2-Bromomethyl derivatives of benzofuran and indole and their reactions with some nucleophilic reagents

The corresponding 2-bromomethyl derivatives of benzofuran and indole were obtained by bromination of 2-methyl-3-carbethoxy-5-methoxybenzofuran and 1,2-dimethyl-3-earbethoxy-5-methoxyindole with N-bromosuccinimide. A number of alkyl(aryl)thiomethyl and dialkylaminomethyl derivatives were obtained by reaction of the 2-bromomethyl derivatives with nucleophilic reagents.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 308–311, March, 1973.     

Synthesis of 2-, 6-, and 7-aminomethyl derivatives in the 4,5-dihydroxybenzofuran series

The 2-, 6-, and 7-aminomethyl derivatives have been synthesized from derivatives of 4-hydroxy-5-methoxy- and 4-methoxy-4-hydroxybenzofuran. 2-Methyl-3-carbethoxy-5-methoxy-7-dimethylaminomethylbenzofuran has been converted into the 7-cyanomethyl derivative.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 23–27, January, 1986.     

Preparation of 1-aryl-2-methyl-3-carbethoxy-4,5-dioxo-6-bromoindoles

1-Aryl-2-methyl-3-carbethoxy-5-hydroxy-6-bromoindoles are oxidized by nitric acid to 1-aryl-2-methyl-3-carbethoxy-4,5-dioxo-6-bromoindoles, while 1,2-dimethyl-3-carbethoxy-5-hydroxy-6-bromoindole is converted to the 4,6-dinitro derivative under similar conditions.     

Synthesis and some transformations of halogen-substituted o-quinones in the benzofuran series

The corresponding 6-halo-substituted o-quinones were obtained by the action of nitric acid on 2-methyl(phenyl)-3-carbethoxy-4,6-dihalo-5-hydroxybenzofurans, whereas 2-methyl-3-carboxy-4,6-dibromo-5-hydroxybenzofuran is converted to the 4,6-dinitro derivative under similar conditions. The action of nitric acid on 2-methyl-3-carbethoxy-4-chloro-5-hydroxybenzofuran leads to replacement of the hydrogen in the 6 position by a nitro group. The reduction of o-quinones to the corresponding dihydroxy derivatives and reactions of quinones with amines are described.     

1,2,6-Phosphadiazine-1,3-dione derivatives

A number of new 1-aryloxy-5-methyl-1,2,3,6-tetrahydro-1,2,6-phosphadiazine-1,3-diones were obtained from arylphosphoric acid dichlorides through the corresponding diamidophosphoric acid esters. Conversion of the 1-phenoxy and 1-ethoxy derivatives to 6-methyl-4-hydroxypyrimidine under Vilsmeierformylation conditions was observed. These compounds were thionated to give the corresponding 1,3-dithiones; the 1-phenoxy derivative was subsequently methylated in the 6 position and animated to give the phosphorus-containing analog of 6-methyl-2-thiocytosine. The bromination of the 1-ethoxy compound and replacement of the bromine by a secondary amine residue were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 972–976, July, 1978.     

Synthesis of 3-methyl-4-cyano-3-butenoic acid amides and their cyclization into 6-amino-2-pyridones

Two groups of amides, derivatives of 3-methyl-4-cyano- and 3-methyl-4-cyano-4-carbethoxy-3 acids were obtained from acetoacetamides in the form of mixtures of Z, E-isomers and the pure E-isomers were isolated. It was shown that amides from the first group are cyclized by bases into the corresponding 6-amino-4-methyl-2-pyridones and amides from the second group are cyclized into 6-hydroxy-5-cyano-4-methyl-2-pyridones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1636–1640, December 1992.     

Synthesis of 2,3-diformyl-5-ethylbenzofuran and its derivatives

A mixture of 3-formyl and 3-acetoxymethyl derivatives is formed in the oxidation of 2-carbethoxy-3-methyl-5-ethylbenzofuran with selenium dioxide. Reduction of the products with lithium aluminum hydride gives the corresponding 2,3-dihydroxymethyl derivatives, which are converted to 2,3-diformyl derivatives by successive oxidation by the Fetizon method and with manganese dioxide. The corresponding benzofuro[2, 3-d]pyridazines were synthesized by reaction of 2-carbethoxy-3-formyl-5-ethylbenzofuran with hydrazine hydrate.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 893–895, July, 1982.     

Functional derivatives of thiophene

Acyl derivatives of substituted β-thienylhydrazines were obtained by reaction of 2-methyl-3-carbethoxy-4-hydroxythiophene with acyl hydrazines. Hydrolysis of the products gave a thienylhydrazine derivative and its hydrochloride.     

