Metaboliten der 1,5-Dihydroimidazo[2,1-b]chinazolin-2(3H)-one. Synthese und Reaktionen einiger 1,5-Dihydro-3-hydroxyimidazo[2,1-b]chinazolin-2(3H)-one

Metabolites of 1,5-Dihydroimidazo[2,1-b ]quinazolin-2(3H)-ones. Preparation and Reactions of Some 1,5-Dihydro-3-hydroxyimidazo[2,1-b]quinazolin-2(3H)-ones Hydroxylated 1,5-dihydroimidazo[2,1-b]quinazolin-2(3H)-ones 2–4 and 6 were isolated as metabolites of imidazoquinazolinones 1a and 1b , respectively. The synthesis of 1,5-dihydro-3-hydroxy-3-methylimidazo[2,1-b]quinazolin-2(3H)-ones 3 , 4 , and 6 , and the preparation of some derivatives thereof is described.     

Halogenation of Imidazo[4,5-<Emphasis Type="Italic">b</Emphasis>]pyridin-2-one Derivatives

Chlorination and bromination of 2,3-dihydro-1H-imidazo[4,5-b]pyridin-2-one and its N-methyl-substituted derivatives in acetic acid at 90–95°C leads to formation of the corresponding 5,6-dichloro(dibromo)-2,3-dihydro-1H-imidazo[4,5-b]pyridin-2-ones. Iodination of the same substrates with ICl under analogous conditions yields 6-iodo derivatives. Chlorination of 6-iodo-1,3-dimethyl-2,3-dihydro-1H-imidazo[4,5-b]pyridin-2-one is accompanied by replacement of the iodine atom by chlorine with formation of 5,6-dichloro-1,3-dimethyl-2,3-dihydro-1H-imidazo[4,5-b]pyridin-2-one. Bromination of 6-bromo- and 6-chloro-2,3-dihydro-1H-imidazo[4,5-b]pyridin-2-ones gives 5,6-dibromo- and 5-bromo-6-chloro-2,3-dihydro-1H-imidazo[4,5-b]pyridin-2-ones, respectively.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 4, 2005, pp. 586–589.Original Russian Text Copyright © 2005 by Yutilov, Lopatinskaya, Smolyar, Gres’ko.     

Cyclocondensation of methyl 2-(5-methylisoxazol-3-yl)imino-3,3,3-trifluoropropionate with 1,3-binucleophiles

Cyclocondensation of methyl 2-(5-methylisoxazol-3-yl)imino-3,3,3-trifluoropropionate with 1,3-binucleophiles such as benzamidines, aminothiazoline, and 2-aminocrotonic acid nitrile results in trifluoromethyl-containing 3,5-dihydro-4-ones, 2,3-dihydro-6H-imidazo[2,1-b]thiazol-5-one, and 4,5-dihydro-1H-pyrrole-3-carbonitrile.     

Synthesis of new imidazo[1,2-a]pyrazolo[4,3-e]pyrimidin-4(6H)-one derivatives by iodocyclization of 6-alkenyl(alkynyl)-aminopyrazolo[3,4-d]pyrimidin-4(5H)-ones

6-Allyl(diallyl, prop-2-yn-1-yl)amino-1-R-pyrazolo[3,4-d]pyrimidin-4(5H)-ones reacted with iodine to give angularly fused 8-iodomethyl-7,8-dihydro-1-R-imidazo[1,2-a]pyrazolo[4,3-e]pyrimidin-4(6H)-ones which were treated with sodium acetate to obtain 8-methylidene-1-R-7,8-dihydroimidazo[1,2-a]pyrazolo-[4,3-e]pyrimidin-4(6H)-ones as a result of elimination of hydrogen iodide. 8-Methylidene-1-R-7,8-dihydroimidazo[1,2-a]pyrazolo[4,3-e]pyrimidin-4(6H)-ones were converted into 8-methyl-1-R-imidazo[1,2-a]pyrazolo-[4,3-e]pyrimidin-4(5H)-ones on heating to the melting point. 8-Methylidene-1-phenyl-7,8-dihydroimidazo-[1,2-a]pyrazolo[4,3-e]pyrimidin-4(6H)-one underwent isomerization into linearly fused 6-methyl-1-phenyl-1,8-dihydro-4H-imidazo[1,2-a]pyrazolo[3,4-d]pyrimidin-4-one on heating in sulfuric acid.     

