Methylamine, anhydrous appears as a colorless gas or a liquid. Pungent fishy odor resembling odor of ammonia. The liquid boils at 20.3°F hence vaporizes rapidly when unconfined. Vapors are heavier than air and may collect in low-lying areas. Easily ignited under most conditions. Under prolonged exposure to intense heat the containers may rupture violently and rocket. Used for making pharmaceuticals, insecticides, paint removers, surfactants, rubber chemicals.
颜色/状态:
Colorless gas [Note: A liquid below 21 degrees F. Shipped as a liquefied compressed gas]
气味:
Fish or ammonia-like odor
沸点:
-6.3 °C
熔点:
-93.4 °C
闪点:
-10 °C (14 °F) - closed cup /Methylamine solution 30-50%/
溶解度:
1 volume of water at 12.5 °C dissolves 1154 volumes of gas; at 25 °C dissolves 959 volumes of gas; 10.5 g is contained in 100 mL saturated benzene solution
密度:
0.6624 g/cu cm at 25 °C; 0.0014 g/cu cm at 101.33 kPa
蒸汽密度:
Saturated vapor density: 0.21270 lb/cu ft at 60 °F (Methylamine, anhydrous)
Hazardous decomposition products formed under fire conditions: Carbon oxides, nitrogen oxides (NOx) /Methylamine solution 30-50%/
腐蚀性:
Corrosive to copper, copper alloys, zinc alloys, aluminum, and galvanized surfaces (Methylamine solution)
燃烧热:
-1085.6 kJ/mole at 25 °C (gas)
汽化热:
Molar enthalpy of vaporization at 25 °C: 23.37 kJ/mol
表面张力:
19.15 mN/m at 25 °C
电离电位:
8.97 eV
气味阈值:
The odor of methylamine is faint but readily detectable at less than 10 ppm, becomes strong at from 20 to 100 ppm and intolerably ammoniacal at 100 to 500 ppm.
PURPOSE: It has been claimed that oral creatine supplementation might have potential cytotoxic effects on healthy consumers by increasing the production of methylamine and formaldehyde. Despite this allegation, there has been no scientific evidence obtained in humans to sustain or disprove such a detrimental effect of this widely used ergogenic substance. METHODS: Twenty young healthy men ingested 21 g of creatine monohydrate daily for 14 consecutive days. Venous blood samples and 24-hr urine were collected before and after the 14th day of supplementation. Creatine and creatinine were analyzed in plasma and urine, and methylamine, formaldehyde, and formate were determined in 24-hr urine samples. RESULTS: Oral creatine supplementation increased plasma creatine content 7.2-fold (P < 0.001) and urine output 141-fold (P < 0.001) with no effect on creatinine levels. Twenty-four-hour urine excretion of methylamine and formaldehyde increased, respectively, 9.2-fold (P = 0.001) and 4.5-fold (P = 0.002) after creatine feeding, with no increase in urinary albumin output (9.78 +/- 1.93 mg/24 hr before, 6.97 +/- 1.15 mg/24 hr creatine feeding). CONCLUSION: This investigation shows that short-term, high-dose oral creatine supplementation enhances the excretion of potential cytotoxic compounds, but does not have any detrimental effects on kidney permeability. This provides indirect evidence of the absence of microangiopathy in renal glomeruli.
The regulation of methylamine and formaldehyde metabolism in Arthobacter P1 was investigated in carbon-limited continuous cultures. Evidence was obtained that the synthesis of enzymes involved in the conversion of methylamine into formaldehyde and in formaldehyde fixation is induced sequentially in this organism.
The metabolism of methylamine has been investigated in the rat in order to elucidate the role of monoamine oxidase and intestinal bacteria in the metabolism of the compound. In a series of experiments in which short and long acting inhibitors of monoamine oxidase were administered either alone or in combination prior to methyl (14)C amine hydrochloride injection, the excretion of radioactivity in the expired air and the urine was examined to indirectly assess the role of monoamine oxidase in the metabolism of methylamine. The data ... provide indirect evidence to demonstrate that the effect of iproniazid, an inhibitor of methylamine oxidation, is mediated through enzyme systems separate from MAO systems which have been invoked as major contributors to metabolism of methylamine by other investigators. The bacterial oxidation of methylamine in the intestine plays a minor role in the overall metabolism of the compounds.
