Imidazo[5,1-f][1,2,4]triazin-2-amines as novel inhibitors of polo-like kinase 1.

The synthesis and biological activities of imidazo[5,1-f][1,2,4]triazin-2-amines (imidazotriazines) as novel polo-like kinase 1 inhibitors are reported.

Stereocontrolled synthesis of cis-dibenzoquinolizine chlorofumarates: curare-like agents of ultrashort duration.

The quaternizations of dibenzoquinolizines 9 and 14 with 3-halo-1-propanols are highly cis-selective (94-100% cis), results consistent with the N-methylation of O-methylcapaurine (7b), but in contrast to the proposed trans-stereochemistry of dibenzo[a,h]quinolizine methiodide 10 and the analogous quaternizations of 1-benzyl- and 1-phenylisoquinoline congeners 5b and 5c. In this report, we describe stereoselective preparation of the unique cis-dibenzoquinolizinium propanols 15 and 16and their transformation into bis- and mixed-onium chlorofumarates 19, 20ab, and 26. Dibenzo[a,g]quinolizinium propanol 15 was prepared enantioselectively in three steps from dihydroisoquinoline 11. Asymmetric transfer hydrogenation of 11 in the presence of triethylamine/formic acid and Noyori's chiral ruthenium catalyst 12 produced R-(-)-5',8-dimethoxynorlaudanosine (13) in 98% yield and 87% ee. Pictet-Spengler cyclization of 13 in formalin/formic acid afforded the dibenzo[a,g]quinolizine 14 in 65% yield. Quaternization of 14 with 3-chloro-1-propanol under Finkelstein conditions generated cis-dibenzoquinolizinium propanol 15 in 85% yield with >94% cis-selectivity. The cis-dibenzo[a,h]quinolizinium propanol 16 was obtained as a single stereoisomer by reaction of the known tetramethoxyquinolizine 9 with neat 3-iodo-1-propanol. Bis-onium chlorofumarates 18 and 19 and the mixed-onium derivative 20ab were prepared by a pool synthesis procedure from (1R)-trans-6a, 16, and chlorofumaryl chloride (17). Mixed-onium alpha-chlorofumarate 26 was synthesized from (1S)-trans-6d, 15 and (+/-)-trans-2,3-dichlorosuccinic anhydride (22), employing a recently disclosed chlorofumarate mixed-diester synthesis. The title compounds (19, 20ab, and 26) displayed curare-like effects of ultrashort duration in rhesus monkeys.

Synthesis and biological activity of a novel series of indole-derived PPARgamma agonists.

The synthesis and structure-activity relationships of a novel series of indole 5-carboxylic acids that bind and activate peroxisome proliferator-activated receptor gamma (PPARgamma) are reported. These new analogs are selective for PPARgamma vs the other PPAR subtypes, and the most potent compounds in this series are comparable to in vitro potencies at PPARgamma reported for the thiazolidinedione-based antidiabetic drugs currently in clinical use.

Synthesis of ultra-short-acting neuromuscular blocker GW 0430: a remarkably stereo- and regioselective synthesis of mixed tetrahydroisoquinolinium chlorofumarates.

[formula: see text] The stereo- and regioselective synthesis of ultra-short-acting nondepolarizing neuromuscular blocker GW 0430 (5a) is described. Key steps involved the enantioselective transfer hydrogenation of imine 8 employing Noyori's catalyst, the stereoselective crystallization and methanolysis of trans-bataines 11 and 12, and the stereo- and regioselective trans elimination of hydrogen chloride from 14. The latter transformation allowed complete control of the position of the chloro substituent and stereochemistry at the double bond of the linker in 15.

N-(2-Benzoylphenyl)-L-tyrosine PPARgamma agonists. 1. Discovery of a novel series of potent antihyperglycemic and antihyperlipidemic agents.

We have identified a novel series of antidiabetic N-(2-benzoylphenyl)-L-tyrosine derivatives which are potent, selective PPARgamma agonists. Through the use of in vitro PPARgamma binding and functional assays (2S)-3-(4-(benzyloxy)phenyl)-2-((1-methyl-3-oxo-3-phenylpropenyl)+ ++amin o)propionic acid (2) was identified as a structurally novel PPARgamma agonist. Structure-activity relationships identified the 2-aminobenzophenone moiety as a suitable isostere for the chemically labile enaminone moiety in compound 2, affording 2-((2-benzoylphenyl)amino)-3-(4-(benzyloxy)phenyl)propionic acid (9). Replacement of the benzyl group in 9 with substituents known to confer in vivo potency in the thiazolidinedione (TZD) class of antidiabetic agents provided a dramatic increase in the in vitro functional potency and affinity at PPARgamma, affording a series of potent and selective PPARgamma agonists exemplified by (2S)-((2-benzoylphenyl)amino)-3-¿4-[2-(methylpyridin-2-ylamino+ ++)ethoxy ]phenyl¿propionic acid (18), 3-¿4-[2-(benzoxazol-2-ylmethylamino)ethoxy]phenyl¿-(2S)-((2- benzoylph enyl)amino)propanoic acid (19), and (2S)-((2-benzoylphenyl)amino)-3-¿4-[2-(5-methyl-2-phenyloxazol-4-y l)e thoxy]phenyl¿propanoic acid (20). Compounds 18 and 20 show potent antihyperglycemic and antihyperlipidemic activity when given orally in two rodent models of type 2 diabetes. In addition, these analogues are readily prepared in chiral nonracemic fashion from L-tyrosine and do not show a propensity to undergo racemization in vitro. The increased potency of these PPARgamma agonists relative to troglitazone may translate into superior clinical efficacy for the treatment of type 2 diabetes.

A serum-resistant cytofectin for cellular delivery of antisense oligodeoxynucleotides and plasmid DNA.

Development of antisense technology has focused in part on creating improved methods for delivering oligodeoxynucleotides (ODNs) to cells. In this report, we describe a cationic lipid that, when formulated with the fusogenic lipid dioleoylphosphatidyliethanolamine, greatly improves the cellular uptake properties of antisense ODNs, as well as plasmid DNA. This lipid formulation, termed GS 2888 cytofectin, (i) efficiently transfects ODNs and plasmids into many cell types in the presence or absence of 10% serum in the medium, (ii) uses a 4- to 10-fold lower concentration of the agent as compared to the commercially available Lipofectin liposome, and (iii) is > or = 20-fold more effective at eliciting antisense effects in the presence of serum when compared to Lipofectin. Here we show antisense effects using GS 2888 cytofectin together with C-5 propynyl pyrimidine phosphorothioate ODNs in which we achieve inhibition of gene expression using low nanomolar concentrations of ODN. This agent expands the utility of antisense ODNs for their use in understanding gene function and offers the potential for its use in DNA delivery applications in vivo.

Mechanism of time-dependent inhibition of 5 alpha-reductases by delta 1-4-azasteroids: toward perfection of rates of time-dependent inhibition by using ligand-binding energies.

Finasteride (17 beta-N-tert-butylcarbamoyl-4-aza-5 alpha-androstan-1-en-3- one) is a time-dependent, apparently irreversible inhibitor of 5 alpha-reductases, but does not fully inhibit the activity of 5 alpha-reductase in vivo. This limited efficacy has been attributed to its slow rate of inhibition against the type-1 isozyme [Tian, G. (1995) J. Pharm. Sci. (in press)]. Here the feasibility of increasing the rate of inhibition of 5 alpha-reductases by providing binding energies with the inhibitor at a site remote from the center of chemical transformation was explored. Substitution of N-(2,5-bis(trifluoromethyl)phenyl) group, which had been shown to benefit 6-azasteroids in the binding to 5 alpha-reductases [Frye, S., Haffner, C. D., Maloney, P. R., Hiner, R. N., Unwalla, R. J., Batchelor, K. W., Bramson, H. N., Stuart, J. D., Schweiker, S. L., Van Arnold, J., Bickett, D. M., Moss, M. L., Tian, G., Lee, F. W., Tippin, T. K., James, M. K., Grizzle, M. K., Long, J. E., & Croom, D. K. (1995) J. Med. Chem. 38, 2621-2627], for the N-tert-butyl substituent at C-17 of finasteride did not perturb the mechanism of inhibition but significantly increased the rate of inhibition of type-1 5 alpha-reductase. The rate of inhibition was too fast to determine accurately when the normal substrate testosterone was used in the progress curve analysis as this inhibition rate is approaching the value of kcat/Km for the enzyme reaction.

6-Azasteroids: structure-activity relationships for inhibition of type 1 and 2 human 5 alpha-reductase and human adrenal 3 beta-hydroxy-delta 5-steroid dehydrogenase/3-keto-delta 5-steroid isomerase.

6-Azaandrost-4-en-3-ones were synthesized and tested versus human type 1 and 2 steroid 5 alpha-reductase (5AR) and human adrenal 3 beta-hydroxy-delta 5-steroid dehydrogenase/3-keto-delta 5-steroid isomerase (3BHSD) to explore the structure-activity relationship of this novel series in order to optimize potency versus both isozymes of 5AR and selectivity versus 3BHSD. Compounds with picomolar IC50's versus human type 2 5AR and low nanomolar Ki's versus human type 1 5AR with 100-fold selectivity versus 3BHSD were identified (70). Preliminary in vivo evaluation of some optimal compounds from this series in a chronic castrated rat model of 5AR inhibitor-induced prostate involution and dog pharmacokinetic measurements identified a series of 17 beta-[N-(diphenylmethyl)carbamoyl]-6-azaandrost-4-en-3-ones (compounds 54, 66, and 67) with good in vivo efficacy and half-life in the dog. Inhibitors with, at the minimum, low nanomolar potency toward both human 5AR's and selectivity versus 3BHSD may show advantages over previously known 5AR inhibitors in the treatment of disease states which depend upon dihydrotestosterone, such as benign prostatic hyperplasia.

17 beta-(N-tert-butylcarbamoyl)-4-aza-5 alpha-androstan-1-en-3-one is an active site-directed slow time-dependent inhibitor of human steroid 5 alpha-reductase 1.

17 beta-(N-tert-butylcarbamoyl)-4-aza-5 alpha-androstan-1-en-3-one (finasteride), which has been approved for treatment of benign prostatic hyperplasia, is shown here to be a slow time-dependent inhibitor of human steroid 5 alpha-reductase isozyme 1. This inhibition is characterized by an initial, fast step where the inhibitor binds to the enzyme followed by a slow step that leads to a final enzyme-inhibitor complex (EI*). No recovery of activity from this EI* complex was observed after dialysis for 3 days. The formation of EI* is diminished in the presence of a competitive, reversible inhibitor, indicating that the inhibition is active site-directed. At 37 degrees C and pH 7.0, the rate constant for the second, slow inhibition step, k3, is (1.40 +/- 0.04) x 10(-3) s-1 and the pseudo-bimolecular rate constant, k3/Ki, is (4.0 +/- 0.3) x 10(3) M-1 s-1. This latter rate constant is less than the value of 2.7 x 10(5) M-1 s-1 determined for the inhibition of 5 alpha-reductase 2 by finasteride [Faller, B., Farley, D., & Nick, H. (1993) Biochemistry 32, 5705-5710].(ABSTRACT TRUNCATED AT 250 WORDS)