Reactions of 1,3-Dialkyl-5-amino-1,3-dihydro-2<Emphasis Type="Italic">H</Emphasis>-imidazo-[4,5-<Emphasis Type="Italic">b</Emphasis>]pyridin-2-ones with acetylacetone and ethyl acetoacetate

1,3-Dialkyl-5-amino-1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-ones reacted with acetylacetone to give the corresponding 4-(1,3-dialkyl-2-oxo-1,3-dihydro-2H-imidazo[4,5-b]pyridin-5-ylamino)pent-3-en-2-ones which underwent intramolecular cyclization to 1,3-dialkyl-5,7-dimethyl-1,3-dihydro-2H-imidazo[4,5-b]-[1,8]naphthyridin-2-ones on heating in polyphosphoric acid or diphenyl ether. Analogous reaction of 1,3-dialkyl-5-amino-1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-ones with ethyl acetoacetate led to the formation of ethyl 3-(1,3-dialkyl-2-oxo-1,3-dihydro-2H-imidazo[4,5-b]pyridin-5-ylamino)but-2-enoates whose cyclization afforded 1,3-dialkyl-8-hydroxy-7-methyl-1,3-dihydro-2H-imidazo[5,4-b][1,8]naphthyridin-2-ones.     

Synthesis of 1-(1,3-dialkyl-2-oxo-2,3-dihydro-1<Emphasis Type="Italic">H</Emphasis>-imidazo-[4,5-<Emphasis Type="Italic">b</Emphasis>]pyridin-5-yl)-5-oxopyrrolidine-3-carboxylic acids

Nitration of 2,3-dihydro-1H-imidazo[4,5-b]pyridin-2-one gave its 5-nitro derivative which was subjected to alkylation with dimethyl sulfate, diethyl sulfate, and benzyl(dimethyl)phenylammonium chloride. The resulting 1,3-dimethyl-, 1,3-diethyl-, and 1,3-dibenzyl-5-nitro-2,3-dihydro-1H-imidazo[4,5-b]pyridin-2-ones were reduced to the corresponding 1,3-dialkyl-5-amino-2,3-dihydro-1H-imidazo[4,5-b]pyridin-2-ones, and the latter reacted with itaconic acid to produce 1-(1,3-dialkyl-2-oxo-2,3-dihydro-1H-imidazo[4,5-b]pyridin-5-yl)-5-oxopyrrolidine-3-carboxylic acids. 1-(2-Oxo-2,3-dihydro-1H-imidazo[4,5-b]pyridin-5-yl)-5-oxopyrrolidine-3-carboxylic acid was obtained by analogous reaction with 5-amino-2,3-dihydro-1H-imidazo[4,5-b]-pyridin-2-one.     

A synthesis of 6,11-dihydro-2-methyl-6H-pyrimido[2,1-b]quinazolin-4-ones

Reductive cyclization of 2-methylthio-1-(2-nitrobenzyl)-6-pyrimidones with stannous chloride and acetic acid in methanol gives 6,11-dihydro-6H-pyrimido[2,1-b]quinazolin-4-ones, and, with trialkylphosphites, 6,11-dihydro-11-alkylpyrimido[2,1-b]quinazolin-4-ones.     

Synthesis and anticonvulsant activity of 3H-imidazo[4,5-c]-pyridazine, 1H-imidazo[4,5-d]pyridazine and 1H-benzimidazole analogues of 9-(2-fluorobenzyl)-6-methylamino-9H-purine

The 3H-imidazo[4,5-c]pyridazine, 1H-imidazo[4,5-d]pyridazine, and 1H-benzimidazole analogues of the potent anticonvulsant purine 9-(2-fluorobenzyl)-6-methylamino-9H-purine (1, 78U79) were synthesized and tested for anticonvulsant activity. The 3H-imidazo[4,5-c]pyridazines 8 and 9 were prepared in five stages from 3,4,5-trichloropyridazine (2) . The 1H-imidazolo[4,5-d]pyridazine 15 was synthesized in four stages from 5-[(benzyloxy)methyl]-1,5-dihydro-4H-imidazo[4,5-d] pyridazin-4-one (10a) . The benz-imidazole analogues 18 and 20 were prepared from 2,6-dinitroaniline in three stages. These compounds were one-tenth or less as active as 1 in protecting rats against maximal electroshock-induced seizures.     

