Synthesis and characterization of some nitrogen heterocycles from d-galactose derivatives

The tetrazoles 5-(6′-acetamido-6′-deoxy-1′,2′:3′,4′-di-O-isopropylidene-D-glycero-α-D-galactohexopyranos-6′-yl)tetrazole ( 1 ) and 5-(6′-acetamido-6′-deoxy-1′,2′:3′,4′–di-O-isopropylidene-L-glycero-α-D-galacto-hexopyranos-6′-yl)-tetrazole ( 2 ) were synthesized by the 1,3-dipolar cycloaddition reaction of the epimeric α-acetamidonitriles 5 and 6 , respectively, with sodium azide. Reaction of tetrazole 1 with acetic anhydride in the presence of pyridine afforded the N-acetyl-1,3,4-oxadiazole derivative 3 and the N-acetylacetamido-1,3,4-oxadiazole derivative 7 . The N-acetylacetamido-1,3,4-oxadiazole derivative ( 8 ) was isolated when the tetrazole 2 was allowed to react under the same conditions. The physical and spectroscopic data of the five new compounds 1, 2, 3, 7 and 8 are presented.     

Synthesis of some indole based spiro and condensed heterocycles as potential biologically active agents

The reactions of isatin with cyclic ketones, viz camphor (dl, Mp 174–181°C, specific rotation ?1.5° to +1.5°) available from s. d. fine‐ CHEM LTD and menthone (I, Bp 207°–210° C, density 0.893 g/mL) isolated from peppermint oil, in refluxing ethanol in the presence of t‐BuOK afforded the corresponding indolylidene compounds ( 3a ) and ( 3b ) (a mixture of stereochemical isomers E and Z in both the cases) respectively, all obtained as racemates. Cyclocondensation of ( 3a ) and ( 3b ) with thiourea, urea, ethylenediamine and o‐phenylenediamine afforded new spiro ( 4a,b‐7a,b ) and condensed systems ( 4a',b'‐7a',b' ) respectively, whereas with 2‐aminopyridine spiro compounds exclusively were obtained ( 8a,8b ). All the new spiro and condensed systems generated have been isolated as racemates and evaluated for their antimicrobial activity.     

Synthesis of highly condensed heterocycles using radical reactions

Using radical chemistry novel highly condensed heterocycles have been synthesized. The mechanism for their formation is discussed.     

Synthesis of condensed heterocycles via cyclopropylimine rearrangement of cyclopropylazoles

Thermal cyclopropylimine rearrangement of cyclopropylazoles into condensed heterocycles and factors affecting the regioselectivity and conversion are reported. A method of conducting the reaction in the absence of solvents is developed. A series of 2-cyclopropylazoles, including novel examples, is synthesized and their transformations into the corresponding condensed heterocyclic compounds (2,3-dihydro-1H-pyrroles and 6,7-dihydro-5H-pyrrolo[2,1-b]thiazolium salts) are studied.     

Synthesis of some condensed benzofurans

The condensation of O-phenylhydroxylamine (Ia) with tetrahydro-4-thiopyrone, 1-methyl-4-piperidone (IIb), 1,2,5-trimethyl-4-piperidone, and 4-thiochromanone and of O-(4-tolyl)-hydroxylamine with IIb was used to synthesize the corresponding benzofuran derivatives (IIIa-e), from which IIIa and IIIb were obtained by deamination of 8-amino-3,4-dihydro-1H-thiopyrano-[4,3-b]benzofuran and 2-methyl-8-amino-1,2,3,4-tetrahydrobenzofuro[3,2-c]pyridine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 740–742, June, 1972.     

Gas-phase pyrolysis of benzimidazole derivatives: novel route to condensed heterocycles

Gas-phase pyrolysis of N-(1H-benzimidazol-2-yl)-N′-arylidenehydrazines 1a-e gave the corresponding arylnitriles 2a-e, 2-aminobenzimidazole 3, 2,4,5-triphenylimidazole 4, 1,3-diphenyl-8H-2,3a,8-triazacyclopenta[a]indene 5, and 5,11-diphenyl-6H,12H-dibenzimidazo[1,2-a];1’,2’-d]pyrazine 6. The kinetics and analysis of the products of reaction are reported and used to elucidate the mechanism of the elimination process.     

