摘要:

AbstractA general approach to isosteric phosphonate analogues of ulose‐l‐phosphates is described. A base‐catalysed chain elongationviaaMichaeladdition of 1‐deoxy‐1‐nitro‐sugars4, 8, and16to the vinylphosphonate18followed by hydrolysis of the nitro adducts gave the analogues ofD‐ribulose‐1‐phosphate,D‐fructose‐1‐phosphate, andD‐sedoheptulose‐1,7‐diphosphate21, 23, and2

ISSN:0018-019X    

DOI:10.1002/hlca.19850680402

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

Nature and Stability of Some Metallic Complexes of Dinucleating Cryptands in Solution II. Polythiamacrotricycles and Related Monocyclic SubunitsThe stability constants of the Cu2+and Ag+complexes of the cylindrical macrotricycle1a(1,7,13,19‐tetraaza 4,16‐dioxa 10,22,27,32‐tetrathiatricyclo[17.5.5.5]tetratriacontane) have been determined by pH‐metry, as well as those of the Cu2+, Co2+, Zn2+, Cd2+, Pb2+, and Ag+complexes of the monocyclic subunit2a(1,7‐dimethyl‐1,7‐diaza 4,10‐dithiacyclododecane), in aqueous solutions (NaClO4) at 25°. In the Cu(II) systems, equilibria were reached slowly, and the results established by pH‐metry were confirmed by UV/VIS spectrophotometric studies. The tricycle1aforms dinuclear cryptates with copper and silver, with overall stability constants log β210(Cu2‐1a)4+= 18.5, log β21‐2(Cu2‐1a(OH)2)2+= 4.8, log β210(Ag2‐1a)2+= 23.0. Ag+also forms a mononuclear (Ag‐1a)+complex, with log β110= 13.1, but no mononuclear species were detected in the Cu‐1asystem. The absorption spectra of the bis‐Cu(II) complexes of1aand2ain aqueous medium, MeOH and propylene carbonate (PC) are given, as well as those, in MeOH and PC, of the bis‐copper complexes of the related monocycles3and4(1,7‐diaza‐4,10,13‐trithiacyclopentadecane and 1.10‐diaza 4,7,13,16‐tetrathiacyclooctadecane, respectively), and tricycle5with two benzyl groups in the lateral chains.The complexing properties of the polyoxa‐ and polythia macrotricycles (Parts I and II of this series) are compared to those of other bis‐chelating ligand

ISSN:0018-019X    

DOI:10.1002/hlca.19850680403

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

Nature and Stability of Some Metallic Complexes of Dinucleating Cryptands in Solution III. The Monocycle [22]‐Py2N4The nature and stability of complexes formed by a new 22‐membered monocycle L = [22]‐Py2N4with the cations Mn+= Cu2+, Co2+, Ni2+, Zn2+, Cd2+, Pb2+, and Ag+have been determined in aqueous solutions (0.01M NaClO4, 25°) by pH‐metry and also, for the copper system, by UV‐absorption spectrophotometry. The stepwise protonation constants of the four amine functions of L were 9.1, 8.3, 7.1 and 3.7 logarithms units, respectively. No evidence was found for the protonation of the two pyridine nitrogen atoms. Mononuclear complexes MLn+were identified in all systems investigated, but the dinuclear species M2L2n+were only found with Cu2+and Ag+. The logarithms of the overall stability constants for the copper and silver complexes are CuL2+, 12.9; Cu2L4+, 18.6; Agl+, 6.3; Ag2L2+, 10.9, respectively. Mononuclear hydroxy species MLOH(n−1)+were identified in all systems except those of copper and silver. No dinuclear hydroxy complexes were detected. The complexing properties of L are compared to those of the large and less ri

ISSN:0018-019X    

DOI:10.1002/hlca.19850680404

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

AbstractThe regioselectivity of nucleophilic substitution of the nitro groups in 3,5‐dinitrophthalic anhydrides and 3,5‐dinitrophthalimides (Scheme) with a variety of nucleophiles (Nu−) was studied. In all cases, the 3‐nitro group was selectively substituted. With excess of the same nucleophilic reagent or with other nucleophiles, the 5‐nitro group could subsequently be

