159180-69-5

Upstream product

• 91-21-4 1,2,3,4-tetrahydroisoquinoline 
• 118-48-9 isatoic anhydride 
• 118-92-3 anthranilic acid 
• 6970-83-8 ethyl-N-(2-phenethyl)carbamate 

Relevant academic research and scientific papers

Electrosynthesis of polycyclic quinazolinones and rutaecarpine from isatoic anhydrides and cyclic amines

A direct decarboxylative cyclization between readily available isatoic anhydrides and cyclic amines was established to construct polycyclic fused quinazolinones employing electrochemical methods. This procedure was performed in an undivided cell without the use of a transition-metal-catalyst and external oxidant. A broad scope of polycyclic fused quinazolinones were obtained in moderate to good yields. Additionally, rutaecarpine was also prepared through our method in one step in good yield. This journal is

Copper-Catalyzed Intramolecular α-C-H Amination via Ring-Opening Cyclization Strategy to Quinazolin-4-ones: Development and Application in Rutaecarpine Synthesis

A copper-catalyzed intramolecular α-C-H amination has been developed for the synthesis of quinazolin-4(3 H)-one derivatives from commercially available isatoic anhydride and primary and secondary benzylamines via ring-opening cyclization (ROC). This method shows good functional group tolerance and allows access to a range of 2-aryl, 2-alkyl, and spiroquinazolinone derivatives. However, 2-methylquinazolin-4(3 H)-one was synthesized from 2-amino- N -isopropylbenzamide by C-C bond cleavage, and N -benzyl-2-(methylamino)benzamide afforded 1-methyl-2-phenylquinazolin-4(1 H)-one along with 2-phenylquinazolin-4(3 H)-one by N-C bond cleavage for aromatization. It is the first general method to construct the potentially useful 2-methylquinazolin-4(3 H)-one by copper-catalyzed intramolecular C-H amination. Also this ROC strategy has been successfully applied to the synthesis of quinazolinone alkaloid rutaecarpine.

Light-Driven Intramolecular C?N Cross-Coupling via a Long-Lived Photoactive Photoisomer Complex

Reported herein is a visible-light-driven intramolecular C?N cross-coupling reaction under mild reaction conditions (metal- and photocatalyst-free, at room temperature) via a long-lived photoactive photoisomer complex. This strategy was used to rapidly prepare the N-substituted polycyclic quinazolinone derivatives with a broad substrate scope (>50 examples) and further exploited to synthesize the natural products tryptanthrin, rutaecarpine, and their analogues. The success of gram-scale synthesis and solar-driven transformation, as well as promising tumor-suppressing biological activity, proves the potential of this strategy for practical applications. Mechanistic investigations, including control experiments, DFT calculations, UV-vis spectroscopy, EPR, and X-ray single-crystal structure of the key intermediate, provides insight into the mechanism.

Metal-Free Synthesis of Polycyclic Quinazolinones Enabled by a (NH4)2S2O8-Promoted Intramolecular Oxidative Cyclization

An efficient metal-free, (NH4)2S2O8 mediated intramolecular oxidative cyclization for the construction of polycyclic heterocycles was disclosed. A series of polycyclic quinazolinone derivatives with good functional group tolerance were obtained in high yields. The natural products tryptanthrin and rutaecarpine, as well as their derivatives, were easily synthesized by this strategy. A preliminary mechanism study suggested the carbon-centered radical was involved in the catalytic cycle.

Exploratory synthetic studies of the α-methoxylation of amides via cuprous ion-promoted decomposition of o-diazobenzamides

A convenient nonelectrochemical amide oxidation method has been developed. The process involves a cuprous ion-promoted decomposition of o-diazobenzamides like 4, generated in situ from the corresponding o-aminobenzamides, to give N-acyliminium ion intermediate 9 via a 1,5-H-atom transfer, followed by metal-catalyzed oxidation of the resulting α-amidyl radical. The transformation produces α-methoxybenzamides 15 in good yields. An attempt was made to apply this oxidation method to a total synthesis of the alkaloid (-)-anisomycin (16). Scalemic o-aminobenzamide pyrrolidine derivatives 18a/18b underwent oxidation to give α-methoxylated amide substrates 19a/19b, respectively, in good yields. However, alkylation of the N-acyliminium intermediate 20 with (p-methoxybenzyl)magnesium chloride gave the undesired anti-compounds 22a/22b as the major products. The amide oxidation exhibits good regioselectivity with many unsymmetrical 2-substituted piperidine and pyrrolidine systems. In general, it appears that the larger the C-2 substituent, the greater the methylene/methine H-atom abstraction ratio. A mechanistic rationale for this selectivity is suggested based upon amide rotamer populations. An extension of this methodology can be used to conduct two sequential amide oxidations using readily prepared 2-amino-6-nitrobenzamides such as 68 and 69.