Preparation of 4,6-diaminopyrazolo[3,4-d] pyrimidines with variations in substitution at the 1- and 3-positions

A number of new derivatives of 4,6-diaminopyrazolo[3,4-d]pyrimidines substituted in the 1- and/or 3-positions have been obtained from reactions of guanidine carbonate with 1- and/or 3-substituted-5-amino-4-cyanopyrazoles. Use of triethanolamine as a reaction medium permitted preparation of certain derivatives which could not be obtained from the previously described fusion procedure. Some derivatives of 4-aminopyrazolo[3,4-d]pyrimidine with substitution at the 1 - and/or 3-positions were also obtained from reactions of formamide with the same 5-amino-4-cyanopyrazoles. The new compounds were screened for in vivo antimalarial activity, but were found inactive.     

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.     

PTC‐Promoted Japp–Klingmann Reaction for the Synthesis of Indole Derivatives

Abstract

Indole derivatives have been efficiently synthesized from ethyl 2‐phenylhydrazono‐5‐phthalimido‐pentanoate and its derivatives, which were obtained by Japp–Klingmann reaction under phase‐transfer catalytic (PTC) conditions. Several different phase‐transfer catalysts were investigated and dimethyldioctadecyl ammonium chloride (DMDOA) was found to promote this reaction efficiently. Using DMDOA as the PTC, aryl hydrazones were obtained in yields of 90%. The pure aryl hydrazones were then efficiently cyclized to indole derivatives in yields of more than 80%.     

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,cytotoxic activity,and fluorescence properties of a set of novel 3-hydroxyquinolin-4(1H)-ones

The targeted solid-phase synthesis of 3-hydroxyquinolin-4(1H)-one derivatives is described. Primary and secondary amines, 3-amino-4-(methoxycarbonyl)benzoic acid and 2-bromo-1-(4-chloro-3-nitrophenyl)ethanone were used as starting materials. The structures of the final compounds were designed in accordance with previous information obtained from structure–activity relationship studies of similar cytotoxic derivatives. Representative prepared compounds were subjected to in vitro screening of cytotoxic activity against various cancer cell lines; the results obtained are discussed. Fluorescence properties of selected compounds were also studied to compare the data with those obtained in analogous derivatives.     

Lipase-Catalysed Regioselective Deacetylation of androstane derivatives

A series of acetoxy derivatives of androstane was deacetylated in organic solvents by several lipases. The most satisfactory results were obtained with lipase from Candida cylindracea (CCL) and Candida antarctica (CAL). In some derivatives, CCL and CAL showed an overwhelming regioselectivity towards the removal of the 3β- or the 17β-acetyl group (see Table 2). Three new steroid derivatives were obtained through this approach. A hypothetical rationale for the behaviour of these enzymes is given.     

MIRC reactions of 2-bromo-5-(l-menthyloxy)furan-2(5H)-one with stabilized anions. Preparation of homochiral bicyclic γ-butyrolactones

Homochiral (5R)-4-bromo-5-(l-menthyloxy)furan-2(5H)-one with stabilized carbanions (from nitroalkanes, malononitrile and ethyl acetoacetate) afforded enantiopure bicyclic compounds in good yield (70–90%). 3-Oxabicyclic[3.1.0]hexan-2-one derivatives were obtained with nitromethane and malonic acid derivatives. However, dihydrofuro[3,4-d]isoxazol-6-one and dihydrofuro[3,4-b]furan-6(4H)-one derivatives were obtained from nitroethane and ethyl acetoacetate, respectively.     

Efficient Synthesis of Nitroflavones by Cyclodehydrogenation of 2′-Hydroxychalcones and by the Baker-Venkataraman Method

Summary. Several nitroflavone derivatives were synthesized by cyclodehydrogenation of 2′-hydroxychalcones and by the Baker-Venkataraman approach, starting from 2′-hydroxyacetophenones and benzoic acid derivatives. Nitroflavones synthesised by the first synthetic approach were obtained in better global yields than those obtained by the later method. The structures of all new compounds were elucidated by microanalyses, 1D and 2D NMR, IR, and mass spectroscopic measurements.     

