene oxide in medical device materials.

An interlaboratory comparison of four gas chromatographic test procedures for the quantification of ethylene oxide in an acrylic polymer was conducted by thirteen laboratories. The procedures included extractions with water, acetone, and N,N-dimethylformamide, and headspace gas analysis. The results of this study, using only the data from the labs that did not deviate from the procedure, showed that the average estimated total coefficient of variation ranged from 8 to 22% for the four different methods. Each of the methods is suitable for use as a reference test method for determining residual ethylene oxide in polymeric materials.

Chromatography, Gas↗
PubMed1989

Synthesis and antimicrobial activity of new substituted 10-methyl-1,2-dihydro-1-oxo-1,2,4-triazino(4,5-a)indoles.

Ten new 4,8-disubstituted 10-methyl-1,2-dihydro-1-oxo-1,2,4-triazino(4,5-a)indoles (5 and 6) were prepared by refluxing various 5-substituted indole-2-carbohydrazides (4) with triethylorthoformate or triethylorthoacetate in dimethylformamide. These derivatives were evaluated for their antimicrobial activity. Some of the title compounds possess fairly potent antimicrobial activity.

Anti-Bacterial Agents↗
PubMed1979

Regulation of dome formation in differentiated epithelial cell cultures.

Rat mammary (Rama 25) and dog kidney (MDCK) epithelial cell cultures formed 'domes' of cells due to fluid accumulation in focal regions between the culture dish and the cell monolayer. Addition of ouabain caused collapse of domes, suggesting that transport functions were required for maintenance of domes. Dome formation in both epithelial cell lines was stimulated by a broad spectrum of known inducers of erythroid differentiation in Fried erythroleukemia cells. Among these inducers were: 1) polar solvents such as dimethyl-sulfoxide, dimethylformamide, and hexamethylene bisacetamide; 2) purines such as hypoxanthine, inosine, and adenosine; 3) low-molecular-weight fatty acids such as n-butyrate; and 4) conditions expected to elevate levels of cyclic AMP. In the latter group were activators of adenylate cyclase such as cholera toxin and prostaglandin E 1; cyclic AMP phosphodiesterase inhibitors such as theophylline and 1-methyl-3-isobutylxanthine; and analogs of cyclic AMP. Induction of domes occurred 15--30 h after addition of inducer to the culture medium. Induction by chemicals was serum-dependent and required protein synthesis but not DNA synthesis. Induced dome formation was reversible after removal of inducer, requiring the continuous presence of inducer. Reversal was also observed after either either removal of serum or addition of inhibitors of protein synthesis. These results suggest that hypothesis that domes arise in these epithelial cultures by a process that is similar to cell differentiation and is influenced by cyclic AMP.

Animals↗
PubMed2006

Analysis of amides in the air by sampling with SPME and detection by GC-FID.

This paper proposes a solid-phase microextraction (SPME) method for the passive sampling and determination of N,N-dimethylacetamide (DMA) and N,N-dimethylformamide (DMF) in air by capillary GC with flame ionization detection. The optimized conditions for SPME method were grab sampling, polydimethylsiloxane/divinylbenzene fiber, extraction for 90 min at 25 +/- 2 degrees C, desorption for 3 min at 220 degrees C, and relative humidity 45 +/- 2%. Under these conditions, the method presented good linearity (R = 0.996), repeatability (%RSD 2.79 and 9.85 for DMF and DMA, respectively), and detection limit (0.021 and 0.024 mg/m3 for DMF and DMA, respectively).

Journal Article↗
PubMed1984

Synthesis and evaluation of immobilized androgens for affinity chromatography in the purification of nuclear androgen receptor.

