NIOSH REL: TWA 10 ppm (30 mg/m3), IDLH 500 ppm; OSHA PEL: TWA 10
ppm; ACGIH TLV: TWA 10 ppm (adopted).
介电常数:
36.710000000000001
LogP:
-1.010
物理描述:
N,n-dimethylformamide appears as a water-white liquid with a faint fishy odor. Flash point 136°F. Slightly less dense than water. Vapors heavier than air. Toxic by inhalation or skin absorption. May irritate eyes.
N,N-dimethylformamide (DMF) is metabolized by the microsomal cytochrome p-450 into mainly N-hydroxymethyl- N-methylformamide (HMMF), which further breaks down to N-methyformamide (NMF). However, the detailed mechanism of its toxicity remains unclear. We investigated the metabolism and the toxicity of DMF using the isolated perfused liver model. DMF was added to the recirculating perfusate of the isolated perfused rat liver at concentrations of 0, 10 and 25 mM. Samples were collected from the inferior vena cava at 0, 30, 45, 60, 75, and 90 minutes following addition of the DMF. The metabolites of DMF were analyzed using Gas-chromatography (GC). The changes in the rate of oxygen consumption by the DMF were monitored during perfusion. The enzyme activities (aspartic aminotransferase:AST, alanine aminotransferase:ALT, and lactic dehydrogenase:LDH)) in the perfusate were monitored to see if DMF caused hepatotoxicity. As the perfusion progressed, the DMF concentration in the perfusate decreased, but the level of NMF increased to a maximum of 1.16 mM. The rate of oxygen consumption increased at DMF concentrations of 10 mM and 25 mM. However, when a known inhibitor of cytochrome P-450, SKF 525A (300 uM), was used to pretreat the perfusate prior to the addition of the DMF, the rate of oxygen consumption was significantly inhibited, indicating the cytochrome P-450 system was responsible for the conversion of DMF to NMF. On addition of the DMF, the activities of the enzymes AST, ALT and LDH were significantly increased a time and dose dependent manner. However, following pretreatment with SKF 525A, their releases were inhibited.
... Two groups of workers investigated metab of DMF on volunteers. ... Both found that majority of absorbed substance is eliminated within 24 hr and that main urinary metabolite is n-methyl formamide. Its concn was related to intensity of exposure.
It is known that dimethylformamide is metabolized in man by sequential N-demethylation to methylformamide and formamide, which are largely eliminated in the urine.
Blood and urine samples of rats and dogs which had been exposed to DMF were examined by GLC analysis and N-methylformamide(NMF) and formamide were detected in addition to DMF. These metabolites were eliminated faster in rats than in dogs. It has been suggested recently that the major metabolite of DMF which has been characterized an NMF by GLC is no NMF but N-hydroxymethyl-N-methylformamide (HMMF). HMMF is the immediate product of methyl C-hydroxylation of DMF and is a relatively stable carbinolamide in aqueous soln. It is, however thermally labile so that it decomposes quantitatively to NMF and presumably formaldehyde on the GLC column. The evidence that the metabolite which has been characterized as NMF is really HMMF is based on three studies. /One study/ found a formaldehyde precursor in the urine of mice which had received DMF. This metabolite liberated formaldehyde only after alkaline hydrolysis. In aqueous soln, authentic HMMF also decomposed to formaldehyde only on alkaline hydrolysis. /Another study/ isolated a urinary metabolite of DMF in rats by HPLC and subjected it to mass spectrometric analysis. The observed fragmentation pattern suggested the presence of HMMF, even though the mass fragments, including the one corresponding to the molecular ion, were also detected in control urine samples. Unequivocal evidence for the contention that HMMF and not NMF is the major metabolite of DMF was recently obtained by high-field proton NMF spectroscopy of urine samples of mice which had received DMF. HMMF exists in 2 rotameric forms and the methyl and formyl protons in the two rotamers are not equivalent. The resonance frequencies corresponding to the methyl and formyl protons of both rotamers were prominent signals in the NMR spectrum of the urine. However, at the resonance frequency of the methyl protons of NMF only a minute signal was observed. In this study dimethylamine and methylamine were found to be minor urinary metabolites of DMF in mice.