Uremic toxins tend to accumulate in the blood either through dietary excess or through poor filtration by the kidneys. Most uremic toxins are metabolic waste products and are normally excreted in the urine or feces.
IDENTIFICATION AND USE: Methylamine is colorless gas. A liquid below 21 degrees F. Shipped as a liquefied compressed gas. it is used as an intermediate for accelerators, dyes, pharmaceuticals, insecticides, fungicides, surface active agents, tanning, dyeing of acetate textiles, fuel additive, polymerization inhibitor, component of paint removers, solvent, photographic developer, rocket propellant. HUMAN STUDIES: Olfactory fatigue occurs readily. Brief exposures to 20 to 100 ppm produce transient eye, nose, and throat irritation. No symptoms of irritation are produced from longer exposures at less than 10 ppm. Allergic or chemical bronchitis was reported in a worker exposed to methylamine at concentrations ranging from 2 to 60 ppm, and some irritation was noted at about 25 ppm. Stimulation of DNA synthesis in human fibroblast cultures by epidermal growth factor, insulin, and serum is inhibited by methylamine. ANIMAL STUDIES: Application of 0.1 mL of a 40% aqueous solution of methylamine to the skin of a guinea pig caused necrosis. Liquified methylamine caused change in guinea pig skin color with swelling and purple hue within a few minutes, gray and necrotic in 48 hr. At 12 days fresh granulation tissue had appeared covered by flat epidermis with no hair follicles. A drop of 5% solution in water applied to animal eyes caused hemorrhages in the conjunctiva, superficial corneal opacities, and edema. Methylamine caused interstitial pneumonitis progressing to fibrosis in rats. Methylamine was positive when tested for genotoxicity in a mouse lymphoma cell assay. Methylamine was negative when tested for genotoxicity in Salmonella typhimurium strains (TA1535, TA1537, TA97, TA98, and TA100) in the presence and absence of metabolic activation. Methylamine occurs endogenously from amine catabolism and its tissue levels increase in some pathological conditions, including diabetes. Methylamine is an endogenous aliphatic amine exhibiting anorexigenic properties in mice. The effects of methylamine on feeding depend on the hypothalamic release of nitric oxide and dopamine. ECOTOXICITY: Isolated individual fertilized eggs from zebrafish (Brachydanio rerio) developed in vitro can be used to elucidate possible actions of hazardous agents on embryogenesis. Methylamine at concentration 0.1 - 5 mg/mL incubation media caused mortality of most of eggs by cytotoxic effects essentially at stage 24. Malformations were not observed.
Uremic toxins such as methylamine are actively transported into the kidneys via organic ion transporters (especially OAT3). Increased levels of uremic toxins can stimulate the production of reactive oxygen species. This seems to be mediated by the direct binding or inhibition by uremic toxins of the enzyme NADPH oxidase (especially NOX4 which is abundant in the kidneys and heart) (A7868). Reactive oxygen species can induce several different DNA methyltransferases (DNMTs) which are involved in the silencing of a protein known as KLOTHO. KLOTHO has been identified as having important roles in anti-aging, mineral metabolism, and vitamin D metabolism. A number of studies have indicated that KLOTHO mRNA and protein levels are reduced during acute or chronic kidney diseases in response to high local levels of reactive oxygen species (A7869)
来源:Toxin and Toxin Target Database (T3DB)
毒理性
致癌物分类
对人类不具有致癌性(未被国际癌症研究机构IARC列名)。
No indication of carcinogenicity to humans (not listed by IARC).
来源:Toxin and Toxin Target Database (T3DB)
毒理性
健康影响
长期暴露于尿毒症毒素可能会导致多种疾病,包括肾脏损伤、慢性肾病和心血管疾病。
Chronic exposure to uremic toxins can lead to a number of conditions including renal damage, chronic kidney disease and cardiovascular disease.
