Reaction Kinetics Direct a Rational Synthesis of an HIV-1 Inactivator of Nucleocapsid Protein 7 and Provide Mechanistic Insight into Cellular Metabolism and Antiviral Activity

Article abstract of DOI:10.1002/chem.201801253

Mercaptobenzamide thioester SAMT-247 is a non-toxic, mutation-resistant HIV-1 maturation inhibitor with a unique mechanism of antiviral activity. NMR spectroscopic analyses of model reactions that mimic the cellular environment answered fundamental questions about the antiviral mechanism and inspired a high-yielding (64 % overall), scalable (75 mmol), and cost-effective ($4 mmol^?1) three-step synthesis that will enable additional preclinical evaluation.

Full text of DOI:10.1002/chem.201801253

A Journal of
Accepted Article
Title: Reaction Kinetics Direct a Rational Synthesis of an HIV-1
Inactivator of Nucleocapsid Protein 7 and Provide Mechanistic
Insight into Cellular Metabolism and Antiviral Activity
Authors: Herman Nikolayevskiy, Michael T Scerba, Jeffrey R
Deschamps, and Daniel H. Appella
This manuscript has been accepted after peer review and appears as an
Accepted Article online prior to editing, proofing, and formal publication
of the final Version of Record (VoR). This work is currently citable by
using the Digital Object Identifier (DOI) given below. The VoR will be
published online in Early View as soon as possible and may be different
to this Accepted Article as a result of editing. Readers should obtain
the VoR from the journal website shown below when it is published
to ensure accuracy of information. The authors are responsible for the
content of this Accepted Article.
To be cited as: Chem. Eur. J. 10.1002/chem.201801253
Link to VoR: http://dx.doi.org/10.1002/chem.201801253
Supported by

