2,2'-Dithiobisbenzamides derived from alpha-, beta- and gamma-amino acids possessing anti-HIV activities: synthesis and structure-activity relationship

Nucleocapsid protein (NCp7), which contains highly conserved retroviral zinc fingers, is essential in the early as well as the late phase of human immunodeficiency virus (HIV) life cycle and constitutes a novel target for AIDS therapy. HIV-1 NCp7 is a basic 55 amino acid protein containing two C(X)2C(X)4H(X)4C motif zinc fingers flanked by basic amino acids on each side. 2,2'-dithiobisbenzamides have previously been reported to release zinc from these NCp7 zinc fingers and also to inhibit HIV replication. Specifically, 2,2'-dithiobisbenzamides derived from simple amino acids showed good antiviral activities. The benzisothiazolone 3, the cyclic derivative of 2, was selected for clinical trials as an agent for AIDS therapy. Herein we report the syntheses and antiviral activities, including therapeutic indices, of 2,2'-dithiobisbenzamides derived from alpha-, beta- and gamma-amino acids. Electrospray ionization mass spectrometry was used to study the zinc-ejection activity of these compounds. Among the alpha-amino acid derived 2,2'-dithiobisbenzamides, analogues containing alkyl side chains were found to be antivirally active with good therapeutic indices. 2,2'-Dithiobisbenzamides, derived from beta- and gamma-amino acids, were found to possess better antiviral and therapeutic efficacies than the alpha-amino acid analogues. Thus compound 59 was found to possess an EC50 of 1.9 microM with a therapeutic index of > 50. Interestingly, 2,2'-dithiobisbenzamides derived from alpha-amino acids containing a protected acid function and polar side chains also exhibited very good antiviral activity.     

Inhibition of sandfly fever Sicilian virus (Phlebovirus) replication in vitro by antiviral compounds

Sandfly fever Sicilian virus (SFSV) was used in our laboratory to screen antiviral substances active toward viruses of the Bunyaviridae family. Antiviral activity was estimated by the reduction of the cytopathic effect of SFSV on infected Vero cells. Cytotoxicity was evaluated by determining the inhibition of Trypan blue exclusion. The specificity of action of each tested compound was estimated by the selectivity index (CD50/ED50). Selectivity indices of human recombinant interferon-alpha (IFN alpha) (Roferon and Introna), iota-, kappa- and lambda- carrageenans, fucoidan and 6-azauridine were much higher than that of ribavirin, the only antiviral substance which has been previously investigated for its inhibitory effects on Phlebovirus infections. Other compounds showed significant antiviral activity: glycyrrhizin, suramin sodium, dextran sulphate and pentosan polysulphate. All these compounds caused a concentration-dependent reduction in the virus yield. Ribavirin, 6-azauridine and IFN alpha have been shown to inhibit a late step of the virus replicative cycle, whereas glycyrrhizin and suramin sodium were active at an early step and the sulphated polysaccharides inhibited adsorption of SFSV on the cells. The antiviral compounds selected in this study as specific inhibitors of in vitro replication of SFSV are promising candidates for the chemotherapy of haemorrhagic fevers caused by viruses of the Bunyaviridae family. The combination of IFN alpha and ribavirin, which showed a synergistic antiviral effect, should be evaluated for the treatment of these infections.     

Association of human herpes virus 6 (HHV-6) with multiple sclerosis: increased IgM response to HHV-6 early antigen and detection of serum HHV-6 DNA

Viruses have long been suggested to be involved in the etiology of multiple sclerosis (MS). This suggestion is based on (1) epidemiological evidence of childhood exposure to infectious agents and increase in disease exacerbations with viral infection; (2) geographic association of disease susceptibility with evidence of MS clustering; (3) evidence that migration to and from high-risk areas influences the likelihood of developing MS; (4) abnormal immune responses to a variety of viruses; and (5) analogy with animal models and other human diseases in which viruses can cause diseases with long incubation periods, a relapsing-remitting course, and demyelination. Many of these studies involve the demonstration of increased antibody titers to a particular virus, whereas some describe isolation of virus from MS material. However, no virus to date has been definitively associated with this disease. Recently, human herpesvirus 6 (HHV-6), a newly described beta-herpes virus that shares homology with cytomegalovirus (CMV), has been reported to be present in active MS plaques. In order to extend these observations, we have demonstrated increased IgM serum antibody responses to HHV-6 early antigen (p41/38) in patients with relapsing-remitting MS (RRMS), compared with patients with chronic progressive MS (CPMS), patients with other neurologic disease (OND), patients with other autoimmune disease (OID), and normal controls. Given the ubiquitous nature of this virus and the challenging precedent of correlating antiviral antibodies with disease association, these antibody studies have been supported by the detection of HHV-6 DNA from samples of MS serum as a marker of active viral infection.     

