18818-41-2Relevant academic research and scientific papers
N^N^O hydrazone capped pincer type palladium complex catalysed construction of quinazolinones from alcohols
Anandaraj, Pennamuthiriyan,Kamatchi, Thangavel Sathiya,Ramesh, Rengan
, (2022/01/11)
New Pincer type Pd(II) complex [Pd(NNO)(PPh3)] (1) prompted synthesis of quinazolinones via dehydrogenative coupling of readily accessible alcohols, and o-aminobenzamide is described. A diverse range of quinazolinones has been synthesized efficiently with good to excellent yields employing low catalyst loading (0.5 mol%) under the aerobic condition without any additives/oxidants. A plausible mechanism for the construction of quinazolinones has been proposed via cyclic aminal intermediate. Large-scale synthesis attests to the productiveness of the current strategy.
Access to 2-Arylquinazolin-4(3H)-ones through Intramolecular Oxidative C(sp3)?H/N?H Cross-Coupling Mediated by I2/DMSO
Wen, Simiaomiao,Du, Yifan,Liu, Yiwen,Cui, Xiaofeng,Liu, Qixing,Zhou, Haifeng
, (2021/12/01)
A novel approach for the synthesis of 2-arylquinazolin-4(3H)-ones was developed. A series of title compounds were obtained with good functional group tolerance and good yields by I2/DMSO-mediated intramolecular oxidative cross-coupling of 2-(benzylamino)benzamides to form C=N double bonds. This method was applicable for gram-scale synthesis. A proposed reaction pathway based on some control experiments was also provided.
Regioselective Synthesis of 2° Amides Using Visible-Light-Induced Photoredox-Catalyzed Nonaqueous Oxidative C-N Cleavage of N, N-Dibenzylanilines
Neerathilingam, Nalladhambi,Bhargava Reddy, Mandapati,Anandhan, Ramasamy
supporting information, p. 15117 - 15127 (2021/10/25)
A visible-light-driven photoredox-catalyzed nonaqueous oxidative C-N cleavage of N,N-dibenzylanilines to 2° amides is reported. Further, we have applied this protocol on 2-(dibenzylamino)benzamide to afford quinazolinones with (NH4)2S2O8 as an additive. Mechanistic studies imply that the reaction might undergo in situ generation of α-amino radical to imine by C-N bond cleavage followed by the addition of superoxide ion to form amides.
Improved, gram-scale synthesis of sildenafil in water using arylacetic acid as the acyl source in the pyrazolo[4,3-d]pyrimidin-7-one ring formation
Laha, Joydev K.,Gulati, Upma,Saima,Gupta, Anjali,Indurthi, Harish Kumar
supporting information, p. 2643 - 2648 (2021/02/16)
An improved, gram-scale synthesis of the blockbuster drug sildenafil, used for the treatment of male erectile dysfunction, has been developed. Unlike the previous literature, the current method demonstrates the use of arylacetic acid as an acyl source, a cheap oxidant K2S2O8, and water as the reaction medium in the key step of pyrrazolo[4,3-d]pyrimidin-7-one ring formation. As well as being a green and benign approach, the current method reduces the cost by half compared to our previous strategy. In addition, the general relevance of the method has been demonstrated in the synthesis of a variety of quinazolinone and benzothiazole derivatives with excellent functional group tolerance.
Method for synthesizing 2 -phenylquinazolone compound by taking styrene compound as raw material
-
Paragraph 0047-0056, (2021/03/03)
The invention discloses a method for synthesizing a 2-phenyl quinazolinone compound. The method comprises the steps of adopting a styrene compound and 2-aminobenzamide as reaction raw materials; underthe combined action of a palladium catalyst, a ligand and oxygen, reacting to obtain the 2-phenyl quinazolinone compound, wherein the reaction temperature is 80 DEG C to 110 DEG C, a reaction formulais as shown in the below figure, and R is hydrogen, fluorine, chlorine, bromine, methyl, trifluoromethyl, nitro or methoxyl. The method provided by the invention has the beneficial effects that the raw material styrene compound is cheap and easy to get, so that the method is more economical; a preparation method is simple and convenient to operate, and the obtained product is easy to post-process, so that the method is suitable for large-scale industrial production; no high temperature and high pressure is needed, and a reaction condition is mild; the method is short in reaction time, high efficient to react, high in yield, and higher in reaction efficiency after reaction amplification.
Photocatalyst-free visible-light-promoted quinazolinone synthesis at room temperature utilizing aldehydes generatedin situ viaC=C bond cleavage
Xie, Zongbo,Lan, Jin,Yan, Liyuan,Chen, Xuehua,Li, Qian,Meng, Jia,Le, Zhanggao
, p. 2436 - 2441 (2021/04/02)
This is the first report on a facile tandem route for synthesizing quinazolinones at room temperature from various aminobenzamides andin situ-generated aldehydes. The latter was formedviaC=C bond cleavage, and the overall reaction proceeded using molecular oxygen as a clean oxidant in the absence of a photocatalyst. Visible light, which was indispensable for the entire course of the reaction, played multiple roles. It initially cleaved styrene to an aldehyde, then facilitated its cyclization with ano-substituted aniline, and finally promoted the dehydrogenation of the cyclized intermediate. The previous step provided the feedstock for the next step in the reaction, thereby preventing volatilization, oxidation, and polymerization of the aldehyde. Thus, the overall process is simple, environmentally benign, and economically feasible.
