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Related: benzo-fused O-Heterocyles, benzo-fused S-Heterocycles, N-substitution

Synthesis of benzo-fused N-Heterocycles and similar compounds

Synthesis of      

Indoles

Indolenines

Indolines

Oxindoles

Isatins
 
Azaindoles

Carbazoles

Isoindoles

Isoindolines

Isoindolinones

Phthalimides

Benzimidazoles

Benzimidazolones
   

Indazoles

2H-Indazoles
   

Benzoxazoles

Benzoxazolones

Benzothiazoles
 

Benzisoxazoles
 
Benzisothiazoles
 

Benzotriazoles

2H-Benzotriazoles
   

Indolizines

Indolizinones
   

Imidazo[1,2-a]pyridines

Imidazo[1,5-a]pyridines

1,2,4-Triazolo[1,5-a]pyridines

1,2,4-Triazolo[4,3-a]pyridines

Tetrazolo[1,5-a]pyridines
     

Quinolines

Tetrahydro-
quinolines


1,2-
Dihydroquinolines

 

Isoquinolines
and rel. comp.

3,4-dihydroisoquinolines

Tetrahydroisoquinolines

Phthalazines

1,8-
Naphthyridines

Quinazolines

Quinoxalines

Tetrahydro-
quinoxalines

1,2,4-benzotriazines
     

4-Quinolones

2-Quinolones

Isoquinolones

Isoquinolin-3-ones

Quinazolinones

Quinoxalinones

2,3-Dihydroquinazolinones


Quinazolinediones

Benzoxazinones
     


Recent Literature


A Rh/Pd/Cu catalyst system led to an efficient one-pot synthesis of dihydroquinolinones without any intermediate workup. The conjugate-addition/amidation/amidation reaction sequence is highly modular, divergent, and practical.
L. Zhang, L. Sonaglia, J. Stacey, M. Lautens, Org. Lett., 2013, 15, 2128-2131.


A mild and efficient one-pot procedure starting from o-aminoacetophenones and aromatic aldehydes in the presence of silver(I) triflate provides various 2-aryl-2,3-dihydroquinolin-4(1H)-ones. This method has several advantages, such as the use of easily available starting materials, the efficiency of the catalyst, a simple operation, and tolerance of a wide range of functionality in the aldehydes.
R. P. Pandit, K. Sharma, Y R. Lee, Synthesis, 2015, 47, 3881-3890.


In the presence of CuCl, a three-component reaction of o-iodoanilines and K2S with TosMIC proceeded smoothly to yield the corresponding benzothiazolethiones in very good yields. Notably, isocyanide served as a carbon source and K2S functioned as a sulfur source.
P. Dang, W. Zeng, Y. Liang, Org. Lett., 2015, 17, 34-37.


A molecular iodine-catalyzed oxidative cyclization of 2-aminopyridine/amidine and isothiocyanate via N-S bond formation enables the synthesis of N-fused and 3,4-disubstituted 5-imino-1,2,4-thiadiazole derivatives at ambient temperature. This transition-metal-free protocol provides a facile and highly efficient regiospecific synthesis of various 1,2,4-thiadiazole derivatives with good to excellent yields using inexpensive I2 as a catalyst.
N. Tumula, N. Jatangi, R. K. Palakodety, S. Balasubramanian, M. Nakka, J. Org. Chem., 2017, 82, 5310-5316.


A broad range of substituted benzisoxazolines have been synthesized by a mild [3 + 2] cycloaddition of nitrones and arynes. The process tolerates various functional groups.
C. Lu, A. V. Dubrovskiy, R. C. Larock, J. Org. Chem., 2012, 77, 2279-2284.


Iron(II) bromide catalyzes the transformation of aryl and vinyl azides with ketone or methyl oxime substituents into 2,1-benzisoxazoles, indazoles, or pyrazoles through the formation of an N-O or N-N bond. This transformation tolerates various functional groups and facilitates access to a range of benzisoxazoles or indazoles.
B. J. Stokes, C. V. Vogel, L. K. Urnezis, M. Pan, T. G. Driver, Org. Lett., 2010, 12, 2884-2887.


Rhodium(II) perfluorobutyrate-mediated decomposition of vinyl azides allows rapid access to a variety of complex, functionalized N-heterocycles in two steps from commercially available starting materials.
B. J. Stokes, H. Dong, B. E. Leslie, A. L. Pumphrey, T. G. Driver, J. Am. Chem. Soc., 2007, 129, 7500-7501.


