摘要:

Syntheses and Chemical Properties of New ‘Donor‐Acceptor’‐stahilized Molecular Systems with a Central Bicyclo[4.4.1] undeca‐l(10).3,6,8‐tetraene‐2,5‐diylidenc GroupThe synthesis of X‐methyl‐2‐(5‐oxobicyclo[4.4.1]undeca‐l)10(,3,6,8‐tetraen‐2‐yliden)‐l,3‐benzodithiol (4) is described starting with the keto‐enol mixture2and 5‐methyl‐1,3‐benzodithiolium perchlorate. Under rearomatization of the central frame protonation of4yields the salt4c.The reaction of4with dicyanoketene gives the ‘push‐pull‐substituted’5, and with 9‐carbonylfluorene the fulvalene derivative7, which can be protonated by CF3CO2H at C(9″) to the salt8.The reaction of 2‐methylthio‐l,3‐dithiolium jodide9with the keto‐enol mixture2yields10, which, on protonation at the carbonyl group by CF3CO2H, gives the salt11under rearomatization. The spectral data of the

ISSN:0018-019X    

DOI:10.1002/hlca.19820650502

出版商:WILEY‐VCH Verlag GmbH    

年代:1982

数据来源: WILEY

摘要:

AbstractOne of the fish‐toxic chlorinated resin acids, 14‐chlorodehydroabietic acid (5), found in kraft mill effluent is examined. When exposed to the fungusMortierella isabellina,5is converted into a number of hydroxylated derivatives which show low levels of toxicity to fish. These biotransformation products were isolated and characteri

ISSN:0018-019X    

DOI:10.1002/hlca.19820650503

出版商:WILEY‐VCH Verlag GmbH    

年代:1982

数据来源: WILEY

摘要:

AbstractAn improved synthesis of the isomeric 12‐ and 14‐chlorodehydroabietic acids (3and2, respectively) and 12,14‐dichlorodehydroabietic acid (4) is described. The monochioro isomers were conveniently separated as the imidazole derivatives, and conversion of the latter to the free acids or their corresponding methyl esters could be achieved in high yield. Studies involving microbial degradation of2–4are u

ISSN:0018-019X    

DOI:10.1002/hlca.19820650504

出版商:WILEY‐VCH Verlag GmbH    

年代:1982

数据来源: WILEY

摘要:

AbstractTwo new types of iso‐oxacephems have been synthesized in which a phosphonate group replaces either the carboxyl group or C(3). The latter compound exists as a stable trialkoxyphosphonium ylide.Potassium thioacetate and O2in DMF are transformed in an autocatalytic, probably sulfur‐catalyzed process to CH3COOK and sulfur; the latter two reagents are sufficient to transform the methanesulfonate7to the isopena

ISSN:0018-019X    

DOI:10.1002/hlca.19820650505

出版商:WILEY‐VCH Verlag GmbH    

年代:1982

数据来源: WILEY

摘要:

AbstractThe synthesis of an iso‐oxacephem is described. Reaction of methanesulfonyl chloride with hydroxyaldylmalonates can form sulfones or sulfonates, their ratio varying with the basicity of the tertiary amine used in the sulfonatio

ISSN:0018-019X    

DOI:10.1002/hlca.19820650506

出版商:WILEY‐VCH Verlag GmbH    

年代:1982

数据来源: WILEY

摘要:

AbstractThe synthesis of the title compound is described.

ISSN:0018-019X    

DOI:10.1002/hlca.19820650507

出版商:WILEY‐VCH Verlag GmbH    

年代:1982

数据来源: WILEY

摘要:

AbstractThe synthesis of some β‐lactams and one Δ1‐carbapenem is described. The electronic activation of monocyclic β‐lactams of type1is not sufficient to generate a bioactive

ISSN:0018-019X    

DOI:10.1002/hlca.19820650508

出版商:WILEY‐VCH Verlag GmbH    

年代:1982

数据来源: WILEY

摘要:

AbstractThe water exchange of [V(H2O)6]Cl2in aqueous solution has been studied as a function of temperature and pressure (up to 250 MPa), by measuring the17O‐FT‐NMR. line‐widths of the free water resonance at 8.13 MHz. The kinetic parameters obtained areK 298m= 87±4 s−1,ΔH*= +61.8 ± 0.7 kJ mo1−1andΔS*= −0.4±1.9 J mol−1K−1. A pressure‐independent volume of activationΔV*= −4.1±0.1 cm3mol−1is obtained, suggesting an associative interchange (Ia) mechanism for

ISSN:0018-019X    

DOI:10.1002/hlca.19820650509

出版商:WILEY‐VCH Verlag GmbH    

年代:1982

数据来源: WILEY

摘要:

AbstractReactions of [2N]cyclophanes (N = 2, ⃛6) with solvated electrons in 1,2‐di‐methoxyethane at 193 K have been studied by ESR. and ENDOR. spectroscopy. All but the two most highly bridged cyclophanes (N = 5 and 6) are reduced to paramagnetic species under these conditions. Whereas the radical anions of [2.2]‐paracyclophane and [23](1,2,4)‐ and [24](l,2,4,5)cyclophanes are sufficiently persistent to be characterized by their hyperfine data, those of the remaining five cyclophanes undergo a rapid cyclization to the radical anions of 4,5,9,10‐tetrahydropyrenes. These have been identified as the unsubstituted tetrahydropyrene (from [2.2]‐metacyclophane and [23](l,2,3)cyclophane), the 2,7‐dimethyl‐derivative (from [23](1,3,5)‐ and [24](l,2,3,5)cyclophanes) and the 1,8‐dimethyl‐derivative (from (24l,2,3,4)cyclophane). The persistence of the cyclophane radical anions seems to depend on the numbers, nmetaand npara, of themeta‐andpara‐positions of the bridging ethano groups in the two benzene rings. The prerequisite for the radical anion to b

ISSN:0018-019X    

DOI:10.1002/hlca.19820650510

出版商:WILEY‐VCH Verlag GmbH    

年代:1982

数据来源: WILEY

摘要:

Abstract4,5,7,13,15,16‐Hexamethyl‐(3)and 4,5,7,8,12,13,15,16‐octamethyl[2.2]paracyclophane(4)have been oxidized to their radical cations in solution under relatively mild conditions. Substantial hyperfine splittings in the ESR. spectra of3⊕.and4⊕.arise from the methyl protons, whereas those from methylene protons are very small. This result indicates that the ethano bridges, unlike the methyl substituents, are rather ineffective in delocalizing the positive charge in3⊕.and4⊕.It is in line with the interpretation proposed previously to rationalize the gas‐phase ionization potentials of multiply bridged [2N]cyclophanes and methyl derivatives of [2.2]paracyclophane. The π‐spin distributions in3⊕.and4⊕.are discussed in terms of a simple model in which the singly occupied orbitals are represented as the antibonding combinations

ISSN:0018-019X    

DOI:10.1002/hlca.19820650511

出版商:WILEY‐VCH Verlag GmbH    

年代:1982

数据来源: WILEY