ISSN:0018-019X    

DOI:10.1002/hlca.19920750302

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractThe green seaweedCaulerpa taxifolia(VAHL) C. AGARDH(Caulerpales), which, after its recent accidental introduction, is growing in the region of Cap Martin much more vigorously than in the tropics, is shown to contain the known sesquiterpenic toxins caulerpenyne (1) – in larger amounts than in tropical Caulerpales – and oxytoxin 1 (2). Novel, potentially toxic products isolated in small amounts from this seaweed include the sesquiterpenes taxifolial A ( = (5E)‐6,10‐dimethyl‐2‐[(E)2‐oxoethylidene]undeca‐5,9‐dien‐7‐ yne‐1,3‐diyl diacetate;3), taxifolial B (= (1E,6E,10E)‐3‐[(Z)‐acetoxymethylidene]‐7, 11‐dimethyl‐12‐oxododeca‐1,6,10‐trien‐8‐yne‐1,4‐diyl diacetate;4), 10,11‐epoxycaulerpenyne ( = (1E,6E)‐3‐[(Z)‐acetoxymethylidene]‐10,11‐epoxy‐7, 11‐dimethyldodeca‐1,6‐dien‐8‐yne‐1,4‐diyl diacetate; 1:1 diastereoisomer mixture;5), and taxifolial C ( = (2Z,6E)‐3‐formyl‐7,11‐dimethyldodeca‐2,6,10‐trien‐8‐yne‐1,1, 4‐triyl triacetate;6), besides, as the first exampl

ISSN:0018-019X    

DOI:10.1002/hlca.19920750303

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractThe syntheses and biological activities of some nitrostyrene derivatives of adenosine 5′‐glutarates, a novel class of selective, bi‐substrate‐type inhibitors of the EGF receptor protein tyrosine kinase withIC50values around 1 μM. Only marginal inhibition of the tyrosine kinasesv‐ableandc‐srcand of the serine/threonine kinase PKC was observed. Compounds8, 9, 11, and12– lacking the adenosine moiety – were ten times less active than the most potent derivatives, whereas17– lacking the nitrostyryl part – showed no inhibitory activity at all. Most of the compounds showed potent antiproliferative activity against an EGF‐dependent mouse

ISSN:0018-019X    

DOI:10.1002/hlca.19920750304

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractMulti‐O4‐phospho‐L‐tyrosine‐containing peptides can be synthesized by the global as well as the buildingblock approach. Thus, we prepared by both strategies the triphosphorylated and the three regioisomeric diphosphorylated insulin‐receptor‐(1142–1153)‐dodecapeptide derivatives7and4–6, respectively, of the parent Thr‐Arg‐Asp‐Ile‐Tyr‐Glu‐Thr‐Asp‐Tyr‐Tyr‐Arg‐Lys (3). These phosphorylated peptides are valuable tools to study the regioselecti

ISSN:0018-019X    

DOI:10.1002/hlca.19920750305

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractMichaeladdition ofN‐nitroacetyl derivatives1of proline esters using KF under phase‐transfer catalysis resulted in the formation of adducts3–9with chemical yields ranging from 40–90% (Scheme). Stereoselectivity of up to 51% was obtained on addition of benzylN‐(nitroacetyl)‐L‐prolinate (1a). The absolute configuration at the newly created chiral centre was established in the case of9by carrying out a reductive acylation and comparing the product10with an authentic sample of ethylN‐(O5‐ethylN2‐acetyl‐L‐glutam‐1

ISSN:0018-019X    

DOI:10.1002/hlca.19920750306

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractA general synthetic strategy for the preparation of polyazamacrocycles containing long aliphatic chains is reported. These compounds are 22‐ or 24‐membered hexaazamacrocycles incorporating two diethylenetriamine subunits (H2NCH2CH2NHCH2CH2NH2) linked together either by two CH2CH2OCH2CH2(see4–6), two tetramethylene (see7), or two pentamethylene (see8) fragments. Whereas for compound4, one of the centrally located amine functionalities of the triamine subunit bears a hexadecyl chain, for compound5, two of such chains are centrally attached to both subunits. In macrocycles6–8, all six amino functionalities bear hexadecyl chains. Compounds4–8are potential candidates for the construction of selective chemical sensors such as specific electrodes for adenosine mono‐, di‐, and tri‐phosphate. They may also be used for nucleoside polyphosphates extraction a

ISSN:0018-019X    

DOI:10.1002/hlca.19920750307

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractThe 4,4′,6,6′‐tetrasubstituted 2,2′‐alkylidenebis(phenols)1reacted with CISCOI to give spiro[1,3‐benzoxathiepin‐4(5H), 1′‐cyclohexa[2,4]diene]‐2,2′‐diones4, together with cyclic carbonates5. The structures of the products were elucidated mainly by13C‐N

ISSN:0018-019X    

DOI:10.1002/hlca.19920750308

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractUnusual and novel C11H16olefins with (E)‐ or (E,E)‐configuration instead of the previously known (Z)‐ or (E,Z)‐configuration at the double bond(s) within the longer side chain are the main products of the Australian phaeophyteDictyopteris acrostichoides. This configuration anomaly refers to all four series of alicyclic C11H16hydrocarbons, namely the disubstituted cyclopentenes and cyclopropanes, as well as the monosubstituted cycloheptadienes and cyclopentenes. Chiral compounds within the above series have the same absolute configuration. The two (cyclopent‐3‐enyl)hexa‐1, 3‐dienes11and13are found for the first time. The absolute configuration and optical purity of the hydrocarbons are determined by gas chromatography on modified cyclodextrins as chiral stationary phases. The synthesis of chiral referencesvialipase‐catalyzed resolut

ISSN:0018-019X    

DOI:10.1002/hlca.19920750309

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractBy unambiguous methods, (Z)‐ and (E)‐2, 3‐dimethyl(1, 1, 1, 4, 4, 4‐2H6)but‐2‐enes (3) were synthesized and transformed to the epoxides4with 3‐chloroperbenzoic acids. Both the isotopomeric olefins and the epoxides are detected separately by1H‐NMR at 400 MHz. Epoxidation of (Z)‐3with [RhICl(PPh3)3]/cumene hydroperoxide resulted in a 1: 1 mixture of (Z)‐ and (E)‐4, while reaction of (Z)‐3with [FeIII(tpp)]Cl/PhIO gave only (Z)‐4(tp

ISSN:0018-019X    

DOI:10.1002/hlca.19920750310

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractThe absolute configuration of the gamete‐releasing and ‐attracting pheromone 2‐vinyl‐3‐(5′‐vinylcyclopent‐2′‐enyl)oxirane ( =(+)‐caudoxirene; (+)‐1) of the marine brown algaPerithalia caudatais established as (2R,3R,1′S,5′S). Highly diastereoselective syntheses and the biological activities of three diastereoisomers of1are described. Compound (+)‐(2R,3R,1′S,5′S)‐1is the first fully characterized epoxypheromone fro

ISSN:0018-019X    

DOI:10.1002/hlca.19920750311

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY