摘要:

AbstractBiochemical studies on mode of action enable the chemist to optimize biologically active chemical structures. As a case study we describe the optimization process of fungicides inhibiting sterol biosynthesis. The spiroketalamines obtained represent new chemicals with various modes of action on sterol biosynthesis. These examples demonstrate that biochemixal studies allow directed pesticide design. The value of biochemistry in pesticide discovery has to be seen in a stepwise optimization rather than in “de‐novo”

ISSN:0941-1216    

DOI:10.1002/prac.19933350702

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

Acyl Migrations on 3(5)‐Amino‐pyrazole3(5)‐Amino‐pyrazole1form 3 isomeric monoacylation products, 4 diacylation products and 3 triacylation products by reaction with electrophiles like cyanates, isocyanates or carboxylic and chlorides, respectively. Acyl migrations are observed depending on the reaction temperature and the structure of the acyl residue. The structures of the acyl derivatives of 3(5)‐amino‐pyrazole were characterized by nmr

ISSN:0941-1216    

DOI:10.1002/prac.19933350703

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

Diazo Compounds. 72. Diazoalkylphosphanes – Synthesis by Electrophilic Diazoalkane Substitution and Oxidative Addition Reactions at PhosphorusElectrophilic diazoalkane substitution of the diazomethyl compounds1a,bwith the chloro phosphanes2a‐oin the presence of lithium diethylamide yields the diazoalkyl phosphanes3a‐z. Oxidative addition of oxygen, sulfur and selenium at phosphorus leads into the series of oxo, thioxo and selenoxo phosphanes having diazoalkyl substituents (4a‐d, 5a‐mand7a‐d). The silyl group of5n,ois cleaved by chromatography on aluminium oxide to yield the (diazomethyl)phosphane s

ISSN:0941-1216    

DOI:10.1002/prac.19933350704

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

Tetrathiafulvalenes. XXVII. Syntheses and Properties of cis‐ and trans‐Isomers of Dihydrophenanthreno‐TetrathiafulvalenesThe synthesis of anellated tetrathiafulvalenes (TTF)10a–c,11a–bvia the 1,3‐dithiolium salt/triethylamin or 1,3‐dithiole‐2‐thione/triethyl phosphite route is described. The dihydrophenanthreno‐anellated TTFs10a, bcan be thermally transformed into the phenanthreno‐anellated TTFs11a, b. Only in the case of the dihydrophenanthreno‐anellated TTF10b(with “α‐naphthyl structure”) the isolation of the cis‐ and trans‐isomer was possible due to differences in the solubility. Starting from the pure cis‐ or trans‐isomer the radical salts of10bare reducible to a 1:1 mixture of the cis/trans stereo isomers. The spectroscopic, electrochemical, and conductivity properties of the synthesized TTFs and their complexes wi

ISSN:0941-1216    

DOI:10.1002/prac.19933350705

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

Free Radical Reactions of N‐Heterocyclic Compounds. XI. Reaction of 3‐Methyl‐pyrazolin‐5‐ones with Phenoxy RadicalsPyrazolin‐5‐ones (3a–i) were oxidized with 2,4,6‐trisubstituted phenoxy radicals (2a–d) to the corresponding radicals (4a–i), which dimerised or combined with phenoxy radical (2a) depending on the R1‐ and R4‐substituents in (3). In the case of 3‐methyl‐1‐phenyl‐pyrazolin‐5‐one (3f) the primary radical combination products were not found, but the corresponding quinone methide (17) and the o‐phenol derivative (18) were isolated. Products and yields have been investigated as a function of mol ratio substrate: oxidant and solvent. The radical combination products (7–10) could de‐tertbutylated in the presence of aluminium chloride or in the presence of trifluoroarcetic acid, forming het

ISSN:0941-1216    

DOI:10.1002/prac.19933350706

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

1‐Arylimino‐pyrazole Betaines, Pyrazoles and 1,2,4‐Triazines from 3‐Arylazo‐propenoic Acid N‐ChloramidesReaction of 3‐arylazo‐propenoic acid amides5with NaOCl yields N‐chloroamides6which give under alkaline conditions 1,2,4‐triazines9and10(products of a Hofmann degradation). This reaction competes with an intramolecular electrophilic amination and a 1,2‐shift reaction giving 1‐arylimino‐pyrazole betaines11and 4‐chloroimino‐pyrazolones13. Exchange of the halogen in11with nucleophiles leads to further betaines12. Bis‐pyrazole14and 1,2,3‐triazoles15are available from13b. The X‐ray structure

ISSN:0941-1216    

DOI:10.1002/prac.19933350707

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractThe syntheses of 1,10‐ and 4,7‐phenanthroline derivatives having glycidyl, oxaziridinyl, N, N‐diethylaminoethoxy and thiosemicarbazone groups, and related compounds are reported. Their activities against experimental human tumor cells A 549 in vitro in relation to the molecular structures are disc

ISSN:0941-1216    

DOI:10.1002/prac.19933350708

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractBy screening several lipases and proteases as catalysts for an enantioselective partial deacylation of methyl (±)‐2,3‐di‐O‐acylglycerates, it was found that methyl (R)‐2,3‐di‐O‐butanoylglycerate can be obtained with an enantiomeric excess of>96% and a yield of 20% related to the racemic starting material. This was prepared from methyl acrylate through dihydroxylation with potassium permanganate at −30°C and a subs

ISSN:0941-1216    

DOI:10.1002/prac.19933350709

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

ISSN:0941-1216    

DOI:10.1002/prac.19933350710

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

ISSN:0941-1216    

DOI:10.1002/prac.19933350711

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY