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The corresponding amides and hydrazides were obtained by the reaction of 1-hydroxy-1H-imidazole-2-carboxylates with amines and hydrazine. In the reaction of an ester of 1-methoxy-4-methyl-5-(thiophen-2-yl)-1H-imidazole-2-carboxylic acid with NBS, bromination occurred at the thiophene ring, whereas in the reaction with 1,3-dibromo-5,5-dimethylhydantoin it took place at both the methyl group and the thiophene ring; its nitration led to mononitro- or dinitrothiophene derivatives. The reaction of 1-hydroxy-1H-imidazole-2-carboxylates with chloroacetone in Me2CO in the presence of Et3N resulted in the formation of reduced compounds. [ABSTRACT FROM AUTHOR]

The reaction of 4-amino-substituted 6-hydrazinyl-1,3,5-triazin-2(1H)-ones with triethyl orthoacetate proceeded as a cascade reaction. The initially formed 7-amino-substituted 3-methyl[1,2,4]triazolo[4,3-a][1,3,5]triazin-5(1H)-ones underwent a Dimroth-type rearrangement with the formation of 5-amino-substituted 2-methyl[1,2,4]triazolo[1,5-a][1,3,5]triazin-7(3H)-ones. The latter underwent alkylation at three positions: at the exocyclic oxygen atom with the formation of 7-ethoxy-2-methyl[1,2,4]triazolo[1,5-a][1,3,5]triazines, at the N-3 nitrogen atom with the formation of 3-ethyl-2-methyl[1,2,4]triazolo[1,5-a][1,3,5]triazin-7(3H)-ones, and at the N-1 nitrogen atom to form 1-ethyl-2-methyl[1,2,4]triazolo[1,5-a][1,3,5]triazin-7(3H)-ones. For the latter compound, a retro-Dimroth-type rearrangement occurred with the formation of betaine-type 7-amino-substituted 2-ethyl-3-methyl[1,2,4]triazolo[4,3-a][1,3,5]triazin- 2-ium-5-olates. A possible mechanism for the alkylation of 5-amino-substituted 2-methyl[1,2,4]triazolo[1,5-a][1,3,5]triazin-7(3H)-ones with ortho esters was proposed. [ABSTRACT FROM AUTHOR]

Water-soluble chlorin e6 cationic derivatives with one and two galactose fragments at the quaternized nitrogen atom were synthesized, and the dark and photoinduced cytotoxicity of the obtained compounds was evaluated. [ABSTRACT FROM AUTHOR]

Instead of the expected C-alkylation at the dinitromethyl group, the reaction of potassium salts of [7-(dialkylamino)[1,2,4]triazolo[4,3-a]-[1,3,5]triazin-5-yl](dinitro)methanides with allyl and benzyl bromide led to alkylation at the N-1 and N-2 atoms of the triazole ring to form zwitterionic (dinitro)([1,2,4]triazolo[4,3-a][1,3,5]triazin-1(2)-ium-5-yl)methanides with a positive charge on the nitrogen atom of the 1,2,4-triazole ring, to which an alkyl substituent was attached, and a negative charge localized on the dinitromethyl group. The structure of the products was established on the basis of the NMR spectra and X-ray structural analysis data. The obtained experimental results are in good agreement with the results of quantum-chemical calculations. [ABSTRACT FROM AUTHOR]

1-Aryl-2-[(1-aryl-5H-2,3-benzodiazepin-4-yl)sulfanyl]ethanones were obtained by the alkylation of 1-aryl-2,3-benzodiazepine-4(3H,5H)-thiones with 1-aryl-2-bromoethanones. A reaction for the annulation of the thiophene core to the 1,2-diazepine ring as a result of intramolecular cyclization involving a 4-aroylmethylsulfanyl substituent and C(4)–C(5) bond of diazepine was developed. Derivatives of a new thieno[2,3-d][2,3]benzodiazepine heterocyclic system were synthesized. [ABSTRACT FROM AUTHOR]