Efficient Synthesis of Nitroflavones by Cyclodehydrogenation of 2′-Hydroxychalcones and by the Baker-Venkataraman Method

Several nitroflavone derivatives were synthesized by cyclodehydrogenation of 2′-hydroxychalcones and by the Baker-Venkataraman approach, starting from 2′-hydroxyacetophenones and benzoic acid derivatives. Nitroflavones synthesised by the first synthetic approach were obtained in better global yields than those obtained by the later method. The structures of all new compounds were elucidated by microanalyses, 1D and 2D NMR, IR, and mass spectroscopic measurements.     

Synthesis of triaza-2- cyclohexene derivatives

Di- and trialkyl derivatives of 1,3,4-triaza-2-cyclohexene were synthesized by reaction of N,N'-dimethylethyleneaminohydrazine with monocarboxylic acid and their anhydrides, esters, amides, and hydrazides. Alkyl derivatives of ,-bis [2-(1,3,4-triaza-2-cyclohexenyl)]alkanes were obtained as a result of the reaction of N,N'-dimethylethyleneaminohydrazine with dicarboxylic acids and their derivatives. 1-Ammo-1,3,4-triaza-2-cyclohexene derivatives were obtained from ethylenedihydrazine and monocarboxylic acid esters.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 127–129, January, 1977.     

The synthesis of compounds with antithyroid activity

N-Acyl derivatives of imidazole-2-thione and its derivatives were obtained by the reaction of imidazole2-thione and its derivatives with aliphatic anhydrides and with benzoyl chloride in pyridine. The hydrochlorides of 1-methyl and 4 (5)-methyl-S benzoylimidazole-2-thione were obtained by the reaction of 1-methyl- and 4 (5)-methylimidazole-2-thione with benzoyl chloride in dry ethanol. The acylation of imidazole-2-thione and of some of its derivatives was investigated with the aid of their IR spectra, and the importance of the medium in the formation of N- and S -acyl derivatives was shown, as well as the possibility of the migration of substituants from the S — to the N atom under its influence.For part VI see [1].     

Synthesis and characterization of poly[(3,4-dihydro-2h-pyran)-alt-(maleic anhydride)] and its derivatives: Biologically active polymers

The syntheses of several monomers, bioactive poly[(3, 4-dihydro-2H-pyran)-alt-(maleic anhydride)] and its derivatives, which have different substituents (e.g., acetoxy, methoxy, ethoxy, methoxycarbonyl, formyl, acetoxymethyl, and tosyloxymethyl groups) in the 2-position of the tetrahydropyran ring of the copolymer backbone, are described. The alternating sequences in copolymers of the dihydropyran derivatives and maleic anhydride were obtained from the equimolar and larger ratios of maleic anhydride to dihydropyran derivative at the onset of the copolymerization. The molecular weights of the copolymers were found to be low (M_n = 1000–7500) due to a transfer reaction of the dihydropyran derivatives. Hydrolyses of the anhydride groups in the copolymers without catalyst afforded poly[(dihydropyran)-alt-(maleic acid)] and its derivatives, whereas an additional three copolymers having substituents, e.g., hydroxy, hydroxymethyl, and carboxyl groups were obtained by hydrolyses of the pendent groups (acetoxy, acetoxymethyl, and methoxycarbonyl) with the aid of a hydroxide catalyst. Carbamoyl groups on the polymers were obtained from ammonolysis of methoxycarbonyl groups. The polymers having mercaptomethyl or aminomethyl groups were obtained by substitution of hydrogen sulfide or ammonia for tosyloxylmethyl groups.     

A free radical cyclization approach to indolo-benzodiazocine derivatives

A versatile route to indolo[2,1-d][1,5]benzodiazocine derivatives has been developed based on a free radical cyclization approach from 1-substituted indole derivatives with appropriately positioned haloacetamide functionalities. Fair yields of the indole- and dihydroindole-fused eight-membered ring derivatives were obtained from N-substituted iodo- and bromoacetamide precursors. Synthetic and mechanistic aspects of the regiospecific cyclization are discussed.     

