Large-scale synthesis of GMP grade N'- [2-(2-thiophene) ethyl]-N'- [2- (5-bromopyridyl)] -thiourea (HI-443), a new anti-HIV drug candidate.

The thiourea compound N'-[2-(2-thiophene)ethyl]-N'-[2-(5-bromopyridyl)]-thiourea (HI-443, CAS 258340-15-7), was found to be a potent anti-HIV agent with remarkable activity against nucleoside analog reverse transcriptase (NRT)-resistant, non-nucleoside analog reverse transcriptase (NNRT)-resistant, as well as multidrug-resistant HIV. Now the method of producing HI-443 under current Good Manufacturing Practice (cGMP) conditions on the scale of kilograms is reported. The availability of GMP-grade HI-443 will promote the preclinical and clinical development efforts aimed at making this new drug candidate available to HIV-infected persons.

Large-scale synthesis of GMP grade alpha-cyano-beta-hydroxy-beta-methyl-N-(2,5-dibromophenyl) propenamide (LFM-A13), a new anti-cancer drug candidate.

The leflunomide (CAS 75706-12-6) metabolite (LFM) analog alpha-cyano-beta-hydroxy-beta-methyl-N-(2,5-dibromophenyl)-propenamide (LFM-A13, DDE-28, CAS 244240-24-2), is a rationally designed inhibitor of the anti-apoptotic enzyme Bruton's tyrosine kinase (BTK). LFM-A13 is being developed as a novel dual-function anticancer drug with apoptosis-promoting and anti-thrombotic properties. LFM-A13 was prepared under current Good Manufacturing Practice (cGMP) conditions on the scale of kilograms.

Anti-retroviral activity of GMP-grade stampidine against genotypically and phenotypically nucleoside reverse transcriptase inhibitor resistant recombinant human immunodeficiency virus. An in vitro study.

The in vitro potency of GMP-grade stampidine (CAS 217178-62-6) was examined against 3 clinical HIV-1 isolates and 6 recombinant HIV-1 clones with multi-NRTI 'resistance (NRTI: nucleoside reverse transcriptase inhibitors). GMP-grade stampidine active drug substance (Lot #'s MPR-M0008.00-01 and MPR-M0008.01-01) as well as GMP-grade stampidine extracted from the clinical stampidine capsules (GMP-Grade Clinical Batch, Pharmaceutical Service Lot Number 159I0601) were highly potent and exhibited nanomolar IC50 values against clinical HIV-1 isolates as well as recombinant HIV-1 clones with multi-NRTI resistance containing common patterns of reverse transcriptase mutations responsible for NRTI resistance.

Preclinical toxicity and pharmacokinetics of the Bruton's tyrosine kinase-targeting anti-leukemic drug candidate, alpha-cyano-beta-hydroxy-beta-methyl-N- (2,5-dibromophenyl) propenamide (LFM-A13).

The leflunomide (CAS 75706-12-6) metabolite (LFM) analog alpha-cyano-beta-hydroxy-beta-methyl-N-(2,5-dibromophenyl)-propenamide (LFM-A13, DDE-28, CAS 244240-24-2) is a rationally-designed specific inhibitor of the TEC family protein tyrosine kinase, Bruton's tyrosine kinase (BTK). LFM-A13 exhibited favorable pharmacokinetics in CD-1 mice, BALB/c mice, rats, and dogs. The intraperitoneal bioavailability was estimated to be -100%, while the oral bioavailability was -30%. LFM-A13 enters, but does not bind to multiple tissues followed by a rapid elimination from most of the tissues. Limited distribution of LFM-A13 to extravascular tissues and its corresponding low volume of distribution could be attributed to its plasma protein binding. LFM-A13 was not toxic to mice, rats, or dogs at daily dose levels as high as 100 mg/kg. LFM-A13 formulated as a suspension and hard gelatin capsules for oral administration showed a rapid absorption and favorable pharmacokinetic features. These preclinical research studies provide the basis for future pre-IND studies and clinicaldevelopment of LFM-A13 as an intravenously or orally administered new anti-leukemia agent targeting BTK.

Large-scale synthesis and formulation of GMP-grade stampidine, a new anti-HIV agent.

The arylphosphoramidate derivative of stavudine (STV, d4T, 2,3'-didehydro-3'-deoxythymidine, CAS 3056-17-5), stampidine (STAMP, DDE-113, HI-113, N-[p-(4-bromophenyl)-2',3'-didehydro-3'-deoxy-5'-thymidylyl]-L-alanine methyl ester, CAS 217178-62-6), is a novel anti-HIV agent. STAMP was prepared under current Good Manufacturing Practice (cGMP) conditions on the scale of kilograms. Solid STAMP was subsequently formulated as a capsule under GMP conditions for oral administration.

Targeting JAK3 and BTK tyrosine kinases with rationally-designed inhibitors.

Multifunctional rational drug design of protein tyrosine kinases inhibitors allows a potent drug to be utilized to treat more than one disease for greater patient benefits. Many protein tyrosine kinases (PTK), including Janus kinase 3 (JAK3) and Bruton's tyrosine kinase (BTK), have been identified as potential drug targets to treat diverse diseases including cancer and disorders of the immune system. Here we review advances in JAK3 and BTK inhibitors and describe the therapeutic potential of these potent agents in the clinical setting.

Fluoride Reactions with Hydrotris(pyrazolyl)borate Rhenium Oxo Complexes: Re-F vs B-F Bond Formation.