Electrochemical activation of trialkylstannylmethyl group as an electroauxiliary for carbenium ion generation enables the intramolecular Friedel–Crafts alkylation. Electrochemical activation of stannylmethyl group forms carbenium ion which can be trapped by intramolecular (het)aromatic nucleophiles for the formation of new 6-membered cycles. [ABSTRACT FROM AUTHOR]

1-Hetarylmethylidene-4-sulfanylfuro[3,4-c]pyridin-3-ones were accessed from 4-thioxo-4,5-dihydrofuro[3,4-c]pyridin-3(1H)-one employing a condensation reaction with heteroaromatic aldehydes followed by thioalkylation, but not vice versa. Alkylation of 1-hetarylmethylidene-6-methyl-4-thioxo-4,5-dihydrofuro[3,4-c]pyridin-3-ones in an alkaline medium proceeded regioselectively at the sulfur atom to form sulfanyl derivatives. [ABSTRACT FROM AUTHOR]

Imidazo[1,2-a]pyridine derivatives have been shown to possess a broad range of biological activity. 2-Amino-1-propargylpyridinium and 2-amino-1-(2-bromoallyl)pyridinium bromides, the structures of which were established on the basis of X-ray structural analysis, reacted with sodium methoxide, leading to the formation of 2-methylimidazo[1,2-a]pyridine. 2-Methylimidazo[1,2-a]pyridine further reacted with bromine and iodine, providing 3-halo-2-methyl-1H-imidazo[1,2-a]pyridinium trihalides, the structure of which was confirmed by X-ray structural analysis. 3-Halo-2-methyl-1H-imidazo[1,2-a]pyridinium halides were obtained from the respective trihalides. 3-Bromo- 2-methyl-1H-imidazo[1,2-a]pyridinium bromide showed antimicrobial properties against Staphylococcus aureus at the concentrations of 2700 and 675 μg/ml. [ABSTRACT FROM AUTHOR]

An efficient approach to the gram-scale synthesis of 3(5)-substituted, 1,3- and 1,5-disubstituted 1,2,4-triazole-derived building blocks is described. The key synthetic precursors – 1,2,4-triazole-3(5)-carboxylates (20 examples, 35–89% yield) were prepared from readily available acyl hydrazides and ethyl 2-ethoxy-2-iminoacetate hydrochloride. Further transformations were performed following the convergent synthetic strategy and allowed the preparation of 1,3- and 1,5-disubstituted 1,2,4-triazole-derived esters (16 examples, 25–75% yield), 3(5)-substituted, 1,3- and 1,5-disubstituted carboxylate salts (18 examples, 78–93% yield), amides (5 examples, 82–93% yield), nitriles (5 examples, 30–85% yield), hydrazides (6 examples, 84–89% yield), and hydroxamic acids (3 examples, 73–78% yield). Considering wide applications of the 1,2,4-triazole motif in medicinal chemistry, these compounds are valuable building blocks for lead-oriented synthesis; they have also great potential for coordination chemistry. [ABSTRACT FROM AUTHOR]

Recent progress from 2015 to 2022 in alkylation and arylation reactions of purine N-7 and N-9 positions is shown. [ABSTRACT FROM AUTHOR]

A method for the synthesis of 1,3-dialkyl-4-[(arylmethylidene)amino]glycolurils was developed based on nucleophilic substitution of the sulfur atom with the oxygen atom in the corresponding thioglycolurils via alkylation of the latter followed by acid hydrolysis of alkylsulfanyl derivatives of thioglycolurils, both with the isolation of alkylsulfanyl intermediates and by the one-pot method. The structure of the synthesized compounds was confirmed by X-ray structural analysis of several examples. [ABSTRACT FROM AUTHOR]

Alkylation of the primary amino group of hydrazones of (+)-camphor and (–)-fenchone with dihaloalkanes leading to the production of novel nitrogen-containing heterocyclic derivatives was investigated. It was shown that the reaction of hydrazones with 1,2-ethanedithiol in the presence of formaldehyde with the addition of 5% Sm(NO3)3·6H2O leads to the formation of compounds containing the 1,5,3-dithiazepane fragment. The method developed by us offers the advantage of the use of commercially available reagents and good yields in the synthesis of hydrazone heterocyclic derivatives. Studies of antiviral activity have shown that camphor-based N-heterocyclic compounds can be considered promising agents with activity against influenza A. [ABSTRACT FROM AUTHOR]

The synthesis of previously unknown nitriles, esters, and an amide of 6-alkoxy-2-alkylsulfanyl-4-methyl(4,4-dimethyl)nicotinic acid has been developed. The structure of a number of the obtained derivatives was proved by X-ray structural analysis. [ABSTRACT FROM AUTHOR]

The reaction of substituted 4,4-diphenyl-3,4(1,4)-dihydroquinazolines with various alkylating agents in DMSO–KOH leads (depending on the structure of the alkylating agent) to the formation of the corresponding N1-monoalkyl-substituted 1,4-dihydroquinazolines or, in the reaction with ethyl bromoacetate, to N-{[5-bromo-2-(methylamino)phenyl]diphenylmethyl}benzamide with opening of the heterocyclic ring. The molecular structures of 1-ethyl-2,4,4-triphenyl-1,4-dihydroquinazoline and 1-ethyl-2-(7-methoxy-1,3-benzodioxol-5-yl)-4,4-diphenyl-1,4-dihydroquinazoline were investigated and proven by X-ray structural analysis. [ABSTRACT FROM AUTHOR]

The mechanism of a multicomponent reaction between aminoazoles, 1-morpholino-2-nitroalkenes, and benzaldehyde was studied in acidic medium. Performing the reaction in acetic acid led to the formation of 6-nitro-5-phenyl-4,5,6,7-tetrahydropyrazolo[1,5-a]-pyrimidines, which subsequently underwent a rearrangement. Reaction conditions were proposed for a multicomponent synthesis with trioxane, and the alkylation reactions of 4,7-dihydroazolo[1,5-a]pyrimidine nitro derivatives were optimized. [ABSTRACT FROM AUTHOR]

The directions of thermodynamically controlled rearrangements and transformations of alkyl substituents under the conditions of acidcatalyzed alkylation of unsubstituted and 5(3)-substituted 3(5)-nitro-1H-1,2,4-triazoles with butyl alcohols (n-, i-, tert-, sec-BuOH) were studied. [ABSTRACT FROM AUTHOR]

The reaction of 2-chloromethylthiirane with 3,5-dibromo-4-nitropyrazole in H2O and the aprotic solvent MeCN in the presence of bases was investigated. It was found that thiirane-thietane rearrangement occurs in an aqueous medium with the formation of 3,5-dibromo-4-nitro-1-(thietan-3-yl)-1H-pyrazole. In MeCN, 3,5-dibromo-4-nitro-1-(thiiran-2-ylmethyl)-1H-pyrazole and the product of its reaction with the starting pyrazole, 6-bromo-2-[(3,5-dibromo-4-nitro-1H-pyrazol-1-yl)methyl]-7-nitro-2,3-dihydropyrazolo[5,1-b]thiazole, are formed, the yields of which depend on the molar ratio of the reactants. [ABSTRACT FROM AUTHOR]

The reaction of 2-chloro-N-(3-oxoalkenyl)acetamides with 1,3-benzothiazole-2(3H)-thione, 1,3-benzoxazole-2(3H)-thione, and 1-methyl-1,3-dihydro-2H-benzimidazole-2-thione led to the formation of 2-(heteroarylsulfanyl)-N-(3-oxoalkenyl)acetamides. By the action of a base, these compounds were converted into pyridin-2(1H)-ones containing a divalent sulfur atom in position C-3 bonded to a heterocyclic ring. Bromination, nitration, alkylation of 3-(1,3-benzothiazol-2-ylsulfanyl)pyridin-2(1H)-ones have been studied. The action of zinc in acetic acid transformed these compounds into 3-sulfanylpyridin-2(1H)-ones. [ABSTRACT FROM AUTHOR]

