Antihypertensive dihydropyridines with 1,4,4-trisubstitution.

Dihydropyridines with 1,4,4-trisubstitution were synthesized and tested for antihypertensive activity in a spontaneously hypertensive rat model. This substitution pattern on the dihydropyridine nucleus differs markedly from that found most active in the structure-activity relationship established for nifedipine-like compounds. However, some were found to significantly lower blood pressure at testing doses (30 mg/kg, ip and 100 mg/kg, po) for up to 24 h. Methyl 1,4-dihydro-4,4-dimethyl-1-pyridinepropanoate (2-1), for example, lowered blood pressure 71 mmHg at 30 mg/kg, ip and the effect endured for greater than 24 h. Unlike prototypical dihydropyridines such as nifedipine, these compounds did not seem to have any effect on calcium channels.

Synthesis, characterization, and anorectic testing of the four stereoisomers of cyclo(histidylproline).

All four possible stereoisomers of cyclo(histidylproline) were individually synthesized, purified, and characterized. They were each tested for anorectic activity in rats with a free feeding paradigm over 24 h. Contrary to literature reports, none significantly reduced food intake at any time over the test period.

A novel series of N-(1-aminoalkylidene)carboximidamides as potential hypoglycemic agents.

Nitrogen heterocyclic carboximidamides, such as linogliride, 1a, have been shown to possess significant hypoglycemic activity and have shown clinical efficacy as potential antidiabetic agents. We evaluated the biological significance of the heterocyclic ring A of general structure 1, which has always been maintained in this class of compounds, by preparing acyclic compounds of general structure 2. Preliminary in vivo biological testing, i.e., the glucose tolerance test in rats, indicates that a number of the specific acyclic carboximidamides prepared, 6a-kk, possessed significant hypoglycemic activity often comparable to, and in some cases better than, the activity noted for our model compound, 1a. These results suggest that the heterocyclic ring A of 1 is not essential for hypoglycemic activity for this class of compounds.

Synthesis and anti-HIV-1 activity of 4,5,6,7-tetrahydro-5-methylimidazo[4,5,1-jk][1,4]benzodiazepin- 2(1H)-one (TIBO) derivatives.

A series of 6-substituted 4,5,6,7-tetrahydro-5-methylimidazo[4,5,1-jk][1,4]benzodiazepin- 2(1H)-ones (9) have been synthesized and tested for their ability to inhibit the replication of the HIV-1 virus in MT-4 cells. Two synthetic methods are described, one of which allows the synthesis of single enantiomers of the final products. A structure-activity study was done within the series of compounds to determine the optimum group for the 6-position substitution and to determine whether the activity was enantiospecific at the 5-position, which was substituted with a methyl group. The best analogue, 9jj, inhibited HIV-1 with an IC50 of 4 microM, which is comparable to the activity level of DDI, a 2',3'-dideoxynucleoside-type structure undergoing clinical trials as an anti-AIDS therapy.

Synthesis and anti-HIV-1 activity of 4,5,6,7-tetrahydro-5-methylimidazo[4,5,1-jk][1,4]benzodiazepin-2(1H)-on e (TIBO) derivatives. 2.

In the first paper of this series a new structure with anti-HIV-1 activity was disclosed and analogues were synthesized to explore the structure-activity relationship of changes in the substituent (R) attached at the N-6 position of 9. This study describes the syntheses and anti-HIV-1 testing of analogues with variations of the five-membered urea ring of the 4,5,6,7-tetrahydro-5-methylimidazo[4,5,1-jk] [1,4]benzodiazepin-2(1H)-one (TIBO) structures. Although many different rings were synthesized to replace the cyclic urea of TIBO, most were found to be inactive in inhibiting the replication of the HIV-1 virus in MT-4 cells. The exceptions were replacement of the urea oxygen with sulfur or selenium to give the corresponding thio- or selenoureas. These were found to be more active than the oxygen counterparts. A small series of analogues was synthesized and tested which allowed direct comparison of urea and thiourea derivatives. Without exception, the latter were always more active than the former. The most active compound of this series (8d) was found to inhibit the HIV-1 virus with an IC50 of 0.012 microM which is comparable to that of AZT.

Synthesis and anti-HIV-1 activity of 4,5,6,7-tetrahydro-5-methylimidazo-[4,5,1-jk][1,4]benzodiazepin- 2(1H)-one (TlBO) derivatives. 4.

In previous papers, we have described the discovery of a new series of compounds, 4,5,6,7-tetrahydro-5-methylimidazo[4,5,1-jk][1,4]benzodiazepin-2(1 H)- ones, TlBO (1 and 1a), with potent anti-HIV-1 activity and the synthesis of analogues to better define the structure-activity relationships (SAR) in terms of changes in substituents at the N-6 position and variations of the five-membered urea ring as well as the seven-membered diazepine ring. This paper describes the synthesis of TlBO analogues with various substitutents on the aromatic ring and their SAR in terms of anti-HIV-1 properties. Substituents on the 8-position furnished the most rewarding results and gave a large improvement in potency versus the parent compound. These included halogen, thiomethyl, and methyl. Analogues like 8-cyano, -methoxy, and -acetylene were equipotent, while 8-amino, -acetylamino, -dimethylamino, and -nitro were inactive (Table 1). Substituents at the 9-position tended to have little effect on activity, and 10-substituents decreased activity. The 8-chloro compound 6a with IC50 = 0.0043 microM is currently under clinical development.

Synthesis and anti-HIV-1 activity of 4,5,6,7-tetrahydro-5-methylimidazo [4,5,1-jk][1,4]benzodiazepin-2(1H)-one (TIBO) derivatives. 3.

4,5,6,7-Tetrahydro-5-methylimidazo[4,5,1-jk][1,4]benzodiazepin-2 (1H)-ones (TIBO), 1, have been shown to significantly inhibit HIV-1 replication in vitro by interfering with the virus's reverse transcriptase enzyme. They have also demonstrated potential clinical efficacy in combating HIV-1, on the basis of a preliminary study. Our prior publications have discussed the discovery of this series of compounds and reported some preliminary chemical and biological studies around N-6 substitutions and 5-membered ring variations of 1. This manuscript describes our synthetic endeavors around 4, 5, and 7 mono- and disubstitutions of 1 and discusses related HIV-1 inhibitory structure-activity relationships. On the basis of inhibition of HIV-1's cytopathic effects in MT-4 cells, we found that 5-mono-Me-substituted analogues, the original substitution in the early lead compounds, and 7-mono-Me-substituted analogues of 1 were comparable as being consistently the most active compounds. Although generally less active, the 4,5,7-unsubstituted, 4-mono-substituted, cis- and trans-5,7-di-Me-substituted, and cis-4,5-di-Me-substituted analogues of 1 also exhibited some significant desired activity. The remaining trans-4,5-di-Me-substituted, cis- and trans-4,7-di-Me-substituted, and all 4,5-, 5,6-, 6,7-, and 7,8-fused disubstituted analogues of 1 possessed no noticeable desired activity.

Modulation of gastrointestinal function by MuDelta, a mixed µ opioid receptor agonist/ µ opioid receptor antagonist.

BACKGROUND & PURPOSE: Loperamide is a selective µ opioid receptor agonist acting locally in the gastrointestinal (GI) tract as an effective anti-diarrhoeal but can cause constipation. We tested whether modulating µ opioid receptor agonism with δ opioid receptor antagonism, by combining reference compounds or using a novel compound ('MuDelta'), could normalize GI motility without constipation. EXPERIMENTAL APPROACH: MuDelta was characterized in vitro as a potent µ opioid receptor agonist and high-affinity δ opioid receptor antagonist. Reference compounds, MuDelta and loperamide were assessed in the following ex vivo and in vivo experiments: guinea pig intestinal smooth muscle contractility, mouse intestinal epithelial ion transport and upper GI tract transit, entire GI transit or faecal output in novel environment stressed mice, or four weeks after intracolonic mustard oil (post-inflammatory). Colonic δ opioid receptor immunoreactivity was quantified. KEY RESULTS: δ Opioid receptor antagonism opposed µ opioid receptor agonist inhibition of intestinal contractility and motility. MuDelta reduced intestinal contractility and inhibited neurogenically-mediated secretion. Very low plasma levels of MuDelta were detected after oral administration. Stress up-regulated δ opioid receptor expression in colonic epithelial cells. In stressed mice, MuDelta normalized GI transit and faecal output to control levels over a wide dose range, whereas loperamide had a narrow dose range. MuDelta and loperamide reduced upper GI transit in the post-inflammatory model. CONCLUSIONS AND IMPLICATIONS: MuDelta normalizes, but does not prevent, perturbed GI transit over a wide dose-range in mice. These data support the subsequent assessment of MuDelta in a clinical phase II trial in patients with diarrhoea-predominant irritable bowel syndrome.

