Madhusudan V. Paradkar

One‐Pot Synthesis of 3‐Phenacylphthalides

Abstract Acid catalyzed condensation of phthalaldehydic acid (1) with aromatic methyl ketones (2) providing 3‐phenacylphthalides (3) is described.

One pot solvent free synthesis and in vitro antitubercular screening of 3-Aracylphthalides against Mycobacterium tuberculosis

One pot synthesis of 3-Aracylphthalide was accomplished in good yield by reacting 2-carboxy benzaldehyde with various aromatic methyl ketones in presence of methane sulphonic acid. Various phthalides thus obtained were characterized with spectral techniques. These phthalides were subjected to in vitro antitubercular screening against Mycobacterium tuberculosis H37Ra (MTB) by using XRMA protocol. Among the phthalides screened, four exhibited half maximal inhibitory concentration (IC(50)) in the range of 0.81-1.24 μg/ml thereby providing potential lead compounds for future drug discovery studies.

Novel Synthesis of Linear Furonaphthoquinones

Abstract An efficient synthesis of naturally occurring and biologically active furonaphthoquinones is described starting from suitably substituted dihydronaphthofuraps.

A Facile Synthesis of New [4,4′-BI-2H-1-Benzopyran]-2,2′-Diones

Abstract The paper describes the reaction of 2,2′-dihydroxybenzil 1 with Wittig reagent14 2 leading to the formation of a new heterocyclic system 4,4′-bicoumarins 3. Exclusive formation of bicoumarin and not Tactone 4 is described.

Synthesis of Naturally Occurring Pyranonaphthoquinones: (±) 9-Demethoxyeleutherin, (±) 9-Demethoxyisoeleutherin, and Pentalongin via Nef Reaction

Abstract The article describes alternative method for the synthesis of (±) 9-demethoxyeleutherin and (±) 9-demethoxyisoeleutherin, the analogs of naturally occurring pyranonaphthoquinones antibiotics eleutherin and isoeleutherin. This methodology has provided the target molecules using a shorter route involving five simple chemical transformations with Nef reaction as a key step. All the intermediates and target molecules were completely characterized by spectral techniques and confirmed by comparison with literature data. Further we have extended Nef protocol toward formal synthesis of naturally occuring pyranonaphthoquinone pentalongin. We accomplished synthesis of of 2-(1,4-dimethoxynaphthalen-2-yl)acetic acid devoid of very toxic cyanide intermediates, which has been converted into pentalongin. GRAPHICAL ABSTRACT

An efficient synthesis of dimethoxyphthalides

This communication describes a convenient route for the synthesis of naturally occurring dimethoxyphthalides using a Vilsmeier-Haack formylation.

Convenient syntheses of 3‑aryl‑3,4‑dihydroisocoumarins

A convenient method for the synthesis of naturally occurring 3,4-dihydroisocoumarins by judicious use of Friedel-Craft acylation, regioselective formylation and oxidative cyclisation reactions is described. O-methylated analogues of montroumarin and thunberginols C and D and have been synthesised using 3,5-dimethoxyphenylacetic acid as a starting material. Furthermore, the starting material 3,5-dimethoxyphenylacetic acid was synthesised by a route involving an oxidative Nef reaction.

CONVENIENT SYNTHESIS OF 2-ALLYL-3-BROMO-1,4- DIMETHOXYNAPHTHALENE: KEY INTERMEDIATE AS BUILDING BLOCK FOR BIOACTIVE PYRANONAPHTHOQUINONES

Abstract Synthesis of a key precursor 2-allyl-3-bromo-1,4-dimethoxynaphthalene (1) used in constructing various naturally occurring biologically active pyranonaphthoquinones is carried out utilizing easily available 1-methoxynaphthalene as a starting material. The synthesis was accomplished with Dakins oxidation and Claisen rearrangement, thereby providing another easy approach toward (1) without involving highly lachrymatric 2-bromonaphthoquinone. GRAPHICAL ABSTRACT

Synthesis of chlorohomophthalic acids, key intermediates in the synthesis of chlorinated isocoumarins

Efficient synthesis of chlorohomophthalic acids (6) and (7), key intermediates in the synthesis of chlorinated isocoumarins (3) and (4) is described.

A facile synthesis of dihydronaphthopyrans

Efficient syntheses of naturally occurring linear dihydronaphthopyran (6a) and its angular analogues (3b and 4), from appropriate ortho-methoxynaphthaldehydes, have been described.