Electrophilic heterocyclization of 6-alken(yn)ylsulfanyl-pyrazolo[3,4-<Emphasis Type="Italic">d</Emphasis>]pyrimidin-4(5<Emphasis Type="Italic">H</Emphasis>)-ones

6-Allylsulfanyl-1-arylpyrazolo[3,4-d]pyrimidin-4(5H)-ones react with iodine and sulfuric acid to give angular pyrazolothiazolopyrimidine derivatives. The reaction of 6-(prop-2-yn-1-ylsulfanyl)-1-(4-tolyl)-pyrazolo[3,4-d]pyrimidin-4(5H)-one with sulfuric acid gives angularly fused pyrazolo[4,3-e][1,3]thiazolo-[3,2-a]pyrimidin-4-one, whereas in the reaction with sodium methoxide linearly fused pyrazolo[3,4-d][1,3]-thiazolo[3,2-a]pyrimidin-4-one was formed. Linearly fused pyrazolo[3′,4′:4,5]pyrimido[2,1-b][1,3]thiazole derivatives were also obtained by reaction of 1-aryl-6-(3-phenylprop-2-en-1-ylsulfanyl)pyrazolo[3,4-d]pyrimidin-4(5H)-ones with sulfuric acid.     

Reactions of 2-(2-propynylsulfanyl)-5,6,7,8-tetrahydrobenzo[<Emphasis Type="Italic">b</Emphasis>]thieno[2,3-<Emphasis Type="Italic">d</Emphasis>]pyrimidin-4(<Emphasis Type="Italic">3H</Emphasis>)-one with arylsulfenyl chlorides

2-(2-propynylsulfanyl)-5,6,7,8-tetrahydrobenzo[b]thieno[2,3-d]pyrimidin-4(3H)-one with arylsulfenyl chlorides in chloroform gave products of anti-Markownikoff Ad _E-addition. The use of nitromethane as solvent in the presence of lithium perchlorate additives favored intramolecular electrophilic cyclization into 1-arylsulfanyl-1,2,6,7,8,9-hexahydro-4H-benzo[4,5]thieno[3,2-e][1,3]thiazolo[3,2-a]-pyrimidin-5-one.     

Thienooxazolopyrimidinium salts. Reaction of 1-bromomethyl-5-oxo-4-phenyl-1,2,4,5,6,7,8,9-octahydro[1]benzothieno-[3,2-<Emphasis Type="Italic">e</Emphasis>][1,3]oxazolo[3,2-<Emphasis Type="Italic">a</Emphasis>]pyrimidin-11-ium bromide with oxygen-centered nucleophiles

Reactions of [1]benzothieno[3,2-e][1,3]oxazolo[3,2-a]pyrimidin-11-ium bromide with oxygen-containing nucleophiles involve opening of the dihydrooxazole ring and lead to the formation of new functionally substituted thieno[2,3]-d]pyrimidine derivatives.     

Reaction of <Emphasis Type="Italic">N</Emphasis>-aryl-3-oxobutanethioamides with 2-amino-1,3-thiazole and 2-amino-1,3-benzothiazole

N-Aryl-3-oxobutanethioamides react with 2-amino-1,3-thiazole (2-amino-1,3-benzothiazole) in acetic acid to give mixtures of 7-methyl-5H-[1,3]thiazolo[3,2-a]pyrimidine-5-thione (2-methyl-4H-pyrimido-[2,1-b][1,3]benzothiazole-4-thione) and 5-arylimino-7-methyl-5H-[1,3]thiazolo[3,2-a]pyrimidines (4-arylimino-2-methyl-4H-pyrimido[2,1-b][1,3]benzothiazoles), whose ratio depends on the nature of the aryl substituent in the initial butanethioamide.     

