Total synthesis of (.+-.)-calanolide A, a non-nucleoside inhibitor of HIV-1 reverse transcriptase

1993 ◽  
Vol 58 (21) ◽  
pp. 5605-5606 ◽  
Author(s):  
Balan Chenera ◽  
Michael L. West ◽  
Joseph A. Finkelstein ◽  
Geoffrey B. Dreyer
ChemInform ◽  
2010 ◽  
Vol 25 (5) ◽  
pp. no-no
Author(s):  
B. CHENERA ◽  
M. L. WEST ◽  
J. A. FINKELSTEIN ◽  
G. B. DREYER

2011 ◽  
Vol 56 (1) ◽  
pp. 341-351 ◽  
Author(s):  
Xiaofan Lu ◽  
Li Liu ◽  
Xu Zhang ◽  
Terrence Chi Kong Lau ◽  
Stephen Kwok Wing Tsui ◽  
...  

ABSTRACTNonnucleoside reverse transcriptase inhibitors (NNRTIs) are one of the key components of antiretroviral therapy drug regimen against human immunodeficiency virus type 1 (HIV-1) replication. We previously described a newly synthesized small molecule, 10-chloromethyl-11-demethyl-12-oxo-calanolide A (F18), a (+)-calanolide A analog, as a novel anti-HIV-1 NNRTI (H. Xue et al., J. Med. Chem. 53:1397–1401, 2010). Here, we further investigated its antiviral range, drug resistance profile, and underlying mechanism of action. F18 consistently displayed potent activity against primary HIV-1 isolates, including various subtypes of group M, circulating recombinant form (CRF) 01_AE, and laboratory-adapted drug-resistant viruses. Moreover, F18 displayed distinct profiles against 17 NNRTI-resistant pseudoviruses, with an excellent potency especially against one of the most prevalent strains with the Y181C mutation (50% effective concentration, 1.0 nM), which was in stark contrast to the extensively used NNRTIs nevirapine and efavirenz. Moreover, we induced F18-resistant viruses byin vitroserial passages and found that the mutation L100I appeared to be the dominant contributor to F18 resistance, further suggesting a binding motif different from that of nevirapine and efavirenz. F18 was nonantagonistic when used in combination with other antiretrovirals against both wild-type and drug-resistant viruses in infected peripheral blood mononuclear cells. Interestingly, F18 displayed a highly synergistic antiviral effect with nevirapine against nevirapine-resistant virus (Y181C). Furthermore,in silicodocking analysis suggested that F18 may bind to the HIV-1 reverse transcriptase differently from other NNRTIs. This study presents F18 as a new potential drug for clinical use and also presents a new mechanism-based design for future NNRTI.


2001 ◽  
Vol 45 (5) ◽  
pp. 1379-1386 ◽  
Author(s):  
Terri Creagh ◽  
Jon L. Ruckle ◽  
Dwain T. Tolbert ◽  
Jeremy Giltner ◽  
David A. Eiznhamer ◽  
...  

ABSTRACT (+)-Calanolide A is a novel, naturally occurring, nonnucleoside inhibitor of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase first isolated from a tropical tree (Calophyllum lanigerum) in the Malaysian rain forest. Previous studies have demonstrated that (+)-calanolide A has specific activity against the reverse transcriptase of HIV-1 and a favorable safety profile in animals. In addition, (+)-calanolide A exhibits a unique HIV-1 resistance profile in vitro. The safety and pharmacokinetics of (+)-calanolide A was examined in four successive single-dose cohorts (200, 400, 600, and 800 mg) in healthy, HIV-negative volunteers. In this initial phase I study, the toxicity of (+)-calanolide A was minimal in the 47 subjects treated. Dizziness, taste perversion, headache, eructation, and nausea were the most frequently reported adverse events. These events were not all judged to be related to study medication nor were they dose related. While 51% of subjects reported mild and transient dizziness, in many cases this appeared to be temporally related to phlebotomy. Calculation of the terminal-phase half-life (t 1/2) was precluded by intrasubject variability in the 200-, 400-, and 600-mg dose cohorts but was approximately 20 h for the 800-mg dose group. (+)-Calanolide A was rapidly absorbed following administration, with time to maximum concentration of drug in plasma (T max) values occurring between 2.4 and 5.2 h postdosing depending on the dose. Plasma levels of (+)-calanolide A at all dosing levels were quite variable; however, both the mean concentration in plasma (C max), and the area under the plasma concentration-time curve increased proportionately in relation to the dose. Although raw plasma drug levels were higher in women than in men, when doses were normalized for body mass, the pharmacokinetic profiles were virtually identical with those observed for males. In general, levels of (+)-calanolide A in human plasma were higher than would have been predicted from animal studies, yet the safety profile remained benign. In conclusion, this study demonstrated the safety and favorable pharmacokinetic profile of single doses of (+)-calanolide A in healthy, HIV-negative individuals.