Rhenium-oxo-fluoride complexes are readily prepared using hydrotris(3,5-dimethyl-1-pyrazolyl)borate [HB(3,5-Me(2)pz)(3)(-), Tp] as a supporting ligand. For instance, treatment of TpRe(O)(OH)Cl with concentrated aqueous HF cleanly forms the chloro-fluoride complex TpRe(O)(F)Cl. Related fluoro-iodide, fluoro-triflate, and difluoride complexes are also described. In contrast, a variety of reactions of analogous compounds with the unsubstituted hydrotris(1-pyrazolyl)borate ligand [HB(pz)(3)(-), Tp] have failed to produce fluoro complexes. Extended refluxing of TpRe(O)I(2) with an excess of NaF in acetonitrile in the air gives a modest yield of an unusual rhenium &mgr;-pyrazolyl &mgr;-oxo dimer, {[kappa(2)-H(F)Bpz(2)]Re(O)}(2)(&mgr;-pz)(2)(&mgr;-O) (5) (pz = pyrazolyl). The X-ray crystal structure of 5 shows that one pyrazolyl of each Tp ligand has been substituted for fluoride. The different reactivity of the Tp and Tp complexes is apparently due to the greater steric protection of the boron afforded by the Tp() ligand. Crystallographic data for 5: monoclinic; space group Cc; a = 19.103(4) Å, b = 10.482(2) Å, c = 14.240(3) Å, beta = 114.82(3) degrees; Z = 4; R = 3.73%, R(w) (observed data) = 4.73%; GOF = 1.20.

Synthesis and Structure of Bis(pi-cyclopentadienyl)vanadium(IV) 1,10-Phenanthroline and 2,2'-Bipyridine Compounds and Their Interactions with Artificial Membranes.

The reaction of in situ generated Cp(2)V(OTf)(2) (Cp = cyclopentadienyl; OTf = O(3)SCF(3)) with excess 1,10-phenanthroline and 2,2'-bipyridine yields the d(1) vanadocene coordination compounds [Cp(2)V(phen)][OTf](2) (1) and [Cp(2)V(bpy)][OTf](2) (2), respectively. The compounds have been characterized by UV-vis and EPR spectroscopy and by cyclic voltammetry. The complexes have relatively low vanadium(IV)-vanadium(III) reduction potentials (-0.62 V vs Cp(2)Fe(+/0) in acetonitrile). Structures of 1 and 2 have been determined by X-ray crystallography. Compound 1 crystallized in a monoclinic system, space group P2(1)/n, with a = 10.2763(5) Å, b = 18.1646(9) Å, c = 13.5741(7) Å, beta = 99.4150(10) degrees, and Z = 4. Refinement of its structure by full-matrix least-squares techniques gave final residuals R = 0.040 and R(w) = 0.096. Compound 2 crystallized in a monoclinic system, space group P2(1)/c, with a = 10.6451(6) Å, b = 18.3863(10) Å, c = 12.6993(7) Å, beta = 98.6220(10) degrees, and Z = 4. Refinement of its structure by full-matrix least-squares techniques gave final residuals R = 0.046 and R(w) = 0.101. The two nitrogen atoms and centroids of the two cyclopentadienyl rings for both compounds occupy a distorted tetrahedral geometry around the vanadium(IV) center. The chelated ring plane is inclined closer to one of the neighboring Cp rings with the tilt more evident in 1 ( approximately 8 degrees ) than 2 ( approximately 4 degrees ). The membrane interactions of these compounds and the titanium analogues, [Cp(2)Ti(phen)][OTf](2) (3) and [Cp(2)Ti(bpy)][OTf](2) (4), have been studied with zwitterionic unilamellar liposomes as artificial membranes. We show that the ability of metallocenes to enhance the permeability of a liposomal membrane depends on the hydrophobicity, as well as the size and planarity of the ancillary chelated ligands, but not the nature of the central metal ion. Also provided is evidence that metallocene-induced permeability changes in artificial membranes are not caused by lipid peroxidation.

Synthesis and Characterization of Rhenium(VI) cis-Dioxo Complexes and Examination of Their Redox Chemistry.

Reaction of rhenium(V)-oxo-halo-triflate complexes (HB(pz)(3))ReO(X)OTf (1, X = Cl, Br, I) with 1 equiv of pyridine N-oxide forms rare d(1) rhenium(VI) cis-dioxo compounds (HB(pz)(3))ReO(2)X (2, X = Cl, Br, I). This reaction likely occurs by initial formation of the d(0) rhenium(VII) dioxo cation (HB(pz)(3))ReO(2)X(+) by oxygen atom transfer, followed by a rapid one electron reduction. The chloride derivative 2a has been characterized by an X-ray crystal structure. The d(1) dioxo compounds are fairly stable, disproportionating slowly to (HB(pz)(3))ReO(3) and (HB(pz)(3))ReOX(2). Electrochemical oxidations of (HB(pz)(3))ReO(2)X to Re(VII) cations are reversible and are at remarkably high potentials (E(1/2) = 0.93 V vs Cp(2)Fe(+/0) in acetonitrile for 2a). When Me(2)SO is used as the oxidant instead of pyridine N-oxide, the Re(V) adducts [(HB(pz)(3))ReO(X)(OSMe(2))][OTf] (5) are formed by triflate displacement. These complexes reversibly lose SMe(2) (for 5a, k = 3.3(4) x 10(-)(6) s(-)(1) at 297 K in CD(2)Cl(2)), as shown by isotope exchange experiments. The intermediate Re(VII) cations (HB(pz)(3))ReO(2)X(+) oxidize Me(2)S much faster than Me(2)SO, indicating that they are highly electrophilic oxygen atom transfer reagents. Complexes 2, however, are relatively unreactive materials. Crystallographic data for 2a: C(9)H(10)BClN(6)O(2)Re; monoclinic, Cc; a = 14.716(3), b = 7.651(2), c = 13.232(3) Å; beta = 110.61(3) degrees; Z = 4.