Nitrogen bridgehead compounds. Part 55 Synthesis of substituted 7,8-dihydro-5H,13H-indolo[2′,3′:3,4]pyrido[2,1-b]quinazolin-5-ones

Fischer indolization of 6-arylhydrazono-6,7,8,9-tetahydro-11H-pyrido[2,1-b]quinazolin-11-ones 1 afforded substituted 7,8-dihydro-5H,13H-indolo[2′,3′:3,4]pyrido[2,1-b]quinazolin-5-ones 3-12 in high yields.     

Reaction of 3-aminoquinoline-2,4-diones with isothiocyanic acid—an easy pathway to thioxo derivatives of imidazo[1,5-c]quinazolin-5-ones and imidazo[4,5-c]quinolin-4-ones

3-Amino-1H,3H-quinoline-2,4-diones react with thiourea or potassium thiocyanate in boiling acetic acid to give novel 2,3-dihydro-3-thioxoimidazo[1,5-c]quinazolin-5(6H)-ones in high yields. However, if the starting compounds are substituted with a benzyl group at position 3, a C-debenzylation proceeds to give 2,3-dihydro-2-thioxo-1H-imidazo[4,5-c]quinolin-4(5H)-ones. According to a proposed reaction mechanism, a molecular rearrangement of the primarily formed mono-substituted thiourea takes place. All compounds were characterized by ¹H, ¹³C and ¹⁵N NMR and IR spectroscopy as well as by mass spectrometry.     

Synthesis,Structure and Cytotoxicity Testing of Novel 7-(4,5-Dihydro-1H-imidazol-2-yl)-2-aryl-6,7-dihydro-2H-imidazo[2,1-c][1,2,4]triazol-3(5H)-Imine Derivatives

The appropriate 1-arylhydrazinecarbonitriles 1a–c are subjected to the reaction with 2-chloro-4,5-dihydro-1H-imidazole (2), yielding 7-(4,5-dihydro-1H-imidazol-2-yl)-2-aryl-6,7-dihydro-2H-imidazo[2,1-c][1,2,4]triazol-3(5H)-imines 3a–c, which are subsequently converted into the corresponding amides 4a–e, 8a–c, sulfonamides 5a–n, 9, ureas 6a–I, and thioureas 7a–d. The structures of the newly prepared derivatives 3a–c, 4a–e, 5a–n, 6a–i, 7a–d, 8a–c, and 9 are confirmed by IR, NMR spectroscopic data, as well as single-crystal X-ray analyses of 5e and 8c. The in vitro cytotoxic potency of these compounds is determined on a panel of human cancer cell lines, and the relationships between structure and antitumor activity are discussed. The most active 4-chloro-N-(2-(4-chlorophenyl)-7-(4,5-dihydro-1H-imidazol-2-yl)-6,7-dihydro-2H-imidazo[2,1-c][1,2,4]triazol-3(5H)-ylidene)benzamide (4e) and N-(7-(4,5-dihydro-1H-imidazol-2-yl)-2-(p-tolyl)-6,7-dihydro-2H-imidazo[2,1-c][1,2,4]triazol-3(5H)-ylidene)-[1,1′-biphenyl]-4-sulfonamide (5l) inhibits the growth of the cervical cancer SISO and bladder cancer RT-112 cell lines with IC₅₀ values in the range of 2.38–3.77 μM. Moreover, N-(7-(4,5-dihydro-1H-imidazol-2-yl)-2-phenyl-6,7-dihydro-2H-imidazo[2,1-c][1,2,4]triazol-3(5H)-ylidene)-4-phenoxybenzenesulfonamide (5m) has the best selectivity towards the SISO cell line and induces apoptosis in this cell line.     

Preparation of novel tricyclic ring systems containing the pyridazinone ring

Novel tricyclic ring systems, irmdazo[3,4-d]pyridazino[4,5-b][1,4]thiazines 3 , imidazo[2,1-b]pyridazino[4,5-e][1,3,4]thiadiazines 15 and 18 were prepared by the reaction of 5-amino-4-chloropyridazin-3(2H)-ones 1 and 5(4)-(1-methylhydrazino)-4(5)-chloropyridazin-3(2H)-ones 13 (16) with isothiocyanates 2 and 7 .     