2000 ◽  
Vol 11 (5) ◽  
pp. 321-327 ◽  
Author(s):  
Robert W Buckheit ◽  
Julie D Russell ◽  
Ze-Qi Xu ◽  
Michael Flavin

The natural product (+)-calanolide A, a unique non-nucleoside reverse transcriptase inhibitor (NNRTI) of HIV-1 replication, is currently being evaluated in clinical trials in the USA. (+)-Calanolide A, the congeners costatolide and dihydrocostatolide, and (+)-12-oxo(+)-calanolide A, were evaluated in combination with a variety of mechanically diverse inhibitors of HIV replication to define the efficacy and cellular toxicity of potential clinical drug combinations. These assays should be useful in prioritizing the use of different combination drug strategies in a clinical setting. The calanolides exhibited synergistic antiviral interactions with other nucleoside and non-nucleoside reverse transcriptase inhibitors and protease inhibitors. Additive interactions were also observed when the calanolides were used with representative compounds from each of these classes of inhibitors. No evidence of either combination toxicity or antagonistic antiviral activity was detected with any of the tested compounds. The combination antiviral efficacy of three-drug combinations involving the calanolides, and the efficacy of two- and three-drug combinations using a (+)-calanolide A-resistant challenge virus (bearing the T139I amino acid change in the reverse transcriptase), was also evaluated in vitro. These assays suggest that the best combination of agents based on in vitro anti-HIV assay results would include the calanolides in combination with lamivudine and nelfinavir, since this was the only three-drug combination exhibiting a significant level of synergy. Combination assays with the (+)-calanolide A-resistant strain yielded identical results as seen with the wild-type virus, although the concentration of the calanolides had to be increased.


1999 ◽  
Vol 43 (8) ◽  
pp. 1827-1834 ◽  
Author(s):  
Robert W. Buckheit ◽  
E. Lucile White ◽  
Valerie Fliakas-Boltz ◽  
Julie Russell ◽  
Tracy L. Stup ◽  
...  

ABSTRACT (+)-Calanolide A (NSC 650886) has previously been reported to be a unique and specific nonnucleoside inhibitor of the reverse transcriptase (RT) of human immunodeficiency virus (HIV) type 1 (HIV-1) (M. J. Currens et al., J. Pharmacol. Exp. Ther., 279:645–651, 1996). Two isomers of calanolide A, (−)-calanolide B (NSC 661122; costatolide) and (−)-dihydrocalanolide B (NSC 661123; dihydrocostatolide), possess antiviral properties similar to those of calanolide A. Each of these three compounds possesses the phenotypic properties ascribed to the pharmacologic class of nonnucleoside RT inhibitors (NNRTIs). The calanolide analogs, however, exhibit 10-fold enhanced antiviral activity against drug-resistant viruses that bear the most prevalent NNRTI resistance that is engendered by amino acid change Y181C in the RT. Further enhancement of activity is observed with RTs that possess the Y181C change together with mutations that yield resistance to AZT. In addition, enzymatic inhibition assays have demonstrated that the compounds inhibit RT through a mechanism that affects both the Km for dTTP and theV max, i.e., mixed-type inhibition. In fresh human cells, costatolide and dihydrocostatolide are highly effective inhibitors of low-passage clinical virus strains, including those representative of the various HIV-1 clade strains, syncytium-inducing and non-syncytium-inducing isolates, and T-tropic and monocyte-tropic isolates. Similar to calanolide A, decreased activities of the two isomers were observed against viruses and RTs with amino acid changes at residues L100, K103, T139, and Y188 in the RT, although costatolide exhibited a smaller loss of activity against many of these NNRTI-resistant isolates. Comparison of cross-resistance data obtained with a panel of NNRTI-resistant virus strains suggests that each of the three stereoisomers may interact differently with the RT, despite their high degree of structural similarity. Selection of viruses resistant to each of the three compounds in a variety of cell lines yielded viruses with T139I, L100I, Y188H, or L187F amino acid changes in the RT. Similarly, a variety of resistant virus strains with different amino acid changes were selected in cell culture when the calanolide analogs were used in combination with other active anti-HIV agents, including nucleoside and nonnucleoside RT and protease inhibitors. In assays with combinations of anti-HIV agents, costatolide exhibited synergy with these anti-HIV agents. The calanolide isomers represent a novel and distinct subgroup of the NNRTI family, and these data suggest that a compound of the calanolide A series, such as costatolide, should be evaluated further for therapeutic use in combination with other anti-HIV agents.


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