Straightforward method for the synthesis of pyrrolo[1,2-b]cinnolines starting from 2-nitrobenzaldehydes and 2-methylfurans has been elaborated. The key steps of the process are oxidative furan ring opening with diazonium cation and intramolecular alkylation of azo group of the resulted cinnoline with secondary allyl alcohol. [ABSTRACT FROM AUTHOR]

Alkylation of indolizinethione at the sulfur atom by the action of RCOCH2Br (R = Me, Ar, CO2Me, OEt) leads to thioethers, and subsequent closure of the thiazine ring of which leads to the formation of stable antiaromatic thiazino[4,3,2-cd]indolizines. [ABSTRACT FROM AUTHOR]

Examples of the use of α-diazocarbonyl compounds in the N–H insertion reactions with the formation of the products of selective N-alkylation of various five-membered nitrogen heterocycles and their derivatives are considered. The literature data is systematized according to the number of N atoms in the heterocycle. The review contains information published in the period from 2003 to 2020. [ABSTRACT FROM AUTHOR]

The multicomponent reaction of aromatic and heteroaromatic aldehydes, malonodithioamide, 1-(cyclohex-1-en-1-yl)piperidine, and alkylating reagents was studied. A wide range of new 2-(alkylsulfanyl)-4-aryl(hetaryl)-5,6,7,8-tetrahydroquinoline-3-carbonitriles were synthesized, and their molecular and crystalline structures were studied by X-ray structural analysis. [ABSTRACT FROM AUTHOR]

The reaction of imidazole and benzotriazole derivatives with 1,3-diiodopropan-2-one in the absence of bases and catalysts leads to the formation of linear and cyclic salt systems in one preparative step. [ABSTRACT FROM AUTHOR]

The reaction of 2-aryl-4,4-diphenyl-3,4-dihydroquinazoline with methyl iodide in acetone in the presence of potassium hydroxide at 40°C leads to the formation of the corresponding 1-methyl-4,4-diphenyl-1,4-dihydroquinazolines and 1,3-dimethyl-4,4-diphenyl-1,4-dihydroquinazolin-3-ium iodides. The structure of 2-(7-methoxy-1,3-benzodioxol-5-yl)-1-methyl-4,4-diphenyl-1,4-dihydroquinazoline was established by heteronuclear correlation NMR spectroscopy. [ABSTRACT FROM AUTHOR]

The regioisomeric 6-hydroxy-4-methyl- and 4-hydroxy-6-methylaurones were synthesized. Aminomethylation by the action of aminals of secondary amines was investigated. It was shown that the reaction proceeds selectively with the formation of 7-aminomethyl-6-hydroxy-4-methyl- and 5-aminomethyl-4-hydroxy-6-methylaurones, respectively. The use of an excess of the aminals allows to obtain 5,7-bis(aminomethyl) derivatives of 6-hydroxy-4-methylaurones. [ABSTRACT FROM AUTHOR]

It is shown that alkylation of pyrazoles with (E)/(Z)-1,3-dichlorobut-2-enes can be carried out in an alkaline aqueous medium in the presence of N-methylmorpholine N-oxide. In some cases, this technique may substitute phase-transfer catalysis. Conformational analysis of the reaction products showed that a mixture of (E)/(Z) isomers is formed in a ratio of 9:1. [ABSTRACT FROM AUTHOR]

The first annulated heterocyclic derivatives of tetrahydro-2-pyrimidin-2(1H)-one were synthesized in one preparative step on the basis of a solventless three-component reaction of tetrahydro-2-pyrimidin-2(1H)-one with 1-iodopropan-2-one, 2-iodo-1-phenylethan-1-one, 2-iodo-1-(thiophen-2-yl)ethan-1-one, or 1,3-diiodopropan-2-one and elemental iodine in the absence of a base. [ABSTRACT FROM AUTHOR]

