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Chichibabin Reaction
The Chichibabin reaction (pronounced ' (chē')-chē-bā-bēn) is a method for producing 2-aminopyridine derivatives by the reaction of pyridine with sodium amide. It was reported by Aleksei Chichibabin in 1914. The following is the overall form of the general reaction: : The direct amination of pyridine with sodium amide takes place in liquid ammonia. Following the Addition-elimination reaction, addition elimination mechanism first a nucleophilic addition, nucleophilic NH2− is added while a hydride (H−) is leaving. Ciganek describes an example of an intramolecular Chichibabin reaction in which a nitrile group on a fused ring is the source of nitrogen in amination. Mechanism : It is widely accepted that the Chichibabin reaction mechanism is an addition-elimination reaction that proceeds through an σ-adduct (Meisenheimer complex, Meisenheimer adduct) intermediate (the third structure). First, the nucleophilic NH2− group adds to the δ+ ring carbon atom pushing electrons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aleksei Chichibabin
Alekséy Yevgényevich Chichibábin (russian: Алексей Евгеньевич Чичибабин) was a Soviet Union, Soviet/Russian organic chemist, born , Kuzemin village, current Sumy Oblast, Ukraine, died in Paris, France, 15 August 1945. His name is also written ''Alexei Yevgenievich Chichibabin'' and ''Alexei Euguenievich Tchitchibabine''. Life Chichibábin was born at Kuzemin on March 17, 1871. He studied at the University of Moscow from 1888 until 1892, and received his PhD from the University of Saint Petersburg. In 1896, Chichibáin married Vera Vladimirovna as his wife. He became a professor at the Imperial College of Technology in Moscow in 1909, and remained there until 1929. After losing his daughter Natacha, a chemist, to an industrial oleum accident (explosion) that he deemed preventable, Chichibábin moved to Paris where he remained despite threat of and eventual stripping of his Soviet citizenship and his position in the Academy of Sciences (1936, Academy st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2-aminopyridine
2-Aminopyridine is an organic compound with the formula H2NC5H4N. It is one of three isomeric aminopyridines. It is a colourless solid that is used in the production of the drugs piroxicam, sulfapyridine, tenoxicam, and tripelennamine. It is produced by the reaction of sodium amide with pyridine, the Chichibabin reaction. Structure Although 2-hydroxypyridine converts significantly to the pyridone tautomer, the related imine tautomer (HNC5H4NH) is less important for 2-aminopyridine. Toxicity The acute toxicity is indicated by the LD50 In toxicology, the median lethal dose, LD50 (abbreviation for "lethal dose, 50%"), LC50 (lethal concentration, 50%) or LCt50 is a toxic unit that measures the lethal dose of a toxin, radiation, or pathogen. The value of LD50 for a substance is the ... = 200 mg/kg (rat, oral). References External links MSDS {{DEFAULTSORT:Aminopyridine, 2- Aminopyridines 2-Pyridyl compounds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyridine
Pyridine is a basic heterocyclic organic compound with the chemical formula . It is structurally related to benzene, with one methine group replaced by a nitrogen atom. It is a highly flammable, weakly alkaline, water-miscible liquid with a distinctive, unpleasant fish-like smell. Pyridine is colorless, but older or impure samples can appear yellow, due to the formation of extended, unsaturated polymeric chains, which show significant electrical conductivity. The pyridine ring occurs in many important compounds, including agrochemicals, pharmaceuticals, and vitamins. Historically, pyridine was produced from coal tar. As of 2016, it is synthesized on the scale of about 20,000 tons per year worldwide. Properties Physical properties The molecular electric dipole moment is 2.2 debyes. Pyridine is diamagnetic and has a diamagnetic susceptibility of −48.7 × 10−6 cm3·mol−1. The standard enthalpy of formation is 100.2 kJ·mol−1 in the liquid phase ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Amide
Sodium amide, commonly called sodamide (systematic name sodium azanide), is the inorganic compound with the formula . It is a salt composed of the sodium cation and the azanide anion. This solid, which is dangerously reactive toward water, is white, but commercial samples are typically gray due to the presence of small quantities of metallic iron from the manufacturing process. Such impurities do not usually affect the utility of the reagent. conducts electricity in the fused state, its conductance being similar to that of NaOH in a similar state. has been widely employed as a strong base in organic synthesis. Preparation and structure Sodium amide can be prepared by the reaction of sodium with ammonia gas, but it is usually prepared by the reaction in liquid ammonia using iron(III) nitrate as a catalyst. The reaction is fastest at the boiling point of the ammonia, c. −33 °C. An electride, , is formed as a reaction intermediate. : is a salt-like material and as such, c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chichibabin Overall
