Mitsuo Kodomari

Solvent-free synthesis of 2-aryl and 2-alkylbenzothiazoles on silica gel under microwave irradiation

Abstract 2‐Substituted benzothiazoles have been synthesized by the condensation of o‐aminothiophenol and aromatic or aliphatic aldehydes in the presence of silica gel under microwave irradiation (MW) and solvent‐free conditions. The silica gel can be easily recovered and reused for subsequent reactions without loss of the activity.

Solvent-free synthesis of 1,5-benzothiazepines and benzodiazepines on inorganic supports

Abstract 1,5‐Benzothiazepines and 1,5‐benzodiazepines have been synthesized in solvent‐free conditions from chalcones and o‐aminothiophenol or o‐phenylenediamine in the presence of inorganic support. Silica gel was found to be an effective support for the synthesis of 1,5‐benzothiazepines, whereas alumina was effective for the synthesis of 1,5‐benzodiazepines.

One-pot synthesis of 2-aminothiazoles using supported reagents

Abstract A simple and efficient method has been developed for the synthesis of 2-aminothiazoles from α-bromo ketones in one-pot using a supported reagents system, KSCN/SiO 2 –RNH 3 OAc/Al 2 O 3 , in which α-bromo ketone reacts first with KSCN/SiO 2 and the product, α-thiocyano ketone, reacts with RNH 3 OAc/Al 2 O 3 to give the final product, 2-aminothiazole, in high yield.

Direct allylation of aromatic compounds with allylic chloride using the supported reagents system ZnCl2/SiO2–K2CO3/Al2O3

Although the reaction of aromatic compounds with allylic chlorides using ZnCl2/SiO2 gives 2-chloro-1-arylalkanes accompanied with diarylalkanes, similar reaction using ZnCl2/SiO2–K2CO3/Al2O3 produces the monoallylated compound as the major product in good yield.

Convenient synthesis of aryl-substituted halo olefins from aromatic ketones and acetyl halides in the presence of silica gel-supported zinc halides

Abstract A simple and efficient procedure has been developed for the synthesis of aryl-substituted chloro and bromo olefins from aromatic ketones and acetyl halides in the presence of silica gel-supported zinc halides. The Z-isomer is selectively formed.

Graphite as an effective catalyst for Friedel–Crafts acylation

Graphite is found to promote Friedel–Crafts acylation of aromatic compounds such as anisole, toluene and o-xylene with acyl halides to give the corresponding acylated products in high yields.

A Convenient Synthesis of Thioacetates and Thiobenzoates Using Silica-Gel Supported Potassium Thioacetate

Abstract A simple and efficient procedure has been developed for the synthesis of thioesters by a reaction of alkyl halides with silica-gel supported potassium thioacetate or thiobenzoate under mild conditions.

Solvent‐Free Synthesis of Benzothiazolines in the Presence of Alumina

Abstract o‐Aminothiophenol reacted with ketones and β‐keto esters in the presence of alumina under mild and solvent‐free conditions to afford the corresponding benzothiazolines in high yields. Alumina can be reused for subsequent reactions without any loss of the activity.

Regioselective dehydrogenation of 3-keto-steroids to form conjugated enones using o-iodoxybenzoic acid and trifluoroacetic acid catalysis.

Mild and regioselective conversion of 3-keto-5α- and 3-keto-5β-steroids (trans A/B- and cis A/B-ring juncture, respectively) to the corresponding enones (Δ(1)- and Δ(4)-3-ketones) by treatment with o-iodoxybenzoic acid (IBX) catalyzed by trifluoroacetic acid (TFA) in DMSO, is described. The IBX-mediated reaction involved dehydrogenation of the α- and β-hydrogen atoms of the 3-ketones to give the enones regioselectively in good isolated yields without concomitant formation of related dienones and trienones.

Silica-Gel Supported Sulfamic Acid (SA/SiO2) as an Efficient and Reusable Catalyst for Conversion of Ketones into Oxathioacetals and Dithioacetals

Abstract A simple and efficient method for the conversion of carbonyl compounds to oxathioacetals and dithioacetals using SA/SiO2 as an acid catalyst has been achieved. SA/SiO2 is easily recovered from the reaction mixture and can be reused at least 15 times without loss of catalytic activity. GRAPHICAL ABSTRACT