A new synthetic route to 1,3,4-oxadiazoles. Pharmacological study of some new derivatives

2-Substituted 1,3,4-oxadiazoles have been examined as possible prodrugs of antidepressant hydrazides. A new method of synthesis of this heterocycle from thionoester and five new oxadiazoles substituted at the 2-position by a 4-pyridyl or 4-aminophenyl group and at the 5-position by a phenyl group are described.     

A new synthetic route to the synthesis of nordasycarpidone derivatives

A new synthetic route for the synthesis of the nordasycarpidone derivative 11 which has hexahydro‐1,5‐methanoazocino[4,3‐b]indol skeleton, is described. Construction of the tetracyclic structure was achieved by catalytic reduction and cyclization reaction of the nitrile derivative. Also many new tetrahydrocarbazole derivatives ( 4, 5, 6, 7, 8, 9 ) and a dasycarpidol derivative ( 10 ) were synthesized.     

A new synthetic route to phomoidride B and its derivatives

We have developed a new synthetic route to phomoidride B, which could also be applied to the synthesis of phomoidride B derivatives using Pd-catalyzed coupling reaction of a thiolester with an organozinc reagent. In addition, direct construction of the maleic anhydride moiety has been achieved by a Pd-catalyzed carbonylation reaction.     

A general synthetic route to indenofluorene derivatives as new organic semiconductors

A series of 2,6-disubstituted indenofluorene derivatives were obtained in high purity via a general route involving the Suzuki coupling reaction. The potential of these conjugated indenofluorenes as new organic semiconductors was demonstrated by the light-emitting diode reaching a high luminance of 1400 Cd/m(2) below 10 V. [structure: see text]     

Pyrazoline derivatives: A convenient synthetic route to new pyrazolo-benzothia-(oxa) or diazepinone derivatives

New pyrazolo-[3,4-b]-[1,5]-benzoazepinone derivatives are reported. One pot reactions of 5-chloro-4-carboxy-1-phenyl (3-substituted) pyrazole derivatives with o-thioaminophenol, o-phenylenediamine, and o-aminophenol derivatives were realized. The influences of the polarizability of the heteroatoms on the reaction rates and chemical yields are discussed. © John Wiley & Sons, Inc.     

A new synthetic route to 4,6-diarylpyridazinones and some of their derivatives

A novel approach to the titled ring system starting from conveniently available chalcones 1 is proposed. It involves a catalysed exchange of hydrogen cyanide between acetone cyanohydrin and 1 . The resulting γ-ketonitriles 2 give the expected 4,6-diarylpyridazinones 4 and 5 via hydrolysis and cyclisation by hydrazine. The action of phosphorus oxychloride on 5 followed by that of amines provides aminopyridazines 7 .     

A new synthetic route to aminothiazolinones

Novel 2-(5-R-1,3,4-thiadiazol-2-yl)aminothiazolin-4-ones 6a—h and 2-imino-3-(5-R-1,3,4-thiadiazol-2-yl)thiazolidin-4-ones 7a—h were prepared by treating N-(5-R-1,3,4-thiadiazol-2-yl)thioureas 4a—h with chloroacetic acid on various solid supports under microwave irradiation. Tautomeric mixtures of compounds 6a—h and 7a—h were obtained in all cases. In alkaline and neutral media, compounds 6a—h were the major products, while in acid media, 7a—h were the major products.     

A new synthetic route to trimethylgallium

A new synthetic route to trimethylgallium was developed. It is based on preparation of gallium methyl derivatives by the Green reaction, followed by their alkylation with methyl Grignard reagent. The suggested procedure is well reproducible, with the yield of pure trimethylgallium exceeding 90%.     

A new synthetic route to aminophosphines

The reactions of R₂PPR₂ (R = Me, Et, Ph) and (MeP)₅ with Me_3−nAs(NMe₂)_n (n = 1, 2, 3) and of Me₂PPMe₂ with Me₂AsNR′₂ (R′ = Et, Prⁿ, and Prⁱ) were investigated as a function of time at room temperature using ¹H and ³¹P NMR spectroscopy. For the diphosphine/Me₂AsNR′₂ reactions, the NMR spectral data suggest a reaction pathway involving the initial formation of R₂PAsMe₂ and the respective acyclic dialkylaminophosphine, R₂PNR′₂. The P---As intermediate then symmetrizes to R₂PPR₂ and Me₂AsAsMe₂, the parent aminoarsine is completely consumed, and additional R₂PNR′ is formed. The relative rate of aminophosphine production is dependent upon the nature of the substituent on the phosphorus and nitrogen atoms. For systems involving MeAs(NMe₂)₂ and As(NMe₂)₃ as reactants, the intermediates could not be characterized, but the products were the expected aminophosphine and (MeAs)₅ or elemental arsenic, respectively. (MeP)₅ reacts to give MeP(NMe₂)₂ and the expected As---As bonded species. A comparison of the reactivity of these systems with analogous diarsine/aminoarsine systems is discussed. The results of the NMR study were utilized in designing a convenient, high yield, synthetic route to acyclic aminophosphines.     

