Synthesis of regioisomeric 6,9-(chlorofluoro)-substituted benzo[g]quinoline-5,10-diones,benzo[g] isoquinoline-5,10-diones and 6-chloro-9-fluorobenzo[g]quinoxaline-5,10-dione

Treatment of difluoro or chloro fluoro-substituted benzyl bromides 5a-c with zinc dust in tetrahydro-furan leads to the corresponding benzylic zinc bromides 6a-c. These organometallics on treatment with chlorosubstituted heterocyclic esters 4A and 4B mediated by nickel catalysis undergo couplings to yield dihalobenzyl substituted heterocyclic esters 7Aa-c and 7Ba-c. Treatment of 4c with 6c under Pd catalysis leads to 7Cc. The acids 8, prepared by hydrolysis of these esters, with treatment of fuming sulfuric acid undergo cyclizations and oxidations to yield the desired regioisomeric dihalo-substituted heterocyclic quinones 2.     

Synthesis and chemiluminescent activity of 8,9‐dihydrobenzo[g] pyridazino[4,5‐b]indole‐7,10(11H)‐diones

Substituted and unsubstituted naphthylamines were transformed into the corresponding triazole derivatives, which were converted to dimethyl 1H‐benz[g]indole‐2,3‐dicarboxylates by photocyclization. The reaction of the diesters with hydrazine hydrate gave the corresponding 8,9‐dihydrobenzo[g]‐pyridazino[4,5‐b]indole‐7,10(11H)‐diones (5) . One of compounds 5 was found to have chemiluminescent activity similar to luminol.     

Synthesis of new benzo[h]‐ and benzo[f]chromeno[2,3‐b]‐pyridine‐5‐ones

A number of new benzo[h]‐ and benzo[f]chromeno[2,3‐b] pyridine‐5‐ones derivatives were synthesized from benzo[h]‐ and benzo[f]‐chromone‐carbonitriles and amino‐benzo[h]‐ and benzo[f]chromone‐carbaldehydes. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:2–7, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20152     

Synthesis of 1-substituted 1,2,3,4-tetrahydrobenz[g]isoquinoline-5,10-diones

1,2-Disubstituted 1,2,3,4-tetrahydrobenz[g]isoquinoline-5,10-diones are prepared for the first time through an activated Pictet-Spengler reaction of the corresponding imines of 2-(1,4-dimethoxynaphth-2-yl)ethylamine in the presence of an acyl chloride and AlCl(3) followed by an oxidation with silver(II) oxide in nitric acid. Depending on the reaction conditions the N-trichloroacetyl protecting group could be cleaved off, converted to an N-methoxycarbonyl group or transformed to an N-(2-oxoacetamide) moiety. The synthesized 1,2-disubstituted 1,2,3,4-tetrahydrobenz[g]isoquinoline-5,10-diones constitute a new class of quinones, which has not been reported yet.     

Synthesis of 4‐Aryl‐3‐Methyl‐1‐Phenyl‐1H‐Benzo[h]Pyrazolo[3,4‐b]Quinoline‐5,10‐diones Using Diammonium Hydrogen Phosphate as an Efficient and Versatile Catalyst in Water

A simple and efficient synthesis of 4‐aryl‐3‐methyl‐1‐phenyl‐1H‐benzo[h]pyrazolo[3,4‐b]quinoline‐5,10‐diones has been accomplished by the one‐pot condensation reaction of 3‐methyl‐1‐phenyl‐1H‐pyrazol‐5‐amine, aldehydes and 2‐hydroxynaphthalene‐1,4‐dione in water in the presence of diammonium hydrogen phosphate.     

Synthesis of benzo[g]quinoline derivatives

The synthesis of 4-aminobenzo[g]quinoline has been effected by the following three methods: 1) replacement of the halogen in 4-chlorobenzo[g]quinoline by an amino group; 2) dehydrogenation of the oxime of 1,2,3,4-tetrahydro-4-oxobenzo[g]quinoline; 3) direct condensation of 1,2,3,4-tetrahydro-4-oxobenzo[g]quinoline with ammonia.     

Synthesis of benzo [g]quinoline derivatives

The IR spectra of linear benzoquinoline derivatives at 700–900, 1400–1700, and 2800–3600 cm^–1 are discussed, and the characteristic frequencies are related to the peculiarities of the structures of the synthesized compounds.See [1] for communication VIIITranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 367–372, March, 1972.     

Synthesis of benzo[g]quinoline derivatives

It has been established that the cyclization of -(2-carboxy-3-naphthylamino)propionic acid into N-acetyl-4-oxo-1, 2, 3, 4-tetrahydrobenzo[g]quinoline takes place with the participation of acetic anhydride and an alkali metal acetate. In the absence of the alkali metal acetate cyclization takes place in a different direction. A mechanism for this reaction has been proposed as taking place through the formation of an internal mixed anhydride, which decomposes under the reaction conditions into N-acetyl-4-oxo-1, 2, 3, 4-tetrahydrobenzo[g]-quinoline and carbon dioxide.For part V, see [1].     

Synthesis of benzo[g]quinoline derivatives

The electronic spectra of linear benzo[g]quinoline, its 4-substituted derivatives, and some hydrogenated derivatives are examined and discussed.See [1] for communication IX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 662–665, May, 1972.     

