K. Abiraj

Reductive cleavage of azo compounds catalyzed by commercial zinc dust using ammonium formate or formic acid

Abstract Azo compounds, both symmetric and unsymmetric, are cleaved to amine(s) by using commercial zinc dust and ammonium formate or formic acid in methanol, tetrahydrofuran or dioxane at room temperature. The reductive cleavage occurs without hydrogenolysis or hydrogenation of reducible moieties, such as -OH, -CH 3 , -OCH 3 , -COOH, -COCH 3 , halogen, etc. The cleavage is very fast, clean, cost effective and high-yielding if compared with earlier methods, such as those using cyclohexene/5% Pd on asbestos, cyclohexene/10% Pd C or hydrazine/10% Pd C or Raney nickel.

The synthesis of azo compounds from nitro compounds using lead and triethylammonium formate

Aromatic nitro compounds were reduced to the corresponding symmetrically substituted azo compounds using lead as catalyst and triethylammonium formate as hydrogen donor. Various azo compounds containing additional reducible substituents including halogens, nitrile, acid, phenol, ester, methoxy functions, etc, have been synthesized in a single step by the use of this reagent. The conversion is reasonably fast, clean, high yielding and occurs at room temperature in methanol.

Magnesium‐Catalyzed Proficient Reduction of Oximes to Amines Using Ammonium Formate

Abstract Various aldoximes and ketoximes were selectively reduced to the corresponding amines by catalytic transfer hydrogenation employing low cost magnesium powder and ammonium formate at room temperature. Many other functionalities such as halogens, –OH, –OCH3, –COOH and –CH3 remained unaffected. The hydrogenation is fast, mild, clean, cost effective and high yielding.

Zinc/ammonium formate: a new facile system for the rapid and selective reduction of oximes to amines †

Various oximes, both aldoximes and ketoximes, are selectively reduced to corresponding amines employing low cost zinc dust and ammonium formate despite presence of other functional groups such as halogens, –OH, –OCH3, –COOH, –CN, > C = C < and –CH3.

Lead-Catalyzed Synthesis of Azo Compounds by Ammonium Acetate Reduction of Aromatic Nitro Compounds

Abstract Lead/ammonium acetate is a convenient reagent for the reduction of aromatic nitro compounds to the corresponding symmetrically substituted azo compounds. Various azo compounds containing additional reducible substituents such as halogen, nitrile, acid, phenol, ester, methoxy, etc., functions have been synthesized in a single step by the use of this reagent. The conversion is reasonably fast, clean, high yielding and occurs at room temperature in methanol.

Heterogeneous catalytic transfer hydrogenation in peptide synthesis

A review. Heterogeneous catalytic transfer hydrogenation is a very versatile, selective, cost-effective, mild and rapid method for deprotection of protected peptides and for cleavage of peptides from the resin support. Catalytic transfer hydrogenation has potential in combinatorial chem. for the selective deblocking of benzyl-type protecting groups. [on SciFinder(R)]

MAGNESIUM/HYDRAZINIUM MONOFORMATE: A NEW HYDROGENATION SYSTEM FOR THE SELECTIVE REDUCTION OF NITRO COMPOUNDS

ABSTRACT The nitro group in aliphatic and aromatic nitro compounds, which also contain reducible substituents such as alkenes, nitriles, carboxylic acids, phenols, halogens, esters, etc., is selectively and rapidly reduced at room temperature to the corresponding amine in good yield by employing hydrazinium monoformate in the presence of magnesium powder. It was observed that, hydrazinium monoformate is more effective than hydrazine or formic acid or ammonium formate and reduction of the nitro group occurs without hydrogenolysis in the presence of low-cost magnesium compared to expensive metals like palladium, platinum, ruthenium, etc.

Transfer Hydrogenation of Aromatic Nitro Compounds Using Polymer‐Supported Formate and Pd‐C

Abstract Transfer hydrogenation of aromatic nitro compounds using recyclable polymer‐supported formate as hydrogen donor and Pd‐C as a catalyst produces corresponding amines in excellent yields (90–98%).

Facile Synthesis of Azo Compounds from Aromatic Nitro Compounds using Magnesium and Triethylammonium Formate

Magnesium/triethylammonium formate is a convenient reagent for the reduction of aromatic nitro compounds to corresponding symmetrically substituted azo compounds. Various azo compounds containing additional reducible substituents, including halogen, nitrile, acid, phenol, ester, and methoxy functions, have been synthesized in a single step by the use of this reagent. The conversion is reasonably fast, clean, high yielding, and occurs at room temperature in methanol.

New hydrogenation catalyst: An advantageous method for the removal of hydrogenolysable protecting groups in peptide synthesis

Removal of some commonly used protecting groups in peptide synthesis by catalytic transfer hydrogenation employing ammonium formate and magnesium is described. This method is equally competitive with other methods in deblocking most of the commonly used protecting groups in peptide synthesis.tert-Butyl derived and base labile protecting groups were completely stable under these conditions. The use of ammonium formate and magnesium makes this a rapid, low-cost alternative to palladium and reduces the work-up to a simple filtration and extraction operation.