Seven biospecific adsorbents containing immobilized androgens were synthesized: dihydrotestosterone-17 beta-succinyl agarose, and both the unsubstituted and the 17 beta-acetyl derivatives of dihydrotestosterone-7 alpha-undecanoyl agarose, testosterone-7 alpha-undecanoyl agarose, and 19-nortestosterone-7 alpha-undecanoyl agarose. The retention capacities for nuclear androgen receptor were generally between 40-80% with little variation in reproducibility; the amount of binding was greatest with dihydrotestosterone-17 beta-succinyl agarose and dihydrotestosterone-17 beta-acetoxy-7 alpha-undecanoyl agarose. Rapid flow rates were obtained with all gels, and no tendency for decomposition was observed over a period of 1 year. Factors that affected retention included the concentration of immobilized androgen, length of the linker arm, occupation of receptor sites, interval of contact with the gel, and temperature of incubation. Chemical dissociation of androgens from androgen receptor complexes with 0.2 mM mersalyl increased the retention of receptor by dihydrotestosterone-17 beta-succinyl agarose. Two elutants showed promise for the dissociation of gel-bound receptor: 1) 0.2 mM mersalyl in the presence of 1.5 mg/ml of ovalbumin; 2) 10% (v/v) dimethylformamide:water containing 30 microM [1,2-3H] dihydrotestosterone and 0.5 M sodium thiocyanate.

Androgens↗
PubMed2004

Experimental validation of theoretical potassium and sodium cation affinities of amides by mass spectrometric kinetic method measurements.

In this study the theoretical Gaussian-2 K(+)/Na(+) binding affinities (enthalpies) at 0 K (in kJ mol(-1)) for six amides in the order: formamide (109.2/138.5) < N-methylformamide (117.7/148.6) < acetamide (118.7/149.5) < N,N-dimethylformamide (123.9/156.4) < N-methylacetamide (125.6/157.7) < N,N-dimethylacetamide (129.2/162.6), reported previously (Siu et al., J. Chem. Phys. 2001; 114: 7045-7051), were validated experimentally by mass spectrometric kinetic method measurements. By monitoring the collision-induced dissociation (CID) of K(+)/Na(+)-bound heterodimers of the amides, the relative affinities were shown to be accurate to within +/-2 kJ mol(-1). With these six theoretical K(+)/Na(+) binding affinities as reference values, the absolute K(+)/Na(+) affinities of imidazole, 1-methylimidazole, pyridazine and 1,2-dimethoxyethane were determined by the extended kinetic method, and found to be consistent (to within +/-9 kJ mol(-1)) with literature experimental values obtained by threshold-CID, equilibrium high-pressure mass spectrometry, and Fourier transform ion cyclotron resonance/ligand-exchange equilibrium methods. A self-consistent resolution is proposed for the inconsistencies in the relative order of K(+)/Na(+) affinities of amides reported in the literature. These two sets of validated K(+) and Na(+) affinity values are useful as reference values in kinetic method measurements of K(+)/Na(+) affinity of model biological ligands, such as the K(+) affinities of aliphatic amino acids.

Amides↗
PubMed2004

Characterisation of estrone-nucleic acid adducts formed by reaction of 3,4-estrone-o-quinone with 2'-deoxynucleosides/deoxynucleotides using capillary liquid chromatography/electrospray ionization mass spectrometry.

