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At least 19 recordsLinked to original sources
PubMed1989

Biotransformation of aliphatic formamides: metabolites of (+-)-N-methyl-N-(1-methyl-3,3-diphenylpropyl) formamide in rats.

The in vivo biliary and urinary metabolites of (+-)-N-methyl-N-(1-methyl-3,3-diphenylpropyl) formamide (1) from male Wistar rats have been characterized by gas chromatography/mass spectrometry. In urine, non-conjugated metabolites included 1,1-diphenyl-3-butanone (4) and 3-methylamino-1,1,diphenylbutane (7). beta-Glucuronidase liberated 4, 1,1-diphenyl-3-butanol (5), 1,1-diphenyl-3-butanone oxime (6), N-hydroxymethyl-N-(1-methyl-3, 3-diphenylpropyl) formamide (3), 1-(4-hydroxyphenyl)-1-phenyl-3-butanone (11), 1-(4-hydroxyphenyl)-1-phenyl-3-butanone oxime (12), N-methyl-N-(1-methyl-3-(4-hydroxyphenyl)-3-phenylpropyl) formamide (8), 1-(4-hydroxy-3-methoxyphenyl)-1-phenyl-3-butanone (16); 1-(4-hydroxy-3-methoxyphenyl)-1-phenyl-3-butanol (17), 1-(4-hydroxy-3-methoxyphenyl)-1-phenyl-3-butanone oxime (18), N-(1-methyl-3-(4-hydroxy-3-methoxyphenyl)-3-phenylpropyl) formamide (14) and N-methyl-N-(1-methyl-3-(4-hydroxy-3-methoxyphenyl)-3-phenylpropyl) formamide (13). Most of the carbinolamide (3) decomposed in the gas chromatograph inlet to N-(1-methyl-3,3-diphenylpropyl) formamide (2) unless stabilized as a trimethylsilyl (TMS) derivative. In bile, compounds 1, 2, 3, 5, 6, 11, 12 and 16 were present as non-conjugated metabolites. beta-Glucuronidase also liberated N-(1-methyl-3-(4-hydroxyphenyl-3-phenylpropyl) formamide (9), and all of the previously listed compounds except 7. Trimethylsilylation of the conjugated bile fraction revealed the presence of an additional two compounds: N-hydroxymethyl-N-(1-methyl-3-(4-hydroxyphenyl)-3-phenylpropyl) formamide (10) and N-hydroxymethyl-N-(1-methyl-3-(4-hydroxy-3-methoxyphenyl)-3-phenylpropyl ) formamide (15). A stable carbinolamide metabolite standard was synthesized and the mass spectral fragmentations of its TMS derivative studied by tandem mass spectroscopy. This is the first report on stable carbinolamide metabolites of high-molecular-weight formamides.

Animals↗
PubMed1999

Low-temperature crystallization and structure determination of N-(trifluoromethyl)formamide, N-(2,2,2-trifluoroethyl)formamide and 2,2,2-trifluoroethyl isocyanide.

Crystals of N-(trifluoromethyl)formamide, C(2)H(2)F(3)NO, (I), N-(2,2,2-trifluoroethyl)formamide, C(3)H(4)F(3)NO, (II), and 2,2,2-trifluoroethyl isocyanide, C(3)H(2)F(3)N, (III), were grown in situ on an X-ray diffractometer and analysed by single-crystal X-ray diffraction methods at low temperatures. Crystal data: (I) orthorhombic, P2(1)2(1)2(1), a = 4.547 (2) Å, b = 5.947 (3) Å, c = 14.731 (9) Å, V = 398.3 (4) Å(3), Z = 4, M(r) = 113.05, T = 143 K, D(x) = 1.885 Mg m(-3); (II) monoclinic, P2(1)/n, a = 4.807 (1) Å, b = 16.707 (3) Å, c = 6.708 (1) Å, beta = 109.90 (1) degrees, V = 506.6 (2) Å(3), Z = 4, M(r) = 127.07, T = 141 K, D(x) = 1.666 Mg m(-3); (III) orthorhombic, P2(1)2(1)2(1), a = 5.668 (2) Å, b = 9.266 (3) Å, c = 8.626 (2) Å, V = 453.0 (2) Å(3), Z = 4, M(r) = 109.06, T = 163 K, D(x) = 1.599 Mg m(-3). The results showed that in the crystal both formamides (I) and (II) are exclusively present in the form of the Z isomer, although measurements of solutions of (I) have shown that the E isomer prevails [Lentz et al. (1987). Angew. Chem. 99, 951-953]. In addition ab initio calculations for (I) predicted the E isomer to be the more stable one. In compound (III) the isocyanide group is staggered with respect to the trifluoroethyl group. In the crystal packing of (I) and (II) intermolecular N-H.O hydrogen bonds generate infinite chains. In (I), these chains are linked to form sheets by C-H.O contacts. In the crystal structure of (III) each isocyanide dipole is surrounded by four electronegative F atoms with intermolecular C.F contacts between 3.4 and 3.5 Å.

