Acid-catalyzed Ring Contraction of Dibenzothiepin-10,11-dione

1968 ◽  
Vol 7 (2) ◽  
pp. 128-129 ◽  
Author(s):  
A. Lüttringhaus ◽  
G. Creutzburg
Keyword(s):  
Ring Contraction ◽  
Acid Catalyzed

ChemInform Abstract: ACID-CATALYZED RING CONTRACTION OF STEROIDAL 1α,2α-EPOXY-4-EN-3-ONES

1977 ◽  
Vol 8 (10) ◽  
pp. no-no
Author(s):  
A. M. MAIONE ◽  
I. TORRINI ◽  
A. ROMEO
Keyword(s):  
Ring Contraction ◽  
Acid Catalyzed

scholarly journals UO22+-mediated ring contraction of pyrihexaphyrin: synthesis of a contracted expanded porphyrin-uranyl complex

2019 ◽  
Vol 10 (21) ◽  
pp. 5596-5602 ◽  
Author(s):  
James T. Brewster ◽  
Harrison D. Root ◽  
Daniel Mangel ◽  
Adam Samia ◽  
Hadiqa Zafar ◽  
...  
Keyword(s):  
Uranyl Complex ◽  
Ring Contraction ◽  
Acid Catalyzed ◽  
Expanded Porphyrin

A new mixed hexaphyrin, pyrihexaphyrin (0.1.0.0.1.0) (1), was prepared via an acid catalyzed cyclization between 5,5′-(pyridine-2,6-diyl)bis(pyrrole-2-carbaldehyde) (2) and terpyrrole (3).

Acid-catalyzed synthesis of functionalized arylthio cyclopropane carbaldehydes and ketones

2018 ◽  
Vol 54 (96) ◽  
pp. 13547-13550 ◽  
Author(s):  
Stefania Porcu ◽  
Alberto Luridiana ◽  
Alberto Martis ◽  
Angelo Frongia ◽  
Giorgia Sarais ◽  
...  
Keyword(s):  
Carbonyl Compounds ◽  
General Strategy ◽  
Reaction Sequence ◽  
Ring Contraction ◽  
Acid Catalyzed ◽  
High Yields ◽  
Ring Contraction Reaction

A general strategy for the synthesis of arylthio cyclopropyl carbaldehydes and ketones via acid catalysed arylthiol addition/ring contraction reaction sequence has been exploited. The procedure led to a wide panel of cyclopropyl carbonyl compounds in high yields and broad substrate scope.

The acid-catalyzed rearrangement of methyl 3,4-O-benzylidene-β-D-ribopyranoside

1977 ◽  
Vol 55 (23) ◽  
pp. 4071-4077 ◽  
Author(s):  
David M. Clode
Keyword(s):  
Acid Concentration ◽  
Equilibrium Mixture ◽  
Nmr Spectrum ◽  
Ring Contraction ◽  
Acidic Conditions ◽  
Acid Catalyzed ◽  
Sole Product

Methyl 3,4-O-(R)-benzylidene-β-D-ribopyranoside (2) rapidly rearranged, under anhydrous acidic conditions, to give methyl 2,3-O-(R)-benzylidene-β-D-ribopyranoside (6). Further rearrangement of 2 and 6 gave the (S)-isomers 4 and 8, an equilibrium mixture of the four pyranoside acetals 2, 4, 6, and 8 resulting. At higher acid concentrations, the rearrangement proceeded, with ring contraction, to give the diastereomeric forms of methyl 2,3-O-benzylidene-β-D-ribofuranoside (11 and 13) as the sole product. Treatment of methyl 3,4-O-(S′)-benzylidene-β-D-ribopyranoside (4) with acid resulted in the immediate formation of the equilibrium mixture of pyranoside acetals. On increasing the acid concentration this mixture again underwent ring contraction to give the diastereomers 11 and 13 as the final product. The rearrangement of 2 and 4 was monitored by following the change in signals in the benzyl proton region of the nmr spectrum.

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