One-pot synthesis of benzo[a]phenanthridin-5-ones by photoinduced cycloaddition of 3-chloroisoquinolin-1-ones with styrenes

One-pot synthesis of benzo[a]phenanthridin-5-ones and benzo[k]phenanthridin-6-ones in fairly good yields was achieved by the photocycloaddition reactions of 3-chloroisoquinolin-1-ones and 3-chloroquinolin-2-ones with styrenes. The reactions were proceeded via photoinduced dechlorinative coupling of 3-chloroisoquinolin-1-ones and 3-chloroquinolin-2-ones with styrenes and subsequent photocyclization, oxidative aromatization.     

Synthesis and tautomerization of benzo[cd]azulen-3-ones

This report describes a type of tautomerization reaction that proceeds via isomerization of π-bonds across the azulene moieties of tricyclic benzo[cd]azulen-3-ones. The reaction mechanism shows similarities to an elimination reaction that was recently developed in our group. Furthermore, the facile four-step syntheses of the benzo[cd]azulen-3-ones, the starting materials for the tautomerization reactions, and computational analyses of the tautomerization reaction are included.     

Three distinct reactions of 3,4-dihydroisoquinolines with azlactones: novel synthesis of imidazoloisoquinolin-3-ones, benzo[a]quinolizin-4-ones, and benzo[d]azocin-4-ones

A facile and direct synthetic entry to tricyclic imidazoloisoquinolin-3-ones and benzo[a]quinolizin-4-ones is reported based on the ring annulation of 1-unsubstituted and 1-substituted dihydroisoquinolines with azlactones under neutral conditions in a one-step procedure. Bicyclic 2,3-dihydrobenzo[d]azocin-4-ones were also prepared using simple azlactone and 1-substituted dihydroisoquinolines in a one-pot reaction. [reaction: see text]     

Rearrangement of 2-[1(3h)-oxodihydrobenzo[c]furan-3-yl] quinuclidin-3-ones to tetrahydrobenzo[b]quinolizines. A novel synthesis of benzo[b]quinolizine ring systems.

A new two step synthesis of benzo[b]quinolizine ring systems via the rearrangement of 2-[1(3H)-oxodihydrobenzo[c]furan-3-yl] quinuclidin-3-ones is described.     

An efficient synthesis of benzo[b]benzofurano[2,3-e]-[1,6]naphthyridine-8-ones

An efficient method for the synthesis of benzo[b]benzofurano[2,3-e][1,6]naphthyridine-8-one derivatives has been developed via Pictet-Spengler reaction of 4-(3-aminobenzofuran-2-yl)quinoline-2-ones,which could be obtained from alkylation of 4-bromomethylquinoline-2-ones with salicylonitrile and subsequent Thorpe-Ziegier isomerization,with aromatic aldehydes under p-TsOH as catalyst in good yields.     

An efficient synthesis of novel benzo[b]pyrido[3',2':4,5] thieno[2,3-e][1,6]naphthy-ridine-8-ones

An efficient method for the synthesis of novel benzo[b]pyrido[3',2':4,5] thieno[2,3-e][1,6] naphthyridine-8-one derivatives has been developed using a Pictet-Spengler reaction between 4-(3-aminothieno[2,3-b]pyridin-2-yl)quinoline-2-ones, which could be obtained from the alkylation of 4-bromomethylquinoline-2-ones with 3-cyanopyridine-2-thione followed by a Thorpe-Ziegler isomerization, and aromatic aldehydes under p-TsOH as catalysis in good yields.     

Palladium-mediated intramolecular carbonylative annulation of o-alkynylphenols to synthesize benzo[b]furo[3,4-d]furan-1-ones

[reaction in text] The carbonylative annulation of o-alkynylphenols mediated by PdCl(2)(PPh(3))(2) and dppp in the presence of CsOAc at 55 degrees C in acetonitrile under a balloon pressure of CO generates functionalized benzo[b]furo[3,4-d]furan-1-ones in good yields. This novel synthetic approach provides a highly efficient method for diversification of the benzofuran scaffold for combinatorial synthesis.     

