Convenient, High-Yield Method for the Methylation of 1,3-Diketones
作者:Anil Choudhary、Alfons L. Baumstark
DOI:10.1055/s-1989-27359
日期:——
A general method for the facile dimethylation of 1,3-diketones is presented. The method involves the use of readily available, inexpensive reagents and is carried out under mild conditions. Monomethylation may be carried out by slight modification (simplification) of the procedure. Several examples are presented which show that the method is applicable to alkylations with primary halides as well. Isolated yields for monoalkylation are approximately 95% while those for dialkylation are â90%. Alkylation is taking place by the reaction of the enolates of 1,3-diketones [generated in toluene by treatment with anhydrous potassium carbonate in the presence of tetraalkylammonium bromide (phase-transfer catalyst)] with alkyl halides.
CHOUDHARY, ANIL;BAUMSTARK, ALFONS L., SYNTHESIS,(1989) N, C. 688-690
作者:CHOUDHARY, ANIL、BAUMSTARK, ALFONS L.
DOI:——
日期:——
The EPR D-parameter of 1,3-diarylcyclopentane-1,3-diyl triplet diradicals as a probe for steric substituent effects in benzyl-type radicals †
作者:Waldemar Adam、Claus van Barneveld、Jan-Stefan Gerke、Frank Gerrit Klärner
DOI:10.1039/a905773k
日期:——
The zero-field splitting Dparameter of a set of ortho-substituted 1,3-diarylcyclopentane-1,3-diyl tripletdiradicals 3 has been determined by EPR spectroscopy in a 2-methyltetrahydrofuran glass matrix at 77 K. While for meta- and para-substituted tripletdiradicals 3 the Dparameter is only a function of the electronic nature (spin donor versus spin acceptor) of the substituent, for the ortho-substituted