Chichibabin (russian: Чичибабин) is a Russian surname. Notable people with the surname include: *Aleksei Chichibabin (1871–1945), Soviet/Russian organic chemist *Boris Chichibabin Boris Alekseyevich Chichibabin (russian: Бори́с Алексе́евич Чичиба́бин, p=bɐˈrʲis ɐlʲɪˈksʲejɪvʲɪtɕ tɕɪtɕɪˈbabʲɪn, a=Boris Alyeksyeyevich Chichibabin.ru.vorb.oga, uk, Бори́с Олексі́йов ... (1923—1994), Soviet poet {{surname Russian-language surnames ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonia
Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous waste, particularly among aquatic organisms, and it contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to 45% of the world's food and fertilizers. Around 70% of ammonia is used to make fertilisers in various forms and composition, such as urea and Diammonium phosphate. Ammonia in pure form is also applied directly into the soil. Ammonia, either directly or indirectly, is also a building block for the synthesis of many pharmaceutical products and is used in many commercial cleaning products. It is mainly collected by downward displacement of both air and water. Although common in nature—both terrestrially and in the outer planets of the Solar System—and in wide use, ammonia is both caust ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleophilic Addition
In organic chemistry, a nucleophilic addition reaction is an addition reaction where a chemical compound with an electrophilic double or triple bond reacts with a nucleophile, such that the double or triple bond is broken. Nucleophilic additions differ from electrophilic additions in that the former reactions involve the group to which atoms are added accepting electron pairs, whereas the latter reactions involve the group donating electron pairs. Addition to carbon–heteroatom double bonds Nucleophilic addition reactions of nucleophiles with electrophilic double or triple bond (π bonds) create a new carbon center with two additional single, or σ, bonds.March Jerry; (1985). Advanced Organic Chemistry reactions, mechanisms and structure (3rd ed.). New York: John Wiley & Sons, inc. Addition of a nucleophile to carbon–heteroatom double or triple bonds such as >C=O or -C≡N show great variety. These types of bonds are polar (have a large difference in electronegativity betwe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chichibabin Mechanism
Chichibabin (russian: Чичибабин) is a Russian surname. Notable people with the surname include: *Aleksei Chichibabin (1871–1945), Soviet/Russian organic chemist *Boris Chichibabin Boris Alekseyevich Chichibabin (russian: Бори́с Алексе́евич Чичиба́бин, p=bɐˈrʲis ɐlʲɪˈksʲejɪvʲɪtɕ tɕɪtɕɪˈbabʲɪn, a=Boris Alyeksyeyevich Chichibabin.ru.vorb.oga, uk, Бори́с Олексі́йов ... (1923—1994), Soviet poet {{surname Russian-language surnames ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meisenheimer Complex
A Meisenheimer complex or Jackson–Meisenheimer complex in organic chemistry is a 1:1 reaction adduct between an arene carrying electron withdrawing groups and a nucleophile. These complexes are found as reactive intermediates in nucleophilic aromatic substitution but stable and isolated Meisenheimer salts are also known. Background The early development of this type of complex takes place around the turn of the 19th century. In 1886 Janovski observed an intense violet color when he mixed ''meta''-dinitrobenzene with an alcoholic solution of alkali. In 1895 Cornelis Adriaan Lobry van Troostenburg de Bruyn investigated a red substance formed in the reaction of trinitrobenzene with potassium hydroxide in methanol. In 1900 Jackson and Gazzolo reacted trinitroanisole with sodium methoxide and proposed a quinoid structure for the reaction product. : In 1902 Jakob Meisenheimer observed that by acidifying their reaction product, the starting material was recovered. With three electron w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydride Ion
The hydrogen anion, H−, is a negative ion of hydrogen, that is, a hydrogen atom that has captured an extra electron. The hydrogen anion is an important constituent of the atmosphere of stars, such as the Sun. In chemistry, this ion is called hydride. The ion has two electrons bound by the electromagnetic force to a nucleus containing one proton. The binding energy of H− equals the binding energy of an extra electron to a hydrogen atom, called electron affinity of hydrogen. It is measured to be or (see Electron affinity (data page)). The total ground state energy thus becomes . Occurrence The hydrogen anion is the dominant bound-free opacity source at visible and near-infrared wavelengths in the atmospheres of stars like the Sun and cooler; its importance was first noted in the 1930s. The ion absorbs photons with energies in the range 0.75–4.0 eV, which ranges from the infrared into the visible spectrum. Most of the electrons in these negative ions come from the i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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