2,4,6‐Tri‐tert‐butylphenyl and 2,4‐di‐tert‐butyl‐6‐methylphenyl groups: Look similar,react differently

The crystal structures of molecules with two phosphaalkene groups have been determined. Differences in the stabilization of the PC π‐bond by the 2,4,6‐tri‐tert‐butylphenyl and 2,4‐di‐tert‐butyl‐6‐methylphenyl groups were observed. It has been found that lithium supermesityl(trimethylsilyl)phosphide could be a very efficient base to remove a proton from acetonitrile.© 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:662–666, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10083     

Microwave‐assisted synthesis of novel 4‐N,N‐dimethylamino‐ and 4‐cycloamino‐ substituted 1,2,4‐triazole‐3‐thiones

4‐N,N‐Dimethylamino‐ and 4‐cycloamino‐5‐phenyl‐1,2,4‐triazole‐3‐thiones 1–13 have been synthesized from benzhydrazides and substituted methyl dithiocarbazates under various conditions including short microwave irradiations. The last method seemed faster than the classical refluxing one. The influence of base and solvent types on the reaction direction has been also examined. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:188–195, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20594     

Microwave‐assisted from synthesis of 2‐arylamino‐2‐imidazolines on a solid support

An efficient synthesis of 2‐arylamino‐2‐imidazolines from dimethyl N‐aryldithioimidocarbonates and ethylenediamine on solid support under microwave irradiation has been developed. The reaction time has been reduced from hours to minutes with improved yields as compared to conventional heating. Their piperidin‐4‐ylmethyl and morpholin‐4‐ylmethyl derivatives were synthesized by treatment with formaldehyde and piperidine or morpholine. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:142–222, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20081     

Enantiopure phosphacymantrene‐2‐carboxaldehyde and some of its derivatives

The resolution of η⁵(2‐formyl‐3,4‐dimethylphospholyl)(triphenylphosphine)‐manganesedicarbonyl 1 has been carried out by chromatography of the acetals derived from (S,S)‐1,2‐diphenylethane‐1,2‐diol. The enantiopure 2‐diphenylphosphinomethyl 4 and diphenylmethylimino 5 derivatives have been prepared from 1 . © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:458–460, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20130     

A convenient synthesis of 2‐alkoxy‐2‐oxo‐1,4,2‐oxazaphosphinanes

A study on the synthesis of the novel cyclic α‐aminophosphonates and 2‐alkoxy‐2‐oxo‐1,4,2‐oxazaphosphinanes 4a‐r has been carried out. The title compounds were obtained in good yields by one‐pot procedure using o‐aminophenol, alkyl dichlorophosphinite, and ketones or benzaldehyde. One of their geometric stereoisomers was isolated and characterized. Configurations of 4k and one isomer of 4r have been established by X‐ray diffraction analysis. The synthetic methods provide an easy access to the organophosphorus heterocycles with the ring system mentioned above. The abnormal chemical shifts of alkyl‐substitute protons in ¹H NMR spectra were given reasonable explanation. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:65–69, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20258     

Synthesis and anti‐HIV activity of substituted 1,2,4‐triazolo‐thiophene derivatives

A new series of substituted 1,2,4‐triazoles bearing thiophene molecules 8 and 10 has been synthesized from cycloaddition of thiophene 3‐and 2‐carbonitriles 5 and 9 , respectively, with the reactive cumulene intermediates 4 . The newly synthesized products have been evaluated for their anti‐HIV activity. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:443–448, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20319     

Contributions to the chemistry of 3‐cyanoacetylhydrazono‐2‐indolinones and X‐ray structure of Z‐3‐cyanoacetylhydrazono‐2‐indolinone monohydrate

The tendency of acylhydrazones to undergo a spontaneous cyclization into 1,3,4‐oxadiazolines has been investigated. Contrary to the literature data, an attempted transformation of isatin cyanoacetylhydrazone in solution generates stereoisomers and not the reported structural isomer oxadiazoline. A similar behavior of the corresponding l‐methyl‐ and l‐acetylisatin derivatives even under acetylation conditions has been found. The crystal structure of the Z isomer of 3‐cyanoacetylhydrazono‐2‐indolinone monohydrate is reported. It contains strong intramolecular hydrogen bond between the hydrazone N H and oxygen atom of the indolinone carbonyl, and in this way the Z isomer over the CN bond is stabilized. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:183–193, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20531     

