Mohammed Hashmat Ali

Oxidation of thiols to disulfides with molecular bromine on hydrated silica gel support

Abstract Results of oxidation of thiols to disulfides with molecular bromine on silica gel solid support are reported. The procedure utilizes organic media and does not require a base to neutralize HBr by-products to suppress acid promoted side reactions. Utilization of silica gel support simplifies work up and product isolation.

Oxidation of sulfides with pyridinium tribromide in the presence of hydrated silica gel

Abstract A variety of sulfides have been oxidized to sulfoxides utilizing pyridinium tribromide in the presence of hydrated silica gel in a non‐aqueous media. A combination of pyridinium tribromide and hydrated silica gel releases molecular bromine slowly in the reaction, affecting the oxidation. Hydrated silica gel also promotes decomposition of the bromosulfonium intermediate to the product. This procedure employs non‐aqueous media for the first time in such a reaction.

A Simple and Efficient Procedure for Oxidation of Sulfides to Sulfoxides on Hydrated Silica Gel with Ceric Ammonium Nitrate (Can) In Methylene Chloride

Abstract A simple, fast and efficient procedure for oxidation of sulfides to the corresponding sulfoxides with CAN mediated by hydrated silica gel in methylene chloride has been developed. To our knowledge, this is the first example of oxidation of sulfides with CAN in a non-aqueous media.

Silica‐Gel‐Supported Ceric Ammonium Nitrate (CAN): A Simple and Efficient Solid‐Supported Reagent for Oxidation of Oxygenated Aromatic Compounds to Quinones

Abstract A silica‐gel‐supported heterogeneous ceric ammonium nitrate (CAN) reagent has been developed for oxidizing oxygenated aromatics to quinones in nonaqueous media. The advantages of this procedure include excellent yields, mild reaction conditions, nonaqueous media, short reaction times, and easy product isolation.

Chemoselective Oxidation of Sulfides to Sulfones with Magnesium Monoperoxyphthalate (MMPP) On Silica Gel Support in Methylene Chloride Solvent

Abstract A simple, efficient and chemoselective, non-aqueous procedure for oxidation of sulfides to the corresponding sulfones with magnesium monoperoxyphthalate on hydrated silica gel has been developed.

SILICA GEL SUPPORTED JONES REAGENT (SJR): A SIMPLE AND EFFICIENT REAGENT FOR OXIDATION OF BENZYL ALCOHOLS TO BENZALDEHYDES

Jones reagent supported on silica gel (SJR) has been used for oxidation of benzyl alcohols to the corresponding benzaldehydes in high yields utilizing organic solvent. This newly developed reagent is easy to prepare and use. SJR is also safer than the traditional Jones reagent.

SILICA GEL SUPPORTED JONES REAGENT (SJR): A SIMPLE, VERSATILE, AND EFFICIENT REAGENT FOR OXIDATION OF ALCOHOLS IN NON-AQUEOUS MEDIA

Oxidation of alcohols to carbonyl compounds has been carried out by utilization of Jones reagent supported on silica gel (SJR). The SJR procedure has advantages over traditional Jones oxidation procedure. This procedure is safer to carry out and simplified workup by allowing organic media.

Oxidative Cleavage of Oximes with Silica‐Gel‐Supported Chromic Acid in Nonaqueous Media

Abstract A simple procedure for a clean and high‐yielding oxidative deoximation of benzaldoximes and ketoximes using a silica‐gel‐supported chromic acid reagent has been developed. This solid‐supported reagent allows us to carry out this reaction in nonaqueous dichloromethane reaction media.

Oxidation of Sulfides with N‐Bromosuccinimide in the Presence of Hydrated Silica Gel

Abstract An efficient and highly selective procedure for oxidation of sulfides to sulfoxides with N‐bromosuccinimide (NBS) in the presence of hydrated silica gel has been developed. Hydrated silica gel supplies the water necessary for decomposition of the intermediate bromosulfonium salt to the product, allowing the reaction to employ a nonaqueous media. Also, this procedure has increased the scope of the reaction by oxidizing a wider variety of sulfides, which was not possible until now.

Oxidation of sulfides to sulfoxides with 1, 3-dibromo-5, 5-dimethylhydantoin in the presence of hydrated silica gel

Chemo selective oxidation of sulfides to sulfoxides with 1,3-dibromo-5,5-dimethylhydantoin in dichloro-methane in the presence of hydrated silica gel has been developed. Decomposition of the bromosulfonium salt intermediate produced in this reaction to the product is facilitated by the water present in hydrated silica gel. Hydrated silica gel, as the source of necessary water, expanded the scope of oxidation reactions of sulfides to sulfoxides with N-halogenated reagents by allowing a wider range of protic and aprotic solvents. Also, the heterogeneous nature of this oxidation procedure made the product isolation easy. The procedure presented here is very simple, fast, and oxidizes a wide variety of sulfides that were difficult to achieve by many N-halo reagents in the past.