Xenobiotic and endobiotic molecules can react with DNA leading to formation of so-called DNA adducts. This modified DNA can be repaired enzymatically, but, if not, these modifications are believed to be responsible for the initiation of carcinogenic processes. Hence, we studied the interaction of 2'-deoxynucleosides and 2'-deoxynucleotides with 3,4-estronequinone (3,4-E(1)Q), a metabolite of estrone (E(1)) and a supposed carcinogen. These estrone-nucleic acid adducts were analysed by capillary liquid chromatography (CapLC) coupled to electrospray ionization mass spectrometry (ESI-MS). Knowledge of their behaviour from in vitro studies is a prerequisite for detecting adducts in in vivo studies. Our initial attempts to synthesise nucleos(t)ide adducts of 3,4-E(1)Q in an aprotic solvent (dimethylformamide) yielded no adducts. However, under acidic aqueous conditions, adducts were obtained. With dGuo, a dGuo adduct was found in addition to a Gua adduct. Earlier publications on adduct formation in protic solvents failed to report formation of any adduct with dAdo. A N(3)-Ade adduct was reported upon reaction of 3,4-E(1)Q with Ade base and with DNA. With dAdo, we obtained two nucleoside adducts and six Ade adducts due to loss of 2'-deoxyribose. Thus, contrary to general belief that only 2,3-E(1)Q can form stable adducts, we showed formation of substantial amounts of intact DNA adducts with 3,4-E(1)Q in addition to deglycosylated adducts. Adducts were also obtained with dGMP and dAMP, but no phosphate alkylation was found. Adducts of dCyd, dCMP, dThd, and dTMP were not detected. Using chromatographic-MS data a structural relationship between the 2'-deoxynucleoside, 2'-deoxynucleotide and base adducts was found in the various reaction mixtures. The adducts of dGuo and dGMP reaction mixtures were alkylated at the same N(7)-position of the nucleobase, as indicated by the occurrence of a rapid deglycosylation reaction. In dAdo and dAMP reaction mixtures, 14 adducts were detected; their relationships from the LC and MS data reduced the number of structures to six adenine base alkylated adducts with respect to alkylation between N(1), N(3), N(7) and/or N(6) in the adenine and C(1), C(2) and/or C(6) in 3,4-E(1)Q. We could infer, in addition, whether they had an A ring attachment or a C(6) attachment on the estrone moiety.

Binding Sites↗
PubMed2006

Determination of refractory elements in atmospheric particulates using slurry sampling electrothermal vaporization inductively coupled plasma optical emission spectrometry and inductively coupled plasma mass spectrometry with polyvinylidene fluoride as chemical modifier.

Electrothermal vaporization (ETV) inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS) with polyvinylidene fluoride (PVDF) as chemical modifier are critically compared for the determination of refractory elements in coal fly ash and airborne particulates. The atmospheric particulates that collected on a PVDF filter were introduced into the graphite furnace in the form of a slurry by dissolving the filter in dimethylformamide, and the dissolved filter PVDF, along with additional added PVDF powder, was used as a chemical modifier for subsequent ETV-ICP-OES and ETV-ICP-MS determination. The vaporization behaviors of analytes (Ti, Zr, V, Mo, Cr, La) in ETV-ICP-OES/MS were studied in detail, and the optimal ETV operating parameters were obtained. Under the optimized operating conditions, the detection limits of target elements were 0.08-2.7 ng m(-3) for ETV-ICP-OES and 0.5-50 pg m(-3) for ETV-ICP-MS, respectively, with analytical precisions of 3.5-7.3% for ETV-ICP-OES and 3.9-9.6% for ETV-ICP-MS, respectively. The tolerable amounts of matrix elements for ETV-ICP-OES are higher than for ETV-ICP-MS. Both ETV-ICP-OES and ETV-ICP-MS were used to directly determine the trace refractory elements in coal fly ash and airborne particulates and the analytical results are comparable.

Journal Article↗
PubMed2001

Analysis of amino acids as formamidene butyl esters by electrospray ionization tandem mass spectrometry.

Amino acid formamidene butyl esters are optimally prepared by heating amino acids with dimethylformamide dimethylacetal (DMF-DMA) for 2 minutes at 65 degrees C and then with n-butanol/hydrogen chloride for 15 minutes at 65 degrees C. The formamidene butyl esters of simple alpha-amino acids and beta-amino acids afford between 1.1 and 20 times the signal intensity of the corresponding butyl esters during electrospray ionization tandem mass spectral analysis. Complex alpha-amino acids, such as ornithine, arginine and citrulline, and gamma-amino acids are better analyzed as butyl esters. Secondary alpha-amino acids, such as proline and sarcosine, give a mixture of two iminium salts with the DMF-DMA derivatization method. A derivative incorporating two molecules of the amino acid predominates at higher derivatization temperatures. Contrary to a previous report, N-formylamino acids were not detected. The presence of secondary amino acids in amino acid mixtures, derivatized as formamidene butyl esters, affords derivatives that incorporate two different amino acids. The new formamidene butylation method is unlikely to replace the butylation procedure used by neonatal blood spot screening programs for amino acid disorders, since a much poorer response was obtained with formamidene butyl esters of arginine and citrulline, important in the diagnosis of arginase deficiency and citrullinaemia.