Journal Article↗
PubMed2006

Phase behavior of mixtures of polyoxyethylene(10) stearyl ether (Brij-76), 1-butanol, isooctane, and mixed polar solvents I. Water and formamide (or N,N-dimethyl formamide).

The isothermal phase diagram of the quaternary system polyoxyethylene(10) stearyl ether (Brij-76)/1-butanol/isooctane/water has been constructed at 30 degrees C with equal amounts of oil and water. A regular fishtail diagram was obtained, confirming the establishment of hydrophile-lipophile balance (HLB) in the system. Mixing of formamide (FA) [or N,N-dimethyl formamide (DMF)] with water as a cosolvent altered the HLB and decreased the solubilization capacity of the quaternary system. No three-phase body appeared at high FA or DMF content. Similar observations were noted for temperature-induced phase diagrams. The effect of DMF was more pronounced than that of FA in reducing the maximum solubilization capacity. The results have been summarized on the basis of HLB and mutual solubility of the components.

Journal Article↗
PubMed2000

Effect of water on the formamide-intercalation of kaolinite.

The molecular structures of low defect kaolinite completely intercalated with formamide and formamide-water mixtures have been determined using a combination of X-ray diffraction, thermoanalytical techniques, DRIFT and Raman spectroscopy. Expansion of the kaolinite to 10.09 A was observed with subtle differences whether the kaolinite was expanded with formamide or formamide-water mixtures. Thermal analysis showed that greater amounts of formamide could be intercalated into the kaolinite in the presence of water. New infrared bands were observed for the formamide intercalated kaolinites at 3648, 3630 and 3606 cm(-1). These bands are attributed to the hydroxyl stretching frequencies of the inner surface hydroxyls hydrogen bonded to formamide with water, formamide and interlamellar water. Bands were observed at similar positions in the Raman spectrum. At liquid nitrogen temperature, the 3630 cm(-1) Raman band separated into two bands at 3633 and 3625 cm(-1). DRIFT spectra showed the hydroxyl deformation mode at 905 cm(-1). Changes in the molecular structure of the formamide are observed through both the NH stretching vibrations and the amide 1 and 2 bands. Upon intercalation of kaolinite with formamide, bands are observed at 3460, 3344, 3248 and 3167 cm(-1) attributed to the NH stretching vibration of the NH involved with hydrogen bonded to the oxygens of the kaolinite siloxane surface. In the DRIFT spectra of the formamide intercalated kaolinites bands are observed at 1700 and 1671 cm(-1) and are attributed to the amide 1 and amide 2 vibrations.

Amides↗
PubMed2001

The Modification of Hydroxyl Surfaces of Formamide-Intercalated Kaolinites Synthesized by Controlled Rate Thermal Analysis.

Controlled rate thermal analysis (CRTA) technology made possible the separation of adsorbed formamide from intercalated formamide in formamide-intercalated kaolinites. X-ray diffraction shows that the CRTA-treated formamide-intercalated kaolinites remain expanded after CRTA treatment. The Raman spectra of the CRTA-treated formamide-intercalated kaolinites are significantly different from those of the intercalated kaolinites with both intercalated and adsorbed formamide. An intense band is observed at 3629 cm(-1), attributed to the inner surface hydroxyls hydrogen bonded to the formamide. Broad bands are observed at 3600 and 3639 cm(-1) and are attributed to the inner surface hydroxyls, which are hydrogen bonded to the adsorbed water molecules. The hydroxyl stretching band of the inner hydroxyl is readily observed at 3621 cm(-1) in the Raman spectra of the CRTA-treated formamide-intercalated kaolinites. The results of thermal analysis show that the amount of intercalated formamide between the kaolinite layers is independent of the presence of water. The Raman bands of the formamide in the CRTA-treated intercalated kaolinites are readily observed. Copyright 2001 Academic Press.

Journal Article↗
PubMed2006

Microsolvation of formamide: a rotational study.

