Synthesis, pharmacological and antiviral activity of 1,3-thiazepine derivatives.

The preparation of new fourteen thiourea and fourteen product of their condensation with 1,4-dibromobutane, viz. 1,3-thiazepine derivatives, of 10-isopropyl-8-methyl-4-aza-tricyclo[5.2.2.0(2,6)]undec-8-ene-3,5-dione and 1-isopropyl-7-methyl-4-aza-tricyclo[5.2.2.0(2,6)]undec-8-ene-3,5-dione is described. Elemental analysis, MS and (1)H NMR spectra confirmed the identity of the products. The molecular structure of linear disubstituted thiourea derivative and its cyclization product was determined by an X-ray crystal structure analysis. Two of new obtained compounds (6b' and 7a') were tested for their pharmacological activity on animal central nervous system (CNS) in behavioral animal tests. With relatively low acute toxicity (LD(50) lower than 2000 mg kg(-1) i.p.) they exhibited significant influence on spontaneous locomotor activity and body temperature. Additionally, compounds reduced number of the "head twitch" episodes after 5-hydroksytryptophan (5-HTP) administration. New compounds were evaluated in vitro against representatives of different virus classes, such as a HIV-1 (Retrovirus), a HBV (Hepadnavirus) and the single-stranded RNA(+) viruses Yellow fever virus (YFV) and Bovine viral diarrhea virus (BVDV), both belonging to Flaviridae. Three of new obtained compounds showed a modest activity against HIV-1 wt(IIIB), BVDV and YFV.

Antiviral and cytotoxic activities of aminoarylazo compounds and aryltriazene derivatives.

Twelve aminoarylazocompounds (A-C) and 46 aryltriazene 7 derivatives (D-G) have been synthesized and evaluated in cell-based assays for cytotoxicity and antiviral activity against a panel of 10 RNA and DNA viruses. Eight aminoazocompounds and 27 aryltriazene derivatives exhibited antiviral activity, sometimes of high level, against one or more viruses. A marked activity against BVDV and YFV was prevailing among the former compounds, while the latter type of compounds affected mainly CVB-2 and RSV. None of the active compounds inhibited the multiplication of HIV-1, VSV and VV. Arranged in order of decreasing potency and selectivity versus the host cell lines, the best compounds are the following; BVDV: 1>7>8>4; YFV: 7>5; CVB-2: 25>56>18; RSV: 14>20>55>38>18>19; HSV-1: 2. For these compounds the EC(50) ranged from 1.6 microM (1) to 12 microM (18), and the S. I. from 19.4 (1) to 4.2 (2). Thus the aminoarylazo and aryltriazene substructures appear as interesting molecular component for developing antiviral agents against ss RNA viruses, particularly against RSV and BVDV, which are important human and veterinary pathogens. Finally, molecular modeling investigations indicated that compounds of structure A-C, active against BVDV, could work targeting the viral RNA-dependent RNA-polymerase (RdRp), having been observed a good agreement between the trends of the estimated IC(50) and the experimental EC(50) values.

Aryl nucleoside H-phosphonates. Part 16: synthesis and anti-HIV-1 activity of di-aryl nucleoside phosphotriesters.

Di-aryl nucleoside phosphotriesters have been explored as a new type of pronucleotides for the purpose of anti-HIV-1 therapy and efficient synthetic protocols, based on H-phosphonate chemistry, have been developed for the preparation of this class of compounds. It was found that anti-HIV-1 activity of the phosphotriesters bearing an antiviral nucleoside moiety (AZT, ddA) and also ddU was due, at least partially, to intracellular conversion into the corresponding nucleoside 5'-monophosphates, and their efficiency correlated well with the pK(a) values of the aryloxy groups present.

Novel modifications in the series of O-(2-phthalimidoethyl)-N-substituted thiocarbamates and their ring-opened congeners as non-nucleoside HIV-1 reverse transcriptase inhibitors.

The structure-activity relationships (SARs) of N-aryl-O-(2-phthalimidoethyl)thiocarbamates (C-TCs) and their imide ring-opened congeners (O-TCs) as non-nucleoside HIV-1 reverse transcriptase inhibitors were further investigated. The SAR strategy involved modifications of the N-phenyl ring followed by the hybridization of the most promising N-aryl and O-(2-phthalimidoethyl) substructures. The role of stereochemistry and tert-butyl substitution of the phthalimidoethyl moiety on activity was also investigated. Seventy-six analogues were prepared by parallel solution-phase synthesis. Twenty-two C-TCs displayed nanomolar activity against wild-type HIV-1 and a number of analogues were effective against the Y181C mutant. Compound 56 combined the highest activity so far identified against Y181C (EC(50)=1.3 microM) with good potency against the K103R mutant (EC(50)=4.8 microM). Docking simulations helped to rationalize the SARs.