Structure-activity relationships of 2'-deoxy-2',2'-difluoro-L-erythro-pentofuranosyl nucleosides

Following the recent discoveries that some L-nucleosides are more or equal potent than their D-counterparts, we synthesized 2'-deoxy-2',2'-difluoro-L-erythro-pentofuranosyl nucleosides as potential antiviral agents. The target compounds were synthesized via the key intermediates 7a or 7b from L-gulono gamma-lactone. Compound 2 was oxidatively cleaved and coupled with ethyl bromodifluoroacetate in the presence of activated zinc under Reformatsky conditions to obtain a diasteomeric mixture of 4(R) and 4(S), in a 4:1 ratio. The major 4(R) isomer was cyclized and treated appropriately to obtain the mesylate 8a or 8b, which was condensed with various silyl-protected pyrimidines. Condensation of the alcohol 7a or 7b with 6-chloropurine under Mitsunobu conditions afforded the 6-chlorpurine analogs 53a or 53b and 54a or 54b. Further treatment of the compounds 53a, 54a and 53b, 54b afforded the inosine and adenine derivatives 57-60, respectively. The condensation of 2-amino-6-chloropurine with compound 8a and subsequent treatment with 2-mercaptoethanol/sodium methoxide afforded the guanine analogs 63 and 64. All of the synthesized nucleosides 31-52, 57-60, 63, and 64 were evaluated for antiviral activity and for cellular toxicity. Adenine derivative 57 showed a moderate activity against HIV-1 in PBM cells (3.4 microM). None of the other compounds showed any significant activities against HIV-1, HBV, HSV-1, HSV-2, and toxicity in Vero, CEM, and PBM cell lines up to 100 microM. The X-ray structure of the 5-iodocytosine analog showed a 2'-exo/3'-endo conformation for the carbohydrate moiety, which is different from those of the biologically active compounds (-)-FTC and L-FMAU.     

Extended duration of action of rocuronium in postpartum patients

Nine perylenequinones (PQ), including some familiar naturally occurring pigments, were compared for their light-mediated antiviral efficacies. Calphostin C was the most active compound against the two target viruses, herpes simplex virus type 1 and Sindbis virus. Hypocrellins A and B were also very active. However, three cercosporin-like PQ were substantially less active in spite of their high quantum yields of singlet oxygen, whereas phleichrome, another efficient singlet oxygen producer, showed no detectable antiviral activity. One other PQ, which was a very weak singlet oxygen producer, also showed no antiviral activity. None of the active compounds showed significant antiviral activity in the dark. Thus, for some groups of PQ there was correlation between quantum yield of singlet oxygen (1O2) and antiviral efficacy, but there are evidently other structural features of PQ that influence activity.     

Inactivation of O6-alkylguanine-DNA alkyltransferase. 1. Novel O6-(hetarylmethyl)guanines having basic rings in the side chain

A number of novel guanine derivatives containing heterocyclic moieties at the O6-position have been synthesized using a purine quaternary salt which reacts with alkoxides under mild conditions. Initially O6-substituents were investigated in which the benzene ring of the known agent, O6-benzylguanine, was replaced by unsubstituted heterocyclic rings. The ability of these agents to inactivate the DNA repair protein O6-alkylguanine-DNA alkyltransferase (ATase), both as pure recombinant protein and in the human lymphoblastoid cell line Raji, has been compared with that of O6-benzylguanine. The present paper focuses on O6-substituents with basic rings, and under standard conditions several of them proved more effective than benzyl for inactivation of both recombinant and Raji ATase. Among the pyridine derivatives, the 2-picolyl compound 7 is not very active in contrast to the 3- and 4-picolyl compounds, and this influenced our choice of isomers of other basic ring systems for study. Since halogen substitution in the thiophene ring considerably increased the activity (17 versus 6), similar modifications in the pyridine series were examined. The more polar O6-substituents in this study are on the whole compatible with the stereochemical requirements of the ATase protein, and their pharmacological properties may be valuable in subsequent in vivo investigations, particularly the thenyl (6), 5-thiazolylmethyl (12), 5-bromothenyl (17), and 2-chloro-4-picolyl (21) derivatives.     