Microsolvated formamide clusters have been generated in a supersonic jet expansion and characterized using Fourier transform microwave spectroscopy. Three conformers of the monohydrated cluster and one of the dihydrated complex have been observed. Seven monosubstituted isotopic species have been measured for the most stable conformer of formamide...H(2)O, which adopts a closed planar ring structure stabilized by two intermolecular hydrogen bonds (N-H...O(H)-H...O=C). The two higher energy forms of formamide...H(2)O have been observed for the first time. The second most stable conformer is stabilized by a O-H...O=C and a weak C-H...O hydrogen bond, while, in the less stable form, water accepts a hydrogen bond from the anti hydrogen of the amino group. For formamide...(H(2)O)(2), the parent and nine monosubstituted isotopic species have been observed. In this cluster the two water molecules close a cycle with the amide group through three intermolecular hydrogen bonds (N-H...O(H)-H...O(H)-H...O=C), the nonbonded hydrogen atoms of water adopting an up-down configuration. Substitution (r(s)) and effective (r(0)) structures have been determined for formamide, the most stable form of formamide...H(2)O and formamide...(H(2)O)(2). The results on monohydrated formamide clusters can help to explain the observed preferences of bound water in proteins. Clear evidence of sigma-bond cooperativity effects emerges when comparing the structures of the mono- and dihydrated formamide clusters. No detectable structural changes due to pi-bond cooperativity are observed on formamide upon hydration.

Journal Article↗
PubMed1989

Osmotic and pharmacological effects of formamide on capacity current, gating current, and sodium current in crayfish giant axons.

Internal perfusion with solutions made hyperosmolar by 10% formamide selectively reduces the initial fast component of ON gating current (fast Ig) in crayfish axons. This result parallels the effects of formamide perfusion seen in Myxicola giant axons (Schauf, C. L., and M. A. Chuman. 1986. Neural Membranes. Alan R. Liss, Inc., New York. 3-23). However, our findings do not confirm their conclusion that internal formamide has a specific pharmacological effect on fast Ig. Formamide-induced suppression of fast Ig is always associated with changes in linear capacity current, indicating a reduction in the rate of rise of the voltage clamp. Furthermore, this suppression of fast Ig can be reversed when clamp rise time is returned to its control rate by increasing compensation for series resistance (Rs) during formamide perfusion. Increases in Rs during 10% formamide perfusion of up to 5 omega.cm2 were measured by evaluating the increase in Rs compensation required to return the following parameters to their control levels: (a) peak capacity current, (b) peak gating current, (c) the voltage maximum of the /Na-V curve, and (d) "tau h". We conclude that hyperosmolar internal formamide increases Rs, reduces clamp speed, and thus selectively suppresses fast Ig. On the other hand, the reversible block of sodium ionic current by internal formamide, reported by Schauf and Chuman, is not eliminated by correcting for series resistance changes during formamide perfusion.

Animals↗
PubMed1977

Renaturation kinetics and thermal stability of DNA in aqueous solutions of formamide and urea.

This paper reports the results of a systematic study of the effects of formamide and urea on the thermal stability and renaturation kinetics of DNA. Increasing concentrations of urea in the range 0 to 8 molar lower the Tm by 2.25 degrees C per molar, and decreases the renaturation rate by approximately 8 percent per molar. Increasing concentrations of formamide in the range from 0 to 50 percent lowers the Tm by 0.60 degrees C per percent formamide for sodium chloride concentrations ranging from 0.035M to 0.88M. At higher salt concentrations the dependence of Tm on percent formamide was found to be slightly greater. Increasing formamide concentration decreases the renaturation rate linearly by 1.1% per percent formamide such that the optimal rate in 50% formamide is 0.45 the optimal rate in an identical solution with no formamide. The effects of urea and formamide on the renaturation rates of DNA are explained by consideration of the viscosities of the solutions at the renaturation temperatures.

DNA↗
PubMed2006

Formamide probes a role for water in the catalytic cycle of cytochrome c oxidase.

