146516-79-2Relevant academic research and scientific papers
Application of Organolithium and Related Reagents in Synthesis XVI: Synthetic Strategies Based on Aromatic Metallation. A Concise Regiospecific Conversion of Chlorobenzoic Acids into their Benzylated Derivatives
Epsztajn, J.,Bieniek, A.,Kowalska, J. A.
, p. 701 - 716 (2007/10/03)
The reaction of benzyl bromide with bis-(N- and C-ortho)-lithiated chloroanilides 4, 5, and 6 has been examined.It has been found that in the case where the lithiated compound was derived from meta-methoxyanilides, pre-addition of LiBr or TMEDA was required to achieve C-benzylation.These results were accounted for by the conversion of the usually formed dimer into a mixed dimer with the LiBr or TMEDA complex in which the C-lithium bond appears to be more accessible towards electrophiles.The practical synthesis of o-benzylchlorobenzoic acids 10, 11, and 12 was accomplished via ionic reductive cleavage (Et3SiH/TiCl4) of the corresponding phthalides 18, 19, and 20.The acids 10, 11b, and 11c afforded the corresponding anthrones, upon treatment with trifluoroacetic anhydride which were oxidized by chromium trioxide to the new chloroantraquinones 21, 22, and 23. - Keywords: Chlorophthalides; Reduction; Benzylation; Benzylbenzoic acids; Chloroantraquinones
Application of Organolithium and Related Reagents in Synthesis, Part X. Metallation-Electrophilic Substitution Sequence of Secondary Chlorobenzamides
Epsztajn, Jan,Bieniek, Adam,Kowalska, Justyna A.,Scianowski, Jacek
, p. 1125 - 1134 (2007/10/02)
The lithiation (BunLi/THF) of 2-chloro- (1), 3-chloro- (2) and 4-chlorobenzanilides (3) and the subsequent reactions of the corresponding bis-lithiated anilides 4-6 with electrophiles (MeI, CH2=CH-CH2Br, Me3SiCl, MeCHO, o-MeOC6H4CHO, p-MeOC6H4CHO, Me2NCHO and p-MeOC6H4CONMe2) towards the synthesis of the ortho substituted chlorobenzoic acids derivatives 12-14 have been described.The effect of the chlorine substituent upon the generation and stability of the bis-lithiated chloro-anilides 4-6 has been studied.It has been found that the bis-lithiated chloro-anilide 5 derived from n-chloro-benzanilide (2) at a temperature above - 30 deg C converts into the corresponding benzyne 9.The anilide moiety (masking group) of the formed ortho-substituted chlorobenzanilides appeared to be effectively removable on acid-driven hydrolysis.Keywords: Secondary chlorobenzamides; Lithiation; Electrophilic substitution; ortho-Substituted chlorobenzoic acids; Phthalides; 2,3-Dihydro-1H-iso-indolin-1-ones; 3,4-Dihydroisocoumarins.
