摘要:

AbstractThe formylation of thieno[3,4‐b]thiophene gives a mixture of 4‐formyl‐ and 6‐formyl‐thieno[3,4‐b]thiophene in a ratio of 70 : 30. Lithiation followed by formylation of the resulting organolithium compounds changes this ratio to 20 : 80. The formylation of methyl thieno[3,4‐b]thiophene‐2‐carboxylate has been shown to give the 4‐ and 6‐substituted isomers in a 50 : 50 ratio. The structures of the substitution products were established by oxidation and desulfurization experiments an

ISSN:0165-0513    

DOI:10.1002/recl.19700890112

出版商:WILEY‐VCH Verlag    

年代:1970

数据来源: WILEY

摘要:

AbstractProtonation of 9‐ethyl‐10‐methylanthracene in HF or CF3COOH/H2O · BF3affords a mixture of the 9H+‐ and 10H+‐9‐ethyl‐10‐methylanthracenium ions. These ions differ in free energy by only 0.9‐1.0 kcal · mole−1. This small difference in stability, which is probably due to steric rather than electronic effects, shows that methyl and ethyl groups are approximately equally effective in stabilizing arenium ions. This result demonstrates, contrary to what was recently concluded1on the basis of calorimetric measurements of the heats of protonation of alkylbenzenes in FSO3HSbF5, that there is no large Baker‐Nathan effect in alkylarenium‐ion formation.The PMR‐spectrum of the 9H+‐9‐ethyl‐10‐methylanthracenium ion exhibits some remarkable features ‐ notably an unusually strong shielding of the ethyl‐CH3protons · that are associated with the particular conformation of the (>CH

ISSN:0165-0513    

DOI:10.1002/recl.19700890113

出版商:WILEY‐VCH Verlag    

年代:1970

数据来源: WILEY

摘要:

AbstractSolutions of lithiated cumulenic ethers and bis‐ethers R2CHCCC(Li)OR3and R1OCHCCC(Li)OR3can be obtained by treatment of the compounds R1OCH(R)2)CCCH2OR3and R1OCH2CCCH(OR3)2respectively with 2 equivalents of butyllithium in ether. Reaction of these solutions with H2O, D2O, methyl iodide, α‐chloro‐ethers or ketones gives the cumulenic compounds or their derivatives in good yields.Solutions of lithiated cumulenic thioethers R2CHCCC(Li)SR3are obtained in an analogous way, but hydrolysis affords the isomeric enynic thioethers R2CHCHCCSR3in addition to the expected cumulenic thioethers R2CHCCCHSR3. Elimination of R1OH from R1OC(R2)2CCCH(SR3)2with 1 equivalent of C4H9Li leads to the cu

ISSN:0165-0513    

DOI:10.1002/recl.19700890114

出版商:WILEY‐VCH Verlag    

年代:1970

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19700890115

出版商:WILEY‐VCH Verlag    

年代:1970

数据来源: WILEY

摘要:

AbstractThe dipole moments and vicinal coupling constants ofcis‐2‐bromo‐,cis‐2‐chloro‐ andcis‐2‐fluoro‐4‐t‐butylcyclohexanone have been determined in several solvents, in order to investigate the conformational homogeneity of these compounds. The dipole moments show a small solvent‐dependence, which is not reflected in the coupling constants. The results can be explained satisfactorily on the assumption that in the solutions only the chair form (with an equatorially orient

ISSN:0165-0513    

DOI:10.1002/recl.19700890116

出版商:WILEY‐VCH Verlag    

年代:1970

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19700890101

出版商:WILEY‐VCH Verlag    

年代:1970

数据来源: WILEY