504-29-0 Usage
Chemical Properties
2-Aminopyridine is a yellow or white crystalline (sand-like) solid with a characteristic odor. It is soluble in water, alcohol, benzene, ether and hot petroleum ether. It tastes bitter and has anesthetic effect. It is a significant synthetic synthon, with unique dual nucleophilic structure. It can react with ketones, aldehydes, acids, multifunctional esters, halogenated aromatics and other compounds to synthesize five- and six-member azaheterocycles. after prolonged storage, may darken in color.
Uses
2-Aminopyridine is used primarily in the pharmaceutical industry as an intermediate in chemical synthesis. It is used to manufacturing analgesic and anti-inflammatory drugs piroxicam and lornoxicam. 2-Aminopyridine is a basic building block of several heterocyclic compounds and Schiff bases. It has been shown to reversibly block voltage-dependent potassium channels, and is also a common impurity from the synthesis of compounds found in hair dyes. It is a derivatizing agent which can be used as a fluorescent label for oligosaccharide detection, chromatographic separation, fluorometric or mass spectrometric analysis. 2AP and its derivatives are good candidates for antimicrobial, anticorrosion and molecular sensing applications.
Preparation
2-Aminopyridine is manufactured using the reaction of pyridine with sodium amide (Chichibabin amination). It is obtained in high yield after the hydrolysis of the intermediate salt (Merck, 2001; Shimizu et al., 1993).
Application
2-Aminopyridine has also been used to derivatize sialyloligosaccharides for detection in FAB-MS. It can also be used:As a reactant in the synthesis of 3-aroylimidazopyridines from chalcones by aerobic oxidative amidation using copper acetate catalyst.In the synthesis of crystalline Cu(II) complex, di-μ-(2-aminopyridine(N,N′))-bis[(2,6 pyridinedicarboxylate)aquacopper(II)] tetrahydrate using 2,6-pyridinedicarboxylic acid and Cu(CH3COO)2.H2O.As an imprinting molecule for the preparation of poly(methacrylic acid–ethylene glycol dimethacrylate) polymer. It is packed in micro-column for selective solid phase extraction of 2-aminopyridine.As a reactant in the synthesis of 2-aryl-3-(pyridin-2-yl)-1,3-thiazolidin-4-ones in the presence of Lewis acid catalysts.As a reactant in the synthesis of 2-(2-aminopyridinium)acetyl starch with antioxidant property.
Synthesis Reference(s)
The Journal of Organic Chemistry, 72, p. 4554, 2007 DOI: 10.1021/jo070189yTetrahedron Letters, 11, p. 3901, 1970
General Description
2-aminopyridine appears as white powder or crystals or light brown solid. It is soluble in water and alcohol. It is toxic by ingestion and by inhalation of the dust. It is used to make pharmaceuticals and dyes. (NTP, 1992)
Air & Water Reactions
Decomposes in air. Soluble in water.
Reactivity Profile
2-Aminopyridine neutralizes acids in exothermic reactions to form salts plus water. May be incompatible with isocyanates, halogenated organics, peroxides, phenols (acidic), epoxides, anhydrides, and acid halides. May generate hydrogen, a flammable gas, in combination with strong reducing agents such as hydrides. Reacts with oxidizing agents .
Hazard
Toxic.
Health Hazard
2-Aminopyridine causes central
nervous system effects.
Fire Hazard
2-Aminopyridine is combustible.
Safety Profile
Poison by ingestion, inhalation, subcutaneous, intravenous, and intraperitoneal routes. Toxic effects resemble strychnine poisoning. Human systemic effects by inhalation: somnolence, convulsions, and antipsychotic effects. Human central nervous system effects by inhalation. When heated to decomposition it emits highly toxic fumes of NOx,.
Potential Exposure
2-Aminopyridine is used in the manufacture of pharmaceuticals; especially antihistamines.
Carcinogenicity
The LD50 in mice by intraperitoneal injection
was 35 mg/kg; lethal doses in animals also
produced excitement, tremors, convulsions
and tetany.1 Fatal doses were readily absorbed
through the skin. A 0.2 M aqueous solution
dropped in a rabbit’s eye was only mildly
irritating.
2-Aminopyridine was not mutagenic in
a variety of Salmonella tester strains with or
without metabolic activation.
Environmental fate
Soil. When radio-labeled 4-aminopyridine was incubated in moist soils (50%) under aerobic
conditions at 30 °C, the amount of 14CO2 released from an acidic loam (pH 4.1) and an alkaline,
loamy sand (pH 7.8) was 0.4 and 50%, respectively (Starr and Cunningham, 1975).
Chemical/Physical. Releases toxic nitrogen oxides when heated to decomposition (Sax and
Lewis, 1987).
Shipping
UN2671 Aminopyridines, Hazard Class: 6.1; Labels: 6.1-Poisonous materials.
Purification Methods
It crystallises from *benzene/pet ether (b 40-60o) or CHCl3 /pet ether. [Beilstein 22/8 V 280.]
Waste Disposal
Incineration with nitrogen oxides removal from effluent gas.
Check Digit Verification of cas no
The CAS Registry Mumber 504-29-0 includes 6 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 3 digits, 5,0 and 4 respectively; the second part has 2 digits, 2 and 9 respectively.
Calculate Digit Verification of CAS Registry Number 504-29:
(5*5)+(4*0)+(3*4)+(2*2)+(1*9)=50
50 % 10 = 0
So 504-29-0 is a valid CAS Registry Number.
InChI:InChI=1/C5H6N2/c6-5-3-1-2-4-7-5/h1-4H,(H2,6,7)/p+1
504-29-0Relevant articles and documents
A novel approach towards chemoselective reduction of nitro to amine
Dasgupta, Hridoydip Ranjan,Mukherjee, Suvodip,Ghosh, Pranab
, (2019)
Chemo selective reduction of a wide range of aromatic nitro compound has been performed by using inexpensive Zn powder and CuSO4 system in water medium at room temperature. This system has high tolerance to other highly reducible groups present in nitro substance along with high conversation and selectivity. This chemo-selective reduction also provides a facile root for the synthesis of other industrially important fine chemicals or biologically important compounds where other highly reducible groups are present in close proximity to the targeted nitro groups.
One-Pot Fabrication of Pd Nanoparticles?Covalent-Organic-Framework-Derived Hollow Polyamine Spheres as a Synergistic Catalyst for Tandem Catalysis
Yang, Xinyi,He, Yajun,Li, Liuyi,Shen, Jinni,Huang, Jianhui,Li, Lingyun,Zhuang, Zanyong,Bi, Jinhong,Yu, Yan
, p. 1864 - 1870 (2020)
Facile fabrication of nanocatalysts consisting of metal nanoparticles (NPs) anchored on a functional support is highly desirable, yet remains challenging. Covalent organic frameworks (COFs) provide an emerging materials platform for structural control and functional design. Here, a facile one-pot in situ reduction approach is demonstrated for the encapsulation of small Pd NPs into the shell of COF-derived hollow polyamine spheres (Pd?H-PPA). In the one-pot synthetic process, the nucleation and growth of Pd NPs in the cavities of the porous shell take place simultaneously with the reduction of imine linkages to secondary amine groups. Pd?H-PPA shows a significantly enhanced catalytic activity and recyclability in the tandem dehydrogenation of ammonia borane and selective hydrogenation of nitroarenes through an adsorption–activation–reaction mechanism. The strong interactions of the secondary amine linkage with borane and nitroarene molecules afford a positive synergy to promote the catalytic reaction. Moreover, the hierarchical structure of Pd?H-PPA allows the accessibility of active Pd NPs to reactants.
Indirect reduction of CO2and recycling of polymers by manganese-catalyzed transfer hydrogenation of amides, carbamates, urea derivatives, and polyurethanes
Liu, Xin,Werner, Thomas
, p. 10590 - 10597 (2021/08/20)
The reduction of polar bonds, in particular carbonyl groups, is of fundamental importance in organic chemistry and biology. Herein, we report a manganese pincer complex as a versatile catalyst for the transfer hydrogenation of amides, carbamates, urea derivatives, and even polyurethanes leading to the corresponding alcohols, amines, and methanol as products. Since these compound classes can be prepared using CO2as a C1 building block the reported reaction represents an approach to the indirect reduction of CO2. Notably, these are the first examples on the reduction of carbamates and urea derivatives as well as on the C-N bond cleavage in amides by transfer hydrogenation. The general applicability of this methodology is highlighted by the successful reduction of 12 urea derivatives, 26 carbamates and 11 amides. The corresponding amines, alcohols and methanol were obtained in good to excellent yields up to 97%. Furthermore, polyurethanes were successfully converted which represents a viable strategy towards a circular economy. Based on control experiments and the observed intermediates a feasible mechanism is proposed.
Cyclic (Alkyl)(amino)carbene Ligand-Promoted Nitro Deoxygenative Hydroboration with Chromium Catalysis: Scope, Mechanism, and Applications
Zhao, Lixing,Hu, Chenyang,Cong, Xuefeng,Deng, Gongda,Liu, Liu Leo,Luo, Meiming,Zeng, Xiaoming
supporting information, p. 1618 - 1629 (2021/01/25)
Transition metal catalysis that utilizes N-heterocyclic carbenes as noninnocent ligands in promoting transformations has not been well studied. We report here a cyclic (alkyl)(amino)carbene (CAAC) ligand-promoted nitro deoxygenative hydroboration with cost-effective chromium catalysis. Using 1 mol % of CAAC-Cr precatalyst, the addition of HBpin to nitro scaffolds leads to deoxygenation, allowing for the retention of various reducible functionalities and the compatibility of sensitive groups toward hydroboration, thereby providing a mild, chemoselective, and facile strategy to form anilines, as well as heteroaryl and aliphatic amine derivatives, with broad scope and particularly high turnover numbers (up to 1.8 × 106). Mechanistic studies, based on theoretical calculations, indicate that the CAAC ligand plays an important role in promoting polarity reversal of hydride of HBpin; it serves as an H-shuttle to facilitate deoxygenative hydroboration. The preparation of several commercially available pharmaceuticals by means of this strategy highlights its potential application in medicinal chemistry.