Fused Pyrimidine Systems: XVII. Imidazo- and Pyrimidopyrido[3,2-<Emphasis Type="Italic">d</Emphasis>]pyrimidin-4(3<Emphasis Type="Italic">H</Emphasis>)-ones

2-(Allylamino)pyrido[3,2-d]pyrimidin-4(3H)-one was converted to linearly fused dihydroimidazo- [1,2-a]pyrido[3,2-d]pyrimidine on heating in polyphosphoric acid, whereas its reactions with molecular iodine and chlorosulfanylarenes afforded mainly angularly fused analogs. 2-(Cinnamylamino)pyrido[3,2-d]pyrimidin- 4(3H)-one reacted with polyphosphoric acid and chlorosulfanylarenes to give linear pyrido[3,2-d]pyrimido-[1,2-a]pyrimidinones, and its iodocyclization led to the formation of angularly fused derivative.     

Iodocyclization of 2-[allyl(methallyl)sulfanyl]-6-(trifluoromethyl)pyrimidin-4(3<Emphasis Type="Italic">H</Emphasis>)-ones

Iodination of 2-[allyl(methallyl)sulfanyl]-6-(trifluoromethyl)pyrimidin-4(3H)-ones was accompanied by cyclization to 2,3-dihydro[1,3]thiazolo[3,2-a]pyrimidin-4-ium triiodides. 3-(Iodomethyl)-3-methyl- 7-oxo-5-(trifluoromethyl)-2,3-dihydro[1,3]thiazolo[3,2-a]pyrimidin-4-ium triiodide was reduced with sodium iodide to 3,3-dimethyl-7-oxo-5-(trifluoromethyl)-2,3-dihydro[1,3]thiazolo[3,2-a]pyrimidin-4-ium iodide.     

Fused pyrimidine systems: XVI. Electrophilic intramolecular cyclization of 2-(alkenylsulfanyl)pteridin-4(3<Emphasis Type="Italic">H</Emphasis>)-ones

2-[Allyl(but-3-en-1-yl, pent-4-en-1-yl)sulfanyl]pteridin-4(3Н)-ones at heating in polyphosphoric acid undergo an intramolecular cyclization affording respectively 9-methyl-8,9-dihydro-5H-[1,3]thiazolo[3,2-a] pteridin-5-one and 10-methyl(ethyl)-9,10-dihydro-5Н,8Н-[1,3]thiazino[3,2-a]pteridin-5-ones of angular structure. The cyclization of 2-(alkenylsulfanyl)pteridin-4(3Н)-ones under the action of iodine or arylsulfenyl chlorides afforded iodo(arylsulfanyl) derivatives of angularly fuzed thiazolo- and thiazinopteridines.     

Modification of silica nanoparticles with stereisomers of <Emphasis Type="Italic">p</Emphasis>-<Emphasis Type="Italic">tert</Emphasis>-butylthiacalix[4]arene containing four 2-oxo-2-{[3-(triethoxysilyl)prop-1-yl]amino}ethoxy substituents at the lower rim

Three stereoisomers (cone, partial cone, and 1,3-alternate) of p-tert-butylthiacalix[4]arene bearing four anchor propyltriethoxysilane substituents at the lower rim were synthesized for the first time. Surface modification of silica nanoparticles (d = 12 nm) with the synthesized macrocycles gave novel hybride thiacalix [4]arene?SiO₂ particles. The obtained nanostructured adsorbents were found to efficiently extract nitroaromatic compounds from aqueous solutions. The partial cone and 1,3-alternate thiacalix[4]arene–SiO₂ hybrid particles showed affinity to nitrophenols.     

Diastereoselective 1,3-Dipolar Cycloaddition of Nitrones to 1<Emphasis Type="Italic">H</Emphasis>-Pyrrole-2,3-diones. Synthesis of pyrrolo[3,2-<Emphasis Type="Italic">d</Emphasis>]isoxazoles

1H-pyrrol-2,3-diones react with nitrones affording substituted pyrrolо[3,2-d]isoxazoles. The structures of ethyl (3R*,3aR*,6aR*)-6-benzyl-3-(4-bromophenyl)-4,5-dioxo-2,6a-diphenylhexahydro-3aHpyrrolo[ 3,2-d]isoxazole-3a-carboxylate and dimethyl (3R*,3aR*,6aS*)-3-(4-bromophenyl)-4,5-dioxo-2,6-diphenyltetrahydro-3aH-pyrrolo[3,2-d]isoxazole-3a,6a(4H)-dicarboxylate were proved by single-crystal X-ray analysis.     

