Efficient and convenient synthesis of pyrido [2,1-b]benzothiazole, pyrimidopyrido[2,1-b]benzothiazole and benzothiazolo[3,2-a][1,8]naphthyridine derivatives

New 3-aryl-pyrido[2,1-b][1,3]benzothiazole derivatives 2a–e were synthesized in excellent yields via the reaction of benzothiazoleacetonitrile (1) with different aromatic aldehydes. The treatment of 2-(benzo[d]thiazol-2-yl)-3-(pyridin-4-yl)acrylonitrile (6) with malononitrile afforded 1-amino-3-(pyridin-4-yl)-3H-pyrido[2,1-b][1,3]benzothiazole-2,4-dicarbonitrile (7), which was allowed to react with a variety of reagents to provide pyrimido[5′,4′:5,6]pyrido[2,1-b][1,3]benzothiazole 8, 9 and [1,3]benzothiazolo[3,2-a][1,8]naphthyridine 10, 15 derivatives. All synthesized products were confirmed by elemental analysis, IR, 1H-NMR, 13C-NMR, and mass spectral data.

Straightforward entry to pyrido[2,3-d]pyrimidine-2,4(1H,3H)-diones and their ADME properties

A straightforward synthesis of pyrido[2,3-d]pyrimidine-2,4(1H,3H)-diones was developed starting from 2-chloropyridine-3-carboxylic acid by esterification, nucleophilic aromatic substitution and amide formation in one step, and ring closure allowing their synthesis with two identical or two different group attached to nitrogen. The structural diversity of these [2,3-d]pyrimidine-2,4(1H,3H)-diones resulted in significant variation in the biopharmaceutical properties. This was reflected by the broad range in fasted state simulated intestinal fluid solubility values (12.6 μM to 13.8 mM), Caco-2 permeability coefficients (1.2 × 10(-6)cm/s to 90.7 × 10(-6)cm/s) and in vitro-predicted human in vivo intrinsic clearance values (0 to 159 ml/min/kg).

Synthesis and antimicrobial activity of some new benzo and naphthonitrile derivatives

The reaction of 2-(cyanomethyl)benzonitrile (1) with different diazonium salts gave the corresponding aryldiazenyl derivatives 2a-e which reacted with sodium hydroxide and ethyl chloroacetate and hydroxylamine hydrochloride to afford the corresponding acetamides 4a-e, pyrazoloisoquinolines 6a-e and triazoloisoquinoline derivatives 8a-e, respectively. Moreover, the reaction of 1 with arylidene malononitriles 9a-c afforded dihydronaphthalenes 11a, b and naphthalene derivative 12, respectively. The newly synthesized compounds were characterized by analytical and spectral data. The investigated compounds were screened for their antibacterial activity against Gram-positive bacteria, Gram-negative bacteria and antifungal activity. Among the synthesized compounds, (E)-2-(cyano((4-nitrophenyl)diazenyl)methyl)benzonitrile (2e) exhibited a significant activity toward both Gram-positive, Gram-negative bacteria and exhibit the most potent in vitro antifungal with MIC's (6.25 μg/mL) against Botrytis fabae.

Synthesis and antioxidant and antitumor activity of novel pyridine, chromene, thiophene and thiazole derivatives

2-Tosylacetonitrile (1) when reacted with α,β-unsaturated nitriles 2a-c or a mixture of formaldehyde and 3-amino-2-substituted-pent-2-endinitriles 6a,b yielded pyridine derivatives 3a-c and 9a,b, respectively, while when subjected to react with salicylaldehyde yielded chromene derivatives 4 and 5, subsequently. The behavior of thiocarbamoyl derivative 10 derived from 1 towards some α-halogenated compounds have been investigated as well as its behavior towards elemental sulfur and phenyl isothiocyanate. Newly synthesized compounds were screened for their antioxidant activity, erythrocytes haemolysis and bleomycin-independent DNA damage. Some of the tested compounds exhibited promising activities.