1.Synthesis and Antimicrobial Screening of Novel Thioglycosides and Acyclonucleoside Analogs Carrying 1,2,3-Triazole and 1,3,4-Oxadiazole Moieties.
Aouad MR1,2. Nucleosides Nucleotides Nucleic Acids. 2016 Jan 2;35(1):1-15. doi: 10.1080/15257770.2015.1109098. Epub 2016 Jan 25.
The solvent-free 1,3-dipolar cycloaddition reaction of dimethylacetylene dicarboxylate (1) with 2-chlorophenyl azide (2) afforded 1,2,3-triazole diester 3 that upon hydrazinolysis, furnished the corresponding bis-acid hydrazide 4. The treatment of compound 4 with carbon disulfide in a refluxing potassium hydroxide solution furnished the desired bis-1,3,4-oxadiazole-2-thione 5 tethered to a 1,2,3-triazole moiety. The respective SOx-glycosides 9-11 were obtained by glycosylation of bis-oxadiazole 5 with 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl bromide (6), 2,3,4,6-tetra-O-acetyl-α-d-galactopyranosyl bromide (7), and 2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-α-d-glucopyranosyl chloride (8) in dry acetone in the presence of Et3N, which acted as a base. However, alkylation of 5 with halogeno-alkanol 12 or 13, chloroglycerol 14, bromoethers 20 or 21, and epichlohydrin 22 in the presence of K2CO3 in DMF yielded the corresponding acyclonucleoside analogs 16-18 and 23-25.
2.Synthesis and antibacterial screening of S-substituted derivatives of 5-(3,4-methylenedioxyphenyl)-1,3,4-oxadiazol-2-thiol.
Siddiqa A1, Rehman AU1, Abbasi MA1, Siddiqui SZ1, Rasool S1, Sattar A1, Khan KM2, Ahmad I3, Afzal S3. Pak J Pharm Sci. 2016 Jan;29(1):27-34.
The most emerging class among the heterocyclic compounds is 1,3,4-oxadiazoles for their diverse biological activities. In the present research work, piperonylic acid (1) was converted consecutively into corresponding ester (2), hydrazide (3) and 1,3,4-oxadiazole (4) through intermolecular cyclization. The synthesized compound 4 was subjected further to S-alkylation/aralkylation, using alkyl/aralkyl halides (5a-m) and S-substituted-1,3,4-oxadiazole derivatives were synthesized (6a-m). The structure elucidation of the synthesized molecules was processed through (1)H-NMR, IR and mass spectral data. The antibacterial activity showed these molecules moderately good inhibitors of gram-negative and gram-positive bacteria.
3.Crystal structure of 2-(2,3-di-methyl-anilino)-N'-[(1E)-2-hy-droxy-benzyl-idene]benzohydrazide.
Mohamed SK1, Mague JT2, Akkurt M3, Mohamed AF4, Albayati MR5. Acta Crystallogr E Crystallogr Commun. 2015 Nov 21;71(Pt 12):o957-8. doi: 10.1107/S2056989015021532. eCollection 2015.
The asymmetric unit of the title compound, C22H21N3O2, consists of two independent mol-ecules (A and B) having differing conformations. The differences mainly concern the dihedral angles which the hy-droxy-phenyl and di-methyl-phenyl rings subtend to the central phenyl-ene ring, these being 30.16 (6) and 58.60 (6)° in mol-ecule A and 13.42 (7) and 60.31 (7)° in B. With the exception of the dimethyphenyl substituent, the conformations of the rest of each mol-ecule are largely determined by intra-molecular O-H⋯N and N-H⋯O hydrogen bonds. In the crystal, N-H⋯O hydrogen bonds link the mol-ecules into chains extending parallel to the a axis in which the types of mol-ecules alternate in an …A…B…A…B… fashion.
4.New Inducible Nitric Oxide Synthase and Cyclooxygenase-2 Inhibitors, Nalidixic Acid Linked to Isatin Schiff Bases via Certain l-Amino Acid Bridges.
Naglah AM1,2, Ahmed AF3,4, Wen ZH5, Al-Omar MA6, Amr Ael-G7,8, Kalmouch A9. Molecules. 2016 Apr 15;21(4). pii: E498. doi: 10.3390/molecules21040498.
A series of new Schiff bases were synthesized by condensation of isatins with the nalidixic acid-l-amino acid hydrazides. Prior to hydrazide formation, a peptide linkage has been prepared via coupling of nalidixic acid with appropriate l-amino acid methyl esters to yield 3a-c. The chemical structures of the new Schiff bases (5b and 5d-h) were confirmed by means of IR, NMR, mass spectroscopic, and elemental analyses. The anti-inflammatory activity of these Schiff bases was evaluated via measurement of the expressed inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in the lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells model. The Schiff bases exhibited significant dual inhibitory effect against the induction of the pro-inflammatory iNOS and COX-2 proteins with variable potencies. However, they strongly down-regulated the iNOS expression to the level of 16.5% ± 7.4%-42.2% ± 19.6% compared to the effect on COX-2 expression (<56.