Synthesis,characterization, and antimicrobial evaluation of some novel anthracene heterocycles derivatives

A series of novel heterocyclic compounds containing anthracene moiety was synthesized. Reaction of (11R,15S)-9,10-dihydro-9,10-[3,4]furanoanthracene-12,14-dione with 2-cyanoacetohydrazide gave 2-cyano-pyrroloanthracen acetamide (1) , which acts as an adaptable material for the synthesis of new heterocyclic compounds. The synthesized compounds were examined for their antimicrobial activity against Escherichia coli and Staphylococcus aureus via p-iodonitrotetrazolium violet formazon assay. The results exhibited great activity against the tested strains with a minimum bactericidal concentration range from 0.636 to 3.8 mg/mL) and 0.159 to 3.6 mg/mL for E coli and S aureus, respectively. Interestingly, the highest activity was recorded for chromene derivative (6) against both strains.     

Synthesis and NMR analysis of spiranic heterocycles from carbohydrate derivatives

We report the synthesis of some furanose and pyranose acylhydrazones and their heterocyclization products. The new compounds were characterized physically and spectroscopically and the syn‐anti and (R)‐(S) configuration was determined by NOESY experiments. We discuss the influence of the nucleophile, the temperature and the precursor structure on the heterocyclization products.     

Synthesis of some new mesoionic heterocycles

The synthesis of various substituted 1-hydroxy-2-chloroacetyl-6-thia-10b-aza-2a-azoniaaceanthrylene hydroxide inner salt, 1-hydroxy-6-thia-10b-aza-2a-azoniaaceanthrylene hydroxide inner salt, 1-hydroxy-2-piperidinoacetyl-6-thia-10b-aza-2a-azoniaaceanthrylene hydroxide inner salt is described. The ir is also included.     

Synthesis of fluorescein derivatives containing metal-coordinating heterocycles

Fluorescein derivatives that contain Lewis basic heterocycles have been synthesized by concise reaction sequences. The preparation of these compounds proceeds by functionalization of an electron-rich aromatic precursor and subsequent condensation to form the fluorophore. These compounds are envisioned as components of metal-based sensors.     

Condensed heterocycles. 39. Quantum-chemical calculations of the reactivities of some condensed sulfur and selenium heterocycles

A number of isomeric thienothiophenes, selenophenothiophenes, and selenopheno-selenophenes, as well as their C-protonated forms ( complexes), were calculated by the self-consistent-field (SCF) MO LCAO method with the CNDO/2 approximation and the spd basis. Their reactivities in electrophilic substitution reactions were investigated theoretically by means of the localization energy approach. The results were compared with the available experimental data. The dependence of the specificity of electrophilic attack on the size of the attacking reagent was investigated for compounds with various heteroatoms. It is shown that the reactivity of the position relative to the selenium atom should increase as the size of the attacking reagent increases.See [1] for communication 38.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 199–202, February, 1980.     

Synthesis of adamantane derivatives—XXX: Synthesis of some adamantane spiro heterocycles by utilizing ionic- and cycloadditions

Synthesis and some reactions of adamantane spiro heterocycles such as aziridine, oxaziridine, azetidine and 1,2-diazetidine derivatives have been described.The 1,3-dipolar cycloadditions of methyleneadmantane (2) and adamantylidenecyanoacrylate (14) have also been reported as a facile route to some 5-membered adamantane spiro heterocycles.     

Synthesis and properties of condensed derivatives of resorufin

10-Hydroxy-5H-dibenzo(a,i)phenoxazin-5-one and its 6-chloro derivative - condensed derivatives of resorufin, simultaneously containing in the molecule linearly and angularly condensed benzene rings - were synthesized. Their spectral-luminescent properties were investigated.     

Synthesis of new condensed and cyclized coumarin derivatives

Condensation of 4-chloro-2-oxo-2H-chromene-3-carbonitrile with selected heteroarylamines in acetonitrile containing a catalytic amount of triethylamine, followed by intramolecular cyclization, gave the new coumarin derivatives with yields ranging from 43 % to 78 %. The novel compounds were subjected to acid hydrolysis giving the corresponding oxo derivatives in 66–70 % yield. The structural assignments of the synthesized compounds were based on elemental, IR, ¹H and ¹³C NMR analyses.