Parvathi Neelakantan

One-Pot Synthesis of α-Aminophosphonates: An Inexpensive Approach

Abstract A one-pot synthesis of the α-aminophosphonates from aldehydes and amines using trimethyl phosphite catalyzed by aluminum chloride at ambient temperature is reported. #IICT Communication No. 20412.

An Inexpensive Protocol for Biginelli Reaction

Abstract A one‐pot synthesis of the 3,4‐dihydropyrimidin‐2(1H)‐ones catalysed by cupric chloride–lithium chloride combination catalyst system in high yields is reported. #IICT communication number: 020612.

A SIMPLE DEBENZYLATION OF O-SUBSTITUTED PHENOL ETHERS USING HYDROBROMIC ACID IN PRESENCE OF PHASE TRANSFER CATALYST

Abstract A simple methodology for the debenzylation of ortho substituted phenol ethers in two phase system with aqueous hydrobromic acid in the presence of tetrabutylammonium bromide as a phase transfer catalyst is described.

A NOVEL ONE POT SYNTHESIS OF γ-BUTYROLACTONES*

ABSTRACT α-Arylidene-γ-phenyl-Δβ,γ-butenolides were converted to the respective γ-butyrolactones in methyl alcohol with sodium borohydride in presence of triethylamine in a single pot. *IICT communication No. 4391.

A Facile and Convenient Method for the Synthesis of Nitro Phenols and Chloropyridinols

An efficient, simple, and practical method of preparation of nitro phenols and chloropyridinols has been reported by the active chlorine displacement of chloro nitro benzenes and poly chloro pyridines in the presence of alkali metal hydroxide in low polarity solvent with very good yields.

A New Synthesis of, α-Unsaturated Aldehydes: Synthesis of Traumatin and Bombykol

Abstract A novel conversion of an alkene to a higher homologue αβ-unsaturated aldehyde was achieved in three steps. The aldehydes were used for the synthesis of traumatin, a wound hormone and bombykol, the pheromone of bombyx mori.

CONVERSION OF α-ARYLIDENE-γ-ΚEΤΟ ESTERS TO DIARYLFURAN CARBOXYLIC ACID ESTERS†

Formation of unsymmetrical 2,5 diarylfuran-3-carboxylic acid methyl asters from a-arylidene-7-oxo-benzenebutanoic acid methyl esters in presence of Nbromosuccinimide is described. Introduction Polysubstituted furans have attracted considerable attention due to their presence as key structural units in many of the natural products, important pharmaceuticals, and also as good building blocks in synthetic chemistry. This has led to tremendous interest and demand for flexible synthetic strategies. In general furans are synthesized by the ring closure of suitably substituted 1,4diketones. Alkynyloxiranes, alkynyl allyl alcohols and acetylenic ketones are other wellknown synthons utilized for the synthesis of 2,3,5-trisubstituted furans. Treatment of Grignard reaction product of 3-bromo 2,5-diphenyl furan with carbondioxide and selenium initiated conversions of α-substituted β,γ-unsaturated ketones happen to be few of the known methods reported for the synthesis of 2,5-disubstituted derivatives of furan3-carboxylic acid/ester. During the course of our study on the A-butenolides we came across a novel hitherto observation of forming furans from a-arylidene-y-oxo-benzenebutanoic acid methyl ester IICT Communication No. 01/11/05 Vol. 8, No. 4, 2002 Conversion of a-arylidene-y-keto esters to diarylfuran carboxylic acid esters COOCH3 (II) on treatment with N-bromosuccinimide (NBS) as shown in scheme 1. Ar TM . χΎ NBS/ -> fft 1 Π m Scheme-1 : Formation of furan derivatives with NBS Compound II, can be obtained in quantitative yield from the respective A-butenolides (I) by treatment with triethylamine in methyl alcohol at room temperature, the reaction time being 1 to 4 h. Results and Discussion We envisaged the bromination of the active methylene of compound II with NBS, to extend it further for the synthesis of heterocycles, but instead resulted in the formation of 2-aryl 5-phenylfuran-3-carboxylic acid methyl esters (III) In a typical reaction a-arylidene-7-oxo-benzenebutanoic acid methyl ester was treated with equimolar quantities of N-bromosuccinimide in refluxing carbon tetrachloride. Unsymmetrical diaryl substituted furan-3-carboxylic acid esters (III) were obtained in good yields. All the products obtained were characterized on the basis of IR, NMR, Mass spectra and HRMS. The Table-1 depicts the results of the present investigation. Table-1 : Effect of substitution in product formation Entry Ar Product Yield (%) Melting Point (°C) 1. 4-OCH3CeH4 95 78 2. 4-CH3CeH4 80 101 3. 4-OHCeH4 50 124 4. 4-OH-3-OCH3CeH3 80 72 5. CeH5 No reaction 6. 4-N02CeH4 No reaction 7. 2,6-Cl2CeH3 No reaction 8. 3-OPhCeH4 No reaction