3-carboxylate by using vicarious substitution of hydrogen, followed by intramolecular reductive heterocyclization. Some chemical properties of the target compound were characterized. As observed for the first time in the series of linear hetaryl-fused anthraquinones, the alkylation of hydroxy groups in naphtho[2,3- f]indole-5,10-diones gave not only 4,11-dialkoxy derivatives, but also the isomeric 5,10-dialkoxy derivatives of naphtho[2,3- f]indole-4,11-dione. [ABSTRACT FROM AUTHOR]

The reaction of 2-mercaptoimidazoline with 1-iodopropan-2-one or 1,3-diiodopropan-2-one in the absence or in presence of iodine allowed to synthesize new types of annulated heterocyclic systems in one preparative step. [ABSTRACT FROM AUTHOR]

Aroylmethyl esters of 4-formylpyrazole-3-carboxylic acids underwent intramolecular cyclocondensation in the presence of sodium acetate in refluxing acetic anhydride, giving moderate yields of 5-aroylpyrano[3,4- с]pyrazol-7(2 Н)-ones. [ABSTRACT FROM AUTHOR]

The alkylation of 5-nitrotetrazole sodium salt with dimethyl sulfate was studied in a two-phase water-dichloromethane system in the presence of tetrabutylammonium bromide as a phase-transfer catalyst. The reaction produced a mixture of regioisomers - 1-methyl- and 2-methyl-5-nitrotetrazoles in 1:3 ratio. 2-Methyl-5-nitrotetrazole was obtained from this mixture as individual compound in 52% yield. The application of phase-transfer catalysis allowed to obtain 5-nitrotetrazole N-alkyl derivatives under conditions that did not require preliminary isolation of highly impact and friction sensitive 5-nitrotetrazole salts from aqueous solutions. [ABSTRACT FROM AUTHOR]

The reactions of benzimidazol-2-amines with ethyl 3-ethoxy-2-nitroacrylate were used to synthesize a series of pyrimido[1,2 -a]-benzimidazoles. An alkylation reaction of the obtained compounds was studied. [ABSTRACT FROM AUTHOR]

Herein, we report on the 5-step synthesis of new 3-[4-(arylalkoxy)phenylethyl]-2-thioxo-1,3-thiazolidin-4-ones without 5-arylidene fragments starting from tyramine The construction involved protection with Boc2O, regioselective O-alkylation, deprotection with 6 M HCl, neutralization, and finally reaction of bis(carboxymethyl)trithiocarbonate under microwave irradiation. The intermediates and the N-substituted rhodanine have been also evaluated for their in vitro inhibition of cell proliferation (Huh7, Caco 2, MDA-MB231, HCT 116, PC3, NCI-H727, HaCat). Two compounds have shown a selective potent activity against HCT116 cell line. [ABSTRACT FROM AUTHOR]

The results of pioneering research on the alkylation of fused [1,2,4]triazolo[1,5- a][1,3,5]triazine system are presented, including computational studies of the reaction between 5-dimethylamino[1,2,4]triazolo[1,5- a][1,3,5]triazin-7(3 H)-one and bromoethane. The reaction of 5-amino-substituted [1,2,4]triazolo[1,5- a][1,3,5]triazin-7(3 H)-ones with allyl bromide, bromoethane, or (2-acetoxyethoxy)methyl bromide occurred selectively with the formation of products due to alkylation at the N-3 nitrogen atom of the heterocyclic system. The removal of acetyl protecting group from 5-amino-substituted {2-[(7-oxo[1,2,4]triazolo[1,5- a][1,3,5]triazin-3(7 H)-yl)methoxy]ethyl}acetates gave 5-aza analogs of acyclovir, containing a substituted amino group at position 5 of the heterocyclic 3-[(2-hydroxyethoxy)methyl][1,2,4]-triazolo[1,5- a][1,3,5]triazin-7(3 H)-one system. [ABSTRACT FROM AUTHOR]