来源:Toxin and Toxin Target Database (T3DB)
毒理性
暴露途径
该物质可以通过吸入被身体吸收。
The substance can be absorbed into the body by inhalation.
来源:ILO-WHO International Chemical Safety Cards (ICSCs)
Methylamine can be converted by semicarbazide-sensitive amine oxidase (SSAO) to formaldehyde and hydrogen peroxide, which have been proven to be toxic towards cultured endothelial cells. /The authors/ investigated whether or not these deaminated products from methylamine can exert potentially hazardous toxic effects in vivo. Long lasting residual radioactivity in different tissues was detected following administration of [14C]-methylamine in the mouse. Approximately 10% of the total administered radioactivity could even be detected 5 days after injection of [14C]-methylamine. Eighty percent of the formation of irreversible adducts can be blocked by a highly selective SSAO inhibitor, (E)-2-(4-fluorophenethyl)-3-fluoroallylamine hydrochloride (MDL-72974A). The residual radioactivity was primarily associated with the insoluble tissue components and the soluble macromolecules. Radioactively labelled macromolecules were fragmented following enzymatic proteolysis. Results suggest that the formaldehyde derived from methylamine interacts with proteins in vivo. In the streptozotocin-induced diabetic mice, both SSAO activity and the formation of residual radioactivity were found to be significantly increased in the kidney. Chronic administration of methylamine enhances blood prorenin level, which strongly suggests that uncontrolled deamination of methylamine may be a risk factor for initiation of endothelial injury, and subsequent genesis of atherosclerosis.
/MILK/ ...The presence of volatile aliphatic amines ... in human breast milk and amniotic fluid /was measured/ to assess their role in neonatal hypergastrinemia. These volatile nitrogenous amino acid metabolites have been previously demonstrated to stimulate gastrin release in in vivo and in vitro laboratory preparations. ... The present study ... demonstrated that these gastrin-stimulatory volatile amines were present in significant concentrations in breast milk during the first several weeks after parturition and in amniotic fluid. The individual amines that were identified in both human milk and amniotic fluid samples were methylamine, dimethylamine, ethylamine, trimethylamine, propylamine, isobutylamine, and butylamine. This study provides indirect evidence to support the possibility that the hypergastrinemia measured in the fetus/neonate during the period immediately before and after birth may be attributable, in part, to the ingestion of fluid containing high concentrations of gastrin-stimulating amines.
BACKGROUND: Dialysis adequacy is currently judged by measures of urea clearance. However, urea is relatively non-toxic and has properties distinct from large classes of other retained solutes. In particular, intracellularly sequestered solutes are likely to behave differently than urea. METHODS: We studied an example of this class, the aliphatic amine monomethylamine (MMA), in stable hemodialysis outpatients (n = 10) using an HPLC-based assay. RESULTS: Mean MMA levels pre-dialysis in end-stage renal disease subjects were 76 +/- 15 ug/L compared to 32 +/- 4 ug/L in normal subjects (n = 10) (P < 0.001). Mean urea reduction was 62% while the reduction ratio for MMA was 43% (P < 0.01). MMA levels rebounded in the 1 hour post-dialytic period to 85% of baseline, whereas urea levels rebounded only to 47% of baseline. MMA had a much larger calculated volume of distribution compared to urea, consistent with intracellular sequestration. Measures of intra-red blood cell (RBC) MMA concentrations confirmed greater levels in RBCs than in plasma with a ratio of 4.9:1. Because of the intracellular sequestration of MMA, we calculated its clearance using that amount removed from whole blood. Clearances for urea averaged 222 +/- 41 mL/min and for MMA 121 +/- 14 mL/min, while plasma clearance for creatinine was 162 +/- 20 mL/min (P < 0.01, for all differences). Using in vitro dialysis, in the absence of RBCs, solute clearance rates were similar: 333 +/- 6, 313 +/- 8 and 326 +/- 4 mL/min for urea, creatinine and MMA, respectively. These findings suggest that the lower MMA clearance relative to creatinine in vivo is a result of MMA movement into RBCs within the dialyzer blood path diminishing its removal by dialysis. CONCLUSION: In conclusion, we find that, in conventional hemodialysis, MMA is not cleared as efficiently as urea or creatinine and raise the possibility that RBCs may limit its dialysis not merely by failing to discharge it, but by further sequestering it as blood passes through the dialyzer.