New tetrahydroimidazo[4,5,1-jk][1,4]-benzodiazepin-2(1H)-one and -thione derivatives are potent inhibitors of human immunodeficiency virus type 1 replication and are synergistic with 2',3'-dideoxynucleoside analogs.

Tetrahydro-imidazo[4,5,1-jk][1,4]-benzodiazepin-2(1H)-one and -thione (TIBO) derivatives were shown to specifically block human immunodeficiency virus type 1 (HIV-1) replication through a unique interaction with the HIV-1 reverse transcriptase (RT). Through further modification of the lead compounds and structure-activity relationship analysis several new TIBO derivatives that show high potency, selectivity, and specificity against HIV-1 have been obtained. A new TIBO derivative, R86183, inhibits the replication of HIV-1, but not HIV-2, in a variety of CD4+ T-cell lines and peripheral blood lymphocytes, at a concentration of 0.3 to 30 nM, which is at least 4 orders of magnitude lower than the 50% cytotoxic concentration. Whereas an HIV-1 strain containing the Leu-100-->Ile mutation in the RT gene is about 400-fold less susceptible, R86183 still inhibits the replication of an HIV-1 strain containing the Tyr-181-->Cys RT mutation by 50% at a concentration of 130 nM. R86183 inhibits the poly(C).oligo(dG)12-18-directed HIV-1 RT reaction by 50% at a concentration of 57 nM. The antiviral activity of 22 TIBO derivatives in cell culture correlated well with their activity against HIV-1 RT. No such correlation was found for their cytotoxicity. The combination of R86183 with either zidovudine or didanosine resulted in a synergistic inhibition of HIV-1 (strain IIIB) replication. Combination of R86183 with the protease inhibitor Ro31-8959 was found to be additive. Also described is a dilution protocol circumventing overestimation and underestimation of antiviral activity due to adherence to plastic surfaces.

Potent and selective inhibition of HIV-1 replication in vitro by a novel series of TIBO derivatives.

In the search for compounds active against human immunodeficiency virus (HIV), we have found that members of a novel series of tetrahydro-imidazo[4,5,1-jk][1,4]-benzodiazepine-2(1H)-one and -thione (TIBO) derivatives inhibit the replication of HIV-1, the main aetiological agent of AIDS, but not of HIV-2, or of any other DNA or RNA viruses. In five cell systems, HIV-1 is inhibited by TIBO derivatives in nanomolar amounts, which are 10(4)-10(5) times lower than the cytotoxic concentration. The unprecedented specificity of these compounds may be due to an interaction with a reverse transcriptase-associated process. By contrast, AZT (3'-azido-2',3'-dideoxythymidine), which is used for the treatment of AIDS, and DDC (2',3'-dideoxycytidine) and DDI (2',3'-dideoxyinosine), whose clinical application is being assessed, inhibit both HIV-1 and HIV-2 at concentrations that, depending on the cell systems, are 2 to 4 orders of magnitude below their cytotoxic concentration. TIBO-derivatives are new chemicals unrelated to any other antiviral agents. We believe that they are the most specific and potent inhibitors of HIV-1 replication studied so far.

Synthesis and anti-HIV activity of 1,3,4,5-tetrahydro-2H-1,4-benzodiazepin-2-one (TBO) derivatives. Truncated 4,5,6,7-tetrahydro-5-methylimidazo[4,5,1-jk][1,4]benzodiazepin-2( 1H)-on es (TIBO) analogues.

4,5,6,7-Tetrahydro-5-methylimidazo[4,5,1-jk][1,4]benzodiazepin-2(1 H)-ones (TIBO), 1, have been shown to significantly inhibit HIV-1 replication, as reported in detail in our prior publications. Since our earlier reports, we have modified the TIBO structures 1 by removing the 5-membered ring of 1, generating 1,3,4,5-tetrahydro-2H-1,4-benzodiazepin-2-ones (TBO), 4, a bicyclic series of compounds. Although compounds 4 possess modest activity when compared to TIBO analogues 1, they clearly demonstrated significant anti-HIV-1 activity.