The alkylation reactions of fused tetrazolo[1,5- a][1,3,5]triazine system were studied. The results of quantum-chemical calculations for the reaction of 5-(dimethylamino)tetrazolo[1,5- a][1,3,5]triazin-7(3 H)-one with ethyl bromide are presented. The reactions of 5-aminosubstituted tetrazolo[1,5- a][1,3,5]triazin-7(3 H)-ones with ethyl-, butyl-, and allyl halides led to the formation of products due to alkylation at the N-3 nitrogen atom of the ring system, 3-alkyl-5-amino-substituted tetrazolo[1,5- a][1,3,5]triazin-7(3 H)-ones, as well as products due to alkylation at the exocyclic oxygen atom with tetrazole ring opening, 2-amino-substituted 6-alkoxy-4-azido-1,3,5-triazines. Besides that, the product that was alkylated at the ring N-3 nitrogen atom underwent hydrolytic cleavage of the 1,3,5-triazine ring with elimination of the carbonyl functional group and formation of N-(1-alkyl-1 H-tetrazol-5-yl)- N'-alkyl- and N-(1-alkyl-1 H-tetrazol-5-yl)- N', N'-dialkylguanidines. [ABSTRACT FROM AUTHOR]

1-Benzyl- N-tolyl-1,2,3-triazole-4-carboxamide was accessed via rearrangement of N-benzyl-1-tolyl-1,2,3-triazole-4-carboxamide. It is shown that by boiling in various solvents an equilibrium between isomeric triazoles and diazomalondiamides is established, and that the equilibrium is shifted toward 1-benzyl-1,2,3-triazole. The two isomeric triazoles are shown to undergo alkylation reactions. For 5-hydroxy-1-tolyl-1,2,3-triazole, the alkylation occurs at position 3 of the heterocycle to form a mesoionic triazol-5-olate, whereas for 1-benzyl-5-hydroxy-1,2,3-triazole, alkylation leads to the formation of a 5-alkoxy derivative. [ABSTRACT FROM AUTHOR]

Reactions of α,ω-dibromoalkanes with pyrazole and 3,5-dimethylpyrazole in superbasic medium of dimethyl sulfoxide - potassium hydroxide were used for the synthesis of bidentate ligands: bis(pyrazol-1-yl)alkanes and bis(3,5-dimethylpyrazol-1-yl)alkanes linked by alkyl chains containing between four and twelve methylene groups. Oxidative iodination of the obtained compounds with I2-HIO-HSO system in acetic acid provided diiodo derivatives: bis(4-iodopyrazol-1-yl)alkanes and bis(4-iodo-3,5-dimethylpyrazol-1-yl)alkanes. The obtained diiodo derivatives of pyrazole were further converted to mono- and dipyrazolium salts by alkylation of nitrogen atom at position 2 of the pyrazole rings with iodomethane, as well as with methyl triflate. These products are of interest as precursors to mesoionic N-heterocyclic carbene complexes. The cytotoxicity of the obtained compounds was studied against THP-1 monocytic leukemia cells. [ABSTRACT FROM AUTHOR]

[Figure not available: see fulltext.] A two-step approach towards the synthesis of imidazo[1,2- a]indoles from 2-chloroindole-3-carbaldehyde has been developed. It comprises the N-alkylation of indole ring by 2-bromo-1,1-diethoxyethane followed by a treatment with aromatic amine hydrochlorides. The reaction proceeds as a nucleophilic substitution of the chlorine atom at position 2 of the indole ring followed by cyclization along with the condensation at the aldehyde group. Imidazo[1,2- a]indoles were isolated as protonated Schiff bases. Their structure was proved by H and C NMR spectroscopy and X-ray structural analysis. [ABSTRACT FROM AUTHOR]

[MediaObject not available: see fulltext.] It is shown that alkylation of 3-nitro-1,2,4-triazole with alkyl bromides may be carried out in an aqueous alkaline medium in the presence of N-methylmorpholine N-oxide. Alkylation of 3-nitro-1,2,4-triazole with dibromoethane and propargyl bromide occurs regioselectively with the formation of the substitution products at the N-1 atom of the heterocycle. Alkylation with allyl bromide under similar conditions proceeds with low selectivity leading to regioisomeric substitution products at both N-1 and N-2 atoms. Establishing the structures of the obtained regioisomers by NMR spectroscopy and X-ray crystallography is discussed. [ABSTRACT FROM AUTHOR]