In this study, we examined the effect of two creatine monohydrate supplementation regimes on 24-hr urinary creatine and methylamine excretion. Nine male participants completed two trials, separated by 6 weeks. Participants ingested 4 x 5 g x day(-1) creatine monohydrate for 5 days in one trial and 20 x 1 g x day(-1) for 5 days in the other. We collected 24-hr urine samples on 2 baseline days (days 1-2), during 5 days of supplementation (days 3-7), and for 2 days post-supplementation (days 8-9). Urine was assayed for creatine using high-performance liquid chromatography and methylamine using gas chromatography. Less creatine was excreted following the 20 x 1 g x day(-1) regime (49.25 +/- 10.53 g) than the 4 x 5 g x day(-1) regime (62.32 +/- 9.36 g) (mean +/- s; P < 0.05). Mean total excretion of methylamine (n = 6) over days 3-7 was 8.61 +/- 7.58 mg and 24.81 +/- 25.76 mg on the 20 x 1 g x day(-1) and 4 x 5 g x day(-1) regimes, respectively (P < 0.05). The lower excretion of creatine using 20 x 1 g x day(-1) doses suggests a greater retention in the body and most probably in the muscle. Lower and more frequent doses of creatine monohydrate appear to further attenuate formation of methylamine.
摘要 使用美国国家太阳天文台傅里叶变换光谱仪以约 0.005 cm -1 的分辨率测量了 HCN 各种同位素的 710-cm -1 谱带。分析了六个 HCN 波段、一个 H 13 CN 波段和一个 HC 15 N 波段以获得准确的波段原点和旋转常数。对于大多数波段,计算的波段原点的精度优于 0.0003 cm -1。通过与模拟的比较,已经从这些光谱中导出了相对积分强度,并给出了所用方法的示例。
The synthesis of 1-chloroalkyl carbonates and their reaction with various type of amines are described. This reaction is useful for the synthesis of carbamate pesticides and for the protection of various amino groups, including amino acids.
Enantioselective Transfer Hydrogenation of Aliphatic Ketones Catalyzed by Ruthenium Complexes Linked to the Secondary Face of β-Cyclodextrin
作者:Alain Schlatter、Wolf-D. Woggon
DOI:10.1002/adsc.200700558
日期:2008.5.5
Ruthenium-η-arene complexes attached to the secondary face of β-cyclodextrin catalyze the enantioselective reduction (ee up to 98%) of aliphatic and aromatic ketones in aqueous medium in the presence of sodium formate (HCOONa).
medium. Dimethylchloramine prepared in a pure state undergoes dehydrohalogenation in an alkaline medium: the principal products formed are N-methylmethanimine, 1,3,5-trimethylhexahydrotriazine, formaldehyde, and methylamine. The kinetics of this reaction was studied by UV, GC, and HPLC as a function of temperature, initial concentrations of sodium hydroxide, and chlorinated derivative. The reaction is of
Identification of Pyridine Synthase Recognition Sequences Allows a Modular Solid-Phase Route to Thiopeptide Variants
作者:Walter J. Wever、Jonathan W. Bogart、Albert A. Bowers
DOI:10.1021/jacs.6b05389
日期:2016.10.19
Bacillus cereus ATCC 14579. Through a series of truncations, we define a minimum recognition sequence (RS) that is necessary and sufficient for TclM activity. This RS can be readily synthesized and ligated to linear thiopeptide cores prepared via solid-phase peptide synthesis (SPPS), giving an efficient and modular route to thiopeptide variants. We exploit this strategy to define C-terminal core peptide requirements