Substituted pyrido[3,2-b]oxazin-3(4H)-ones: synthesis and evaluation of antinociceptive activity

Novel Benzoxazin-3-one Derivatives: Design, Synthesis, Molecular Modeling, Anti-HIV-1 and Integrase Inhibitory Assay

Introduction:

Integrase is a validated drug target for anti-HIV-1 therapy. The second generation integrase inhibitors display π-stacking interaction ability with 3’-end nucleotide as a streamlined metal chelating pharmacophore.

Method:

In this study, we introduced benzoxazin-3-one scaffold for integrase inhibitory potential as bioisostere replacement strategy of 2-benzoxazolinone.

Results:

Molecular modeling studies revealed that amide functionality alongside oxadiazole heteroatoms and sulfur in the second position of oxadiazole ring could mimic the metal chelating pharmacophore. The halobenzyl ring occupies hydrophobic site created by the cytidylate nucleotide (DC-16).

Conclusion:

The most potent and selective compound displayed 110 μM IC50 with a selectivity index of more than 2.

Design, synthesis, and herbicidal activity of novel 2-(arylamino)-5-methyl-4-methylene-7-(methylthio)-4H-pyrido[4,3-d][1,3]oxazine-8-carbonitrile derivatives

A series of 5-methyl-4-methylene-7-methylthio-2-arylmino-4 H-pyrido[4,3- d][1,3]oxazine-8-carbonitrile derivatives were synthesized via tandem aza-Wittig and annulation reactions with { N-[3-acetyl-5-cyano-2-methyl-6-(methylthio)pyridin-4-yl]imino}triphenylphosphorane and aryl isocyanate in dry dichloromethane. Their structures were clearly confirmed by infrared, 1H NMR, 13C NMR, high-resolution mass spectrometry, and X-ray single-crystal diffraction. All newly synthesized compounds were screened for herbicidal activities against monocotyledonous and dicotyledonous plants. The results indicated that the target compound 2-[(4-methoxyphenyl)amino]-5-methyl-4-methylene-7-(methylthio)-4 H-pyrido[4,3- d][1,3]oxazine-8-carbonitrile showed 100% inhibition rate to grain sorghum (monocotyledonous) at the concentration of 100 mg L−1.

Crystal structure of 6-ethoxypyridin-1-ium-2-olate

In the title compound, C7H9NO2, all non-H atoms are essentially coplanar [r.m.s. deviation = 0.032 Å]. The largest deviation from the plane of the pyridine ring is 0.105 (6) Å for the terminal C atom of the ethoxy group. In the crystal, molecules are linked by pairs of N—H...O hydrogen bonds, forming inversion dimers. These dimers are further linked by C—H...π interactions and weak π–π interactions between pyridine rings [centroid–centroid distance = 4.023 (1) Å].

Non-peptidic αvβ3 antagonists containing indol-1-yl propionic acids

We describe the synthesis and structure/activity relationship of RGD mimetics that are potent inhibitors of the integrin alpha(v)beta3. Indol-1-yl propionic acids containing a variety of basic moieties at the 5-position, as well as substitutions alpha and beta to the carboxy terminus were synthesized and evaluated. Novel compounds with improved potency have been identified.

A One-Pot Synthesis of Pyrido[2,3-b][1,4]oxazin-2-ones

Pyrido[2,3-b][1,4]oxazin-2-ones are conveniently prepared in excellent yields by a one-pot annulation of N-substituted-2-chloroacetamides with 2-halo-3-hydroxypyridines with use of cesium carbonate in refluxing acetonitrile. The key transformation features a Smiles rearrangement of the initial O-alkylation product and subsequent cyclization.

6-aminoalkyloxazolo[4,5-b]pyridin-2(3H)-ones: synthesis and evaluation of antinoceptive activity

Series of 6-aminoalkyloxazolo[4,5-b]pyridin-2(3H)-ones incorporating structural modifications both in the alkyl chain and basic amino moiety were tested for their analgesic efficacy and safety in mice and rats. Two of the synthesised compounds, 4a (3-methyl-6-[(4-phenyl-1-piperazinyl)methyl]oxazolo[4,5-b]pyridin-2(3H)-one) and 12a (3-methyl-6¿1-[2-(4-phenyl-1-piperazinyl)ethan-1-ol]¿oxazolo[4,5-b]pyridin- 2(3H)-one) were found to be more potent than aspirin with ED50 values of 26 (16.1-42.4) and 15.5 (11.4-21.2) mg/kg po (mouse, phenylquinone writhing test) respectively and 6 (3.1-9.8) and 5.5 (3.5-8.8) mg/kg po (rat, acetic acid writhing test). Compounds 4a and 12a proved to be potent nonopioid nonantiinflammatory analgesics but unfortunately have sedative properties at relatively low doses (respectively 64 and 16 mg/kg po, mice).