Parallel synthesis, molecular modelling and further structure-activity relationship studies of new acylthiocarbamates as potent non-nucleoside HIV-1 reverse transcriptase inhibitors.

The structure-activity relationships (SARs) of acylthiocarbamates (ATCs), a new class of non-nucleoside HIV-1 reverse transcriptase inhibitors, have been expanded. Sixty-six new analogues were prepared by parallel solution-phase synthesis. In general, the potency of new ATCs was better than that of the first series and O-[2-phthalimidoethyl] 4-chlorophenyl(3-nitrobenzoyl) thiocarbamate turned out to be the most potent ATC so far synthesized (EC(50)=1.5nM). Several ATCs were active at micromolar concentrations against HIV-1 strains carrying the RT Y181C mutation and one of them was also moderately active against the K103R variant. Docking simulations were carried out to rationalize the most relevant SARs.

Design, synthesis and anti flaviviridae activity of N(6)-, 5',3'-O- and 5',2'-O-substituted adenine nucleoside analogs.

During a random screening of representative libraries of nucleoside analogues we discovered that the adenine derivatives FEVB28 and FEG118 were Flaviviridae inhibitors endowed with potency comparable, if not superior, to that of ribavirin. Those studies prompted us to design a new class of protected nucleoside analogs, reported herein, which displays interesting anti-bovine viral diarrhea virus (BVDV) activity and low cytotoxicity in cell-based assays (4, 23, 29 EC(50): 14, 11, 26 microM respectively, CC(50)>100 microM) and appreciable activity in enzyme assays against the RNA dependent RNA polymerase (RdRp) of BVDV (4, 23, 29, RdRp inhibition activity 27, 16, 15 microM respectively). A molecular modeling study was also carried out to highlight the possible interactions between this compounds class and the corresponding hepatitis C virus (HCV) enzyme.

Thiocarbamates as non-nucleoside HIV-1 reverse transcriptase inhibitors. Part 2: Parallel synthesis, molecular modelling and structure-activity relationship studies on analogues of O-(2-phenylethyl)-N-phenylthiocarbamate.

To acquire further insight into the structure-activity relationship (SAR) of the thiocarbamates (TCs) described in the preceding work, 57 analogues of the lead compound O-(2-phenylethyl)-N-phenylthiocarbamate I were prepared by parallel solution-phase synthesis. We varied the 2-phenylethyl moiety (mono-substitution on the phenyl ring and modification of the ethyl linker), keeping constant the N-phenyl ring substitutions which have given the best results in the previous series. Most of the new TCs inhibited wild-type HIV-1 at micro- and nanomolar concentrations in MT-4 cell-based assays. Some TCs were also active at micromolar concentrations against the Y181C and/or K103N/Y181C resistant mutants. The SARs were rationalized by docking simulations.

Synthesis and in vitro evaluation of the anti-viral activity of N-[4-(1H(2H)-benzotriazol-1(2)-yl)phenyl]alkylcarboxamides.

A series N-[4-(1H(2H)-benzotriazol-1(2)-yl)phenyl]alkylcarboxamides (8e-k, 9e-i, k, l) and their parent amines (5a-c and 6a-d) were prepared according to Schemes (1 and 2). Compounds were evaluated in vitro for cytotoxicity and antiviral activity against a wide spectrum of RNA (positive- and negative-sense) viruses, like [Bovine Viral Diarrhea Virus (BVDV), Yellow Fever Virus (YFV), Coxsackie Virus B (CVB-2), Polio Virus (Sb-1), Human Immunodeficiency Virus (HIV-1), Respiratory Syncytial Virus (RSV)] or double-stranded (dsRNA) virus, like Reoviridae (Reo-1). The Entero (CVB-2 and Sb-1) were the only viruses inhibited by title compounds. In particular, two of them emerged for their selective, although not very potent, antiviral activity: 8i, which was the most active against CVB-2 (CC50 >100 microM; EC50 = 10 microM) and 9l, which was the most active against Sb-1 (CC50 90 microM; EC50 = 30 microm). Title compounds were evaluated in silico against the Sb-1 helicase, as the crystal structure of this enzyme was not available, the corresponding 3D model was obtained by homology techniques (see Fig. 2).