Synthesis of benzo[g]quinoline derivatives

In the condensation of 1, 2, 3, 4-tetrahydro-4-oxobenzo[g]quinollne with ammonia, which leads to the formation of 4-aminobenzo[g]quinoline, the by-products are benzo[g]quinoline (V) and 1, 2, 3, 4-tetrahydrobenzo]quinoline (VI), which are also obtained from 1, 2, 3, 4-tetrahydro-4hydroxybenzo[g]quinoline by its dehydration and the subsequent disproportionation of the dihydrobenzo[g]quinoline formed.For communication II, see [1].     

Synthesis of benzo[g]quinoline derivatives

A method for the synthesis of 3-substituted benzo[g]quinolin-4-ones by the condensation of 1,2,3,4-tetrahydrobenzo[g]quinolin-4-one with aromatic aldehydes in an alkaline medium has been developed. It has been found that the first stage of the reaction is the formation of the corresponding benzylidene derivative, which then isomerizes into the more stable benzyl derivative. The structure of the 3-substituted benzo[g]quinolin-4-ones obtained, as existing in the tautomeric oxo form, is confirmed by their IR and UV spectra.For Communication VI, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinii, Vol. 6, No. 6, pp. 798–801, June, 1970.     

Synthesis of benzo[g]quinoline derivatives

4-Amino-substituted benzo[g]quinolines have been synthesized for the first time by the condensation of 4-oxo-1,2,3,4-tetrahydrobenzo[g]-quinoline with amines. This reaction is characterized by the addition of the amine, the splitting out of water, and the complete aromatization of the initial hydrogenated heterocyclic system. The UV spectra of the compounds obtained are similar to those of 4-amino-substituted quinolines, their maxima being displaced somewhat into the long-wave region.For part III, see [2].     

An Efficient Synthesis of Benzo[g]thiazolo[2,3‐b]quinazolin‐4‐ium and Benzo[g]benzo[4,5]thiazolo[2,3‐b]quinazolin‐14‐ium Hydroxides by a One‐pot,Three‐component Reaction under Green Conditions

A new series of benzo[g]thiazolo[2,3‐b]quinazolin‐4‐ium and benzo[g]benzo[4,5]thiazolo[2,3‐b]quinazolin‐14‐ium hydroxide derivatives have been synthesized by the one‐pot, three‐component reaction of aryl glyoxal monohydrates, 2‐hydroxy‐1,4‐naphthoquinone, and 2‐aminothiazole or 2‐aminobenzothiazole in the presence of triethylamine and p‐toluenesulfonic acid as organocatalysts in H₂O/acetone (2:1) at room temperature. This method offers mild reaction conditions, excellent yields, easy workup, and readily accessible starting materials and catalysts.     

Two novel bis‐azomethines derived from quinoxaline‐2‐carbaldehyde

The Schiff base compounds N,N′‐bis[(E)‐quinoxalin‐2‐ylmethylidene]propane‐1,3‐diamine, C₂₁H₁₈N₆, (I), and N,N′‐bis[(E)‐quinoxalin‐2‐ylmethylidene]butane‐1,4‐diamine, C₂₂H₂₀N₆, (II), crystallize in the monoclinic crystal system. These molecules have crystallographically imposed symmetry. Compound (I) is located on a crystallographic twofold axis and (II) is located on an inversion centre. The molecular conformations of these crystal structures are stabilized by aromatic π–π stacking interactions.     

Synthesis of benzo[g]quinoline derivatives. XI. 2,4-Diamino-substituted benzo[g]quinolines

Previously unknown 2,4-diamino-substituted benzo[g]quinolines were synthesized from 2,4-dihydroxybenzo[g]quinoline.     

Synthesis and reactions of pyrido[3,2,1‐jk]carbazole‐4,6‐diones

Pyrido[3,2,1‐jk]carbazoles 1 , synthesized from carbazoles and alkyl‐ or arylmalonates, gave regioselective electrophilic substitution reactions at position 5 such as chlorination to 5‐chloro derivatives 2 , nitration to 5‐nitro compounds 3 , or hydroxylation to 5‐hydroxy derivatives 4 . 5‐Hydroxy compounds 4 gave on treatment with strong bases ring contraction to 5 , 6 or the ring opening product 7 . Exchange of the chloro group in 2 with azide or amines gave the corresponding azides 8 and the 5‐amino derivatives 9 and 10 . Alkylation of 1 with benzyl chloride or allyl bromide resulted in the formation of 5‐C‐alkylated products 11 together with 4‐alkyloxy derivatives 12 . J. Heterocyclic Chem., 48, 1039 (2011).     

A simple synthesis of 4‐chloro‐5‐hydroxy‐1H‐benzo[g]indoles

The reaction of methyl 2‐(3‐chloro‐1,4‐dioxo‐1,4‐dihydronaphthalen‐2‐yl)propenoate ( 2a ) with primary amines gave 4‐chloro‐5‐hydroxy‐3‐methoxycarbonyl‐1H‐benzo[g]indoles 5a‐f as major compounds and 3‐methoxycarbonyl‐4,9‐dioxo‐2,3,4,9‐tetrahydro‐1H‐benzo[f]indoles 6a‐d as minor ones. Whereas the reaction of 3‐(3‐chloro‐1,4‐dioxo‐1,4‐dihydronaphthalen‐2‐yl)‐3‐buten‐2‐one ( 2b ) with primary amines afforded the corresponding 1H‐benzo[g]indoles 5g‐i as major products and 3‐acetyl‐4,9‐dihydro‐4,9‐dioxo‐1H‐benzo[f]indoles 7g, h as minor products.