Ceric Ammonium Nitrate/Pyridine: A Mild Reagent for the Selective Deprotection of Cyclic Acetals and Ketals in the Presence of Acid Labile Protecting Groups

Synlett ◽  
2002 ◽  
pp. 1645-1648 ◽  
Author(s):  
Michelangelo Parrilli ◽  
Gaspare Barone ◽  
Emiliano Bedini ◽  
Alfonso Iadonisi ◽  
Emiliano Manzo
Keyword(s):  
Ammonium Nitrate ◽  
Ceric Ammonium Nitrate ◽  
Protecting Groups ◽  
Cyclic Acetals ◽  
Acid Labile

Ceric Ammonium Nitrate/Pyridine: A Mild Reagent for the Selective Deprotection of Cyclic Acetals and Ketals in the Presence of Acid Labile Protecting Groups.

ChemInform ◽  
2003 ◽  
Vol 34 (5) ◽  
Author(s):  
Gaspare Barone ◽  
Emiliano Bedini ◽  
Alfonso Iadonisi ◽  
Emiliano Manzo ◽  
Michelangelo Parrilli
Keyword(s):  
Ammonium Nitrate ◽  
Ceric Ammonium Nitrate ◽  
Protecting Groups ◽  
Cyclic Acetals ◽  
Acid Labile

Hafnium(IV) Chloride Catalyzes Highly Efficient Acetalization of Carbonyl Compounds

2019 ◽  
Vol 16 (6) ◽  
pp. 913-920 ◽  
Author(s):  
Israel Bonilla-Landa ◽  
Emizael López-Hernández ◽  
Felipe Barrera-Méndez ◽  
Nadia C. Salas ◽  
José L. Olivares-Romero
Keyword(s):  
Microwave Heating ◽  
Reaction Times ◽  
Protecting Groups ◽  
Catalyst Loading ◽  
Selective Protection ◽  
Highly Efficient ◽  
Aldehydes And Ketones ◽  
High Yields ◽  
Novel Catalyst ◽  
Acid Labile

Background: Hafnium(IV) tetrachloride efficiently catalyzes the protection of a variety of aldehydes and ketones, including benzophenone, acetophenone, and cyclohexanone, to the corresponding dimethyl acetals and 1,3-dioxolanes, under microwave heating. Substrates possessing acid-labile protecting groups (TBDPS and Boc) chemoselectively generated the corresponding acetal/ketal in excellent yields. Aim and Objective: In this study. the selective protection of aldehydes and ketones using a Hafnium(IV) chloride, which is a novel catalyst, under microwave heating was observed. Hence, it is imperative to find suitable conditions to promote the protection reaction in high yields and short reaction times. This study was undertaken not only to find a novel catalyst but also to perform the reaction with substrates bearing acid-labile protecting groups, and study the more challenging ketones as benzophenone. Materials and Methods: Using a microwave synthesis reactor Monowave 400 of Anton Paar, the protection reaction was performed on a raging temperature of 100°C ±1, a pressure of 2.9 bar, and an electric power of 50 W. More than 40 substrates have been screened and protected, not only the aldehydes were protected in high yields but also the more challenging ketones such as benzophenone were protected. All the products were purified by simple flash column chromatography, using silica gel and hexanes/ethyl acetate (90:10) as eluents. Finally, the protected substrates were characterized by NMR 1H, 13C and APCI-HRMS-QTOF. Results: Preliminary screening allowed us to find that 5 mol % of the catalyst is enough to furnish the protected aldehyde or ketone in up to 99% yield. Also it was found that substrates with a variety of substitutions on the aromatic ring (aldehyde or ketone), that include electron-withdrawing and electrondonating group, can be protected using this methodology in high yields. The more challenging cyclic ketones were also protected in up to 86% yield. It was found that trimethyl orthoformate is a very good additive to obtain the protected acetophenone. Finally, the protection of aldehydes with sensitive functional groups was performed. Indeed, it was found that substrates bearing acid labile groups such as Boc and TBDPS, chemoselectively generated the corresponding acetal/ketal compound while keeping the protective groups intact in up to 73% yield. Conclusion: Hafnium(IV) chloride as a catalyst provides a simple, highly efficient, and general chemoselective methodology for the protection of a variety of structurally diverse aldehydes and ketones. The major advantages offered by this method are: high yields, low catalyst loading, air-stability, and non-toxicity.

ChemInform Abstract: Oxidation of 4-methoxyanilines to 1,4-Benzoquinones Using Ceric Ammonium Nitrate (CAN).

ChemInform ◽  
2011 ◽  
Vol 42 (15) ◽  
pp. no-no
Author(s):  
Yugang Chen ◽  
Weijiang Ying ◽  
Michael Harmata
Keyword(s):  
Ammonium Nitrate ◽  
Ceric Ammonium Nitrate

OXIDATIVE REMOVAL OFN-(p-METHOXYBENZYL) GROUP ON DIKETOPIPERAZINE SKELETON WITH CERIC AMMONIUM NITRATE

1983 ◽  
Vol 12 (7) ◽  
pp. 1001-1002 ◽  
Author(s):  
Juji Yoshimura ◽  
Masanori Yamaura ◽  
Tsuneji Suzuki ◽  
Hironobu Hashimoto
Keyword(s):  
Ammonium Nitrate ◽  
Ceric Ammonium Nitrate ◽  
Oxidative Removal

scholarly journals Synthesis of 4,7-indolequinones. The oxidative demethylation of 4,7-dimethoxyindoles with ceric ammonium nitrate.

1985 ◽  
Vol 33 (5) ◽  
pp. 2122-2128 ◽  
Author(s):  
YOSHIYASU KITAHARA ◽  
SHINSUKE NAKAHARA ◽  
RYUICHI NUMATA ◽  
AKINORI KUBO
Keyword(s):  
Ammonium Nitrate ◽  
Ceric Ammonium Nitrate ◽  
Oxidative Demethylation

Deprotection of benzaldehyde diacetates by ceric ammonium nitrate coated on silica

1992 ◽  
Vol 33 (27) ◽  
pp. 3855-3858 ◽  
Author(s):  
Philippe Cotelle ◽  
Jean-Pierre Catteau
Keyword(s):  
Ammonium Nitrate ◽  
Ceric Ammonium Nitrate

On the mechanism of alcoholysis of allylic and benzylic alcohols and of epoxides in the presence of ceric ammonium nitrate

Tetrahedron ◽  
1996 ◽  
Vol 52 (12) ◽  
pp. 4175-4180 ◽  
Author(s):  
Jean-Marc Chapuzet ◽  
Sophie Beauchemin ◽  
Benoit Daoust ◽  
Jean Lessard
Keyword(s):  
Ammonium Nitrate ◽  
Ceric Ammonium Nitrate ◽  
Benzylic Alcohols
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