Amines Chichibabin amination reaction

Carboxamidation of heteroaromatic compounds, promoted by fluorine, provides a convenient alternative to the well-known Chichibabin amination reaction (Fig. 86) [228]. The mechanism of this reaction was suggested to proceed via a carbene intermediate (Fig 87). 

Diphenyl-l,3,5-triazine undergoes a Chichibabin-type amination reaction, the first example of this reaction to be reported for the 1,3,5-triazines. The 2-methylthio derivative (37 X = MeS) reacts exclusively via an Sn(ANRORC) mechanism rather than the SNAE mechanism (Scheme 21) (76RTC113). 

T.R. Kelly et al. have synthesized bisubstrate reaction templates utilizing the Chichibabin amination reaction during the preparation of one precursor. This reaction template was designed to use hydrogen bonding to bind two substrates simultaneously but transiently, giving rise to a ternary complex, which positions the substrates in an orientation that facilitates their reaction. 

Chichibabin amination reaction Direct amination of pyridine via SNAr reaction. 80... 

The amination of 2.4-diphenyl-1,3,5-triazine (7, X = H) with potassium amide in anhydrous liquid ammonia at -33°C occurs by a Chichibabin-type reaction, i.e. replacement of H" by NH via nucleophilic substitution involving an addition-elimination process (SsAE). In contrast, the 2-methylsulfanyl derivative 7 (X = SMe) is aminated nearly exclusively by a ringopening-ring-closing sequence [Sn(ANRORC)].52... 

A new version of the Chichibabin amination of azaaromatics in liquid ammonia in the presence of potassium permanganate, suggested by H. C. van der Plas, has been applied successfully in the series of 1,2,4-triazines (Scheme 65) <19858884, 2001H(55)127, 2004808(17)357>. The low-temperature amination reaction always takes place at the position 5, even in those cases where the 1,2,4-triazine ring bears a good leaving group at position 3. 

Table 12 Yields of 3-amino-1,2,4-triazine 4-oxides derived from the Chichibabin amination reaction at room temperature ...

Amination of pyridine on heating with sodium amide in refluxing xylene observed by Chichibabin and Zeide nearly 100 years ago [132] was probably the first successful example of amino-dehydrogenation in the series of Jt-deficient aromatic systems. However, rather drastic reaction conditions and a requirement for an appropriate oxidant for the classic Chichibabin amination did not stimulate chemists in earlier days to enter this field of substitutions [23, 133, 134], Later on, van der Plas with coworkers [11, 19-21, 29, 35, 39, 40, 88], Vorbruggen [26], Pozharskii, Gulevskaya, and Maes [34, 45, 46, 48, 67, 68, 71, 72], McGill and Rappa [23], Pagoria, Mitchell, and Shmidt [59, 61, 63], Lopyrev [65, 66], Katritzky [58], and many other researches [11, 21, 45, 55, 58-74] contributed to the field of Sn amination reactions. 

Alexei Eugenivich Chichibabin (Kusemino, nr. Poltava, Russia, 17 March 1871 (O.S.)-Paris, 15 August 1945), assistant in the University of Moscow (1900) and professor (1909) in the Technical High-School there, published much work in organic chemistry, notably on tervalent carbon. The Chichibabin amination reaction (1914) involves the formation of 2-aminopyridine by heating pyridine with sodamide in toluene, and hydrolysis of the product with water. The Chichibabin pyridine synthesis involves the condensation of aldehydes, ketones, etc., with ammonia or amines to form substituted pyridines. ... 

The Chichibabin amination reaction, first reported by Chichibabin and Zeide in 1914, is simply a reaction for the introduction of an amino group to azines. This is one of the first examples of nucleophilic hydrogen substitution (SnH) reactions and is considered one of the most influential reactions in heterocyclic chemistry transformations of pyridines and azines in the 20th century. " ... 

The Chichibabin amination reaction can progress through two distinct mechanisms. Through extensive experimental and spectroscopic data, it was... 

In 1972, Zoltewicz and Helmick reported the first evidence of anionic o-adducts in the Chichibabin amination reaction. The parent diazines a-adduct complex (pyrimidine, pyridazine and pyrazine) in KNH2-NH3/KMn04 (at low temperature 0 to 0 °C) are shown below. Despite the fact that the parent pyrimidine has three possible amination spots, 18 is the adduct formed and similarly for pyridazine and pyrazine, adducts 19 and 20 are formed under the aforementioned conditions. The regio-chemical outcome changes when these rings are substituted. 

---