C‐phosphorylation of 2,5‐dimethyl‐N‐arylpyrroles

C‐Phosphorylation of 2,5‐dimethylpyrroles with phosphorus (III) halides has been studied. Synthetic methods have been elaborated that provide an access to 3‐phosphorylated 2,5‐dimethylpyrroles, including pyrrole‐substituted halogeno and dihalogeno phosphines; on this basis, a variety of trivalent and pentavalent phosphorus derivatives has been obtained. Ortho‐diphosphorylated 2,5‐dimethyl‐N‐arylpyrrole derivatives have been synthesized for the first time. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10:223–230, 1999     

Using the 1,2‐dihydro‐1,2‐diphosphinine ring as a template for the synthesis of new bicyclic structures and new trans‐chelating bis‐phosphines

The 1,2‐dihydro‐1,2‐diphosphinine decacarbonylditungsten complex 1 has been used as a synthetic equivalent of the corresponding 1,2‐dianion 2 . These two 1,2‐positions can be linked by a (CH₂)₄ bridge to yield a [4.4.0] bicyclic structure 6 whose identity has been confirmed by X‐ray crystal structure analysis. Alternatively, two ω‐iodohexyl chains can be grafted onto these positions and the resulting diiodo derivative 9 transformed into a long‐chain bis‐phosphine 10 by reaction with lithium diphenylphosphide. This bis‐phosphine gives a chelate complex with PdCl₂ whose trans‐stereochemistry was established by X‐ray crystal structure analysis. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:44–48, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20073     

Microwave‐assisted synthesis and diels–alder reactions of 1,3‐azaphospholo[5,1‐a]isoquinolines

The application of microwave technique has been extended successfully for the first time to the synthesis of a representative class of azaphospholes, viz. 1,3‐bis(alkoxycarbonyl)‐1,3‐azaphospholo[5,1‐a]isoquinolines ( 2 ), which occurs rapidly giving higher yields. Stereoselectivity is observed in the reaction with 2,3‐dimethyl‐1,3‐butadiene, and isoprene reacts regioselectively as well. 1‐Methyl‐3‐ethoxycarbonyl‐1,3‐azaphospholo[1,5‐a]pyridine ( 4 ) remains inert toward [2+4] cycloaddition. The nonoccurrence of the Diels–Alder reaction in the latter case has been supported by semiempirical PM3 calculations. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:560–563, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10193     

1,3‐Dihydro‐1‐hydroxy‐3‐morpholin‐4‐yl‐2,1‐benzoxaborole: product of the reaction of o‐formylphenylboronic acid with morpholine

o‐Formylphenylboronic acid reacts with morpholine to form 1,3‐dihydro‐1‐hydroxy‐3‐morpholin‐4‐yl‐2,1‐benzoxaborole. The typical hydrogen‐bonded dimer motif with a planar benzoxaborole fragment has been obtained in the solid state. Copyright © 2005 John Wiley & Sons, Ltd.     

The synthesis and characterization of 1,2‐O‐cyclohexylidene‐4‐aza‐8‐aminooctane and some of its transition metal complexes

1,2‐O‐Cyclohexylidene‐4‐aza‐8‐aminooctane (L) has been synthesized starting from 1‐chloro‐2,3‐O‐cyclohexylidene, which has been prepared by the reaction of epichlorohydrin with cyclohexanone. The complexes of this ligand with Co(II), Ni(II), Cu(II), and UO₂(VI) salts were prepared. The structures of the ligand and its complexes are proposed based on elemental analyses, IR, UV‐vis, ¹H, and ¹³C NMR spectra, magnetic susceptibility measurements, thermogravimetric analyses, and differential thermal analyses. © 2000 John Wiley & Sons, Inc. Heteroatom Chem 11:254–260, 2000     

Influence of colloid suspensions of humic acids on the alkaline hydrolysis of N‐methyl‐N‐nitroso‐p‐toluene sulfonamide

The influence of humic substances (HSs) upon the alkaline hydrolysis of N‐methyl‐N‐nitroso‐p‐toluene sulfonamide has been studied. Important inhibition of hydrolysis reaction has been reported. This inhibition has been explained in terms of association of reactants to the humic substances. Kinetic results have been modeled using the micellar pseudophase model. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 316–322, 2010     