ISSN:0018-019X    

DOI:10.1002/hlca.19850680405

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

AbstractThe novel 3‐nitro‐9‐oxo‐9H‐xanthene‐ and 3‐nitro‐9‐oxo‐9H‐thioxanthene‐l‐carboxylic acids2a–dwere prepared by intramolecular acylation of 3‐aryloxy‐ and 3‐arylthio‐5‐nitrophthalic anhydrides1(Scheme). The 3‐nitro group was readily substituted by O‐ and S‐nucleophiles and halide and azide ions to give a range of 3‐substitu

ISSN:0018-019X    

DOI:10.1002/hlca.19850680406

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

Syntheses of Dibenzo[b,e][1,4]dioxin‐2,3‐quinones Including the Ecklonoquinones A and B and the Isoecklonoquinones A and BOxidation of monomesyloxy‐substituted pyrocatechols with MnO2in toluene using phase‐transfer conditions leads in high yield to monomesyloxy‐substituted dibenzo[b,e][1,4]dioxin‐2,3‐quinones with loss of one mesyloxy group. In this way, ecklonoquinone A (2), ecklonoquinone B (3), isoecklonoquinone A (43), and isoecklonoquinone B (44) were prepared. Their structures are based on X‐ray analyses of ecklonoquinone‐A leucoacetate (45) and the mesyloxy‐substituted quinone20. The reddish‐violet dibenzodioxin‐diquinone49was prepared from an intermediate of the iso‐series. The parent compound1has been synthesized in yields better than 50% from pyrocatechol and methyl 2,5‐dioxo‐2,5‐dihydrobenzoate as oxidant and 2‐methoxypyridin as catalyst. To rationalize the specific effect on the dimerisation step of the mesyloxy group, the intermediacy of 1,4‐quinone monoacetals is proposed. This also appl

ISSN:0018-019X    

DOI:10.1002/hlca.19850680407

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

AbstractInductive charge dispersal to the α‐ β‐ and γ‐positions of the solvated quinuclidinium ion has been examined by comparing the pKaand the derived inductivities ρIof several 2‐ 3‐ and 4‐substituted quinuclidinium perchlorates4, 5, and6, respectively. The same inductivity is observed at the practically equidistant β‐ and γ‐positions. It, therefore, appears that polar substituent effects are transmitted directly through the molecule. As expected, inductivity is considerably higher at the α‐positions where through‐bond and direct induction coincide. The fact that the pKaof all three series of salts correlate linearly with each other points to the common nature of these induct

ISSN:0018-019X    

DOI:10.1002/hlca.19850680408

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

Bis (2,4,6,8‐cyclononatetraen‐1‐yl)methanesBis (2,4,6,8‐cyclononatetraen‐1‐yl)methanes (2a–c) have been prepared by reaction of all‐cis‐cyclononatetraenide with 1,1‐dichlorodimethyl ether as well as with carbenium ion precursors9band9c. The title compounds2are attractive precursors of highly delocalised nonafulvenes of type3; however, elimination experime

ISSN:0018-019X    

DOI:10.1002/hlca.19850680409

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

Quinazoline Carboxylic Acids. An Easy Route to (4‐Oxo‐3,4‐dihydroquinazolin‐3‐yl)‐alkanoic Acids, (4‐Oxo‐3,4‐dihydro‐1,2,3‐benzotriazin‐3‐yl)‐alkanoic Acids and their EstersA new route was found for the synthesis of (4‐Oxo‐3,4‐dihydroquinazolin‐3‐yl)‐alkanoic acids (8) and (4‐Oxo‐3,4‐dihydro‐1,2,3‐benzotriazin‐3‐yl)‐alkanoic acids (6) by cyclization of theN‐(2‐aminobenzoyl)amino acids5with HCOOH or HNO2. 2H‐3,1‐Benzoxazine‐2,4(1H)‐diones (1) reacted with glycine esters to2, which were cyclized by HNO2to the esters4. Ester4was hydrolyzed to6(X = CH2). Diones1reacted with the most common amino acids (as the ammonium salt of tertiary amine) to amino‐alkanoic acids5, which were

ISSN:0018-019X    

DOI:10.1002/hlca.19850680410

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

AbstractThe reaction of anthranilamide with phosphorus pentasulfide in boiling pyridine leads to the benzodiazaphosphorine‐pyridine salt2. The structure is established by elemental analysis,1H‐13C‐15N‐31P‐NMR, and mass spec

ISSN:0018-019X    

DOI:10.1002/hlca.19850680411

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY