Microwave (MW) promoted high yield expedient synthesis of steryl ferulates--A class of novel biologically active compounds: A comparative study of their antioxidant activity with that of naturally occurring γ-oryzanol.

Synthetic steryl ferulates [3-O-(trans-4-feruloyl)-sterols] are currently gaining considerable importance in recent years to be used as nutraceuticals and food additives as well as in pharmaceutical applications substituting γ-oryzanol - a class of naturally occurring steryl ferulates having potent antioxidant and other organoleptic properties. Considering the importance of this class of compounds coupled with green technology associated with microwave energy (MW) in organic synthesis, we report here an expedited and high yield synthesis of steryl ferulates from abundant steroids, viz., cholesterol, cholestanol, stigmasterol, stigmastanol, ß-sitosterol, ß-campesterol, ß-campestanol and ergosterol applying MW energy in the crucial step of esterification process of sterols with trans-4-O-acetylferulic acid to furnish their esterified products, viz., 3-O-(trans-4-O-acetylferuloyl)-sterols for their eventual deprotection to their respective steryl ferulates. We further report an efficient and scalable process of producing acetylferulic acid. Testing of synthesized steryl ferulates against antioxidant assays has also been highlighted.

Microwave (MW) irradiated Ugi four-component reaction (Ugi-4CR): Expedited synthesis of steroid-amino acid conjugates--A novel class of hybrid compounds.

Microwave (MW) assisted chemical reactions are currently gaining considerable importance in organic synthesis to contribute in green technology. Considering the importance of peptidomimetic steroid-amino acid conjugates - a novel class of hybrid compounds having diverse biological properties, we report here synthesis of these compounds of alanine and valine methyl esters with seco-steroids (A, B and D ring cleavage) in expedited way by MW promoted Ugi-four-component reaction (Ugi-4CR).

Expedited Baeyer-Villiger oxidation of steroidal ketones by microwave irradiation.

Microwave (MW) assisted reactions are currently having considerable importance in the synthesis of organic compounds. Considering the remarkable application of Baeyer-Villiger (BV) reaction in the synthesis of natural products and steroid-peptide conjugates, we report here some of our findings of BV oxidation of carbonyl compounds with special reference to steroidal ketones under MW irradiation justifying its accelerating effect.

A convenient synthesis of the side chain of loteprednol etabonate--an ocular soft corticosteroid from 20-oxopregnanes using metal-mediated halogenation as a key reaction.

A facile synthesis of the side chain of loteprednol etabonate, namely, chloromethyl-17α-[(ethoxycarbonyl))oxy]-11ß-hydro of loteprednol etabonate, viz., chloromethyl-17α-[(ethoxycarbonyl))oxy]-11xy-3-oxoandrosta-1,4-diene-17ß-carboxylate--an ocular soft corticosteroid, has been described starting from a 20-oxopregnane, namely, 3ß-acetoxy-pregn-5(6),16(17)-diene-20-one (16-dehydropregnenolone acetate, i.e., 16-DPA) using our recently developed metal-mediated halogenation as a key reaction.

Synthesis of some new steroidal [16alpha,17alpha-d]-isoxazolines.

Regioselective synthesis of novel steroidal anti-inflammatory ante drug analogues, viz., [16alpha,17alpha-d]-isoxazolines 1(a-h) and 2(a-h) prepared in a single step in good yield by the reaction of 16-dehydropregnenolone acetate (16-DPA) 1 or related 21-chloro-20-oxopregnane 2 with various aldoximes (a-h) in presence of chloramine-T in refluxing ethanol.