Divergent synthesis of 4,6-diarylated pyridin-2(1H)-ones from chalcones: novel access to 2,4,6-triaryl pyridines.

A wide range of 4,6-diarylated/heterylated pyridin-2(1H)-one derivatives were synthesized in good to excellent yields from 1,3-diarylated/heterylated-2-propen-1-ones (chalcones) in one pot under metal and base-free conditions. This domino reaction suggests a novel mechanism comprising of Michael addition followed by amination, subsequent intramolecular amidation and finally dehydronitrosation. The usefulness of the designed 4,6-diarylated/heterylated pyridin-2(1H)-one derivatives has further been demonstrated by synthesizing medicinally important 2,4,6-triaryl/heteryl pyridines via Pd-catalyzed cross-coupling reaction.

Synthesis and structural elucidation of new complexes of 2,4- and 3,5-dimethyl diphenyldithiophosphates with cobalt(II).

A new series of donor-stabilized addition complexes of cobalt(II) with disubstituted diphenyldithiophosphates [{(ArO)2PS2}2CoL2] {Ar = 2,4-(CH3)2C6H3 [(1)-(3)] and 3,5-(CH3)2C6H3 [(4)-(6)]; L = C5H5N [(1), (4)], 3,4-(CH3)2C5H3N [(2), (5)] and 4-(C2H5)C5H4N [(3), (6)]} were successfully isolated and characterized by elemental analyses, magnetic moment measurements, IR and single-crystal X-ray analysis. Complexes (3), (4) and (5) crystallize in the monoclinic space groups P2(1)/n, P2(1)/n and P2(1)/c, respectively, whereas complex (6) crystallizes in the triclinic space group P1¯. X-ray diffraction analysis of complexes (3)-(6) reveals a six-coordinated distorted octahedral geometry for the CoS4N2 chromophore defined by two chelating diphenyldithiophosphate anions as well as two N-donor ligands. Two diphenyldithiophosphate ligands are coordinated to the cobalt ion as a bidentate ligand chelating via the two thiolate S atoms. Each of them forms a four-membered chelate ring in the equatorial plane. The N atoms from two donor ligands are axially coordinated to the Co atom in a mutually trans position.

Synthesis and structural characterization of donor-stabilized disubstituted diphenyldithiophosphates of nickel(II).

Donor-stabilized addition complexes of nickel(II) with disubstituted diphenyldithiophosphates, [{(ArO)2PS2}2NiL2] {Ar = 2,4-(CH3)2C6H3 [(1), (5)], 2,5-(CH3)2C6H3 [(2), (6)], 3,4-(CH3)2C6H3 [(3), (7)] and 3,5-(CH3)2C6H3 [(4), (8)]; L = C5H5N [(1)-(4)] and C7H9N [(5)-(8)]}, were successfully isolated and characterized by elemental analysis, magnetic moment, IR spectroscopy and single-crystal X-ray analysis. Compound (4) crystallizes in the monoclinic space group P2(1)/n whereas compounds (7) and (8) crystallize in the triclinic space group P1. The single-crystal X-ray diffraction analysis of (4), (7) and (8) reveals a six-coordinated octahedral geometry for the NiS4N2 chromophore. Two diphenyldithiophosphate ions act as bidentate ligands with their S atoms coordinated to the Ni centre. Each of them forms a four-membered chelate ring in the equatorial plane. The N atoms from two donor ligands are axially coordinated to the Ni atom.

Synthesis, spectral and antifungal analysis of diaryldithiophosphates of mono- and dibutyltin(IV): x-ray structure of [{(3,5-CH3)2C6H3O)2PS2}2Sn(nBu)2].

Diaryldithiophosphate complexes of mono- and dibutyltin(IV) corresponding to [(ArO)(2)PS(2)(n)Sn(nBu)xCl(4-x-n)] (Ar = o-CH(3)C(6)H(4), m-CH(3)C(6)H(4), p-CH(3)C(6)H(4), 4-Cl-3-CH(3)C(6)H(3), (3,5-CH(3))(2)C(6)H(3); n = 1, 2 for x = 1 and n = 2 for x = 2) were successfully isolated and characterized by elemental analyses, IR, multinuclear NMR ((1)H, (13)C, (31)P and (119)Sn) spectroscopy and X-ray analysis. The thermal properties of the complex [(3,5-CH(3))(2)C(6)H(3)O(2)PS(2)](2)Sn(nBu)(2) (12) have been examined by combined DTA/ DTG thermal analyses. Single crystal X-ray analysis of [(3,5-CH(3))(2)C(6)H(3)O(2)PS(2)](2)S(n)(nBu)(2) (12) revealed that two diaryldithiophosphate ions are coordinated to tin atom in an anisobidentate fashion through the sulfur atoms of each dithiophosphate moiety leading to distorted skew-trapezoidal bipyramidal geometry. The antifungal activity depicts that these complexes are active against fungus Penicillium chrysogenium.

Entrapment and kinetic resolution of stabilized axial and equatorial conformers of spiro-ß-lactams.

The facile synthesis of the stabilized axial and equatorial conformers of spiro-ß-lactams was achieved via entrapment of cyclohexanone imines (Schiff bases) with acetoxyacetyl chloride in a [2 + 2]-cycloaddition reaction followed by their kinetic resolution. The immobilization of the racemic substrates on an inert solid support significantly reduced the reaction time and improved the enantioselectivity of conformers during kinetic resolution. The mechanism of the formation of the spiro-ß-lactams was explored using B3LYP/6-31+G* level quantum chemical calculations.

Alkaloids from Toddalia aculeata.

Two alkaloids N-methyl-4-hydroxy-7-methoxy-3-(2,3-epoxy-3-methylbutyl)-1H-quinolin-2-one (1) and 3-(2,3-dihydroxy-3-methylbutyl)-4,7-dimethoxy-1-methyl-1H-quinolin-2-one (2a) have been isolated from CH(2)Cl(2):methanol (1:1) and methanol extracts of leaves and stems of Toddalia aculeata. Their structures along with that of 15 other compounds, of which three are isolated for the first time from genus Toddalia, were established by their detailed spectral studies including 2D NMR viz. (1)H-(1)H COSY, (1)H-(13)C COSY, and HMBC.