Inactivation of S-adenosyl-L-homocysteine hydrolase and antiviral activity with 5',5',6',6'-tetradehydro-6'-deoxy-6'-halohomoadenosine analogues (4'-haloacetylene analogues derived from adenosine)

Treatment of a protected 9-(5, 6-dideoxy-beta-D-ribo-hex-5-ynofuranosyl)adenine derivative with silver nitrate and N-iodosuccinimide (NIS) and deprotection gave the 6'-iodo acetylenic nucleoside analogue 3c. Halogenation of 3-O-benzoyl-5,6-dideoxy-1, 2-O-isopropylidene-alpha-D-ribo-hex-5-enofuranose gave 6-halo acetylenic sugars that were converted to anomeric 1,2-di-O-acetyl derivatives and coupled with 6-N-benzoyladenine. These intermediates were deprotected to give the 6'-chloro 3a, 6'-bromo 3b, and 6'-iodo 3c acetylenic nucleoside analogues. Iodo compound 3c appears to inactivate S-adenosyl-L-homocysteine hydrolase by a type I ("cofactor depletion") mechanism since complete reduction of enzyme-bound NAD+ to NADH was observed and no release of adenine or iodide ion was detected. In contrast, incubation of the enzyme with the chloro 3a or bromo 3b analogues resulted in release of Cl- or Br- and Ade, as well as partial reduction of E-NAD+ to E-NADH. Compounds 3a, 3b, and 3c were inhibitory to replication of vaccinia virus, vesicular stomatitis virus, parainfluenza-3 virus, and reovirus-1 (3a < 3b < 3c, in order of increasing activity). The antiviral effects appear to correlate with type I mechanism-based inhibition of S-adenosyl-L-homocysteine hydrolase. Mechanistic considerations are discussed.     

Lipophilic, acid-stable, adenosine deaminase-activated anti-HIV prodrugs for central nervous system delivery. 3. 6-Amino prodrugs of 2'-beta-fluoro-2',3'-dideoxyinosine

A series of 6-substituted amino analogs of 9-(2,3-dideoxy-2-fluoro-beta-D-threo-pentofuranosyl) purines (F-ddN) has been synthesized and characterized with the objective of finding compounds which might be superior to existing drugs for the treatment of HIV in the central nervous system. These compounds are intended to be more lipophilic than the currently approved anti-HIV drugs for better blood-brain barrier penetration. Subsequent adenosine deaminase (ADA)-catalyzed hydrolysis of these prodrugs in the brain is expected to produce the anti-HIV agent, 9-(2,3-dideoxy-2-fluoro-beta-D-threo-pentofuranosyl)hypoxanthine (F-ddI). The new compounds, synthesized from the corresponding 6-chloro analog, include F-ddN which contain methylamino, ethylamino, dimethylamino, hydroxylamino, methoxyamino, benzyloxyamino, hydrazino, and nitro substituents in the 6-position. The 6-nitro analog was isolated as an unexpected product during the preparation of the 6-chloro derivative. Among the analogs with anti-HIV activity, the ethylamino and dimethylamino compounds are ca. 100 times more lipophilic than ddI or F-ddI. As expected, 2'-fluoro substitution protects the compounds from acid-catalyzed glycosylic cleavage. Only the hydroxylamino and nitro analogs underwent any nonenzymatic hydrolysis at pH 1.0 or 7.4. This reaction, however, results in hydrolysis of the group in the 6-position rather than glycosylic bond cleavage. ADA catalyzes the hydrolysis of the 6-substituents at rates which vary from slightly slower (NO2, 1.7x) to much slower (NHEt, 5000x) than F-ddA. The 6-dimethylamino analog is the only compound which possesses anti-HIV activity (ED50 18 microM) without ADA hydrolysis. With the exception of the two inactive alkoxyamino compounds, the other prodrugs exhibited cellular protection in the HIV-1/PHA-PBM system with IC50 potencies of 7-40 microM.     