Dimethyl formamide may be absorbed following ingestion, inhalation, and dermal exposure, and is distributed evenly throughout the body. Metabolism takes place in the liver via microsomal enzyme systems, producing N-hydroxymethyl- N-methylformamide (DMF-OH) as the main urinary metabolite.
Dimethylformamide ... is an organic solvent produced in large quantities through-out the world. It is used in the chemical industry as a solvent, an intermediate & an additive. Dimethylformamide is a colorless liquid with an unpleasant slight odor that ... has poor warning properties & individuals may be exposed through the inhalation of vapor. Occupational exposure occurs via skin contact with dimethylformamide liquid & vapors. ... Toxic amounts of dimethylformamide may be absorbed by inhalation & through the skin. Absorbed dimethylformamide is distributed uniformily. The /metabolism/ of dimethylformamide takes place mainly in the liver, with the aid of microsomal enzyme systems. In animals & humans, the main product of dimethylformamide biotransformation is N-hydroxymethyl-N-methylformamide. This metabolite is converted during gas chromatographic analysis to N-methylformamide, which itself (together with N-hydroxymethylformamide & formamide) a minor metabolite. ... In metabolic studies & biological monitoring, urinary concentration are expressed as N-hydroxymethylformamide. ... The determination of the /metabolites/ ... in the urine may be a suitable biological indicator of total dimethylformamide exposure. In experimental animals, it has been demonstrated that dimethylformamide metabolism is saturated at high levels &, at very high levels, dimethylformamide inhibits its own metabolism. Metabolic interaction occurs between dimethylformamide & ethanol. ... The effects of dimethylformamide on the environment have not been well studied. The toxicity for aquatic organisms appears to be low ... The acute toxicity of dimethylformamide in a variety of species is low ... . It is a slight to moderate skin & eye irritant. One study on guinea pigs indicated no sensitization potential. Dimethylformamide can facilitate the absorption of other chemical substances through the skin. Exposure of experimental animals to dimethylformamide via all routes of exposure may cause dose related liver injury. ... In some studies, signs of toxicity in the myocardium & kidneys have been /noted/. Dimethylformamide was ... found to be inactive, both in vitro & in vivo, in an extensive set of short term tests for genetic & related effects. No adequate long term carcinogenicity studies on experimental animals have been reported. ... Skin irritation & conjunctivitis have been reported after direct contact with dimethylformamide in /humans/. After accidental exposure to high levels of /this cmpd/, abdominal pain, nausea, vomiting, dizziness & fatigue occur within 48 hr. Liver function may be disturbed, & blood pressure changes, tachycardia & ECG abnormalities have been reported. ... Following long-term repeated exposure, symptoms include headache, loss of appetite & fatigue. Biochemical signs of liver dysfunction may be observed. Exposure to dimethylformamide, even at concn below 30 mg/cu m may cause alcohol intolerance. Symptoms may include a sudden facial flush, tightness of the chest, & dizziness sometimes accompanied by nausea & dypsnea. ... There is limited evidence that dimethylformamide is carcinogenic for human beings. An incr in testicular tumors was reported in one study, whereas another study showed incr incidence of tumors of the buccal cavity & pharynx, but not the testes. In two studies with limited details, an incr frequency of miscarriages was reported in women exposed to dimethylformamide among other chemicals.
While the mechanism of action of dimethyl formamide has not bee fully elucidated, thiocarbamate pesticides have been shown to inhibit aldehyde dehydrogenases. (A2459)
Evaluation: There is inadequate evidence in humans for the carcinogenicity of dimethylformamide. There is evidence suggesting the lack of carcinogenicity of dimethylformamide in experimental animals. Overall evaluation: Dimethylformamide is not classifiable as to its carcinogenicity in humans (Group 3).