A Homotelechelic bis‐terpyridine macroligand: One‐step synthesis and its metallo‐supramolecular self‐assembly

A homotelechelic macroligand bearing two 2,2′:6′,2″‐terpyridin‐4′‐yl units, as chain ends, is used as building block for the preparation of a linear metallo‐supramolecular chain‐extended polymer. The macroligand has been prepared by nitroxide‐mediated polymerization (NMP) of styrene using a bis‐terpyridine‐functionalized NMP initiator. The controlled character of the NMP process has been confirmed by detailed characterization of the polymer by size‐exclusion chromatography, nuclear magnetic resonance spectroscopy as well as mass spectrometry. Subsequently, the self‐assembly with Fe^II ions into the chain‐extended metallopolymer and the disassembly thereof, in the presence of a strong competitive ligand, has been studied by UV–vis absorption spectroscopy and diffusion‐ordered NMR spectroscopy. The reversibility of the formation of the metallo‐supramolecular material, when addressed by external stimuli, could be proven. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Synthesis,spectral, and antimicrobial studies of 1‐butyl‐3‐substituted‐4‐(2‐aryl‐1H‐indol‐3‐yl)‐2‐azetidinones

Ketene generated from acetyl chloride or chloroacetyl chloride adds on indolyl Schiff's base double bond to afford 1‐butyl‐3‐substituted‐4‐(2‐aryl‐1H‐indol‐3‐yl)‐2‐azetidinones in THF. The reaction proceeds stereospecifically via concerted trans [2+2] cycloaddition. The synthesized compounds have been characterized by elemental analyses and spectral data (IR, PMR, and mass). All synthesized compounds have been evaluated for antibacterial and antifungal activities, and 4g to 4l have shown promising results. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:494–501, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20052     

Syntheses of 1‐thio‐D‐xylose and D‐ribose esters of diorganoarsinous acids and their anticancer activity

Several thio‐D ‐xylose and D ‐ribose esters of dialkylarsinous acids have been synthesized. The crystal structure of 1‐S‐dimethylarsino‐β‐D ‐xylopyranose, 7a, has been obtained. Growth inhibition studies of about 60 strains of human cancer cells have been obtained in vitro for compounds 6a, 7a, 13 , and 14 . The results reveal that these compounds display a strong inhibition to subpanels of leukemia cells in vitro and high selectivity in inhibiting the growth of cancer cells. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:199–206, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20388     

Efficient synthesis of 1‐substituted‐4‐phenyl‐1, 4‐dihydro‐5H‐tetrazole‐5‐thione and (1‐phenyl‐1H‐tetrazol‐5‐yl)thioacetyl derivatives

A new and convenient synthesis of a variety of N‐ and S‐substituted tetrazoles has been developed via azide and Mannich reaction methods. Compounds were characterized by elemental analysis, MALDI MS, and ¹H NMR data. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:637–643, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20353     

Stereochemical behavior of 77Se‐1H spin‐spin coupling constants in pyrazolyl‐1,3‐diselenanes and 1,2‐diselenolane

Conformational study of five derivatives of 2‐(pyrazol‐4‐yl)‐1,3‐diselenane together with related 1,2‐diselenolane in respect to the stereochemical trends of geminal and vicinal ⁷⁷Se‐¹H spin‐spin coupling constants has been carried out by means of high‐level theoretical calculations in combination with experiment. The marked dihedral angle dependences for both types of couplings accounted for the lone pair effect in the case of geminal coupling constants and the Karplus‐type relationship for vicinal couplings have been established, which is of major importance for the stereochemical analysis of saturated selenium containing heterocycles. Copyright © 2012 John Wiley & Sons, Ltd.     

Copper‐catalyzed homo‐ and cross‐coupling reactions of terminal alkynes in ethyl lactate

The bio‐based chemical ethyl lactate (EL) has been discovered to be an excellent medium for the Glaser‐type homo‐ and cross‐coupling reactions of terminal alkynes. Good to excellent yields of conjugate diynes have been obtained under ligand‐free and mild heating conditions in the presence of CuI and molecular oxygen. Copyright © 2014 John Wiley & Sons, Ltd.