Synthesis and pharmacological characterization of novel 6-fluorochroman derivatives as potential 5-HT1A receptor antagonists

A series of novel 6-fluorochroman derivatives was prepared and evaluated as antagonists for the 5-HT1A receptor. N-2-[[(6-Fluorochroman-8-yl)oxy]ethyl]-4-(4-methoxyphenyl)butylami ne (3; J. Med. Chem. 1997, 40, 1252-1257) was chosen as a lead, and structural modifications were done on the aliphatic portion of the chroman ring, the tether linking the middle amine and the terminal aromatic ring, the aromatic ring, and lastly the amine. Radioligand binding assays proved that the majority of the novel compounds behaved as good to excellent ligands at the 5-HT1A receptor, some of which were selective with respect to alpha1-adrenergic and D2-dopaminergic receptors. The antagonist activity of the compounds was assessed in the forskolin-stimulated adenylate cyclase assays in CHO cells expressing the human 5-HT1A receptors. Among the modifications attempted, introduction of an oxo or an optically active hydroxy moiety at the chroman C-4 position was effective in ameliorating the receptor selectivity. Six analogues were selected through the in vitro screens and further evaluated for their in vivo activities. A 4-oxochroman derivative (31n), having a terminal 1, 3-benzodioxole ring, demonstrated antagonist activities toward 8-OH-DPAT-induced behavioral and electrophysiological responses in rats.     

Antiviral activity of biological response modifiers in a murine model of AIDS. Requirement for augmentation of natural killer cell activity and synergy with oral AZT

We employed the Rauscher murine leukemia virus (RMuLV) as a murine retrovirus model of AIDS, to test biological response modifiers (BRM) and antiviral agents for potential therapeutic activity against the human immunodeficiency virus (HIV). We examined the relationship between the augmentation of natural killer (NK) cell activity and antiviral efficacy of a series of BRM, most of which are known inducers of interferon, in this model. Poly [I,C]-LC, MVE-2, and CL 246,738, but not Ampligen, soluble glucan, or 7-thia-8-oxoguanosine, consistently produced antiviral activity. In addition, the combination of suboptimal doses of oral 3'-azido-3'-deoxythymidine (AZT) (in drinking water) and poly [I,C]-LC produced a synergistic antiviral effect. With all the BRM tested, a consistent pattern emerged, namely that antiviral activity always correlated with the augmentation of splenic NK cell activity in infected animals. For instance, poly [I,C]-LC boosted NK activity much more in infected mice treated therapeutically (treatment initiated after infection) than prophylactically (treatment initiated before infection), and it had greater antiviral activity therapeutically than prophylactically. For the BRM tested, antiviral activity did not occur without augmentation of NK activity in infected mice. In contrast, augmentation of NK activity in uninfected mice bore no relationship to antiviral activity. Furthermore, elimination of NK cells by treating mice with anti-asialo GM1 abolished the antiviral activity of poly [I,C]-LC. Although splenic NK activity was ablated by anti-asialo GM1, serum interferon levels were not affected by this treatment. These results point to a causal connection between the augmentation of NK cell activity and the antiviral efficacy of these BRM in this murine AIDS model. NK cells thus appear to play a key role in resistance to this retrovirus, as has been suggested for HIV.     

Effect of satisfaction with one''s abilities on positive and negative affect among individuals with recently diagnosed rheumatoid arthritis

An improved procedure for the synthesis of 3 beta-hydroxyandrost-5-ene-7,17-dione, a natural metabolite of dehydroepiandrosterone (DHEA) is described. The synthesis and magnetic resonance spectra of several other related steroids are presented. Feeding dehydroepiandrosterone to rats induces enhanced formation of several liver enzymes among which are mitochondrial sn-glycerol 3-phosphate dehydrogenase (GPDH) and cytosolic malic enzyme. The induction of these two enzymes, that complete a thermogenic system in rat liver, was used as an assay to search for derivatives of DHEA that might be more active than the parent steroid. Activity is retained in steroids that are reduced to the corresponding 17 beta-hydroxy derivative, or hydroxylated at 7 alpha or 7 beta, and is considerably enhanced when the 17-hydroxy or 17-carbonyl steroid is converted to the 7-oxo derivative. Several derivatives of DHEA did not induce the thermogenic enzymes whereas the corresponding 7-oxo compounds did. Both short and long chain acyl esters of DHEA and of 7-oxo-DHEA are active inducers of the liver enzymes when fed to rats. 7-Oxo-DHEA-3-sulfate is as active as 7-oxo-DHEA or its 3-acetyl ester, whereas DHEA-3-sulfate is much less active than DHEA. Among many steroids tested, those possessing a carbonyl group at position 3, a methyl group at 7, a hydroxyl group at positions 1, 2, 4, 11, or 19, or a saturated B ring, with or without a 4-5 double bond, were inactive.     

Synthesis of 2'-aminomethyl derivatives of N-(2-(phosphonomethoxy)ethyl) nucleotide analogues as potential antiviral agents

A series of purine and pyrimidine N-(2-(phosphonomethoxy)ethyl) derivatives bearing aminomethyl, (dimethylamino)methyl, morpholinomethyl, and (trimethylammonio)methyl groups at the 2'-position were synthesized. The compounds were prepared by alkylation of the heterocyclic bases with appropriately substituted (aminoalkyl)oxiranes followed by condensation of the resulting intermediates with dialkyl ((p-tolylsulfonyl)oxy)methanephosphonate and subsequent treatment of the obtained diester with bromotrimethylsilane. 9-(3-Amino-2-(phosphonomethoxy)propyl)adenine (2a) proved active against varicella zoster virus (VZV), cytomegalovirus (CMV), and Moloney murine sarcoma virus (MSV) in the concentration range of 7-35 micrograms/mL. None of the other aminoalkyl derivatives demonstrated significant antiviral activity against herpes simplex virus type 1 and 2 (HSV-1 and HSV-2), VZV, (CMV), vaccinia virus (VV), MSV, and human immunodeficiency virus type 1 and 2 (HIV-1 and HIV-2).     

Absorption and metabolism of a selective insecticide, 2,2-dimethyl-2,3-dihydrobenzofuranyl-7 N-dimethoxyphosphinothioyl-N-methylcarbamate, in bean plants

The absorption and metabolism of 2,2-dimethyl-2,3-dihydrobenzofuranyl-7 N-dimethoxyphosphinothioyl-N-methylcarbamate (PSC), a selective, insecticidally active carbofuran derivative, was studied in red kidney bean plants. PSC was absorbed from hydroponic culture media and was translocated throughout the plants. PSC was metabolized to carbofuran, 3-hydroxycarbofuran, and 3-ketocarbofuran and these materials accounted for 25% of the recovered radioactivity. Each of these compounds are more toxic to mice than the parent compound. Additionally at least four other oxidized, hydroxylated and/or hydrolyzed metabolites were formed.     

Concurrence of Graves'' disease and dysplastic cerebral blood vessels of the moyamoya variety

A recent observation that (+)-7-deaza-5'-noraristeromycin (1), as an L-like analogue of aristeromycin, possessed meaningful anti-trypanosomal properties has prompted a search of other 7-deazapurines with similar or improved anti-trypanosomal responses. In that direction a series of pyrazolo[3,4-d]pyrimidines (that is, 8-aza-7-deaza-5'-noraristeromycin derivatives, 2-11) related to 1 have been prepared. These derivatives were evaluated against bloodstream forms of Trypanosoma brucei brucei and Trypanosoma brucei rhodesiense grown in vitro. Of these compounds, the parent L-like derivative 2 was less potent (IC50 40-70 microM) than 1 (IC50 0.165-5.3 microM) whereas the D-like analogue 3 was inactive, which is the same trend observed previously with 7-deaza-5'-noraristeromycin. Interestingly, some moderate activity (IC50 12.2-16.8 microM) was seen in the D-like 4'-methyl derivative 7 while its L-like partner was inactive.     

Chemistry and anti-herpes simplex virus type 1 evaluation of cycloSal-nucleotides of acyclic nucleoside analogues

The synthesis of different cycloSal-phosphotriesters of the acyclic nucleoside analogues acyclovir (ACV), penciclovir (PCV) and T-penciclovir (T-PCV) as potential new lipophilic, membrane-soluble pronucleotides is described. The introduction of the cycloSal moiety was achieved by using reactive cyclic chlorophosphane reagents. In addition to the cycloSal-PCV monophosphate (MP) phosphotriesters, a second derivative bearing an acetyl group at the second primary alcohol function was prepared. In hydrolysis studies the cycloSal-ACVMPs showed the expected range of hydrolytic stability dependent on the substituent in the masking group (8-17 h). In contrast, the cycloSal-PCVMP derivatives exhibited a 11- to 15-fold increase in hydrolytic lability as compared to the corresponding cycloSal-ACVMP derivatives. We demonstrated that the free primary alcohol group is responsible for this rate acceleration because cycloSal-OAc-PCVMP, in which the hydroxyl group was blocked by acetylation, did not show the aforementioned acceleration. Unexpectedly, the hydrolysis product was not PCVMP but according to NMR and mass spectrometry it was cycloPCVMP (cPCVMP). The title compounds were evaluated in vitro for their ability to inhibit herpes simplex virus type 1 (HSV-1) and thymidine kinase-negative (TK-) HSV-1 replication in Vero cells. The cycloSal-ACVMP compounds exhibited high antiviral activity in HSV-1-infected cells. More importantly, one derivative retained all activity from the wild-type virus strain in HSV-1/TK(-)-infected Vero cells. The PCV derivatives were markedly less active. The reason for the failure of the cycloSal-PCVMPs seems to be due to the formation of cPCVMP instead of the desired PCVMP.     

