Syed Nawazish Ali

CHEMICAL CONSTITUENTS FROM THE LEAVES OF PSIDIUM GUAJAVA

Five constituents including one new pentacyclic triterpenoid guajanoic acid (1) and four known compounds β-sitosterol (2), uvaol (3), oleanolic acid (4), and ursolic acid (5) have been isolated from the leaves of Psidium guajava.The new constituent1has been characterized as 3β-p-E-coumaroyloxy-2α-methoxyurs-12-en-28-oic acid through 2D NMR techniques and chemical transformations. This is the first report of isolation of compound 3 from the genus Psidium

Analgesic and anti-inflammatory activities of Piper nigrum L.

OBJECTIVE To evaluate and compare the analgesic and anti-inflammatory activity of pure compound, piperine along with hexane and ethanol extracts of Piper nigrum L. fruit in mice and rats. METHODS The analgesic activity was determined by tail immersion method, analgesy-meter, hot plate and acetic acid induced writhing test. While the anti-inflammatory activity was evaluated by carrageenan-induced paw inflammation in rats. RESULTS Piperine at a dose of 5 mg/kg and ethanol extract at a dose of 15 mg/kg after 120 min and hexane extract at a dose of 10 mg/kg after 60 min exhibited significant (P<0.05) analgesic activity by tail immersion method, in comparison to ethanol extract at a dose of 10 mg/kg using analgesy-meter in rats. However, with hotplate method, piperine produced significant (P<0.05) analgesic activity at lower doses (5 and 10 mg/kg) after 120 min. A similar analgesic activity was noted with hexane extract at 15 mg/kg. However, in writhing test, ethanol extract significantly (P<0.05) stopped the number of writhes at a dose of 15 mg/kg, while piperine at a dose of 10 mg/kg completely terminated the writhes in mice. In the evaluation of anti-inflammatory effect using plethysmometer, piperine at doses of 10 and 15 mg/kg started producing anti-inflammatory effect after 30 min, which lasted till 60 min, whereas hexane and ethanol extracts also produced a similar activity at a slightly low dose (10 mg/kg) but lasted for 120 min. CONCLUSIONS It is concluded from the present study that Piper nigrum L possesses potent analgesic and anti-inflammatory activities.

Effect of the molecular structure on the reactivity in a family of tetra-amine compounds derived from Jeffamines

AbstractThe effect of the molecular structure on the reactivity of four first-generation linear-dendritic block copolymers derived from Jeffamines and bearing amine end groups is presented and discussed. Different parameters were investigated via chemical modifications and nuclear magnetic resonance analysis, showing that chain length, hydrophilic/hydrophobic character, and flexibility of the central oligoether block did not produce any change in the amine moiety reactivity. In contrast, the type of branches and the nature of the amine end groups strongly affected the reactivity in an unusual manner. In fact, the copolymer bearing aromatic amine end groups showed better reactivity than those based on aliphatic counterparts.

A new ethylene glycol triterpenoid from the leaves of Psidium guajava

One new pentacyclic triterpenoid psidiumoic acid (5) along with four known compounds β-sitosterol (1), obtusol (2), oleanolic acid (3), and ursolic acid (4) have been isolated from the leaves of Psidium guajava. The new constituent 5 has been characterized as 2α-glycolyl-3β-hydroxyolean-12-en-28-oic acid through 2D NMR techniques. This is the first report of isolation of compound 2 from the genus Psidium.

trans-Cyclo­hex-2-ene-1,4-diyl bis­(4-nitro­phen­yl) dicarbonate

Although the title molecule, C20H16N2O10, does not possess molecular inversion symmetry, it lies on a crystallographic inversion centre which imposes disorder on the central cyclohexene ring. In addition, the cyclohexene ring has non-symmetry-related disorder over two sites, with the ratio of the major and minor components being 0.54:0.46. The overall effect is to produce four disorder components for the atoms of the cyclohexene ring. The side chain is perfectly ordered and the dihedral angle between the atoms of the carbonate group (O=CO2—) and the benzene ring is 72.99 (6)°.

An efficient, mild and solvent-free synthesis of benzene ring acylated harmalines.

A facile synthesis of a series of benzene ring acylated analogues of harmaline has been achieved by Friedel-Crafts acylation under solvent-free conditions at room temperature using acyl halides/acid anhydrides and AlCl3. The reaction afforded 10- and 12-acyl analogues of harmaline in good yield, along with minor quantities of N-acyl-tryptamines and 8-acyl analogues of N-acyltryptamines.

Triterpenoids from the aerial parts of Lantana camara

Abstract Two new pentacyclic triterpenoids lancamarinic acid and lancamarinin have been obtained from the aerial parts of Lantana camara Linn. They were characterized as 22β-acetoxy-3,25-epoxy-3α-hydroxyolean-12-en-28-oic acid and methyl 3,25-epoxy-3α-hydroxy-11-oxo-22β-senecioyloxyolean-12-en-28-oate, respectively, through chemical transformation and exhaustive spectroscopic studies.

Chemical Constituents of the Leaves of Psidium guajava

Five constituents including one new pentacyclic triterpenoid guajanoic acid (1) and four known compounds beta-sitosterol (2), uvaol (3), oleanolic acid (4), and ursolic acid (5) have been isolated from the leaves of Psidium guajava. The new constituent 1 has been characterized as 3beta-p-E-coumaroyloxy-2alpha-methoxyurs-12-en-28-oic acid through 2D NMR techniques and chemical transformations. This is the first report of isolation of compound 3 from the genus Psidium.

Di-tert-butyl cyclo-hex-2-ene-1,4-diyl dicarbonate.

In the title molecule, C16H26O6, the central cyclohexene ring is in a half-chair conformation. The carbonyl groups are in a trans arrangement with respect to each other and the dihedral angle between the mean planes of the carbonate groups is 10.8 (2)°.

2,5-Dimethyl­hexane-2,5-diyl bis­(4-nitro­phen­yl) dicarbonate

The title structure, C22H24N2O10, contains two independent centrosymmetric molecules. The only significant difference between the molecules is the dihedral angle between the unique carbonate group (–O—CO2–) and the benzene ring, the values being 77.35 (8) and 66.42 (8)°. The crystal structure is stabilized by weak intermolecular C—H⋯O hydrogen bonds.