Heterocyclization of functionalized heterocumulenes with C,N- and C,O-binucleophiles: V. Synthesis of imidazo[1,5-<Emphasis Type="Italic">a</Emphasis>]imidazole derivatives by cyclocondensation of 1-chloroalkyl isocyanates with imidazoles and benzimidazole

1-Chloroalkyl isocyanates react with imidazole, 4(5)-phenylimidazole, and 4,5-dimethyl(phenyl)-imidazoles to give 5-aryl-5-trifluoromethyl-5,6-dihydro-7H-imidazo[1,5-a]imidazole-7-ones, and with benzimidazole affording 1-aryl-1-trifluoromethyl-1,2-dihydro-3H-imidazo-[1,5-a]benzimidazole-3-ones.Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 11, 2004, pp. 1686–1691.Original Russian Text Copyright © 2004 by Vovk, Sukach, Pinchuk, Chernega, Pirozhenko, Howard.For communication IV see [1].     

Nitration of 1,3-dihydro-2<Emphasis Type="Italic">H</Emphasis>-imidazo[4,5-<Emphasis Type="Italic">b</Emphasis>]pyridin-2-one derivatives

Nitration of 1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-one and its N-methyl derivatives at 0–5°C and 60°C gives 5-nitro-and 5,6-dinitro-1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-ones, respectively. The latter can also be obtained by nitration of 5-mononitro derivatives under similar conditions. The nitration of 6-chloro-and 6-bromo-1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-ones and their N-methyl-substituted analogs leads to the formation of the corresponding 6-chloro(bromo)-5-nitro compounds. The same products are formed in the nitration of 5,6-dichloro-and 5,6-dibromo-1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-ones. In this case, the process involves replacement of the halogen atom in position 5 of the pyridine fragment by nitro group. The nitration of 6-bromo-5-methyl-1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-one is accompanied by oxidation of the 5-methyl group to carboxy.     

Synthesis and some properties of N-unsubstituted pyrrolo[2,1-c]-1,3-diazacycloalkano[1,2-a]pyrazinones

Reactions of methyl 2-(2-formyl-1H-pyrrol-1-yl)alkanoates with unsubstituted aliphatic 1,2-, 1,3-, and 1,4-diamines gave N-unsubstituted pyrrolo[2,1-c]-1,3-diazacycloalkano[1,2-a]-pyrazinones. Some of them show ring-chain tautomerism. Transformations of these compounds led to a number of novel heterocyclic systems: 2,10-dihydro-3H,5H-imidazo[1,2-a]-pyrrolo[1,2-d]pyrazines, 2,3,4,11-tetrahydro-6H-pyrrolo[1??,2??:4,5]pyrazino[1,2-a]pyrimidines, 1,2,3,5,6,10b-hexahydroimidazo[1,2-a]pyrrolo[2,1-c]pyrazines, 1,3,4,6,7,11b-hexahydro-2H-pyrrolo[2??,1??:3,4]pyrazino[1,2-a]pyrimidines, and 2,3,4,5,6,7-hexahydro-1H-pyrrolo[2,1-c]-[1,4,7]triazacycloundecin-8(9H)-one.     

Recyclization of 1,3-dialkyl-6-nitro-1<Emphasis Type="Italic">H</Emphasis>-imidazo[4,5-<Emphasis Type="Italic">b</Emphasis>]pyridine-2,5(3<Emphasis Type="Italic">H</Emphasis>,4<Emphasis Type="Italic">H</Emphasis>)-diones into imidazole derivatives

Treatment of 5-amino-1,3-dialkyl-2,3-dihydro-1H-imidazo[4,5-b]pyridin-2-ones with sodium nitrite in aqueous HCl gave 1,3-dialkyl-1H-imidazo[4,5-b]pyridine-2,5(3H,4H)-diones which were nitrated with potassium nitrate in sulfuric acid to 6-nitro derivatives, and the latter underwent recyclization into 4-amino-1,3-dialkyl-5-(1H-pyrazol-5-yl)-2,3-dihydro-1H-imidazol-2-ones by the action of hydrazine hydrate.     

One-pot synthesis of quinazolin-4(3H)-ones and fused quinazolinones by a palladium-catalyzed domino process

An efficient one-pot synthesis of quinazolin-4(3H)-ones, benzoimidazo[2,1-b]quinazolin-12(6H)-ones and imidazo[2,1-b]quinazolin-5(1H)-ones via a palladium-catalyzed domino process has been developed. The Pd-catalyzed reactions of 2-azidobenzamides 1 with isocyanides 2 produced quinazolin-4(3H)-ones 4 at room temperature by a domino Pd-catalyzed cross-coupling/carbodiimide-mediated cyclization. However, as 2-azido-N-(2-bromophenyl)benzamides 1 were used under heating condition in the presence of Cs₂CO₃, the benzoimidazo[2,1-b]quinazolin-12(6H)-ones 5 were directly obtained by twice Pd-catalyzed domino cyclization. A domino reogioselective 5-exo-dig intramolecular cyclization reaction of alkynyl-containing azides 6 with isocyanides 2 generated imidazo[2,1-b]quinazolin-5(1H)-ones 9 in 74–93% yields in the presence of catalyst Pd(PPh₃)₄ and K₂CO₃.     