Dimethylformamide reached an average level of 2.8 ug/L in the blood of subjects exposed to 21 ppm of the vapor for 4 hr, and was undetectable at 4 hr after the exposure; the metabolite, methylformamide, averaged between 1 and 2 mg/L in the blood and this level was maintained for at least 4 hr after exposure. Maximal blood levels of about 14 and 8 ug/L were observed for dimethylformamide and methylformamide, respectively, at 0 and 3 hr, after a 4 hr exposure to 87 ppm of the vapor. Repeated daily exposures to 21 ppm of dimethylformamide did not result in accumulation of the chemical or its metabolite in blood. /Dimethylformamide and methylformamide/
Eight healthy male subjects were exposed to dimethylformamide (DMF) vapor at a concn of 8.79 + or - 0.33 ppm for 6 hr daily for 5 consecutive days. All urine voided by the subjects was collected from the beginning of the first exposure to 24 hr past the end of the last exposure and each sample was analyzed for monomethylformamide. Monomethylformamide was rapidly eliminated from the body with urine values peaking within a few hours following the end of each exposure period. The mean for the 7 hr (end of exposure) sample was 4.74 mg/mL.
The amount of N-methylformamide recovered in the urine represents only 2-6% of the dose of dimethylformamide inhaled. A substantial portion of an absorbed dose of DMF is excreted unchanged in the expired breath. The urinary concn of N-methylformamide is probably the best index of worker exponent dimethylformamide.
Certain carbocyclic aryl- and heterocyclic aryl-substituted cyclopropyl N-hydroxyureas, N-hydoroxycarboxamides, and N-acyl-N-hydroxyamides inhibit 5- and/or 12-lipoxygenase and are useful in the treatment of inflammatory disease states.
Fmoc-Based Synthesis of Peptide Thioesters for Native Chemical Ligation Employing a <i>tert</i>-Butyl Thiol Linker
作者:Richard Raz、Jörg Rademann
DOI:10.1021/ol1029723
日期:2011.4.1
toward secondary amines in basic milieu, in contrast to other alkyl and aryl thioesters. Exploiting this enhanced stability, peptide thioesters were synthesized in a direct manner, applying a tert-butyl thiol linker for Fmoc-based solid-phase peptide synthesis.
Compositions for Treatment of Cystic Fibrosis and Other Chronic Diseases
申请人:Vertex Pharmaceuticals Incorporated
公开号:US20150231142A1
公开(公告)日:2015-08-20
The present invention relates to pharmaceutical compositions comprising an inhibitor of epithelial sodium channel activity in combination with at least one ABC Transporter modulator compound of Formula A, Formula B, Formula C, or Formula D. The invention also relates to pharmaceutical formulations thereof, and to methods of using such compositions in the treatment of CFTR mediated diseases, particularly cystic fibrosis using the pharmaceutical combination compositions.
[EN] COMPOUNDS FOR THE TREATMENT OF AMYLOID-ASSOCIATED DISEASES<br/>[FR] COMPOSÉS POUR LE TRAITEMENT DE MALADIES ASSOCIÉES À LA SUBSTANCE AMYLOÏDE
申请人:REMYND NV
公开号:WO2016083490A1
公开(公告)日:2016-06-02
This invention provides novel compounds of formulae (I) or (II) or a stereoisomer, enantiomer, racemic, or tautomer thereof, (I) (II) wherein the substituents are as defined in the specification. The present invention also relates to the novel compounds for use as a medicine, more in particular for the prevention or treatment of amyloid-related diseases, more specifically certain neurological disorders, such as disorders collectively known as tauopathies, disorders characterized by cytotoxic α-synuclein amyloidogenesis. The present invention also relates to the use of said novel compounds for the manufacture of medicaments useful for treating such amyloid-related diseases. The present invention further relates to pharmaceutical compositions including said novel compounds and to methods for the preparation of said novel compounds.