A new synthetic route to oxazole and pyrrole 2-deoxy-C-ribosides

The synthesis of oxazole and pyrrole 3-carbethoxy/3-arylsulfonyl d and l-2-deoxyribosides by TosMIC addition/cyclization on d and l-2-deoxyribo-1-carboxaldehyde and unsaturated esters in moderate to good yields is reported.     

A general synthetic route to nanofibers of polyaniline derivatives

Nanofibrous mats of a wide variety of polyaniline derivatives can be synthesized without the need for templates or functional dopants by simply introducing an initiator into the reaction mixture of a rapidly mixed reaction between monomer and oxidant.     

A new stereoselective synthetic route to perhydrohistrionicotoxin

A stereoselective synthesis of $\text{rel}$-(6S,7S,8S) -7-butyl-8-hydroxy-1-azaspiro[5.5]undecan-2-one, a key intermediate for the synthesis of perhydrohistrionicotoxin, was described.     

A new synthetic route to polyfluorobenzyl alcohol

The synthesis of polyfluorinated benzyl alcohol from pentafluorobenzoic acid has been developed. An economical and effective direct reduction method of polyfluorobenzoic acid by zinc borohydride is described.     

A new synthetic route to fluorine-containing thiochromones

The Michael-addition of polyfluoroalkenoates with thiophenols in acetonitrile in the presence of Na-HCO₃ yielded the corresponding addition products, which were further treated with polyphosphoric acid (PPA) to give a series of new fluorine-containing thiochromones in good yields.     

A structure-activity relationship study of compounds with antihistamine activity

A structure-activity relationship (SAR) analysis of H(1)-, H(2)- and H(3)-antihistamine activity was carried out and chromatographic data of 2-[2-(phenylamino)thiazol-4-yl]ethanamine, 2-(2-benzyl-4-thiazolyl)ethanamine, 2-(2-benzhydrylthiazol4-yl)ethanamine, 2-(1-piperazinyl- and 2-(hexahydro-1H-1,4-diazepin-1-yl)benzothiazole, 2-(1-piperazinyl)benzothiazole, 2-[4-(1-alkyl)piperidinyl]benzothiazole, 2-(N,N',N'-dimethylalkyl-1,2-ethanediamino)benzothiazole, 2[1-(4-aminopiperidinyl)]benzothiazole, 2-[2-phenyl-4-thiazolyl]ethanamine derivatives and selected H(1)- and H(2)-antihistamine drugs were obtained. NP TLC and RP2 TLC plates (silica gel NP 60F(254) and silica gel RP2 60F(254) silanized precoated), impregnated with a solution of aspartic acid (L-Asp) and a solution of an analogue of aspartic acid (propionic acid), were used in two developing solvents as H(1)-, H(2)- and H(3)-antihistaminic interaction models. The lipophilicity data of the examined compounds were obtained and used in the SAR assay. Biochromatographic tests using TLC plates impregnated with solutions of asparic acid or propionic acid were found to be a source of useful data for the qualitative analysis of compounds with different structures, demonstrating activity to histamine H(1)-, H(2)- and H(3)-receptors. The four presented discriminant models based on biochromatographic studies are an efficient tool in the SAR analysis for initial prediction of compound activity direction within histamine receptors.     

A new synthetic route to chloride selective [2]catenanes

A novel anion templation route has been developed to synthesise two new catenanes, which are observed to selectively complex chloride in protic solvent media.     

A cyclopropenone route to new pyrrolizidine derivatives

New pyrrolizidine derivatives 6 and 7 were prepared from the 1, 5-dihydro-2H-pyrrol-2-one 3a via an acidic intramolecular aldol condensation in 16% and 42% yields, respectively. Compound 6 was obtained by dehydration of 7 with p-toluenessulfonic acid in 67% yield.