Formamide is a slow-onset inhibitor of mitochondrial cytochrome c oxidase that is proposed to act by blocking water movement through the protein. In the presence of formamide the redox level of mitochondrial cytochrome c oxidase evolves over the steady state as the apparent electron transfer rate from cytochrome a to cytochrome a(3) slows. At maximal inhibition cytochrome a and cytochrome c are fully reduced, whereas cytochrome a(3) and Cu(B) remain fully oxidized consistent with the idea that formamide interferes with electron transfer between cytochrome a and the oxygen reaction site. However, transient kinetic studies show that intrinsic rates of electron transfer are unchanged in the formamide-inhibited enzyme. Formamide inhibition is demonstrated for another member of the heme-oxidase family, cytochrome c oxidase from Bacillus subtilis, but the onset of inhibition is much quicker than for mitochondrial oxidase. If formamide inhibition arises from a steric blockade of water exchange during catalysis then water exchange in the smaller bacterial oxidase is more open. Subunit III removal from the mitochondrial oxidase hastens the onset of formamide inhibition suggesting a role for subunit III in controlling water exchange during the cytochrome c oxidase reaction.

Animals↗
PubMed1996

Reduced formamide content and hybridization temperature results in increased non-radioactive mRNA in situ hybridization signals.

To define conditions for highly sensitive non-radioactive mRNA in situ hybridization on cryostat sections the influence of decreased formamide content and hybridization temperature was studied. The examination was performed on fibromatosis nodules of palmar fibromatosis visualizing the beta actin mRNA of myofibroblasts. The results show that a decrease in formamide content and hybridization temperature is able to enhance the sensitivity of mRNA detection applicating digoxigenin labelled DNA oligodeoxynucleotide. The best hybridization signal could be obtained under formamide-free conditions. In conclusion, a simplified sensitive formamide-free mRNA in situ hybridization protocol using oligonucleotide probes on human tissue cryostat sections is presented. The negative formamide effect is seen as a result of the chemical interaction of formamide with nucleic acid strands. An omission of formamide is suggested if the target as well as the probe are single stranded.

Actins↗
PubMed2002

Modeling substrate- and inhibitor-bound forms of liver alcohol dehydrogenase: chemistry of mononuclear nitrogen/sulfur-ligated zinc alcohol, formamide, and sulfoxide complexes.

Using a mixed nitrogen/sulfur ligand possessing a single internal hydrogen bond donor (N,N-bis-2-(methylthio)ethyl-N-(6-amino-2-pyridylmethyl)amine (bmapa)), we prepared and structurally and spectroscopically characterized a series of zinc complexes possessing a single alcohol ([(bmapa)Zn(MeOH)](ClO(4))(2) (1)), formamide ([(bmapa)Zn(DMF)](ClO(4))(2) (3), [(bmapa)Zn(NMF)](ClO(4))(2) (4)), or sulfoxide ([(bmapa)Zn(DMSO)](ClO(4))(2) (7), [(bmapa)Zn(TMSO)](ClO(4))(2) (8)) ligand. X-ray crystallographic characterization was obtained for 1.MeOH, 3, 4, 7.DMSO, and 8. To enable studies of the influence of the single hydrogen bond donor amino group of the bmapa ligand on the chemistry of zinc/neutral oxygen donor binding interactions, analogous alcohol ([(bmpa)Zn(MeOH)](ClO(4))(2) (2)), formamide ([(bmpa)Zn(DMF)](ClO(4))(2) (5), [(bmpa)Zn(NMF)](ClO(4))(2) (6)), and sulfoxide ([(bmpa)Zn(DMSO)](ClO(4))(2) (9), [(bmpa)Zn(TMSO)](ClO(4))(2) (10)) complexes of the bmpa (N,N-bis-2-(methylthio)ethyl-N-(2-pyridylmethyl)amine) ligand system were generated and characterized. Of these, 2, 5, 6, and 9.2DMSO were characterized by X-ray crystallography. Solution spectroscopic methods ((1)H and (13)C NMR, FTIR) were utilized to examine the formamide binding properties of 3-6 in CH(3)CN and CH(3)NO(2) solutions. Conclusions derived from this work include the following: (1) the increased donicity of formamide and sulfoxide donors (versus alcohols) makes these competitive ligands for a cationic N/S-ligated zinc center, even in alcohol solution, (2) the inclusion of a single internal hydrogen bond donor, characterized by a heteroatom distance of approximately 2.80-2.95 A, produces subtle structural perturbations in N/S-ligated zinc alcohol, formamide, or sulfoxide complexes, (3) the heteroatom distance of a secondary hydrogen-bonding interaction involving the oxygen atom of a zinc-coordinated alcohol, formamide, and sulfoxide ligand is reduced with increasing donicity of the exogenous ligand, and (4) formamide displacement on a N/S-ligated zinc center is rapid, regardless of the presence of an internal hydrogen bond donor. These results provide initial insight into the chemical factors governing the binding of a neutral oxygen donor to a N/S-ligated zinc center.