Sequential coupling-imination-annulation reactions of ortho-bromoarylaldehydes and terminal alkynes with ammonium acetate in the presence of a palladium catalyst under microwave irradiation gives various substituted isoquinolines, furopyridines, and thienopyridines in good yields.
D. Yang, S. Burugupalli, D. Daniel, Y. Chen, J. Org. Chem., 2012, 77, 4466-4472.


A Pd-catalyzed amide coupling reaction enables a facile synthesis of imidazo[4,5-b]pyridines and -pyrazines. This reaction provides quick access to various substituted products. A model system relevant to the natural product pentosidine has been demonstrated, as well as the total synthesis of the mutagen 1-Me-5-PhIP.
A. J. Rosenberg, J. Zhao, D. A. Clark, Org. Lett., 2012, 14, 1761-1767.


Pyridinium N-(heteroaryl)aminides are robust and practical synthetic equivalents of nucleophilic 1,3-N,N-dipoles in a Au-catalyzed formal cycloaddition onto electron-rich alkynes. Convergent and regioselective access to five types of imidazo-fused heteroaromatics is provided from the appropriate aminide. The efficient transformation tolerates significant structural variation.
M. Garzón, P. W. Davies, Org. Lett., 2014, 16, 4850-4853.


The synthesis of functionalized pyrazolo[1,5-a]pyridines through oxidative [3+2] cycloaddition of N-aminopyridines with α,β-unsaturated carbonyl compounds or electron-withdrawing olefins proceeds in N-methylpyrrolidone as the solvent under metal-free conditions at room temperature.
C. Ravi, S. Samanta, D. C. Mohan, N. N. K. Reddy, S. Adimurthy, Synthesis, 2017, 49, 2513-2522.


The reaction of β,γ-unsaturated γ-alkoxy-α-keto esters with 5-aminopyrazoles proceeds with high regioselectivity to yield new pyrazolo[1,5-a]pyrimidines bearing an ester function in the 7-position. The obtained drug-like compounds have a great potential for medicinal chemistry as they closely resemble the structure of several marketed pharmaceuticals.
O. O. Stepaniuk, V. O. Matviienko, I. S. Kontratov, I. V. Vitruk, A. O. Tolmachev, Synthesis, 2013, 45, 925-930.


A set of benzimidazoles, 3H-imidazo[4,5-b]pyridines, purines, xanthines and benzothiazoles was readily prepared from (hetero)aromatic ortho-diamines or ortho-aminothiophenol and aldehydes using chlorotrimethylsilane in DMF as a promoter and water-acceptor agent, followed by oxidation with air oxygen.
S. V. Ryabukhin, A. S. Plaskon, D. M. Volochnyuk, A. A. Tolmachev, Synthesis, 2006, 3715-3726.


A highly efficient and versatile method for the synthesis of a series of 2-substituted N-H, N-alkyl, and N-aryl benzimidazoles containing a wide range of functional groups was achieved in one step via the Na2S2O4 reduction of o-nitroanilines in the presence of aldehydes.
D. Yang, D. Fokas, J. Li, L. Yu, C. M. Baldino, Synthesis, 2005, 47-56.


The 3-Aminoimidazo[1,2-a]pyrazine scaffold is rapidly accessible through a Groebke-Blackburn-Bienaymé cyclisation starting from an aminopyrazine, an aldehyde and an isocyanide. A scale-up process of this multicomponent reaction has been achieved in high yield and with excellent purity.
M. Baenziger, E. Durantie, C. Mathes, Synthesis, 2017, 49, 2266-2274.


In a regioselective and high-yielding Groebke-Blackburn-Bienaymé reaction, glyoxylic acid is used as formaldehyde equivalent leading to a regioselective, mild, convenient, and effective synthesis of 3-aminoalkyl imidazoazines.
A. Sharma, H.-y. Li, Synlett, 2011, 1407-1412.


In a regioselective and high-yielding Groebke-Blackburn-Bienaymé reaction, glyoxylic acid is used as formaldehyde equivalent leading to a regioselective, mild, convenient, and effective synthesis of 3-aminoalkyl imidazoazines.
A. Sharma, H.-y. Li, Synlett, 2011, 1407-1412.