Alkenyl derivatives of 5-nitro-2-pyridone: Synthesis and halocyclization

Alkylation of 5-nitro-2-pyridone by alkenyl halides in acetone in the presence of K₂СО₃ proceeds with generation of a mixture of N- and О-derivatives with N-isomer prevailing. 1-Allyl- and 1-methylallyl-5-nitro-2-pyridone react with halogens with the formation of 2-halomethyl-6-nitro-2,3-dihydrooxazolo[3,2-a]-pyridinium halides. 1-Prenyl-5-nitro-2-pyridone reacts with bromine with the formation of 3-bromine-2,2-dimethyl-7-nitro-3,4-dihydro-2Н-pyrido[2,1-b][1,3]oxazinium bromide, and with iodine giving 2,2-dimethyl-7-nitro-3,4-dihydro-2Н-pyrido[2,1-b][1,3]oxazinium triiodide.     

Cycloaminomethylation of dihydric phenols catalyzed by <Emphasis Type="Italic">d</Emphasis>- and <Emphasis Type="Italic">f</Emphasis>-metal compounds

An efficient method has been developed for the synthesis of 7,16,25-triaryl-7,8,16,17,25,26-hexahydro-6H,15H,24H-tribenzo[f,m,t][1,5,8,12,15,19,3,10,17]hexaoxatriazacyclohenicosines, 3,8-diaryl-2,3,4,7,8,9-hexahydrobenzo[1,2-e:4,3-e′]bis[1,3]oxazines, 3,9-bis(chlorophenyl)-3,4,9,10-tetrahydro-2H,8H-benzo[1,2-e:3,4-e′]bis[1,3]oxazines, and 2,9-bis(chlorophenyl)-1,2,3,8,9,10-hexahydrobenzo[1,2-e:6,5-e′]bis-[1,3]oxazines via cycloaminomethylation of pyrocatechol, resorcinol, and hydroquinone with N,N-bis(methoxymethyl) anilines in the presence of samarium catalysts.     

Synthesis and Structure of 4-Indolyl-5-(thieno[3,2-<Emphasis Type="Italic">b</Emphasis>]pyrrol-6-yl)imidazoles

A procedure was proposed for regioselective acylation of methyl 2-methyl-4H-thieno[3,2-b]-pyrrole-5-carboxylate with 2-(3-indolyl)-2-oxoacetyl chloride. Reactions of the resulting methyl 6-[2-(3-indolyl)-1,2-dioxoethyl]-2-methyl-4H-thieno[3,2-b]pyrrole-5-carboxylate with aromatic aldehydes and ammonium acetate in acetic acid afforded the corresponding methyl 6-[2-aryl-4-(3-indolyl)imidazol-5-yl]-2-methyl-4H-thieno[3,2-b]pyrrole-5-carboxylates. The structure of methyl 6-[2-(4-chlorophenyl)-4-(3-indolyl)imidazol-5-yl]-2-methyl-4H-thieno[3,2-b]pyrrole-5-carboxylate was studied by X-ray analysis.     

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 novel 4<Emphasis Type="Italic">H</Emphasis>-furo[3,2-c]pyran-4-ones and 4<Emphasis Type="Italic">H</Emphasis>-furo[3,2-<Emphasis Type="Italic">c</Emphasis>]chromen-4-ones

It was found that the condensation of two equivalents of 4-hydroxy-6-methyl-2H-pyran-2-one or 4-hydroxycoumarin with arylglyoxals in boiling formic acid leads to 4H-furo[3,2-c]-pyran-4-ones or 4H-furo[3,2-c]chromen-4-ones, respectively.     

Synthesis of new 1-(3,4-dimethylphenyl)-1,5-dihydropyrazolo[3,4-<Emphasis Type="Italic">d</Emphasis>]pyrimidin-4-one derivatives

New substituted pyrazolo[3,4-d]pyrimidin-4-ones have been synthesized as a result of a series of transformations including hydrolysis of ethyl 5-amino-1H-pyrazole-4-carboxylates, cyclization of the carboxylic acids thus obtained to pyrazolo[3,4-d][1,3]oxazin-4(1H)-ones, and treatment of the latter with substituted anilines. The final pyrazolo[3,4-d]pyrimidin-4-one derivatives can also be synthesized from 5-(arylamido)-1H-pyrazole-4-carboxylic acids in the presence of a catalytic amount of anhydrous zinc(II) chloride.     

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.     

Hetero-diels–alder reaction of 5-ylidene-4-sulfanylidene-1,3-thiazolidin-2-ones with <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>′-bis(methoxycarbonyl)-1,4-benzoquinone diimine

Hetero-Diels–Alder reaction of 5-(propan-2-ylidene)-4-sulfanylidene-1,3-thiazolidin-2-one with N,N′-bis(methoxycarbonyl)-1,4-benzoquinone diimine in boiling toluene afforded 87% of dimethyl 9,9-dimethyl-2-oxo-8a,9-dihydro-2H-thiochromeno[2,3-d][1,3]thiazole-5,8(3H,4aH)-diylidenedicarbamate. Analogous reactions of 5-benzylidene-, 5-{[4-(dimethylamino)phenyl]methylidene}-, and 5-[(2-hydroxyphenyl)-methylidene]-4-sulfanylidene-1,3-thiazolidin-2-ones led to the formation of the corresponding dimethyl 9-aryl-2-oxo-3,9-dihydro-2H-thiochromeno[2,3-d][1,3]thiazole-5,8-diyldicarbamates in 64–82% yield.     

Halocyclization of 1-Allyl-6(7)-methylquinolin-2(1<Emphasis Type="Italic">H</Emphasis>)-ones

Oxidation of 1-allyl-6- and -7-methylquinolinium iodides with potassium hexacyanoferrate(III) gave 1-allyl-6(7)-methylquinolin-2(1H)-ones which reacted with halogens to afford 2-halomethyl-7(8)- methyl-1,2-dihydro[1,3]oxazolo[3,2-a]quinolinium halides.     

Synthesis of Bisthiacalix[4]arene: Reaction of Piperazine with Monoacrylamide Derivative of <Emphasis Type="Italic">p</Emphasis>-<Emphasis Type="Italic">tert</Emphasis>-Butylthiacalix[4]arene

The reaction of acryloyl chloride with the monoamine derivative of p-tert-butylthiacalix[4]arene was used to synthesize p-tert-butylthiacalix[4]arene monoacrylamide in the 1,3-alternate conformation. The effect of the nature of the amine on the result of its Michael reaction with the synthesized p-tert-butylthiacalix[4]arene monoacrylamide was studied. The latter was reacted with piperazine to obtain bisthiacalix[4]arene with the macrocyclic fragments in the 1,3-alternate conformation.     

Microwave synthesis of new azolyl-substituted thiazolo[5,4-<Emphasis Type="Italic">d</Emphasis>]thiazoles

One-pot condensation of dithiooxamide with 4,5-dichloro-1,2-thiazole-3-carbaldehyde and 5-phenyl-1,2-oxazole-3-carbaldehyde, followed by oxidation of intermediate 2,5-dihydro[1,3]thiazolo[5,4-d]-[1,3]thiazoles with selenium dioxide, afforded previously unknown 2,5-bis(4,5-dichloro-1,2-thiazol-3-yl)- and 2,5-bis(5-phenyl-1,2-oxazol-3-yl)[1,3]thiazolo[5,4-d][1,3]thiazoles as first representative of bis-isothiazolyl- and bis-isoxazolyl thiazolothiazoles.