Alkylation↗
PubMed2002

Experimental validation of Gaussian-3 lithium cation affinities of amides: implications for the gas-phase lithium cation basicity scale.

Using a refined Gaussian-3 (G3) protocol, the highest level of ab initio calculations reported so far, we have established the Li+ cation binding enthalpy (affinity) at 0 K (in kJ mol-1) for formamide (195.7), N-methylformamide (209.2), N,N'-dimethylformamide (220.0), acetamide (211.7), N-methylacetamide (222.5), and N,N'-dimethylacetamide (230.1), with an estimated maximum uncertainty of +/-8 kJ mol-1. With these six theoretical lithium cation binding affinities as reference values, the absolute Li+ affinities of imidazole and dimethoxyethane were determined by the extended kinetic method, and by adopting the statistical data treatment protocol recently proposed by Armentrout. The Li+ affinities obtained for these two ligands are in good agreement (within 6 kJ mol-1) with recent values determined by the threshold collision-induced dissociation method, and consistent with the Li+ basicity values first reported by Taft and co-workers in 1990. Our study confirms that the previously suggested, and recently implemented, downward revision of Taft's original basicity scale by 10.9 kJ mol-1 is justified for ligands with revised basicities less than 151 kJ mol-1. However, for selected ligands with Li+ basicities greater than 151 kJ mol-1, including some of the six amides studied in this work, the reported discrepancy between theoretical and experimental estimates in the revised Li+ basicity scale of Burk et al. is likely to arise from experimental uncertainties.

Algorithms↗
PubMed1990

Thalidomide induced alteration in secondary structure of rat embryonic DNA in vivo.

Teratogenicity of thalidomide was demonstrated in Wistar rats following a single maternal intravenous injection during the embryonic organogenetic period. When compared to day 13 embryonic DNA isolated from untreated control mothers, differences were observed in the mean wet weights of day 13 embryos from rats treated with thalidomide during days 10 or 11 of gestation, and significantly less amounts of embryonic DNA were recovered from mothers similarly treated on days 10 or 12 of their respective gestation periods. Rat embryonic DNA may be separated into two fractions by stepwise elution from benzoylated DEAE-cellulose (BD-cellulose) columns with 1.0 M NaCl (SE-DNA) and 1.8% (w/v) caffeine (CE-DNA) solutions, respectively. Other studies using bacterial, yeast, and rat liver DNA suggested that the first fraction contains native DNA, whereas the second may exhibit some degree of single-stranded character. Similar reproducible chromatographic profiles were obtained using a novel "batch method" developed for general application. Rat embryonic DNA was monitored by labelling in vivo with an i.p. injection of [methyl-3H]-thymidine (3H-TdR) during days 5, 6, and 7 of the gestation period. All samples were analysed on day 13 of gestation. A simple increase in percentage of caffeine-eluted DNA was not detected in thalidomide treated samples; however, diversity of percent (%) CE-DNA within litter was noted. Briefly, the percent CE-DNA values for embryos in one litter were ranked and arbitrarily grouped in classes with limits of mean +/- 1 SD, mean +/- 2 SD, and so on to generate a characteristic profile of percent CE-DNA distribution. The number of embryos within the range of each SD unit was expressed as a percentage of each litter. A plot of the ranges of percent CE-DNA versus percentage of each litter was used to illustrate the distribution profile of the particular litter and to be used for comparison between samples from untreated control and thalidomide and/or dimethylformamide (DMF) treated DNA. Treatment of day 12 mothers with thalidomide produced a majority of embryos having percent CE-DNA values similar to those of untreated controls with the exception of the inclusion of a second population of embryos with much higher percent CE-DNA values than those of the untreated controls. Similar treatment of day 11 animals produced a majority of embryos still having percent CE-DNA values similar to those of untreated controls and also having a second group of embryos with a lower percent CE-DNA values than those of untreated controls.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