tert-Butyl 2-{1-[2-Aryl-4-oxothiazol-5- (4H)-ylidene]ethyl}diazene-1-carboxyl- ates: A New Class of 1,2-Diaza-1,3- butadienes

Heterocycles ◽  
1999 ◽  
Vol 51 (10) ◽  
pp. 2423 ◽  
Author(s):  
Paolino Filippone ◽  
Orazio A. Attanasi ◽  
Barbara Guidi ◽  
Francesca R. Perrulli ◽  
Stefania Santeusanio
Keyword(s):  
Tert Butyl ◽  
New Class

ChemInform Abstract: tert-Butyl 2-{1[2-Aryl-4-oxothiazol-5(4H)-ylidene]ethyl}diazene-1-carboxylates: A New Class of 1,2-Diaza-1,3-butadienes.

ChemInform ◽  
2010 ◽  
Vol 31 (5) ◽  
pp. no-no
Author(s):  
Orazio A. Attanasi ◽  
Paolino Filippone ◽  
Barbara Guidi ◽  
Francesca R. Perrulli ◽  
Stefania Santeusanio
Keyword(s):  
Tert Butyl ◽  
New Class

Stable Oxapenem-3-carboxylic Acids – A New Class of β-Lactam Antibiotics. Influence of 2- and 6-Alkyl Substituents

1992 ◽  
Vol 47 (7) ◽  
pp. 1037-1050 ◽  
Author(s):  
Hans Rudolf Pfaendler ◽  
Wolfram Hendel ◽  
Ulrich Nagel
Keyword(s):  
Carboxylic Acids ◽  
Inductive Effect ◽  
X Ray ◽  
Tert Butyl ◽  
New Class ◽  
Structure Determinations

Novel antibacterially active oxapenem-carboxylic acids were prepared. Their increased stability depends on the 2-tert-butyl substituent and arises from its electron releasing inductive effect. The geometry and reactivity of oxapenems are discussed on the basis of two X-ray structure determinations and compared to those of related antibiotics.

N-tert-butyl-N-phosphonyloxyaminyls a new class of persistent radicals

1981 ◽  
Vol 22 (30) ◽  
pp. 2879-2882 ◽  
Author(s):  
M. Negareche ◽  
M. Boyer ◽  
P. Tordo
Keyword(s):  
Tert Butyl ◽  
New Class

scholarly journals Bis-Cyclometalated Indazole and Benzimidazole Chiral-at-Iridium Complexes: Synthesis and Asymmetric Catalysis

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1822
Author(s):  
Sebastian Brunen ◽  
Yvonne Grell ◽  
Philipp S. Steinlandt ◽  
Klaus Harms ◽  
Eric Meggers
Keyword(s):  
Asymmetric Catalysis ◽  
Coordination Sphere ◽  
Conjugate Addition ◽  
Chiral Auxiliary ◽  
Iridium Complexes ◽  
Bidentate Ligands ◽  
Nazarov Cyclization ◽  
Tert Butyl ◽  
New Class ◽  
Acyl Imidazole

A new class of bis-cyclometalated iridium(III) catalysts containing two inert cyclometalated 6-tert-butyl-2-phenyl-2H-indazole bidentate ligands or two inert cyclometalated 5-tert-butyl-1-methyl-2-phenylbenzimidazoles is introduced. The coordination sphere is complemented by two labile acetonitriles, and a hexafluorophosphate ion serves as a counterion for the monocationic complexes. Single enantiomers of the chiral-at-iridium complexes (>99% er) are obtained through a chiral-auxiliary-mediated approach using a monofluorinated salicyloxazoline and are investigated as catalysts in the enantioselective conjugate addition of indole to an α,β-unsaturated 2-acyl imidazole and an asymmetric Nazarov cyclization.

Carbaporphyrins, porphyrin isomers and the legacy of Emanuel Vogel

2012 ◽  
Vol 16 (05n06) ◽  
pp. 423-433 ◽  
Author(s):  
Timothy D. Lash
Keyword(s):  
Strong Support ◽  
Butyl Alcohol ◽  
Electron Delocalization ◽  
Cope Rearrangement ◽  
Tert Butyl ◽  
New Class ◽  
Tert Butyl Hydroperoxide ◽  
Tert Butyl Alcohol ◽  
Carbocyclic Rings ◽  
The Impact

Vogel discovered a large number of bridged annulene structures, including constitutional porphyrin isomers, heteroporphyrinoid species such as the tetraoxaporphyrin dication, corrole isomers and novel expanded porphyrinoid systems. In this review, the impact of Vogel's work on the author's research program is discussed. Carbaporphyrinoid systems with one or two carbocyclic rings replacing the usual pyrrole subunits have been synthesized and their diatropic characteristics can be related to the presence of 18π electron delocalization pathways within these macrocycles. The preparation of a dideazaporphyrin also provides strong support for the concept, espoused by Vogel, that porphyrins are examples of bridged annulenes. Ring contractions of azuliporphyrins to benzocarbaporphyrins with tert-butyl hydroperoxide in the presence of base have been proposed to involve a Cope rearrangement where a cycloheptatriene unit rearranges to give a norcaradiene-fused carbaporphyrinoid, followed elimination of tert-butyl alcohol, and Vogel's investigations into these types of valence tautomerization processes provides insights into these unusual transformations. In addition, a new class of porphyrin isomers has been synthesized and these porphyrin analogs extend the observations previously made for N-confused porphyrins and Vogel's constitutional isomers.

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