1201-25-8Relevant academic research and scientific papers
A Versatile Synthetic Method of 1-Alkylazulenes and Azulene by the Reactions of 3-Methoxycarbonyl-2H-cycloheptafuran-2-one with in situ Generated Enamines
Yasunami, Masafumi,Miyoshi, Shiro,Kanegae, Noriko,Takase, Kahei
, p. 892 - 899 (1993)
Methyl 3-alkylazulene-1-carboxylates were synthesized in high yields by the reaction of 3-methoxycarbonyl-2H-cycloheptafuran-2-one with in situ generated morpholine enamines of aldehydes.Treatment of the esters with 100percent phosphoric acid gave 1-alkylazulenes in excellent yields.Azulene was also synthesized in a good yield via methyl azulene-1-carboxylate with a modification of this method.
Azulene?1?carboxylate - A new azulene-based building block for coordination polymers
Danzmann, Sascha,Liebing, Phil,Engelhardt, Felix,Hilfert, Liane,Edelmann, Frank T.
, p. 176 - 179 (2019)
For the first time, the easily accessible azulene?1?carboxylate anion has been employed as building block for the construction of crystalline coordination polymers. Neutralization of azulene?1?carboxylic acid (3) with NaOH in aqueous solution provided the dark purple sodium salt C10H7CO2Na·H2O (4) in 85% isolated yield. Single-crystal X-ray diffraction of 4 revealed a supramolecular layer structure in the crystalline state. Subsequent treatment of 4 with 1 equiv. of Me3SnCl afforded a rare organotin derivative of azulene, namely polymeric [C10H7CO2SnMe3]n (5) as purple crystals (82% yield).
Regioselective and Chemodivergent Synthesis of Azulenolactones and Azulenolactams from Rhodium(III)-Catalyzed Reactions of Azulenecarboxamides with Sulfoxonium Ylides
Lee, Seung Cheol,Son, Jeong-Yu,Kim, Jin Young,Eom, Hyeonsik,Jang, Seong Bin,Lee, Phil Ho
, p. 512 - 524 (2020/11/30)
A regioselective and chemodivergent synthetic approach for azulenolactones and azulenolactams as a new scaffold was demonstrated through Rh(III)-catalyzed reaction of N-methoxyazulene-1-carboxamides with sulfoxonium ylides. Sulfoxonium ylides that act as a precursor of secondary carbene was described, leading to the selective formation of azulenolactones and azulenolactams bearing two substituents on a newly introduced double bond. This method demonstrated functionalization of less reactive 2-position of azulene to overcome the natural reactivity. (Figure presented.).
Expansion of Azulenes as Nonbenzenoid Aromatic Compounds for C-H Activation: Rhodium- And Iridium-Catalyzed Oxidative Cyclization of Azulene Carboxylic Acids with Alkynes for the Synthesis of Azulenolactones and Benzoazulenes
Maeng, Chanyoung,Son, Jeong-Yu,Lee, Seung Cheol,Baek, Yonghyeon,Um, Kyusik,Han, Sang Hoon,Ko, Gi Hoon,Han, Gi Uk,Lee, Kyungsup,Lee, Kooyeon,Lee, Phil Ho
, p. 3824 - 3837 (2020/02/28)
Rhodium-catalyzed oxidative [4 + 2] cyclization reactions through the C-H activation of azulene carboxylic acids as nonbenzenoid aromatic compounds with symmetrical and unsymmetrical alkynes were developed under aerobic conditions, which produced azulenolactone derivatives with a wide substrate scope and excellent functional group tolerance. Interestingly, azulenic acids in reaction with alkynes underwent iridium-catalyzed [2 + 2 + 2] cyclization accompanied by decarboxylation to afford tetra(aryl)-substituted benzoazulene derivatives. The reactivity order for C-H activation reaction is greater toward azulene-6-carboxylic acid, azulene-1-carboxylic acid, and azulene-2-carboxylic acid. For the first time, the expansion of azulenes having directing group as nonbenzenoid aromatic compounds for C-H activation was successful, indicating that nonbenzenoid aromatic compounds can be used as good substrates for the C-H activation reaction. Therefore, the research area of C-H activation will certainly expand to nonbenzenoid aromatic compounds in future.
Carboxylic Acid Directed C-H Arylation of Azulene
Png, Zhuang Mao,Tam, Teck Lip Dexter,Xu, Jianwei
supporting information, p. 5009 - 5013 (2020/07/04)
The first example of directed C-H activation for azulene is reported. A variety of 2-arylazulenes are obtainable exclusively from 1-azulene carboxylic acids, with yields of up to 82percent. Some heteroaryl groups such as pyridine and thiophene are also tolerated in the reaction. The efficacy of the reaction is found to be highly dependent on the conditions, with a phosphate base and a bulky carboxylic acid being key additives.
