Pyrrole chemistry. XXVIII. Substitution reactions of 1-(phenylsulfonyl)pyrrole and some derivatives

1985 ◽  
Vol 63 (4) ◽  
pp. 896-902 ◽  
Author(s):  
Hugh J. Anderson ◽  
Charles E. Loader ◽  
Ru Xun Xu ◽  
Nghia Lê ◽  
Niall J. Gogan ◽  
...  
Keyword(s):  
Substitution Reactions ◽  
Tert Butyl ◽  
Directing Group

The preparative value of the 1-(phenylsulfonyl) N-blocking and directing group for the synthesis of 3-acylpyrroles has been further evaluated. Acetylation and benzoylation are strongly regiospecific and give good yields. However, the regiospecificity is not general and other substitution reactions give mixtures of 2- and 3-substitution or even mostly 2-substitution. Friedel and Crafts tert-butylation gives 3-tert-butyl-1-(phenylsulfonyl)pyrrole and provides a useful route to tert-butylpyrrole, but ethylation and isopropylation give mixtures. Acylations of 2- and 3-alkyl-1-(phenylsulfonyl)pyrroles show little evidence of useful regiospecificity.

Kinetic Studies on the Reactions of [(TLtBu)PtCl]+ and [Pt(tpdm)Cl]+ Complexes with Some Thiols and Thioethers

2013 ◽  
Vol 66 (5) ◽  
pp. 534 ◽  
Author(s):  
Enisa Selimović ◽  
Biljana Petrović ◽  
Dragan Čcanović ◽  
Živadin D. Bugarčić ◽  
Jovana Bogojeski
Keyword(s):  
Variable Temperature ◽  
Kinetic Studies ◽  
Substitution Reactions ◽  
Tert Butyl ◽  
Naclo4 Solution ◽  
Entropy Of Activation ◽  
Methyl Pyridine

Substitution reactions of the complexes [(TLtBu)PtCl]+ and [Pt(tpdm)Cl]+, where TLtBu = 2,6-bis[(1,3-di-tert-butylimidazolin-2-imino)methyl]pyridine and tpdm = terpyridinedimethane, with nucleophiles: S-methyl-L-cysteine (S-Met-L-Cys), L-cysteine (L-Cys), glutathione (GSH) and L-methionine (L-Met) were studied in aqueous 0.1 M NaClO4 solution in the presence of 10 mM NaCl using variable-temperature UV-vis spectrophotometry. The higher reactivity of the complex with the tpdm ligand could be attributed to the influence of the bulkiness of the tert-butyl-groups from the [(TLtBu)PtCl]+ complex. The order of reactivity of the studied ligands is: S-Met-L-Cys > L-Met > GSH > L-Cys. The thioethers (S-Met-L-Cys and L-Met) are more reactive than the thiols (GSH and L-Cys). This order of reactivity is in relation with their electron properties and structures. The negative values reported for the entropy of activation confirmed the associative mode.

Tert-butyl- and 2,2,2-trifluoro-1,1-diphenylethane-sulfonates -hindrance of SO-scission in SN2-substitution reactions

1987 ◽  
Vol 28 (19) ◽  
pp. 2115-2118 ◽  
Author(s):  
Thomas Netscher ◽  
Reinhard Schwesinger ◽  
Björn Trupp ◽  
Horst Prinzbach
Keyword(s):  
Substitution Reactions ◽  
Tert Butyl

Palladium-Catalyzed sp3 C–H Benzoxylation of Alanine Derivatives Using Aldehydes under Ambient Conditions

Synthesis ◽  
2021 ◽  
Author(s):  
Kyalo Stephen Kanyiva ◽  
Takanori Shibata ◽  
King Hung Nigel Tang ◽  
Jiarui Wang
Keyword(s):  
Palladium Catalyst ◽  
Room Temperature ◽  
High Yield ◽  
Protecting Group ◽  
Ambient Conditions ◽  
Butyl Hydroperoxide ◽  
Tert Butyl ◽  
Tert Butyl Hydroperoxide ◽  
Palladium Catalyzed ◽  
Directing Group

AbstractThe Pd(II)-catalyzed sp3 C–H bond benzoxylation of N-phthaloylalanine derivatives possessing an 8-aminoquinolyl group as a directing group with aldehydes under ambient conditions is reported. When a solution of an alanine derivative and an aldehyde in a toluene/water co-solvent was reacted in the presence of palladium catalyst and tert-butyl hydroperoxide at room temperature, a benzoxylated product was formed in up to 68% yield. The protecting group of the obtained benzoxylated product was smoothly removed to afford a free amide in high yield.

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