Amarendra Patra

Anti‐inflammatory and anticancer compounds isolated from Ventilago madraspatana Gaertn., Rubia cordifolia Linn. and Lantana camara Linn.

Objectives  The aim was to search for anti‐inflammatory and anticancer compounds from three medicinal plants, viz. Ventilago madraspatana Gaertn., Rubia cordifolia Linn. and Lantana camara Linn.

The protoberberine alkaloids of Stephania suberosa

Abstract Six new protoberberines were found in Stephama suberosa root extracts: (−)-tetrahydrostephabine, (−)-stephabinamine, stephabine, 8-oxypseudopalmatine, (−)- trans -xylopinine N -oxide and (−)- cis -xylopinine N -oxide. Ten known alkaloids were also detected: (−)-tetrahydropalmatine, (−)-tetrahydropalmatrubine, (−)-stepholidine, (−)-kikemanine, (−)-capaurimine, (−)-coreximine, (−)-corytenchine, (−)-discretine, pseudopalmatine and (−)-xylopinine.

Konyanin: a new lignan from hapuophyllum vulcaniclm

Abstract Konyanin ( 1 ), obtained from Haplophyllum vulcanicum (Rutaceae), is the first known 1,4-dihydroarylnaphthalene lignan in which the lactone carbonyl is bonded to C-3 rather than to C-2. Detailed NMR spectral data have been complied for the accompanying lignans (-)-kusunokinin ( 5 ) and diphyllin ( 7 ).

Synthesis of novel aminoquinonoid analogues of diospyrin and evaluation of their inhibitory activity against murine and human cancer cells

The synthesis and tumor-inhibitory activity of a series of aminonaphthoquinone derivatives of diospyrin, which was isolated from Diospyros montana Roxb., are presented here for the first time. An aminoacetate derivative showed the maximum (approximately 93%) increase in life span in vivo against murine Ehrlich ascites carcinoma (EAC) at a dose of 1 mg kg(-1)day(-1) (ip; five doses), and the lowest IC50 (0.06 microM) in vitro. Further, the same analogue also exhibited considerable enhancement in antiproliferative activity when evaluated against human cell lines, viz. malignant skin melanoma and epidermoid laryngeal carcinoma (IC50=0.06 and 0.92 microM, respectively) in comparison to the natural precursor, diospyrin (IC50=0.82 and 3.58 microM, respectively). Moreover, diospyrin and all its derivatives were found to show significantly greater (approximately 17- to 1441-fold) cytotoxicity against the tumor cells as compared to normal human lymphocytes. All these quinonoids generated substantial amounts of reactive oxygen species in EAC cells, more or less commensurate to their respective IC50 values.

New Synthesis of 3-Alkyl Coumarins

Abstract 3-Alkyl coumarins are reported to have anthelmintic, hypnotic and insecticidal properties1–3. Here we report a novel general method for the synthesis of 3-alkylated coumarins. This involves direct C-alkylatioa at the C-3 position of 3-carbethoxy-3,4-dihydrocoumarin followed by hydrolysis, decarboxylation and dehydrogenation of the resulting dihydrocoumarin. 3-Methyl-, 3-ethyl-, 3-n-pro-pyl-, and 3-benzylcoumarins have been synthesised in good yields following the same procedure depicted in the Scheme-1.

Synthesis of chiral oxepanes and pyrans by 3-O-allylcarbohydrate nitrone cycloaddition (3-OACNC)

3-O-Allylcarbohydrate nitrone cycloaddition (3-OACNC) furnished pyran and oxepane derivatives from 3-O-allyl hexose N-benzyl nitrones and 3-O-allyl furanoside-5-aldehyde N-benzyl/methyl nitrones. The regioselectivity of 3-OACNC was found to depend on the following factors (a) the structural nature of the nitrone (b) substitution and stereochemistry at 3-C of the carbohydrate backbone (c) substitution at the terminus of the O-allyl moiety. Oxepanes or pyrans obtained from a particular set of a hexose nitrone and the corresponding furanoside nitrone were converted to enantiomeric cyclic ethers through degradation. A mixture of an oxepane and a pyran was formed in the intramolecular oxime olefin cycloaddition (IOOC) of a 3-O-allylcarbohydrate derived oxime.

Benzopyrans. Part 30. Synthesis of substituted xanthones from 3-acyl-2-methyl-1-benzopyran-4-ones

Abstract The xanthone 8 results from the base catalysed self-condensation of the chromone 1 . The chromone 2 gives the xanthones 9 and 11 with sodium and DMF-POCl 3 respectively, phenol 14 with NaOMe, and the pyran 22 with 2-thiomethylchromone 6 . The enamine 16 on Vilsmeier-Haak reaction affords the chloroxanthone 12 . The pyran 15 , isolated as a byproduct from the reaction of ω-acetyl-2-hydroxyacetophenone with HC(OEt) 3 -Ac 2 O, affords the xanthone 13 by refluxing with NaOMe in MeOH.

Synthesis of chiral pyranocyclohexane, oxepanocyclohexane, and furylpyran and -oxepane systems by the application of intramolecular nitrone and nitrile oxide cycloaddition of carbohydrate derivatives

Abstract Chiral nonracemic pyranocyclohexanes 7 and 8 and oxepanocyclohexane 11 and 12 were obtained from a single 1,2-isopropylidene-3-O-cyclohexenyl carbohydrate aldehyde 4 via intramolecular nitrile oxide cycloaddition, and were converted to 2-(2′-tetrahydrofuryl)pyran 28, which incorporates the lasalocid skeleton, and the related oxepane derivative 32 respectively, through modification of the furanoside ring by applying 2-O-allyl carbohydrate nitrone cycloaddition.

Santiagonamine: a new aporphinoid alkaloid incorporating a phenanthridine skeleton

Abstract Santiagonamine (6), the first phenanthridine alkaloid, has been isolated from Berberis darwinii Hook (Berberidaceae).

Binding induced destruction of an excimer in anthracene-linked benzimidazole diamide: a case toward the selective detection of organic sulfonic acids and metal ions

A simple anthracene-linked benzimidazole diamide, 1, has been designed and synthesized. 1 was found to undergo a subtle change in conformation, followed by destruction of the inherently present excimer in the presence of organic sulfonic acids and selective metal ions. Destruction of the excimer did not take place in the presence of carboxylic acids and even stronger trifluroacetic acid. This finding was taken as a possible tool for distinguishing organic sulfonic acids from carboxylic acids. A similar situation arose in the presence of Cu2+, Co2+ and Ni2+, among the other metal ions studied, and the cleft was selective for Cu2+. The binding interaction was followed using 1H NMR, UV-vis and fluorescence spectroscopic methods.