Action of acidic and alkaline agents on dioxonaphthofuran derivatives

The action of sulfuric and polyphosphoric acids and sodium hydroxide on 3-carbethoxy-4,5-dioxonaphthofuran derivatives was studied. 2-Methyl- and 2-phenyl-3-carboxy-4,5-dioxonaphthofurans were obtained by the action of sulfuric acid on the indicated compounds. The action of alkali on 2-methyl- and 2-phenyl-3-carbethoxy-4,5-dioxonaphthofurans and 2-phenyl-4,9-dioxonaphthofurans leads to the formation of 2-hydroxy-3-acetonyl- and 2-hydroxy-3-phenacyl-1,4-dioxonaphthalenes. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 753–754, June, 1980.     

Recyclization of 5-carbethoxy-4-methyl-2-mercapto(amino,hydroxy) pyrimidines to give 5-acetyl-2-mercapto(amino,hydroxy)-4-hydroxypyrimidines

Conditions for the selective preparation of 5-carbethoxy-4-methyl-2-substituted pyrimidines or 5-acetyl-4-hydroxy-2-substituted pyrimidines by condensation of ethoxymethyleneacetoacetic ester with 1,3-binucleophiles are proposed. It is shown that under the influence of sodium ethoxide 5-carbethoxy-4-methyl-2-substituted pyrimidines undergo rearrangement to 5-acetyl-4-hydroxy-2-substituted pyrimidines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1558–1559, November, 1982.     

Reaction of Some Dibromomethyl-Substituted Cyclohexadienones with Molecular Bromine

4-Dibromomethyl-4-methyl-2,5-cyclohexadienone and its 2- and 3-methyl-substituted derivatives react with an equimolar amount of molecular bromine in carbon tetrachloride, yielding vinyl bromination products at the -position with respect to the carbonyl group. The reaction of 4-dibromomethyl-3,4-dimethyl-2,5-cyclohexadienone with a large excess of bromine, apart from the vinyl bromination product, gives the corresponding 3-bromomethyl and 3-dibromomethyl derivatives. 4-Dibromomethyl-2,4-dimethyl-2,5-cyclohexadienone takes up bromine molecule at the C ² ÍC ³ double bond.     

3-Hydroxythiazole and 1-Hydroxyimidazole as Products of a Mutual Ring Closure Reaction: Extension to Selenium Derivatives

A thiazole derivative can be easily prepared, e.g., from an α -thiocyanatoketone and a nitrogen nucleophile. In this work, α -bromopropiophenone was chosen as a starting compound. Since the carbonyl group facilitates nucleophilic substitution, bromine can be simply replaced with the thiocyanato group. The following reaction with hydroxylamine hydrochloride provides an intermediate, which undergoes a ring closure reaction. Finally, 3-hydroxy-5-methyl-4-phenylthiazol-2(3H)-iminium chloride 4a or 1-hydroxy-4-methyl-5-phenyl-1,3-dihydro-2H-imidazole-2-thione 5a arises depending on the presence of a base. In the next part, this interesting phenomenon was successfully investigated on selenium derivatives as well. All prepared substances have not been described in the literature yet.     

Pyrimidines

Dehydrogenation of 2-hydroxy-4-phenyl-3, 4, 5, 6-tetrahydrobenzo[h]quinazoline with Pd/C, diphenyl disulfide, chloranil, and N-bromosuccinimide, was investigated. Dihydroderivatives of 2-hydroxy-4-phenylbenzo[h]quinazoline were obtained. The action of N bromosuccinimide led to dehydrogenation and bromination. Treatment of 2-hydroxy-4-phenylbenzo[h]quinazoline and its bromine derivative with phosphorus oxychloride, followed by hydrogenation, gave 4-phenylbenzo[h]quinazoline. The structures of the compounds prepared are confirmed by spectroscopic data.For Part II see [1].     

Alkyl- and arylamination of 3-hydroxy-4-carbethoxy-5-methylthiophene

N-Alkylaminothiophene derivatives were obtained by the reaction of 3-hydroxy-4-carbethoxy-5-methylthiophene with alkylammonium acetates, while N-arylaminothiophene derivatives were obtained by the reaction of the same thiophene derivative with aromatic amines in the presence of catalytic amounts of iodine.Translated from Khimiya Geterotsilicheskikh Soedinenii, No. 12, pp. 1602–1604, December, 1970.     

Synthesis of 3-Hydroxy-6-Methyl- and 3-Hydroxy-2-(2-phenylethyl)pyridines and Their Sulfur-Containing Amino and Hydroxymethyl Derivatives

The aminomethylation of 3-hydroxy-6-methyl- and 3-hydroxy-2-(2-phenylethyl)pyridines by secondary amines has been investigated. It was shown that like 2-alkyl-3-hydroxypyridine aminomethylation is directed primarily to position 6 and then 4 of the pyridine ring. On heating the aminomethyl derivatives of 3-hydroxy-6-methyl- and 3-hydroxy-2-(2-phenylethyl)pyridines with acetic anhydride the corresponding acetoxy derivatives were obtained, which were converted on heating with hydrochloric or hydrobromic acids into hydroxy and bromomethyl derivatives. Isothioureidomethyl and benzimidazolylthiomethyl derivatives were synthesized by heating the bromomethyl-substituted derivative with thiourea or with 2-mercaptobenzimidazole. The structures of compounds were confirmed by data of ¹H NMR spectra. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1189–1194, August, 2005.     

Chemistry of benzo[b]selenophene

The bromination of benzo[b]selenophene with an equimolecular amount of bromine and its acetylation with acetic anhydride in the presence of boron trichloride etherate proceed to form a mixture of isomeric 2- and 3-substituted derivatives; 2,3-dibromobenzo[b]selenophene is formed on bromination with two equivalents of bromine. Benzo[b]selenophene-2-carboxylic acid, its acid chloride and methyl ester, as well as 2-acetylbenzo[b]selenophene, were synthesized from the lithium derivative of benzo[b]selenophene.See [1] for communication III.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 15–19, January, 1972.     

Different specificities in the bromination of 6-(2-furyl)imidazo[2,1-b]thiazole and its derivatives with 1 mole of bromine

The action of 1 mole of bromine on 6-(2′-furyl)imidazo[2,1-b]thiazole, its 2-methyl-, 3-methyl-, and 2,3-dimethyl-substituted derivatives, and their hydrobromides in chloroform and glacial acetic acid was studied. The bromination of bases containing a methyl group in the 3 position leads primarily to the 5′-derivatives with respect to the furan ring in chloroform, whereas in the remaining cases 5-bromo derivatives with respect to the imidazothiazole system are formed. Compounds of the latter type are formed by the action of bromine in glacial acetic acid or of sodium hypobromite in alkaline media on the bases. The hydrobromides are brominated in both acetic acid and chloroform, regardless of the substituents in the thiazole ring, primarily in the 5′ position of the furan ring. The structures of the bromination products were proved by means of alternative syntheses, thin-layer chromatography, and the PMR spectra.     

Microwave assisted synthesis and unusual coupling of some novel pyrido[3,2-f][1,4]thiazepines

3-Amino-3-thioxopropanamide (1) reacted with ethyl acetoacetate to form 6-hydroxy-4-methyl-2-thioxo-2,3-dihydropyridine-3-carboxamide (2), which reacted with α-haloketones 3 to produce 2,3-disubstituted-8-hydroxy-6-methyl-2H,5H-pyrido[3,2-f]-[1,4]thiazepin-5-ones 4a-c. Benzoylation of 4c led to the formation of the dibenzoate derivative 9. Compounds 4a-c could be prepared stepwise through the formation of S-alkylated derivatives 10a-c. Compounds 2, 4a-c, 9 and 10a-c were prepared using microwave as a source of heat, and gave better yields in shorter times than those achieved by traditional methods. Coupling of 4a-c with arenediazonium chlorides proceeded unusually to give the 6-hydroxy-4-methyl-2-(arylazo)thieno[2,3-b]pyridin-3(2H)-one ring contraction products 14. Structures of the newly synthesized compounds were proven by spectral and chemical methods.     

Recyclization of Condensed Carbethoxypyrimidines Accompanied by Substitution of a Carbon Atom into the Heterocycle

Condensation in ethanol of ethyl ethoxymethyleneacetoacetate with systems containing an amidine fragment (substituted 3-aminopyrazoles and 3-amino-1,2,4-triazole) gave 6-carbethoxy-7-methylpyrazolo[1,5-a]pyrimidines. Addition of base to solutions of the obtained bicyclic carbethoxy derivatives in the course of several minutes caused rearrangement to 6-acetyl-7-hydroxypyrazolo[1,5-a]pyrimidine and 6-acetyl-7-hydroxy-1,2,4-triazolo[1,5-a]pyrimidine respectively. A more prolonged refluxing in 15% aqueous alcohol solution of base caused 6-carbethoxy-7-methyl-2-phenylpyrazolo[1,5-a]pyrimidine and 6-acetyl-7-hydroxy-2-phenylpyrazolo[1,5-a]pyrimidine to recyclize to 7-methylpyrazolo[1,5-a]pyrimidine.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 569–576, April, 2005.     

4-hydroxy-2-quinolones. 200*. Bromination of 1-<Emphasis Type="Italic">R</Emphasis>-4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acid pyridinylmethylene hydrazides

The behavior of 1-R-4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acid pyridinylmethylene- hydrazides under bromination conditions using molecular bromine has been studied. It has been found that the 1-N-allyl derivative is characteristically halocyclized to the corresponding oxazolo[3,2-a]-quinoline, whereas the 1-N-hexyl-substituted acylhydrazone is unexpectedly brominated in the azomethine fragment.