An Au-catalyzed synthesis of fused pyrroloheterocycles from diverse propargyl-substituted heterocycles proceeds via alkyne-vinylidene isomerization with concomitant 1,2-shift of hydrogen, silyl, and stannyl groups. This method allows for mild and efficient synthesis of diverse C-2 substituted N-heterocycles.
I. V. Seregin, V. Gevorgyan, J. Am. Chem. Soc., 2006, 128, 12050-12051.


In a copper-catalyzed synthesis of benzo[d]isothiazol-3(2H)-ones and N-acyl-benzothiazetidine by intramolecular dehydrogenative cyclization, a new nitrogen-sulfur bond is formed by N-H/S-H coupling. The present reaction tolerates various functional groups and gives products in gram scale.
Z. Wang, Y. Kuninobu, M. Kanai, J. Org. Chem., 2013, 78, 7337-7342.


The use of N,N′-bis(2,6-diisopropylphenyl)dihydroimidazol-2-ylidene (SIPr) as a ligand and tBuONa as the base for sequential palladium-catalyzed intra- followed by intermolecular aryl amination enables the synthesis of N-arylated five-, six- and seven-membered nitrogen heterocycles.
R. Omar-Amrani, R. Schneider, Y. Fort, Synthesis, 2004, 2257-2534.


A Rh(III)-catalyzed, N-amino (hydrazine)-directed C-H functionalization with α-diazo-β-ketoesters provides a simple and efficient access to the cinnoline scaffold via successive C-H activation/C-C coupling/intramolecular dehydration.
C. Song, C. Yang, F. Zhang, J. Wang, J. Zhu, Org. Lett., 2016, 18, 4510-4513.


A one-pot method for the Sonogashira coupling and cyclization of 2-bromobenzenesulfonamides and terminal alkynes allows access to various substituted benzosultams regioselectively in excellent yields.
S. Debnath, S. Mondal, J. Org. Chem., 2015, 80, 3940-3948.


A copper-catalyzed three-component tandem reaction enables a convenient and practical synthesis of 1,4-benzothiazines from terminal alkynes, 2-iodophenyl isothiocyanates, and aqueous ammonia.
J.-J. Chu, B.-L. Hu, Z.-Y. Liao, X.-G. Zhang, J. Org. Chem., 2016, 81, 8647-8652.


A regioselective one-pot synthesis of 2-alkyl-3,4-dihydro-3-oxo-2H-1,4-benzoxazines under microwave heating starts from commercially available 2-aminophenols. Base-mediated regioselective O-alkylation with 2-bromoalkanoates gives acyclic intermediates. A subsequent intramolecular amidation reaction furnishes the desired products in good yields.
W.-M. Dai, X. Wang, C. Ma, Tetrahedron, 2005, 61, 6879-6885.


A convenient environmentally friendly method for the cyclization of 2-aminochalcones to 2-aryl-2,3-dihydroquinolin-4(1H)-ones on the surface of silica gel impregnated with indium(III) chloride under microwave irradiation without any solvent has been reported.
K. H. Kumar, D. Muralidharan, P. T. Perumal, Synthesis, 2004, 63-68.


The reaction of o-haloaniline derivatives and carbon disulfide in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene at 80-140˚C provides the corresponding 1,3-benzothiazole-2(3H)-thione derivatives in good yields.
Y. Fu, X. Hu, Y. Chen, Y. Yang, H. Hou, Y. Hu, Synthesis, 2012, 44, 1477-1480.


A H2SO4-mediated intramolecular cyclization enables the preparation of biologically important tetrahydro-1-benzazepines from N-arylated homoallylamines. This solvent- and metal-free, atom- and step-economical transformation offers mild reaction conditions, experimental simplicity, and the use of a readily available, cheap, and nontoxic mediator.
H.-S. Gao, F. Dou, A.-L. Zhang, R. Sun, L.-M. Zhao, Synthesis, 2017, 49, 1597-1602.


An atom-economic, efficient, rapid, and highly regioselective one-pot click reaction allows the synthesis of benzo[e][1,4]oxazepin-5-ones in excellent yields. The method involves epoxide ring-opening-ring-closing cascade with anthranilic acids using neat grinding at room temperature in the presence of lithium bromide as a mild catalyst. Pure products are obtained simply by washing the reaction mixture with warm water.
A. K. Singh, R. Chawla, L. D. S. Yadav, Synthesis, 2012, 44, 2353-2358.