Alcohol Dehydrogenase↗
PubMed1982

Optimization of the ethanol precipitation of RNA from formamide containing solutions.

This study shows that high variability and low recoveries are obtained when conventional ethanol precipitation is used to recover RNA from the 70%-90% formamide containing solutions that are used to elute poly(U) Sepharose columns. Precipitations of RNA at different formamide concentrations show that the variability of the recovery increases with increasing formamide concentration and the recovery decreases by 7% for each 10% increase in the formamide concentration. The formamide concentration curve shows that these factors can be optimized by diluting the formamide containing solutions at least to 30% formamide prior to the precipitation.

Chemical Precipitation↗
PubMed1994

Formamide sensitivity: a novel conditional phenotype in yeast.

Yeast mutants unable to grow in the presence of 3% formamide have been isolated in parallel with mutants sensitive to either 37 degrees or 6% ethanol. The number of formamide-sensitive mutations that affect different genes that can be identified from yeast cells is at least as large as the number of thermosensitive or ethanol-sensitive mutations. These mutations are of two types: those that are sensitive to formamide, temperature and/or ethanol simultaneously; and those that are specific for formamide sensitivity and show no temperature or ethanol sensitivity phenotype. Those genes susceptible to giving rise to formamide-sensitive alleles include the structural gene for DNA ligase, CDC9, and the structural gene for arginine permease, CAN1. The results indicate that formamide sensitivity can be used as a novel conditional phenotype for mutations on both essential and nonessential genes. This work also confirms that ethanol-sensitivity can be used as a conditional phenotype to identify mutations in at least as many genes as those susceptible to temperature or formamide sensitive mutations.

Alleles↗
PubMed1996

Thermodynamic effects of formamide on DNA stability.

Formamide lowers melting temperatures (Tm) of DNAs linearly by 2.4-2.9 degrees C/mole of formamide (C(F)) depending on the (G+C) composition, helix conformation and state of hydration. The inherent cooperativity of melting is unaffected by the denaturant. dTm/dC(F)for 11 plasmid domains of 0.23 < (G+C)<0.71 generally fit to a linear dependence on (G+C)-content, which, however, is consistent with a (G+C)-independent alteration in the apparent equilibrium constant for thermally induced helix <--> coil transitions. Results indicate that formamide has a destabilizing effect on the helical state, and that sequence-dependent variations in hydration patterns are primarily responsible for small variations in sensitivity to the denaturant. The average unit transition enthalpy delta H(m)[see text for complete expression], exhibits a biphasic dependence on formamide concentration. The initial drop of -0.8 kcal/mol bp at low formamide concentrations is attributable to a delta delta H(m)[see text for complete expression], for exchange of solvent in the vicinity of the helix: displacement by formamide of weakly bound hydrate or counterion. The phenomenological effects are equivalent to lowering the bulk counterion concentration. Poly(dA.dT) exhibits a much lower sensitivity to formamide, due to the specific pattern of tightly bound, immobilized water bridges that buttress the helix from within the narrow minor groove. Tracts of three (A.T)-pairs behave normally, but tracts of six exhibit the same level of reduced sensitivity as the polymer, suggesting a conformational shift as tracts are elongated beyond some critical length [McCarthy J.G. and Rich,A. (1991) Nucleic Acids Res. 19, 3421-3429].

Base Composition↗
PubMed1996

Secondary structure content of the HDV ribozyme in 95% formamide.

The Hepatitis Delta Virus (HDV) ribozyme self-cleaving activity in 20 M formamide solutions is unique. Does this catalytic activity result from the conservation of its tertiary structure in 20 M formamide? We followed the ribozyme structure in formamide solutions by monitoring the amount of bound Ethidium Bromide (EB). We were able to measure the quantity of dye bound using time-resolved fluorescence spectroscopy, as an estimate of the ribozyme double helical content. This method, calibrated by using oligonucleotides with defined tertiary structure and denaturing solvents, parallels NMR and UV measurements as a function of temperature. Measurements with the HDV ribozyme lead to three conclusions: (a) both the precursor and product RNAs are structured to 24 M (95% w/w) formamide or 4 M H2O solutions which is equivalent to 4 M H2O; (b) the HDV ribozyme is the only RNA sequence investigated in this study that retains so much structure in formamide; and (c) DNA analogs of formamide resistant HDV ribozyme sequences lose their structure at less than 15 M formamide. Thus, the structural integrity of the HDV ribozyme is an intrinsic property of the RNA molecule and its sequence.

Base Sequence↗