[Figure not available: see fulltext.] We report N-alkylation reactions of pyrrolo[1,2- a][1,4]diazepin-6-ones annulated with a benzene ring or thieno[2,3- b]pyridine system. A range of new N5-substituted pyrrolodiazepines were synthesized, including compounds acting as antidotes against the herbicide 2,4-D. [ABSTRACT FROM AUTHOR]

[Figure not available: see fulltext.] Alkylation of 6-C(O)R-7-aryl-5-methyl-4,7-dihydro[1,2,4]triazolo[1,5- a]pyrimidines with methyl iodide or ethyl bromide in either saturated aqueous KОН-MeCN or NaH-DMF led to the formation of N-alkyl derivatives in good yields (60-98%). Reactivity of the acetyl group of N-alkyl derivatives towards aromatic aldehydes under the conditions of the Claisen-Schmidt reaction was significantly higher than in 4-unsubstituted compounds. The starting 6-C(O)R-7-aryl-5-methyl-4,7-dihydro[1,2,4]triazolo[1,5- a]pyrimidines were synthesized via a three-component condensation of an aromatic aldehyde, 3-amino-1,2,4-triazole, and a dicarbonyl compound (2,4-pentanedione or ethyl acetoacetate) in DMF. [ABSTRACT FROM AUTHOR]

[Figure not available: see fulltext.] The reaction of salicylic alcohol with 5-aryltetrazoles gave mixtures of 2-[(5-aryl-1 H-tetrazol-1-yl)methyl]- and 2-[(5-aryl-2 H-tetrazol-2-yl)methyl]phenols. In the case of other ortho- and para-hydroxybenzyl alcohols, 2,5-disubstituted products were formed selectively. The criteria for detecting 1,5- and 2,5-disubstituted N-benzyltetrazoles by standard 1Н and 13С NMR spectroscopy have been identified. [ABSTRACT FROM AUTHOR]

[MediaObject not available: see fulltext.]The effect of pyrimidine ring saturation in 2-amino[1,2,4]triazolo[1,5- а]pyrimidines on their reactivity as polyfunctional N-nucleophiles was studied by computational methods (reactivity indices and transition state energy values for the model reaction of S2 alkylation with chloromethane, DFT B3LYP/6-311++G(2d,2p)), as well as experimentally (alkylation with benzyl bromide). The global nucleophilicity of partially hydrogenated aminotriazolopyrimidines was shown to be substantially higher than for aromatic analogs. The most likely sites for electrophilic attack in partially hydrogenated aminotriazolopyrimidines were the N-1 and N-3 atoms, as well as the amino group, and the probability of attack at the N-3 atom increased with harder electrophiles. The nucleophilicity of amino group and the N-1 atom was substantially decreased in aromatic aminotriazolopyrimidines, where the most likely sites of attack by hard electrophiles were the N-3 and N-4 atoms. [ABSTRACT FROM AUTHOR]

[Figure not available: see fulltext.] 2-Allylsulfanyl-5-methyl-1,3,4-thiadiazole, 2-(2-bromoallylsulfanyl)-5-methyl-1,3,4-thiadiazole, 2-[(but-3-en-1-yl)sulfanyl]-5-methyl-1,3,4-thiadiazole, and 2-methyl-5-[(pent-4-en-1-yl)sulfanyl]-1,3,4-thiadiazole were obtained by alkylation of 5-methyl-1,3,4-thiadiazole-2-thione. Halocyclization of the obtained unsaturated sulfides produced derivatives of thiazolo[2,3- b][1,3,4]thiadiazolium, 6,7-dihydro-5 H-[1,3,4]-thiadiazolo[2,3- b][1,3]thiazinium, and 5,6,7,8-tetrahydro[1,3,4]thiadiazolo[2,3- b][1,3]thiazepinium systems. [ABSTRACT FROM AUTHOR]