Synthesis of some new mono, bis-indolo[1, 2-c]quinazolines: evaluation of their antimicrobial studies

Rohini, Rondla; Reddy, P. Muralidhar; Shanker, Karuna; Hu, Anren; Vadde, Ramakrishna

doi:10.1590/s0103-50532010000500018

Cited by 19 publications

(5 citation statements)

References 28 publications

(89 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The biological activities of this compound have not been reported due to a shortage of 1 isolated from natural sources. A synthetic supply of this material, therefore, is clearly important for uncovering the biological activity of 1 and its derivatives …”

mentioning

confidence: 99%

Enantioselective Total Synthesis of (+)-Hinckdentine A via a Catalytic Dearomatization Approach

et al. 2016

View full text Add to dashboard Cite

Optically pure hinckdentine A was synthesized on a 300 mg scale via an asymmetric catalysis-based strategy. The key steps to the first asymmetric synthesis involved (i) enantioselective dearomative cyclization of an achiral N-acyl indole that allowed for the efficient construction of the key polycyclic indoline intermediate with a crucial tetrasubstituted stereogenic carbon center, (ii) Beckmann fragmentation-mediated ring expansion, (iii) rearrangement-based introduction of an anilinic nitrogen atom, (iv) regioselective tribromination, and (v) final closure of the cyclic amidine moiety.

show abstract

mentioning

confidence: 99%

Enantioselective Total Synthesis of (+)-Hinckdentine A via a Catalytic Dearomatization Approach

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Since the synthesis of indolo[1,2‐ c ]quinazolines by thermal cyclization of 2‐(2‐aminophenyl)indoles with acyl cyanides followed by HCl treatment, many synthetic methods for such a hybrid scaffold are well documented . Several groups have shown that indolo[1,2‐ c ]quinazolines can be formed by condensation of 2‐(2‐aminophenyl)indoles with aromatic aldehydes and subsequent treatment with powdered KMnO 4 for oxidative cyclization . Such a hybrid scaffold formation was also exemplified by palladium‐catalyzed cyclocarbonylation of bis( o ‐trifluoroacetamidophenyl)‐acetylene with aryl or vinyl halides and triflates and cyclization of 1‐(N‐arylimino)indoles formed by addition‐elimination between indoles and N‐aryltrifluoroacetimidoyl chlorides .…”

Section: Methodsmentioning

confidence: 99%

Copper‐catalyzed CN Coupling and Cyclization of 2‐(2‐Bromophenyl)‐1H‐indoles with Primary Amides Leading to Indolo[1,2‐c]quinazolines

Yoo

Dao

Cho

2018

Bulletin Korean Chem Soc

View full text Add to dashboard Cite

It is well-known that indole-fused quinazolines, indolo [1,2-c]quinazolines exhibit biological activities such as antibacterial and antifungal properties (Scheme 1). 1,2 Since the synthesis of indolo [1,2-c]quinazolines by thermal cyclization of 2-(2-aminophenyl)indoles with acyl cyanides followed by HCl treatment, many synthetic methods for such a hybrid scaffold are well documented. 3,4 Several groups have shown that indolo[1,2-c]quinazolines can be formed by condensation of 2-(2-aminophenyl)indoles with aromatic aldehydes and subsequent treatment with powdered KMnO 4 for oxidative cyclization. 1,2,5 Such a hybrid scaffold formation was also exemplified by palladium-catalyzed cyclocarbonylation of bis(o-trifluoroacetamidophenyl)acetylene with aryl or vinyl halides and triflates 6 and cyclization of 1-(N-arylimino)indoles formed by additionelimination between indoles and N-aryltrifluoroacetimidoyl chlorides. 7 It is also reported that 2-(2-halophenyl)indoles are coupled and cyclized with (aryl)methaneamines, amidine hydrochlorides, and amino acids in the presence of a copper catalyst to give indolo [1,2-c]quinazolines. 8-10 Wang et al. recently reported on synthesis of indolo[1,2-c]quinazolines from N-{2-[(2-aminophenyl)ethynyl]phenyl}amides by ZnBr 2 -promoted domino hydroamination-cyclization. 11During the course of our continuing studies directed towards cyclization reactions, 12 we have identified several new synthetic methods for N-fused hybrid scaffolds. 13 Under these circumstances, this report describes coppercatalyzed coupling and cyclization of 2-(2-bromophenyl)-1H-indoles with primary amides leading to indole-fused quinazolines, indolo[1,2-c]quinazolines.Treatment of 2-(2-bromophenyl)-1H-indole (1a) with an equimolar amount of formamide (2a) in DMF at 130 C for 24 h in the presence of a catalytic amount of CuI (10 mol %) along with Cs 2 CO 3 afforded indolo[1,2-c]quinazoline (3a) in 10% isolated yield with several unidentifiable products (Table 1, entry 1). Higher reaction rate and yield were observed with further addition of L-proline as a ligand (entry 2). It is known that the catalytic system of CuI combined with L-proline effectively catalyzes coupling and cyclization of 2-bromobenzamides with terminal alkynes leading to 3-alkylideneisoindolin-1-ones. 14 The molar ratio of [2a]/[1a] affected the yield of 3a and the yield increased with the increase of the molar ratio up to 2.0 along with complete conversion of 1a (entry 3). Lower reaction temperature resulted in a decreased yield of 3a (entry 4). The reaction proceeded using other amino acids such as glycine, L-phenylalanine, N,N-dimethylglycine, and 4-hydroxy-Lproline in place of L-proline, but the yield of 3a was generally lower than that by the use of L-proline except for 4-hydroxy-L-proline, which exhibited similar activity as Lproline (entries 5-8).Among bases examined under the employed conditions, Cs 2 CO 3 was shown to be the base of choice (entries 3 and 9-11). When used with L-proline and Cs 2 CO 3 , copper catalysts such as CuCl, CuBr...

show abstract

“…6‐Phenylindolo[1,2‐ c ]quinazoline (3e): 18 Eluent: petroleum ether/ethyl acetate (50:1); yield 109 mg (74 %), yellow solid, m.p. 205–206 °C.…”

Section: Methodsmentioning

confidence: 99%

Copper‐Catalyzed Cascade Synthesis of 1H‐Indolo[1,2‐c]quinazoline Derivatives

et al. 2012

View full text Add to dashboard Cite

show abstract

Synthesis of some new mono, bis-indolo[1, 2-c]quinazolines: evaluation of their antimicrobial studies

Cited by 19 publications

References 28 publications

Enantioselective Total Synthesis of (+)-Hinckdentine A via a Catalytic Dearomatization Approach

Enantioselective Total Synthesis of (+)-Hinckdentine A via a Catalytic Dearomatization Approach

Copper‐catalyzed CN Coupling and Cyclization of 2‐(2‐Bromophenyl)‐1H‐indoles with Primary Amides Leading to Indolo[1,2‐c]quinazolines

Copper‐Catalyzed Cascade Synthesis of 1H‐Indolo[1,2‐c]quinazoline Derivatives

Contact Info

Product

Resources

About