Differentiation of isomeric sulfur heterocycles by electron ionization mass spectrometry: 1,4-dithiins, 1,4-dithiafulvenes and their analogues tetrathianaphthalenes,tetrathiafulvalenes and tetrathiapentalenes

The electron ionization mass spectra of the title compounds have been studied along with the product ion spectra of their metastable or collisionally activated molecular ions. The relative abundances of ions in the spectra allow unambiguous isomer differentiation. Isomerization of the molecular ions was observed in the metastable ion spectra of tetrathianaphthalenes and tetrathiafulvalenes. This isomerization reaction parallels the electrochemical or base-induced isomerization observed in solution. The studied tetrathiapentalene derivative does not rearrange to the corresponding tetrathiafulvalene or tetrathianaphthalene isomers.     

Synthesis of 4-nitromethylene-1,4-dihydropyrimidine derivatives as pyrimidine nucleoside analogues

The synthesis of 4-nitromethylene-1,4-dihydropyrimidine derivatives as pyrimidine nucleoside analogues was developed, starting from 3-nitropyran-2-one N-functionalized amidines. Primary amines were reacted with amidines yielding 4-nitromethylene-1,4-dihydropyrimidine derivatives. In an initial survey, several 4-nitromethylene-1,4-dihydropyrimidines turned into 4-nitromethylene-1,2,3,4-tetrahydropyrimidine derivatives under different reduction conditions. The reduction reaction also induced a change in the exocyclic double bond configuration from (E) to (Z), due to an intramolecular hydrogen bond.     

1,2,3-Selenadiazoles as precursors to cyclopentadienylcobalt dithiolenes and 1,4-dithiins: molecular structures of bis(cycloocteno)-1,4-dithiin and bis(cycloocteno)-1,4-diselenin

Cycloocteno-1,2,3-selenadiazole ( 1 ) and cyclopenta-dienyldicarbonylcobalt ( 2 ) react in the presence of an excess of elemental sulfur to yield the dithiolene cyclopentadienyl(1,2-cyclooctenedithiolato)cobalt ( 3 ). Available evidence indicates that this reaction involves the intermediacy of a cobalt–alkyne complex. Compound 3 is the first example of a cyclopentadienylcobalt dithiolene bearing aliphatic substituents. Analogous reactions performed using only catalytic quantities of 2 provide high-yield syntheses of bis(cycloocteno)-1,4-dithiin ( 6 ) and bis(cycloocteno)-1,4-diselenin ( 7 ), whose structures have been determined by X-ray diffraction.     

Synthesis of novel nithiazine analogues containing the 1,4-dihydropyridine structure,and their bioactivity as insecticides

A series of novel nithiazine analogues bearing the 1,4-dihydropyridine structure have been designed and synthesized by reaction of nithiazine, malononitrile or ethyl cyanoacetate, and benzaldehyde. The synthesized compounds were identified by ¹H NMR and IR spectroscopy, and elemental analysis. Preliminary bioassays indicated that most of the compounds had moderate insecticidal activity against Aphis craccivora. The relationship between molecular structure and biological activity is discussed.     

Synthesis of 1,2-benzoquinones by the oxidation of 1,4-benzodioxins by peroxide derivatives

The oxidation reaction of 1,4-benzodioxin 1 by m-chloroperbenzoic acid (m-CPBA) and t-butyl hydroperoxide (t-BHP) are reported. 1,2-Benzoquinone 2 was given in moderate yields by the m-CPBA oxidation of 1,4-benzodioxin 1 , while 1,2-benzoquinone 2 was predominantly formed by t-BHP oxidation.     

Synthesis of 1,2- and 1,4-amino alcohols from 1,3-dienes via oxazines. Rearrangements of 1,4-amino alcohol derivatives to oxazolines

Conjugated dienes were converted to 1,2-oxazines by reaction with an acyl nitroso dienophile. The oxazines were reduced to 1,4-N-acetylamino alcohols, which were rearranged to the corresponding oxazolines upon treatment with methanesulfonyl chloride or anhydride. The oxazolines yielded 1,2-N-acetylamino alcohols upon hydrolysis. Thus either 1,4- or 1,2-N-acetylamino alcohols are available from 1,3-dienes via this methodology. Experimental and spectral data are provided for all new compounds.     

Syntheses of new 1,2-, 1,3-, and 1,4-diazine derivatives. 1. Synthesis of diazinylarylacetonitriles

A number of diazinylarylacetonitriles were obtained in the reactions of properly substituted 3-chloropyridazine, 2-chloropyrimidine, or 2-chloropyrazine derivatives with various arylacetonitriles. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1346–1354, September, 2006.     

Synthesis, crystal structures and in vitro antitumor activities of some arylantimony derivatives of analogues of demethylcantharimide

A series of novel arylantimony derivatives of analogues of demethylcantharimide with the formulae Ar_nSbL_(5−n) and Ar_nSbL^′_(5−n)(LH=N-hydroxy-demethyldehydrogencantharimide, L^′H=N-hydroxy-demethylcantharimide, n=3, 4; ArC₆H₅, 4-CH₃C₆H₄, 3-CH₃C₆H₄, 2-CH₃C₆H₄, 4-ClC₆H₄, 4-FC₆H₄) were synthesized and characterized by elemental analysis, IR, ¹H NMR and mass spectroscopy. The crystal structures of (C₆H₅)₄SbL, (4-CH₃C₆H₄)₃SbL₂ and (3-CH₃C₆H₄)₃SbL^′₂ were determined by X-ray diffraction. The in vitro antitumor activities of all compounds against six cancer cells are reported.     