Preparation of 2-aminosubstituted 3H-imidazo[4,5-c]quinolin-4(5H)-ones by palladium-assisted internal biaryl coupling reaction

Representatives of the 3H-imidazo[4,5-c]quinolin-4(5H)-ones have shown interesting biological activity. We have found 2-aminosubstituted 3H-imidazo[4,5-c]quinolin-4(5H)-one as a potent dipeptidyl peptidase 4 inhibitor. However effective synthesis of this nucleus with various substituents at the 6-9-positions has not been reported. We report herein the development of a novel and efficient synthesis of 2-aminosubstituted 3H-imidazo[4,5-c]quinolin-4(5H)-ones by palladium-assisted internal biaryl coupling reaction. Our optimization of the reaction conditions revealed that the most important factors for this reaction are use of silver carbonate as a base and high reaction temperature.     

SYNTHESIS OF 15H-ISOQUINO[2′,3′:3,4]IMIDAZO[2,1-B]QUINAZOLINE-7,13,15-TRIONES AND 14H-ISOQUINO[2′,3′:3,4]IMIDAZO[2,1-B]BENZO[G]QUINAZOLINE-8,14,16-TRIONE AS NEW POLYCYCLIC FUSED-RING SYSTEMS

3-Thioxo-2H-imidazo[1,5-b]isoquinoline-1,5-dione (3) and 2-sub-stituted 3-thioxo-2H-imidazo[1,5-b]isoquinoline-1,5-diones (4a–l) were prepared from the reaction of 2-thiohydantoin (2) and 3-substituted 2-thiohydantoin (5a–l) with 2-formyl benzoic acid (1). Alkylation of 3 under an anhydrous basic conditions afforded 4a–i. The alkylation of 3 in aqueous basic solution afforded 3-(alkylmercapto)imidazo[1,5-b]isoquinoline-1,5-diones (7a,b). Reactions of the aromatic amino acids 9a,b and 12 with 7a afforded 2-(2H-1,5 dioxoimidazo[1,5-b]isoquinazolin-3-ylideneamino)benzoic acids (10a, b) and 3-(2H-1,5-dioxoimidazo[1,5-b]isoquinazolin-3-ylideneamino)2-naphthalenecarboxylic acid (13), which were then cyclyzed by heating in acetic anhydride to afford 15H-isoquino[2′,3′ :3,4] imidazo[2,1-b]quinazoline-7,13,15-triones (11a,b) and 14H-isoquino[2′,3′:3,4]imidazo[2,1-b]benzo[g]quinazoline-8,14,16-trione (14). Some of the new compounds were tested for their antitumor activities.     

New 6-(4-Bromophenyl)-imidazo[2,1-b]thiazole Derivatives: Synthesis and Antimicrobial Activity

Summary.  New 4-alkyl/aryl-1-((6-(4-bromophenyl)-imidazo[2,1-b]thiazol-3-yl)-acetyl)-3-thiosemicarbazides and 3-alkyl/aryl-2-(((6-(4-bromophenyl)-imidazo[2,1-b]thiazol-3-yl)-acetyl)-hydrazono)-4-thiazolidinones were synthesized from 6-(4-bromophenyl)-imidazo[2,1-b]thiazole-3-acetic acid hydrazide. Their structures were elucidated by elemental analyses and spectroscopic data. All compounds were tested for antibacterial and antifungal activities. The antimicrobial activities of the compounds were assessed by the microbroth dilution technique. The compounds were also evaluated for antituberculosis activity against Mycobacterium tuberculosis H₃₇Rv (ATCC 27294); they exhibited varying degrees of inhibition in the in vitro primary screening at 6.25 μg · cm⁻³. The most active compound was 3-(4-nitrophenyl)-2-(((6-(4-bromophenyl)-imidazo[2,1-b]thiazol-3-yl)-acetyl)-hydrazono)-4-thiazolidinone. Corresponding author. E-mail: nurayulusoy@yahoo.com Received December 10, 2001. Accepted (revised) March 1, 2002