摘要:

[2+2]‐Cycloaddition of ‘Maleic Isoimides’ with Ketenes and Reactions of Spiro‐b̃‐lactams to Muconic and Tetramic AcidsThe [2 + 2]‐cycloaddition of iminolactones of type2(‘maleic isoimides’) with various ketenes affords spiro‐b̃‐lactams4–6. These highly functionalized compounds react with CH3ONa giving ketoadipinic acid derivatives12and/or pyrrolidinediones7, depending on the reaction temperature and the

ISSN:0018-019X    

DOI:10.1002/hlca.19830660132

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

Crossconjugated Cyanines and Merocyanines, Obtained from Salts of 1‐Substituted 2,3‐Dimethylquinoxalines: On the Properties of the Dye Bases in Acidic MediaUV./VIS. and1H‐NMR. spectra of the indicator bases1in acidic solutions are presented. The solutions of the dye acids N and NN′(Scheme 2)are in general not stable due to tautomerism. The relative pKa‐values are set in relation to data of equilibria and half‐life periods. The latter ones depend on the substituents and on the acidity of the solutions. An inverse substituent effect observed in protic solvents is ascribed to solvolytic reactions.The dye base1S(X = SO3Na, R = C6H5) was synthesized starting with chlorobenzene. The cyanines2were obtained on treatment of1with HClO4in CH3CN; solutions of1in H2SO4, however, yielded on dilution tautomeric salts that were isolated as the pe

ISSN:0018-019X    

DOI:10.1002/hlca.19830660133

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

A method is described for the preparation of concentrated solutions (50–70%) of18O‐labelled H2O2in water. All singly2H‐,13C‐ and18O‐labelled species of peroxyformic acid have been synthesized by the reaction of appropriately labelled formic acid

ISSN:0018-019X    

DOI:10.1002/hlca.19830660134

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

ISSN:0018-019X    

DOI:10.1002/hlca.19830660135

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

ISSN:0018-019X    

DOI:10.1002/hlca.19830660101

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY