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At least 199 records · Page 11Linked to original sources
PubMed1986

Influence of the application mode of N-[4-(5-nitro-2-furyl)-2-thiazolyl]-formamide on the localization of its carcinogenic expression in female NMRI-mice.

The administration of N-[4-(5-nitro-2-furyl)-2-thiazolyl]-formamide FANFT) by gavage to female NMRI-mice resulted in a high incidence of neoplasms of the forestomach. From 117 effective animals which were pooled from 3 dosed groups, 30 squamous cell carcinomas and 26/117 papillomas of the forestomach were diagnosed. Only 5/117 neoplasms of the urinary bladder occurred. The average cumulative dose administered was 1180 mg/mouse, and the mean latent period for the induction of forestomach tumours was 574 days. The mode of application seems to be an important factor in the carcinogenicity of FANFT.

Adenocarcinoma↗
PubMed1987

The influence of urinary tract infection on the incidence of urinary tract tumors in N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide induced carcinogenesis in male Sprague-Dawley rats.

Epidemiological studies have demonstrated an association between urinary tract infection and the development of bladder cancer. The present study aimed at evaluating the influence of urinary tract infection in male Sprague-Dawley rats exposed to a sub-carcinogenic dose of N-[4-(nitro-2-furyl)-thiazolyl]formamide (FANFT). A single injection of Escherichia coli into the bladder resulted in a persistent upper urinary tract infection in a high percentage of the rats. Thirty-two percent of the rats exposed to FANFT and E. coli infection developed urinary tract tumors, all but one occurring in the renal pelvis. Urinary tract tumors were not found in rats treated with FANFT or E. coli alone. The present results support that inflammation resulting from infection is actively involved in urinary tract tumorigenesis and may support the epidemiological studies showing an association between infection and human urinary tract cancer. The formation of dimethylnitrosamine or other nitroso compounds from nitrates in the urine or increased cell proliferation due to chronic inflammation or both may be important pathogenetic factors in tumor development.

Animals↗
PubMed1987

Production of urinary tract tumors by co-administration of uracil and N-[4-(5-nitro-2-furyl)-2-thiazolyl]-formamide in F344 rats.

Co-administration of uracil and N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT) to weanling female Fischer rats produced uracil stones in the bladder and significantly reduced the incidence of bladder tumors. Contrary to bladder tumors, the incidence of renal pelvic and ureteric tumors was increased by this regimen. Feeding of uracil alone produced bladder tumors, in addition to the hyperplasia of renal pelvis, ureter and bladder. The mechanism of uracil's effect on FANFT carcinogenesis is not known.

Animals↗
PubMed1991

Enhanced immunoreactivity of ras oncogene p21 protein in urinary bladder epithelium of rats treated with N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide.

Normal urothelium and various lesions of the rat urinary bladder induced by the dietary administration of 0.2% N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT) (up to 77 weeks) or by the combination of 0.2% FANFT and the subsequent administration of 5% sodium saccharin or 2% DL-tryptophan (up to 104 weeks) were evaluated for immunoreactivity with monoclonal antibody to ras p21 by avidin-biotin immunohistochemistry. Seventy-one to 100% of transitional cell carcinomas showed strong reactivity to the antibody to ras p21 depending on treatment with long-term administration of FANFT or by 6 weeks administration of FANFT followed by sodium saccharin or DL-tryptophan. Focal reactivity to the ras p21 antibody was frequently observed in the hyperplastic (57-96%) or normal appearing urinary bladder epithelium (50-100%) in rats treated with FANFT (FANFT alone or in combination with sodium saccharin or tryptophan) but not in hyperplasia or normal epithelium in rats given sodium saccharin or tryptophan alone, without pretreatment with FANFT or in untreated controls. The present results show that there is a close association of enhanced immunoreactivity with ras p21 antibody in the urinary bladder epithelium to FANFT treatment, and that ras p21 is expressed in normal, hyperplastic and neoplastic lesions of the bladder of rats treated with FANFT. These results suggest that enhanced immunoreactivity with ras p21 is observed as a consequence of the treatment with FANFT but it alone does not reflect the progression from benign to malignant lesions.

Animals↗
PubMed1994

Neu is not involved in N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide- induced bladder carcinoma or 2-amino-4-(5-nitro-2-furyl)thiazole transformation of rat bladder epithelial cells.

Enhanced c-erbB-2/neu expression has been linked with a poor prognosis in human bladder cancer. Previous reports have shown that a point mutation at nucleotide T2012 in the coding region of the transmembrane domain of the rat gene is sufficient to confer transformation potential on this gene. We examined the comparative levels of p185neu as well as the sequence around the hotspot (T2012) of the neu gene of rat bladder cells transformed by 2-amino-4-(5-nitro-2-furyl)thiazole (ANFT) or established in culture from N-[-4-(-5-nitro-2-furyl)-2- thiazolyl]formamide (FANFT)-induced rat bladder tumors. We concluded that increased p185neu expression did not correlate significantly with tumorigenicity. No alterations in nucleotide sequences of the neu gene were observed in either in vitro model.

3T3 Cells↗
PubMed1994

neu is not involved in N-[4-(5-nitro-2-furyl)-2-thiazolyl]-formamide-induced bladder carcinoma or 2-amino-4-(5-nitro-2-furyl)thiazole transformation of rat bladder epithelial cells.

Enhanced c-erbB-2/neu expression has been linked with a poor prognosis in human bladder cancer. Previous reports have shown that a point mutation at nucleotide T2012 in the coding region of the transmembrane domain of the rat gene is sufficient to confer transformation potential on this gene. We examined the comparative levels of p185neu as well as the sequence around the hotspot (T2012) of the neu gene of rat bladder cells transformed by 2-amino-4-(5-nitro-2-furyl)thiazole (ANFT) or established in culture from N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT)-induced rat bladder tumors. We concluded that increased p185neu expression did not correlate significantly with tumorigenicity. No alterations in nucleotide sequences of the neu gene were observed in either in vitro model.

Animals↗
PubMed2005

Effect of pulping variables with dimethyl formamide on the characteristics of bagasse-fiber.

Organosolv pulping of bagasse was conducted following a central composite design using a two-level factorial plan involving three pulping variables (temperature: 190-210 degrees C, time: 120-180 min, organic solvent ratio: 40-60% dimethyl formamide). Responses of pulp and handsheets properties to the process variables were analyzed using statistical software (MINITAB 14). Using values of the independent variables the variation ranges considered provided the following optimum values of the dependent variables: 82.7% (yield), 92.9 (kappa number), 1.403% (ash), 370 ml (freeness), 6290 m (breaking length), 9.4 (folding endurance), 5.955 mN m2 g(-1) (Tear index) and 2.811 kN g(-1) (Burst index) for pulps and handsheets. Results showed that acceptable physical and mechanical properties of pulps and papers similar the pulp used for bleaching could be achieved at 210 degrees C for 150 min and 50% DMF. These are the most suitable conditions for obtaining paper sheets with a high breaking length, tear and burst indices. Also bagasse could be pulped with ease to about 55.72% yield with kappa number approximately 35. The cooking temperature was a significant factor while the DMF ratio and cooking time were not as important in term of the properties of the resultant pulps and papers.

Cellulose↗
PubMed2006

Influence of dimethyl formamide pulping of bagasse on pulp properties.

Organosolv pulping of bagasse was conducted following a central composite design using a two-level factorial plan involving three pulping variables (temperature: 190-210 degrees C, time: 120-180 min, organic solvent charge: 40-60% dimethyl formamide). Responses of pulp properties (yield and holocellulose, alpha-cellulose, kappa number, ash and ethanol-dichloromethane extractives contents) and the pH of the resulting wastewater to the process variables were analyzed using statistical software (MINITAB). Main factor analysis revealed that optimum pulp has the following characteristics: 82.7% (yield), 92.9 (kappa number), 95.84% (holocellulose), 83.53% (alpha-cellulose), 1.403% (ash), 2.562% (ethanol-dichloromethane extractives contents) and 6.39 (pH). These results showed that acceptable properties of pulps could be gained at 200-210 degrees C for 150 min and 40-60% DMF. Based on these results, this method could be used for pulping of bagasse equivalent NSSC concerning high yield at a fixed kappa number. In addition, bagasse could be pulped with ease to approximately 55% yield with a kappa number approximately 31. Numerical analyses showed that cooking temperature had the greatest influence on properties of obtained pulps within the DMF concentrations and cooking time as cooking variables.

Dimethylformamide↗
PubMed1987

N-[4-(5-nitro-2-furyl)-2-thiazolyl] formamide-induced bladder cancer in mice: augmentation by sutures through the bladder wall.

The augmenting effect of chronic inflammation on bladder cancer was studied in female Swiss mice treated with N-[4-(5-nitro-2-furyl)-2-thiazolyl] formamide (FANFT), 0.15% by weight of diet for 20 weeks. To produce chronic inflammation one silk suture and one catgut suture were placed through the bladder wall of 63 mice to receive FANFT and 18 to receive normal diet. In remaining mice (no. = 62) the bladder was simply touched without suture insertion. Thirty-two animals treated with FANFT and 33 treated with FANFT + sutures also received supplements to their drinking water throughout the experiment of the sulfhydryl-reducing agent N-acetylcysteine (500 mg./kg. body weight/day). Seven weeks following FANFT treatment, bladder cancers developed in 12% of mice with sutures and FANFT and in 19% of those with sutures, FANFT, and N-acetylcysteine. No cancers developed in mice receiving FANFT alone or FANFT with N-acetylcysteine and none in mice treated with sutures only. Placement of silk sutures through the bladder wall of mice augments FANFT-induced bladder cancer. N-acetylcysteine at these doses does not influence the incidence.

Acetylcysteine↗
PubMed1982

In vitro characterization of four N-[4-(5-nitro-2-furyl)-2-thiazolyl] formamide (FANFT) induced mouse bladder tumors.

Four longterm murine bladder tumor cell lines were established in vitro. The 4 lines were initiated from primary N-[4-(5-nitro-2-furyl)-2-thiazolyl] formamide (FANFT) induced murine bladder tumors arising in C3H/He mice. Each was maintained as a solid tumor in syngeneic mice for at least 30 generations before initiation in tissue culture. The cell lines MBT-2, MBT-8, MBT-409 and MBT-683, have been subcultured over 75 times in vitro for 18 months. They are all epithelial, grow in islands on plastic Petri dishes before confluent growth and form colonies in soft agar suspension culture. Morphologic studies indicate that all 4 lines have epithelial characteristics and karyotypic studies indicate that all lines have polyploidy and marker chromosomes. Population doubling times range from 10 to 26 hours and are consistent for each line.

Animals↗
PubMed2004

Tricarbonylrhenium(I) complexes with thiosemicarbazone derivatives of 2-acetylpyridine and 2-pyridine formamide showing two unusual coordination modes of tridentate thiosemicarbazone ligands.

[NEt(4)](2)[Re(CO)(3)Br(3)] reacts with 2-acetylpyridine phenylthiosemicarbazone (HL(1)) and 2-pyridine formamide thiosemicarbazone (HL(2)) under formation of air-stable, neutral rhenium(I) complexes of the compositions [Re(CO)(3)(L(1)-N,N,S)] and [Re(CO)(3)Br(HL(2)-N,N)]. Spectroscopic studies and X-ray crystallography show that the potentially tridentate thiosemicarbazones adopt unusual coordination modes. Whereas HL(1) deprotonates and binds to the metal in a nonplanar fashion, HL(2) acts as neutral N,N donor ligand. The bond lengths inside the chelate rings are almost uninfluenced by the overall bonding situation.

Journal Article↗
PubMed1978

Antibacterial activity of N-(beta-styryl) formamides related to tuberin.

A series of para-substituted N-(beta-styryl)formamides, analogues of tuberin (4a), has been prepared and assayed for antibacterial activity. The methylthio, ethoxy, and methyl analogues 4e, 4j, and 4t were about twice as active as tuberin against Mycobacterium phlei. Although tuberin lacks activity against Staphylococcus aureus, several of the analogues described were found to inhibit this organism. The phenyl group of tuberin is not a prerequisite for activity since analogues based on naphthyl or ferrocenyl groups were also active. A quantitative structure-activity relationship further implied that an aromatic group need not be present, suggesting the synthesis of the cyclohexyl and n-amyl analogues which were found to possess high activity.

Anti-Bacterial Agents↗
PubMed2000

Anomalous substituent effects in the bischler-napieralski reaction of 2-aryl aromatic formamides

Treatment of some 1-naphthylformamides (or formanilides) possessing a 2,4,5-trioxygenated phenyl substituent at the 2-position with POCl(3) caused an unprecedented carbon insertion reaction into a benzene ring, producing 7-5 ring (azaazulene) systems as valence isomers of isoquinoline skeletons. Precise examination of this abnormal Bischler-Napieralski reaction (BNR) using various substrates led to the following scope and limitations: (i) the 7-5 ring systems were constructed when either 2-alkoxy-4, 5-methylenedioxyphenyl- or 4,5-dialkoxy-2-hydroxyphenyl-substituted formamides were used as a starting substrate; (ii) in the former case the formyl carbon was inserted into the C(1)-C(6) bond of the 2-phenyl group, and normal isoquinoline cyclization competed with an abnormal carbon insertion reaction; (iii) the presence of a hydroxy group at the 2'-position as in the latter cases caused exclusive carbon insertion, in which alternative C(1)-C(2) insertion products were quantitatively formed; (iv) 3, 6-dimethoxy-2-hydroxyphenyl-substituted formanilide electronically equivalent to 4,5-dialkoxy-2-hydroxy derivatives produced an indole-pyrone as an abnormal BNR product. Theoretical approaches using the PM-3 method indicated that these abnormal BNRs could be triggered by ipso attack at the 1'-position yielding spiro intermediates. Ring cleavege of the six-membered ring in the spiro intermediates to a ketene function followed by recyclization was proposed for the 2'-hydroxy-directed abnormal BNRs leading to the C(1)-C(2) insertion product or the indole-pyrone derivative.

Journal Article↗
PubMed2001

Synthesis of primary aromatic amides by aminocarbonylation of aryl halides using formamide as an ammonia synthon.

Primary aromatic amides were prepared by a palladium-catalyzed aminocarbonylation reaction of aryl halides in high yields (70-90%) using formamide as the amine source. The reactions require a palladium catalyst in combination with a nucleophilic Lewis base such as imidazole or 4-(dimethylamino)pyridine (DMAP). Aryl, heteroaryl, and vinyl bromides and chlorides were converted to the primary amides under mild conditions (5 bar, 120 degrees C) using 1 mol % of a palladium-phosphine complex. Best results were obtained in dioxane using triphenylphosphine as the ligand and DMAP as the base. For activated aryl bromides, a phosphine-to-palladium ratio of 2:1 was sufficient, but less reactive aryl bromides or aryl chlorides required ligand-to-palladium ratios up to 8:1 in order to stabilize the catalyst and achieve full conversion. The influence of catalyst, base, solvent, pressure, and temperature was studied in detail. The mechanism of the reaction could be clarified by isolating and identifying the reaction intermediates. In addition, methylamides and dimethylamides were prepared by the same method using N-methylformamide and N,N-dimethylformamide as the amine source.

Journal Article↗
PubMed2005

Theoretical studies on the mechanism of acid-promoted hydrolysis of N-formylaziridine in comparison with formamide.

[reaction: see text] We present an ab initio study of the acid-promoted hydrolysis reaction mechanism of N-formylaziridine in comparison with formamide. Since the rate of amide hydrolysis reactions depends on the formation of the tetrahedral intermediate, we focused our attention mainly on the reactant complex, the tetrahedral intermediate, and the transition state connecting these two stationary points. Geometries were optimized using the density functional theory, and the energetics were refined using ab initio theory including electron correlation. Solvent effects were investigated by using polarizable continuum method calculations. The proton-transfer reaction between the O-protonated and N-protonated amides was investigated. In acidic media, despite that the N-protonated species is more stable than the O-protonated one, it is predicted that both N-protonated and O-protonated pathways compete in the hydrolysis reaction of N-formylaziridine.

Journal Article↗
PubMed2005

Evaporation kinetics of tetraalkylammonium ions from charged formamide drops.

The rate of ion evaporation from the surface of electrically charged liquid drops may be inferred from observations of the minimum drop charge q present on drops of a given radius R. This critical relation q(R) is measured here from the fossil solid residues left by the drops after complete solvent evaporation. We obtain mobility distributions of singly charged clusters formed by charge-reduced electrosprays of tetra-n-alkylammonium salts (C(n)()H(2)(n)()(+1))(4)N(+) (n = 2-10) dissolved in formamide. These distributions exhibit modulated structures, with each wave being associated with an initial charge state of the clusters prior to charge reduction, from which critical q(R) relations follow. For n from 4 to 7, the behavior is weakly dependent on the length of the alkyl chain. Above n = 7, there is a marked increase in solvation energy of the alkylammonium ions, but drop curvature effects contribute a compensating reduction of the energy barrier for ionization. This curvature effect increases monotonically with n and is probably associated with surface activity. Few clear modulations are seen for n < 3, perhaps because of the decreased role of surface activity in transferring solute into very small drops during the Coulombic breakup of larger drops. For this reason, extension of this technique to small inorganic salts is problematic.

Journal Article↗
PubMed2005

Dimers of formic acid, acetic acid, formamide and pyrrole-2-carboxylic acid: an ab initio study.

The intermolecular hydrogen bonds in dimers of formic acid, acetic acid, and formamide were investigated. Additionally, three configurations of the pyrrole-2-carboxylic acid (PCA) dimer were studied to analyze how the pyrrole pi-electron system influences the carboxylic groups connected by double O-H...O hydrogen bonds. The ab initio calculations for the systems investigated were performed at MP2/6-311++G(d,p), MP2/aug-cc-pVDZ, and MP2/aug-cc-pVTZ//MP2/aug-cc-pVDZ levels of theory. The "atoms in molecules" theory of Bader was used and the analysis of the critical points was performed to study the nature of hydrogen bonds. The decomposition of the total interaction energy applied here reveals that the delocalization energy term is a particularly important attractive contribution in these systems, more important in the case of systems forming homonuclear O-H...O double hydrogen bonds than in the case of those connected through heteronuclear N-H...O bonds. Because the systems analyzed may be formally classified as the resonance-assisted hydrogen bonds (RAHBs), it seems that the dominant contribution from the delocalization interaction energy term is a distinguished feature of such interactions.

Journal Article↗