Chemistry - A European Journal
10.1002/chem.201801253
COMMUNICATION
Reaction Kinetics Direct a Rational Synthesis of an HIV-1
Inactivator of Nucleocapsid Protein 7 and Provide Mechanistic
Insight into Cellular Metabolism and Antiviral Activity
[a]
[a]
[b]
[a]
Herman Nikolayevskiy, Michael T. Scerba, Jeffrey R. Deschamps, Daniel H. Appella*
Abstract: Mercaptobenzamide thioester SAMT-247 is a non-toxic,
mutation-resistant HIV-1 maturation inhibitor with unique
derivatives have shown significant promise in preventing HIV
transmission in macaque models.[10] As such, 1 is an ideal
candidate for further preclinical evaluation; however, the lack of
an efficient synthesis (Scheme S1),[7a, 11] as well as gaps in the
basic understanding of how this molecule inhibits HIV maturation
without toxicity, are both hindering preclinical development.
The anti-HIV activity and high therapeutic index of SAMTs
a
mechanism of antiviral activity. NMR spectroscopic analyses of model
reactions that mimic the cellular environment answered fundamental
questions about the antiviral mechanism and inspired a high-yielding
(
64% overall), scalable (75 mmol), and cost-effective ($4/mmol) three-
step synthesis that will enable additional preclinical evaluation.
(
defined as TC50/EC50) is particularly surprising given the range of
potential reactivity for these molecules. The thioester group of 1
A formidable repertoire of >30 FDA-approved HIV inhibitors[1]
successfully decreased AIDS-related mortality by 43% between
is known to react productively with the C-terminal zinc knuckle at
Cys-36 (Scheme 1),[12] yet acetyl transfer to other available
2
010 and 2015.[2] Despite such progress, high annual costs
>$20,000 per person),[3] long-term toxicity,[4] drug resistance,[4]
nucleophiles is also likely, including proteinogenic amino acids (S
(
–
Cys; N – Lys; O – Ser, Thr, Tyr), free cytosolic thiols (GSH), and
and poor accessibility[2] have complicated global HIV-
management efforts, particularly in the third world. In the absence
of a cure, there is a continued and critical need for novel antiviral
medicines that are inexpensive, nontoxic, mutation-resistant, and
synthetically accessible.
the bulk medium (H O). Following acetyl transfer, the
2
corresponding thiol 2 can be re-acetylated in cellulo with acetyl-
CoA, such that 1 is regenerated.[8] The ability of 1 to display
antiviral activity is likely a function of thioester–nucleophile
exchange kinetics and their impact on the stability, availability,
and chemoselectivity of the molecule.
HIV Nucleocapsid Protein 7 (NCp7), a 55-amino acid
portion of the HIV Gag polyprotein, has attracted significant
attention[5] as a next-generation target due to its highly conserved
nature and its pivotal role at many points of the viral replication
cycle.[6] For HIV to replicate, NCp7 must bind to viral RNA via two
In collaboration, we recently demonstrated that the C-
terminal zinc knuckle of NCp7 is in equilibrium with a minor,
unligated form, where Cys-36 loses coordination to the zinc ion.[13]
The relevance of this minor species in the proposed mechanism
of Gag denaturation, which involves initial acetylation of Cys-36
2 4 4
zinc knuckle motifs (CX CX HX C), templating the assembly of
multiple Gag polyproteins at the membrane surface to direct
formation of a new viral particle. After budding, HIV protease
cleaves specific locations in Gag to afford free matrix, capsid, and
NCp7 proteins, which reassemble into a mature, infectious
particle. Interfering in these steps leads to improper HIV
maturation and loss of viral infectivity.
by 1, followed by intramolecular acetyl transfer to Lys-38 and
subsequent zinc ejection (Scheme 1),[12] will also depend on the
rate of thioester–nucleophile exchange, particularly in relation to
the lifetime of the minor species.
Lastly, as a consequence of zinc ejection, previously ligated
NCp7 cysteines become prone to disulfide formation, leading to
cross-linked Gag aggregates.[8] The propensity of aryl thiols to
Mercaptobenzamide thioesters (SAMTs), such as SAMT-
2
47 (1; Scheme 1), are mechanistically unique molecules that
participate in redox chemistry suggests that if the kinetics of
oxidation and acylation are comparable, 2 may play a previously
undisclosed, catalytic role in the formation of inter-Gag disulfides.
inactivate NCp7 in vitro,[5a, 7] induce Gag aggregation in cellulo,[8]
and inhibit proper HIV maturation in vivo.[9] Additionally, SAMTs
display very low toxicity to cells and animals,[8-9] and appear
insusceptible to viral resistance development.[8] Topical
microbicide and slow-release formulations of 1 and related
His
NH
His
NH
SAc O
Cys
H2N
Cys
S
N
S
Cys
H2N
Cys
S
N
S
+
–
H2O
H2O
R
Lys Zn
S
Lys Zn
SH
OH
N
H
Cys
Cys
[a]
Dr. H. Nikolayevskiy, Dr. M. T. Scerba, Dr. D. H. Appella*
Synthetic Bioactive Molecules Section, Laboratory of Bioorganic
Chemistry (LBC)
1; R = (CH2)2CONH2
C-terminal NCp7 zinc knuckle
Minor unligated species
AcCoA
National Institute of Diabetes and Digestive and Kidney Diseases
His
NH
His
NH
(
8
NIDDK), National Institutes of Health (NIH)
Center Drive, Room 404, Bethesda, MD 20892 (USA)
SH
O
Cys
AcHN
Cys
S
N
S
Cys
H2N
Cys
S
N
S
S–N Ac
R
Lys Zn
SH
Lys Zn
SAc
N
H
E-mail: appellad@niddk.nih.gov
Dr. J. R. Deschamps
Transfer
Cys
Cys
[b]
OH
OH
2
Naval Research Laboratory, Code 6910
4555 Overlook Ave. SW, Washington D.C., 20375 (USA)
Maturation inactivation via NCp7 denaturation and crosslinking of HIV Gag
Supporting information for this article is given via a link at the end of
the document.
Scheme 1. Proposed mechanism of SAMT-247 (1)–induced HIV inactivation.