Synthesis of novel benzo[b]pyrimido[4',5':5,4]thieno[2,3-e][1,6]naphthyridine-8-ones via Pictet–Spengler cyclization

An efficient method for the synthesis of novel benzo[b]pyrimido[4',5':5,4]thieno[2,3e]-[1,6]naphthyridine-8-one derivatives via Pictet–Spengler cyclization is reported. The reaction of 4-(3-aminopyrimido[4,5-d]thieno-2-yl)quinoline-2-ones, which could be obtained from Thorpe–Ziegler isomerization of 4-bromomethylquinoline-2-ones and 5-cyano-1,6-dihydro-4-methyl-2-phenyl-6-thioxopyrimidine,with aromatic aldehydes in the presence of BF_3·OEt_2 gives pyrimidothieno[1,6]naphthyridines in good yields.     

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 3-aryl substituted benzo[1,2,5]triazepin-4-ones via intramolecular imine formation

3-Aryl substituted benzo[1,2,5]triazepin-4-ones and their pyrido counterparts have been synthesized in five steps from commercially available starting materials. The key step involves base-induced cleavage of trifluoroacetyl-protected hydrazine intermediates and in situ intramolecular imine formation.     

Chemistry of heterocyclic quinonimines. 10. Transformation of benzo[c]phenoxazine ring into benzo[c]phenazone by aromatic amines

Transformation of benzo[c]phenoxazin-3-one by free arylamines into 2-arylamino-5-arylbenzo[c]phenazin-3-ones is observed. The same reaction with protonation of substrate leads to selective formation of 2-arylaminobenzo[c]phenoxazin-3-ones.Translated from Khimiya Geterotsiklicheskikh Soedinenií, No. 12, pp. 1679–1681, December, 1988.     

Synthesis of diverse benzo[1,4]oxazin-3-one-based compounds using 1,5-difluoro-2,4-dinitrobenzene

This paper discusses the synthesis of benzo[1,4]oxazin-3-one-based compounds from 1,5-difluoro-2,4-dinitrobenzene (1), including benzo[1,4]oxazin-3-ones (5-11) and five novel benzo[1,4]oxazin-3-one-based tricycles: 6-hydroxy-4H-1-oxa-4,5,8-triazaanthracen-3-one (14), 3,8-dihydro-5-oxa-1,3,8-triazacyclopenta-[b]-naphthalene-7-one (15, 17, 21), 3,8-dihydro-5-oxa-1,2,3,8-tetraazacylopenta[b]-naphthalene-7-one (16, 20), 3,8-dihydro-1H-5-oxa-1,3,8-triazacyclopenta[b]-naphthalene-2,7-dione (18, 22), and 5,8-dihydro-4H-1-oxa-4,5,8-triazaanthracene-3,6,7-trione (19). Finally, a chemical library based on 15 was synthesized in parallel solution-phase reactions.     

Microwave-assisted one-pot synthesis of benzo[b][1,4]oxazin-3(4H)-ones via Smiles rearrangement

An efficient method for the synthesis of benzo[b][1,4]oxazin-3(4H)-ones via Smiles rearrangement using a microwave-assisted one-pot, three-step reaction has been developed. Various benzo[b][1,4]oxazin-3(4H)-ones are obtained in good yields (55-86%) from the corresponding substituted 2-chlorophenols and primary amines in short reaction time (18-40 min).     

Synthesis of dibenzo[b,d]pyran-6-ones based on [3 + 3] cyclizations of 1,3-bis(silyl enol ethers) with 3-silyloxy-2-en-1-ones

Functionalized dibenzo[b,d]pyran-6-ones were prepared by formal [3 + 3] cyclization of 1,3-bis(silyl enol ethers) with 3-silyloxy-2-en-1-ones or 1,1-diacetylcyclopropane to give functionalized salicylates, Suzuki cross-coupling reactions of the corresponding triflates, and subsequent BBr3-mediated lactonization. A second approach to dibenzo[b,d]pyran-6-ones relies on the [3 + 3] cyclization of 1,3-bis(silyl enol ethers) with 1-(2-methoxyphenyl)-1-(trimethylsilyloxy)alk-1-en-3-ones and subsequent BBr3-mediated lactonization.     