The effect of incubation periods under 95% oxygen on the stimulated acrosome reaction and motility of human spermatozoa

Roxithromycin has been shown to be a relatively weak inhibitor of cytochrome P450 (P450 or CYP)-dependent drug oxidations, compared with troleandomycin. The potential for roxithromycin and its major metabolites found in human urine [namely the decladinosyl derivative (M1), O-dealkyl derivative (M2), and N-demethyl derivative (M3)] to inhibit testosterone 6beta-hydroxylation after metabolic activation by CYP3A4 was examined and compared with inhibition by troleandomycin and erythromycin in vitro. Of roxithromycin and its studied metabolites, M3 was the most potent in inhibiting CYP3A4-dependent testosterone 6beta-hydroxylation by human liver microsomes and was activated to the inhibitory P450.Fe2+-metabolite complex to the greatest extent. Roxithromycin and its metabolites were N-demethylated by human liver microsomes, although the rates were slower than those measured with troleandomycin and erythromycin as substrates. Recombinant human CYP3A4 in a baculovirus system coexpressing NADPH-P450 reductase was very active in catalyzing the N-demethylation of roxithromycin, M1, and M2, as well as troleandomycin, erythromycin, and M3. The order for inhibition of CYP3A4-dependent testosterone 6beta-hydroxylation activities by these macrolide antibiotics in the recombinant CYP3A4 system was estimated to be troleandomycin > erythromycin >/= M3 >/= M2 > M1 >/= roxithromycin. Erythromycin, roxithromycin, and its metabolites all failed to inhibit CYP1A2-dependent (R)-warfarin 7-hydroxylation and CYP2C9-dependent (S)-warfarin 7-hydroxylation but did inhibit CYP3A4-dependent (R)-warfarin 7-hydroxylation. These results suggest that roxithromycin itself is not as potent an inhibitor of CYP3A4 activities as are troleandomycin and erythromycin, probably because of the slower metabolism of this compound to metabolites M1, M2, and M3 in humans.     

Structural analyses of polymorphic transitions of sn-1, 3-distearoyl-2-oleoylglycerol (SOS) and sn-1, 3-dioleoyl-2-stearoylglycerol (OSO): assessment on steric hindrance of unsaturated and saturated acyl chain interactions

Several compounds that specifically inhibited replication of the H1 and H2 subtypes of influenza virus type A were identified by screening a chemical library for antiviral activity. In single-cycle infections, the compounds inhibited virus-specific protein synthesis when added before or immediately after infection but were ineffective when added 30 min later, suggesting that an uncoating step was blocked. Sequencing of hemagglutinin (HA) genes of several independent mutant viruses resistant to the compounds revealed single amino acid changes that clustered in the stem region of the HA trimer in and near the HA2 fusion peptide. One of the compounds, an N-substituted piperidine, could be docked in a pocket in this region by computer-assisted molecular modeling. This compound blocked the fusogenic activity of HA, as evidenced by its inhibition of low-pH-induced cell-cell fusion in infected cell monolayers. An analog which was more effective than the parent compound in inhibiting virus replication was synthesized. It was also more effective in blocking other manifestations of the low-pH-induced conformational change in HA, including virus inactivation, virus-induced hemolysis of erythrocytes, and susceptibility of the HA to proteolytic degradation. Both compounds inhibited viral protein synthesis and replication more effectively in cells infected with a virus mutated in its M2 protein than with wild-type virus. The possible functional relationship between M2 and HA suggested by these results is discussed.     

A tale of novel intoxication: seven cases of gamma-hydroxybutyric acid overdose

The chemical behaviours of 4-methyl-2-oxo-2H-benzopyran-7-yl oxoacetyl hydrazine (2) towards some different reagents such as anhydride compounds, aromatic aldehydes, carbon disulphide, and nitrous acid yielded the corresponding pathalazine derivatives (3, 4, 5), hydrazone derivative (6), 1,3,4-oxadiazole derivative (7, 8, 9) and acid azide (10) respectively. Treatment of 10 with absolute alcohols, amines and ethyl amino acid ester gave the corresponding carbamate derivative (11), substituted urea derivative (12) and ethyl substituted alkyl acetate (13) respectively. The biological activity of some synthesized compounds was evaluated.