Synthesis and x-ray crystal structures of isonipecotinamide derivatives as reverse amide analogues of fentanyl

Several isonipecotinamide derivatives which represent reverse amide derivatives of the potent analgetic agent fentanyl were prepared and evaluated for analgetic activity. The synthetic approaches utilized and stereochemical assignments are discussed. The most potent compound, 3 , displayed much weaker analgetic activity than fentanyl itself.     

Syntheses based on elemental phosphorus,sulfur, and their derivatives

This review summarizes the data on the synthesis of various phosphorus-and-sulfurcontaining organic compounds based on the reactions of elemental phosphorus and sulfur and their derivatives (various types of esters of trivalent phosphorus thioacids) with a variety of organic compounds. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1706–1711, October, 1993.     

Synthesis, reactions, and biological activity of 1,4-benzothiazine derivatives

Abstract  

6,7-Dimethoxy-2H-1,4-benzothiazin-3(4H)-one reacts with dimethylformamide dimethylacetal (DMF-DMA) to give the novel enaminone 2-(dimethylaminomethylene)-6,7-dimethoxy-2H-1,4-benzothiazin-3(4H)-one. The reaction of the latter with various active methylene compounds afforded pyrido[3,2-b][1,4]benzothiazines. Also, coupling of the enaminone with diazotized aniline derivatives gave 2-(arylhydrazono)-6,7-dimethoxy-2H-1,4-benzothiazin-3(4H)-ones. Spectral data indicated that the latter compounds exist predominantly in the hydrazone tautomeric form. In addition, coupling of the enaminone with diazotized heterocyclic amines afforded tetra- and pentaheterocyclic ring systems. The antitumor and antimicrobial activity of some of the synthesized compounds was screened.     

Synthesis of thiadiazole, dithietane, and imine derivatives of the [1,2]dithiolo[1,4]thiazine ring system

We report the synthesis of some new polysulfur-nitrogen heterocyclics by cycloaddition reactions to the thioketo group of readily available tricyclic 1,2-dithiole-3-thiones. Thus treatment of bis[1,2]dithiolo[1,4]thiazine ketothione 1 with diaryl nitrile imines generated from hydrazonoyl chlorides 2a-g gave [1,3,4]thiadiazolylidenyl[1,2]dithiolo[1,4]thiazines 4a-g in high yield. Compounds 4a-f, bearing the same substituents in both aryl groups, were stable but the analogous 4g,h with a p-nitrophenyl group on carbon gave the bis[1,2]dithiolo[1,4]thiazine dione 9, probably by cycloreversion and hydrolysis during chromatography. Treatment of 1, the bis[1,2]dithiolopyrrole ketothione 13, and dithione 12 with ethoxycarbonyl azide 11 gave imines 12 and 15 and bisimine 16, respectively, by an alternative fragmentation of the initial cycloadduct in which the 1,2-dithiole ring is retained. Reaction of 1 with TosMIC gave the imino-1,3-dithietane 17.     

Heterocyclic compound studies. II. Synthesis of 1,4-benzodioxin, 1,4-benzoxathiin, 1,4-benzoxazine and 1,4-benzothiazine derivatives

Benzocondensed six-membered heterocyclic rings containing two heteroatoms have been synthesized by a generally applicable method starting from disubstituted benzene compounds and methyl 4-chlorobutynoate ( 1 ) or methyl 4-bromobutenoate ( 2 ). The reactions with 1 yield a mixture of endo and exo (E or Z) isomers. The ¹³C nmr spectroscopy was used to assign the structure of the synthesized compounds.     

Cubane derivatives 1. Synthesis and molecular structures of the esters of 1,4-cubanedicarboxylic acid

An effective method of esterification of 1,4-cubanedicarboxylic acid with alkylsulfuric acids is proposed. The derivatives of alkanols with substantially different pK_a Valus are obtained in high yields. Molecular structures of the esters obtained are confirmed by various methods. The X-ray study showed a remarkable effect of the nature of an alkyl radical on the geometry of the cubane core.Translated fromIzyestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp.668–672, April, 1994.The authors thank Dr. G. V. Lagodzinskaya for analyzing the NMR spectra and for useful discussions.     

Synthesis of sulfur and nitrogen analogues of monooxo crown ethers

Sulfur or nitrogen analogues of monooxo crown ethers were prepared via intramolecular cyclization of the corresponding thia or aza oligoethylene glycol carboxylmethyl ethers by using benzenesulfonyl chloride in the presence of alkali metal carbonates.     

Behaviour of host compounds 1,2-DAX and 1,2-DAT in the presence of mixed xylene and ethylbenzene guest solvents,and comparisons with their 1,4 host derivatives

Journal of Inclusion Phenomena and Macrocyclic Chemistry - trans-N,N′-Bis(9-phenyl-9-xanthenyl)cyclohexane-1,2-diamine (1,2-DAX) and...     

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.