An efficient route for synthesis of 2-alkylamino benzo[b]thieno[3,2-d]pyrimidin-4(3H)-one

The carbodiimide 2,obtained from the aza-Wittig reactions of iminophosphorane 1 with alkyl isocyanates,reacted with primary amino to give 2-alkylamino benzo[b]thieno[3,2-d]pyrimidin-4(3H)-ones 4 and 5.The formation mechanism of the title compounds has been investigated.     

Reactions with benzo[b]thiophene-2,3-diones I: Synthesis of 2,3-dihydroxy-2,3-diaryl(aralkyl)benzo[b]thiophene derivatives

Benzo[b]thiophene-2,3-diones ( 1 ) react with Grignard reagents to yield 2,3-dihydroxy-2,3-diaryl(aralkyl)benzo[b]-thiophenes ( 2 ). The latter compounds yield 3,3-diaryl(aralkyl)-benzo[b]thiophene-2-ones ( 3 ) by pinacolone rearrangement. Treatment of 3 by hot ethanolic sodium hydroxide solution yields the corresponding carboxylic acids by hydrolytic heteroring opening.     

Facile synthesis of spiro[benzo[e]indole-2,2′-piperidine] derivatives and their transformation to novel fluorescent scaffolds

The reaction of azaheterocyclic enamines with acrylamide was employed for the preparation of novel fluorescent scaffolds possessing a benzo[e]indoline moiety. Reaction of 3-substituted 2-methylidene-1H-benzo[e]indole with acrylamide gave rise to spiro[benzo[e]indole-2,2′-piperidin]-6′-ones. Ring opening reactions of the latter spiro compounds were investigated. Benzo[e]indoline derivatives possessing 2-(3-carbamoylpropyl), 2-[3-(ethoxycarbonyl)propyl] and 2-(4-aminobutyl) side chains were synthesised. The optical properties of the benzo[e]indoline derivatives were studied by UV-vis and fluorescence spectroscopy.     

New general synthesis of benzo[4,5]imidazo[1,2-<Emphasis Type="Italic">a</Emphasis>]pyrimidine and benzo[4,5]imidazo[2,1-<Emphasis Type="Italic">b</Emphasis>]quinazoline derivatives

The reactions of benzene-1,2-diamine with 5-substituted 2-(alkylsulfanyl)-4-methylpyrimidin-6(1H)-ones and 2-(propylsulfanyl)- and 5-iodo-2-(propylsulfanyl)-3,4-dihydroquinazolines at 175–185°C under solvent-free conditions unexpectedly afforded benzo[4,5]imidazo[1,2-a]pyrimidine, benzo[4,5]imidazo[2,1-b]-quinazoline, and 2,2′-(benzene-1,2-diyldiimino)bis[pyrimidin-4(3H)-ones]. The described reaction is the first example of synthesis of these heterocyclic systems by fusion of benzimidazole to pyrimidine or quinazoline and is likely to follow ANRORC mechanism.     

One-Pot Synthesis of 2,3-Dihydro-2,3-disubstituted Benzo[g]-quinazolin-4(1H)-ones

Condensation of 2H-naphth[2,3-d][3,1] oxazin-2,4 (IH)-dione (1) with schiff bases (2) in acetic acid resulted in the formation of 2,3-dihydro-2,3-diarylbenzo[g]quinazolin-4(IH)-ones (3). Reaction of 1 with ketoanils generated in situ results in 2,3-dihydro-2,2-substituted-3-phenylbenzo[g]quinazolin-4 (IH)-ones (6) and the spiroalkanes (5). Dehydrogenation of 3 gave 2,3-diaryl benzo[g]quinazolin-4(3H)-ones (7).     

The synthesis of benzo[b]phenanthro[d]thiophenes and anthra[b]benzo[d]thiophenes

The synthesis of benzo[b]phenanthro[2, 3-d]thiophene ( 5 ), benzo[b]phenanthro[4, 3-d]thiophene ( 6 ), benzo-[b]phenanthro[2, 1-d]thiophene ( 9 ), benzo[b]phenanthro[3, 2-d]thiophene ( 14a ), anthra[1, 2-b]benzo[d]thiophene ( 24 ), anthra[2, 3-b]benzo[d]thiophene ( 29 ) and anthra[2, 1-b]benzo[d]thiophene ( 30 ) is described as well as the preparation of 13-methylbenzo[b]phenanthro[3, 2-d]thiophene ( 14b ).