α-Keto Acids as Triggers and Partners for the Synthesis of Quinazolinones, Quinoxalinones, Benzooxazinones, and Benzothiazoles in Water
Huang, Jian,Chen, Wei,Liang, Jiazhi,Yang, Qin,Fan, Yan,Chen, Mu-Wang,Peng, Yiyuan
, p. 14866 - 14882 (2021/10/25)
A general and efficient method for the synthesis of quinazolinones, quinoxalinones, benzooxazinones, and benzothiazoles from the reactions of α-keto acids with 2-aminobenzamides, benzene-1,2-diamines, 2-aminophenols, and 2-aminobenzenethiols, respectively, is described. The reactions were conducted under catalyst-free conditions, using water as the sole solvent with no additive required, and successfully applied to the synthesis of sildenafil. More importantly, these reactions can be conducted on a mass scale, and the products can be easily purified through filtration and washing with ethanol (or crystallized).
Iron catalyzed metal-ligand cooperative approaches towards sustainable synthesis of quinolines and quinazolin-4(3H)-ones
Mondal, Rakesh,Chakraborty, Gargi,Guin, Amit Kumar,Pal, Subhasree,Paul, Nanda D.
, (2021/10/12)
Herein we report simple, efficient, and economically affordable metal-ligand cooperative strategies for synthesizing quinolines and quinazolin-4(3H)-ones via dehydrogenative functionalization of alcohols. Various polysubstituted quinolines and quinazolin-4(3H)-ones were prepared in good yields via dehydrogenative coupling of readily available alcohols with ketones and 2-aminobenzamides, respectively under air using a well-defined Fe(II)-catalyst, ([FeL1Cl2] (1)) bearing a redox-active azo-aromatic pincer 2-((4-chlorophenyl)diazenyl)-1,10-phenanthroline) (L1). Control experiments and mechanistic investigation disclose that the one-electron reduced mono-anionic species [1]? bearing an iron-stabilized azo-anion radical ligand catalyzes these reactions. Both iron and the redox-active arylazo ligand participate synergistically during the different steps of these catalytic reactions.
Zinc Stabilized Azo-anion Radical in Dehydrogenative Synthesis of N-Heterocycles. An Exclusively Ligand Centered Redox Controlled Approach
Das, Siuli,Mondal, Rakesh,Chakraborty, Gargi,Guin, Amit Kumar,Das, Abhishek,Paul, Nanda D.
, p. 7498 - 7512 (2021/06/30)
Herein we report an exclusively ligand-centered redox controlled approach for the dehydrogenation of a variety of N-heterocycles using a Zn(II)-stabilized azo-anion radical complex as the catalyst. A simple, easy-to-prepare, and bench-stable Zn(II)-complex (1b) featuring the tridentate arylazo pincer, 2-((4-chlorophenyl)diazenyl)-1,10-phenanthroline, in the presence of zinc-dust, undergoes reduction to form the azo-anion radical species [1b]- which efficiently dehydrogenates various saturated N-heterocycles such as 1,2,3,4-tetrahydro-2-methylquinoline, 1,2,3,4-tetrahydro-isoquinoline, indoline, 2-phenyl-2,3-dihydro-1H-benzoimidazole, 2,3-dihydro-2-phenylquinazolin-4(1H)-one, and 1,2,3,4-tetrahydro-2-phenylquinazolines, among others, under air. The catalyst has further been found to be compatible with the cascade synthesis of these N-heterocycles via dehydrogenative coupling of alcohols with other suitable coupling partners under air. Mechanistic investigation reveals that the dehydrogenation reactions proceed via a one-electron hydrogen atom transfer (HAT) pathway where the zinc-stabilized azo-anion radical ligand abstracts the hydrogen atom from the organic substrate(s), and the whole catalytic cycle proceeds via the exclusive involvement of the ligand-centered redox events where the zinc acts only as the template.
Electro-oxidative cyclization: Access to quinazolinones: Via K2S2O8without transition metal catalyst and base
Hou, Huiqing,Hu, Yongzhi,Ke, Fang,Sun, Weiming,Wu, Xianghua,Yu, Ling,Zhou, Sunying
, p. 31650 - 31655 (2021/11/30)
A K2S2O8-promoted oxidative tandem cyclization of primary alcohols with 2-aminobenzamides to synthesize quinazolinones was successfully achieved under undivided electrolytic conditions without a transition metal and base. The key feature of this protocol is the utilization of K2S2O8 as an inexpensive and easy-to-handle radical surrogate that can effectively promote the reaction via a simple procedure, leading to the formation of nitrogen heterocycles via direct oxidative cyclization at room temperature in a one-pot procedure under constant current. Owing to the use of continuous-flow electrochemical setups, this green, mild and practical electrosynthesis features high efficiency and excellent functional group tolerance and is easy to scale up.
