(2R,3R)-3-[(1R)-1-{[tert-Butyl(dimethyl)silyl]oxy}ethyl]-4-oxoazetidin-2-yl Acetate in Zinc- and Samarium-Promoted Substitution Reactions with Methyl 2-Bromopropanoate and Methyl (2-Bromomethyl)prop-2-enoate. Unusual Cleavage of the N1‒C4 Bond in Azetidin-2-one Derivative with Migration of Methoxycarbonyl Group in Synthetic Approaches to Carbapenems and Their Analogs

2018 ◽  
Vol 54 (7) ◽  
pp. 1023-1030 ◽  
Author(s):  
Z. R. Valiullina ◽  
L. S. Khasanova ◽  
N. K. Selezneva ◽  
L. V. Spirikhin ◽  
Yu. N. Belokon’ ◽  
...  
Keyword(s):  
Substitution Reactions ◽  
Tert Butyl ◽  
Methoxycarbonyl Group ◽  
Unusual Cleavage ◽  
Synthetic Approaches

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.

Monoterpene-based metallophthalocyanines: Sustainable synthetic approaches and photophysical studies

2020 ◽  
Vol 24 (05n07) ◽  
pp. 947-958
Author(s):  
Andreia C. S. Gonzalez ◽  
Liliana Damas ◽  
Rafael T. Aroso ◽  
Vanessa A. Tomé ◽  
Lucas D. Dias ◽  
...  
Keyword(s):  
Room Temperature ◽  
Ultrasound Irradiation ◽  
Conventional Heating ◽  
Quantum Yields ◽  
Microwave Assisted Synthesis ◽  
Aromatic Substitution ◽  
Substitution Reactions ◽  
Fluorescence Quantum Yields ◽  
Photophysical Studies ◽  
Synthetic Approaches

Tetra-substituted zinc(II) and copper(II) phthalocyanines bearing peripheral alkoxy-monoterpene groups were prepared by conventional vs. non-conventional synthetic approaches (ultrasound and microwave irradiation). The synthesis of (1[Formula: see text]-(–)-myrtenol (a) and (1[Formula: see text],2[Formula: see text],5[Formula: see text]-([Formula: see text]-menthol (b) derived phthalonitrile precursors was performed through ipso-nitro aromatic substitution reactions, with optimal conditions being obtained using ultrasound irradiation, which allowed us to achieve full conversions in 4.5 h, with isolated yields up to 74%. The subsequent cyclotetramerization of monoterpene-based phthalonitriles was carried out using Zn(II) or Cu(II) salts as metal templates, and also using conventional and non-conventional heating methods. Microwave-assisted synthesis was shown to be the most efficient approach, providing complete conversions in 1 h, yielding the target monoterpene-based metallophthalocyanines in up to 70% isolated yields. Furthermore, photophysical and photochemical studies revealed that Zn(II) phthalocyanines possess fluorescence quantum yields in the range of [Formula: see text] 0.27–0.29, while Cu(II) phthalocyanines exhibited room temperature phosphorescence. In addition, the monoterpene-based Zn(II) phthalocyanines led to high singlet oxygen quantum yields ([Formula: see text] 0.55–0.69).

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

Pyridyl disulfide-based thiol–disulfide exchange reaction: shaping the design of redox-responsive polymeric materials

2020 ◽  
Vol 11 (48) ◽  
pp. 7603-7624
Author(s):  
Ismail Altinbasak ◽  
Mehmet Arslan ◽  
Rana Sanyal ◽  
Amitav Sanyal
Keyword(s):  
Exchange Reaction ◽  
Functional Materials ◽  
Polymeric Materials ◽  
Disulfide Exchange ◽  
Redox Responsive ◽  
Synthetic Approaches

This review provides an overview of synthetic approaches utilized to incorporate the thiol-reactive pyridyl-disulfide motif into various polymeric materials, and briefly highlights its utilization to obtain functional materials.

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