Azasteroids. Synthesis by Diels-Alder Reaction between Maleimides, Citraconimide, and Triazolindiones and 1-(1-Trialkylsiloxyvinyl)-3,4-dihydronaphthalene Derivatives

Summary. 18-Nor-16-azaestrane derivatives with 8β, 13β, and 14β orientation were isolated from Diels-Alder reactions between maleimides or citraconimide and 1-(1-siloxyvinyl)naphthalene derivatives. (8RS)-13,14,16-Triazaestrane derivatives were synthesized from 1,2,4-triazolin-3,5-diones. The parent 11-oxo derivatives were obtained by desilylation, and they were transformed into 11-hydroxyimino derivatives. 3-Hydroxy derivatives, finally were synthesized by cleavage of the 3-methoxy group with BBr₃. During these transformations the stereochemistry of the steroidal skeleton was not changed. The stereochemistry of these “unnatural” steroids was elucidated by spectroscopic methods, and compared with results from calculations, and with the configuration of natural estrane derivatives. Finally, an improved method for the synthesis of the starting material, 6-methoxy-1-[(1-trialkylsiloxy)-vinyl]-3,4-dihydronaphthalene was developed.     

Synthesis and biological activity of new avermectin 5-O- and 4″-O-acyl derivatives

Acylation of avermectin B₁ with vicinal 1,2-dicarboxylic acid anhydrides leads only to 5-O-acyl derivatives in high yields. Avermectin 4″-O-acyl derivatives were obtained under similar conditions from avermectin B₁ 5-O-TBS-derivatives in good yields. The compounds obtained are of interest as antiparasitic agents.     

Synthesis of imidazolino [1,2-f]xanthin-2-ones and their methylene-group-substituted derivatives

8-Amino-7-theophyllylacetic acids and their esters were obtained by reaction of 8-amino(alkylamino, arylamino)theophyllines with haloacetic acids and their esters. The structures of the products were established, and the conditions for cyclization to imidazolino[1,2-f]xanthin-2-one derivatives were studied. The corresponding methylene-group-substituted derivatives were synthesized by reaction of the imidazolino[1,2-f]xanthin-2-one derivatives with aldehydes, isatin, aromatic nitroso compounds, and arenediazonium salts. The ylidene derivatives of this threering system were also obtained by reaction of 8-amino-7-theophyllylacetic acids or their esters with carbonyl compounds.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1132–1135, August, 1976.     

Synthesis of 1-(3-halotetrahydro-2-furyl) derivatives of uracil, 5-substituted uracils,and cytosine

The cis and trans isomers of 1-(3-halotetrahydro-2-furyl) derivatives of uracil, 5-substituted uracils, and cytosine were obtained by alkylation of 2,4-bis(trimethylsilyl) derivatives of uracil, 5-substituted uracils, and cytosine with 2,3-dihalotetrahydrofurans. 2,3-Anhydro compounds are also formed in the alkylation of 5-halouracil derivatives. The physicochemical properties of the compounds obtained and the antineoplastic activities of the 5-fluorouracil derivatives were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 94–99, January, 1987.     

Study on the stereochemical control of dihydroxylation of vinyl epoxides and their derivatives

The results obtained from a study on the stereochemical control in the dihydroxylation of the double bond of vinyl epoxides and their derivatives (bromo derivatives, azido derivatives and vinyl aziridines) are presented herein. A significant diastereoselectivity was observed for the bromo derivatives, azido derivatives and N-protected vinyl aziridines, whereas vinyl epoxides and unprotected vinyl aziridines showed no diastereoselectivity. The results obtained are generally consistent with the Kishi model.     

Anthra[1,2-b]furan and 1h-naphth[2, 3-g]indole derivatives

A number of previously inaccessible anthra[1,2-b]furan and 1H-naphth[2,3-g]indole derivatives were obtained by condensation of 1,4-anthraquinone with acetoacetic ester and its analogs. Quinones of the anthra[1,2-b]furan series were obtained by oxidation of the methoxy derivatives of anthra[1,2-b]furan.Translated from Khimiya Geterotsiklicheskikh Soedtaenii, No. 8, pp. 1027–1029, August, 1972.     

Synthesis of 2-carbethoxybenzofuran derivatives

A mixture of 3-formyl and 3-acetoxymethyl derivatives is formed in the oxidation of 2-carbethoxy-3-methyl-7-ethylbenzofuran with selenium dioxide. Reduction with lithium aluminum hydride gives 2,3-dihydroxymethyl derivatives, which are converted to 2,3-diformyl derivatives by successive oxidation. A number of derivatives of 3-methyl-7-ethylbenzofurancarboxylic acid were obtained.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 756–759, June, 1987.