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Chemistry - A European Journal
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COMMUNICATION
Elegant work by Whitesides and coworkers on the kinetics
of thiol–thioester exchange and thioester hydrolysis[14] inspired us
to conduct a comprehensive analysis of SAMT acetylative and
oxidative pathways. We present in this manuscript a deeper
understanding of the basic properties and reaction kinetics of 1
toward nucleophiles under conditions designed to simulate the
cellular environment. With insight into the kinetic reactivity of 1,
we propose a detailed model that informs how 1 likely exists in
cells and how it reacts with HIV NCp7 and denatures Gag.
Furthermore, we uniquely apply the reactivity of 1 under
conditions of metabolic mimicry to design a more efficient and
economical synthesis that should enable further preclinical
studies.
excited state (1.2%; lifetime > 5 ms) of the C-terminal zinc finger,
in which the sulfhydryl of Cys-36 is unbound and significantly
more nucleophilic.[13] Furthermore, the surprising stability of 1 in
pH 7.2 buffer (half-life ≈ 8 days; Figure 1D) suggested that
temporary exposure to neutral aqueous conditions would result in
negligible hydrolysis.
The first step in our analysis was to experimentally measure
the thiol pKa in 2. Although a large number of fluorometric and
spectroscopic techniques have been developed for the
determination of pKa and kinetic parameters,[15] we selected to
use NMR spectroscopy as the chemical shifts of all relevant
species were found to be sufficiently resolved.[16] To quantify pKa,
the thiol 2 was dissolved in a deoxygenated solution (93:7) of
2 2
H O/D O, allowing for deuterium-frequency locking and shimming
while avoiding significant deviation from a native aqueous
environment. The pH of the resulting solution was adjusted with
0
.1 M NaOH or 0.1 M HCl under a blanket of nitrogen (16–25 data
1
points per trial in the pH range 2–11), and a water-suppressed H
NMR spectrum was attained. Tracking the chemical shift changes
of H-4 (Figure 1A; 7.48 ppm – 7.80 ppm), a 4PL sigmoidal plot
was constructed; the inflection point of the resulting curve (log IC50
output using Prism 7) was interpreted to be the pKa (Figure 1C).
Repeated in triplicate, the pKa of the thiol 2 was thus determined
to be 5.83 ± 0.04, suggesting the presence of a significant amount
of thiolate under physiological conditions, and high aqueous
solubility during synthetic manipulations.
In cells and also during purification steps, 1 could acetylate
a variety of nucleophiles, such as sulfur, nitrogen, and oxygen, as
well as undergo background hydrolysis. To obtain insight into how
rapidly nucleophiles are acetylated by 1, nucleophile–thioester
exchange rates were determined for mimics of three intracellular
nucleophiles: the thiol 3, the amine 4, and water at 25 °C (Figure
2 2
Figure 1. A) Oxidation of the thiol 2 with H O . B) Nucleophile–thioester
exchange between SAMT-247 (1) and nucleophiles Mesna (3), Taurine (4), or
pH 7.2 PBS buffer to produce the thiol 2. C) Sigmoidal plot of H-4 (of the thiol
2) chemical shift changes as a function of pH. D) Consumption of SAMT-247
(
1) as a function of time for thiol–thioester (1+3) exchange and hydrolysis. Blue
1
B). Experiments were performed in a deoxygenated solution
shapes represent triplicate data points for thiol–thioester exchange, while pink
shapes represent triplicate data points for hydrolysis. E) Normalized triplicate
(
93:7) of PBS 10X buffer/D O (pH adjusted to 7.2 ± 0.1 with 0.5
2
M NaOH). Tracking the loss of H-7 relative to a tert-butanol
internal standard over the course of minutes (S–S exchange for
reaction of 1+3), hours (S–N exchange for reaction of 1+4), or
days (S–O exchange for hydrolysis), rate constants (second order
for 1+3 and 1+4, apparent pseudo-first order for hydrolysis) were
obtained from appropriate integrated rate law plots, in accordance
with the protocol described by Whitesides et al.[14] The rate
constants thus attained differed by multiple orders of magnitude
abundance trace for the oxidation of the thiol 2 (blue) with H
2 2
O to the disulfide
5
(pink), followed disproportionation to the benzisothiazolinone 6 (green). 1
H
NMR data normalized to largest abundance of 5 relative to tert-butanol internal
standard. F) Oxidation rate of N-acetyl-L-cysteine (S6) to N,N’-diacetyl-L-
cystine (S7) with 0.5 equiv H O2 in the presence or absence of 5 mol% 2
2
(repeated in triplicate).
Lastly, we examined the susceptibility of the thiol in 2 to oxidation
(which could inform how this molecule is metabolized under
oxidative stress[17] in cells). The rate of 2 oxidation upon exposure
to 30% hydrogen peroxide (2.3 equiv) in a solution (70:25:5) of
–
1
–1
–1
–1 –1
[
1+3: 84 ± 11 M s ; 1+4: (8.8 ± 0.1)ꢀ×ꢀ10 M s ; hydrolysis:
9.68 ± 0.04)ꢀ×ꢀ10–7 M ], corroborating mechanistic observations
–1
(
that zinc ejection from the C-terminal zinc finger of HIV-1 Gag
NCp7 results from initial intermolecular acetylation of the sulfur of
Cys-36 by 1, followed by intramolecular transacetylation to Lys-
6 2
PBS 10X buffer/DMSO-d /D O (25 °C) is displayed in Figure 1E.
Qualitatively, the thiol 2 is rapidly consumed to produce the
disulfide 5 (half-life ~ 1 min), followed by a more gradual
disproportionation to the benzisothiazolinone 6 (half-life ~ 45 min).
Due to poor aqueous solubility, 5 was observed to precipitate in
3
8.[12] The high rate of thiol–thioester exchange (half-life ≈ 19
min; Figure 1D) suggested that the nucleophile–leaving group
pairing of 2 and 3 may react rapidly in other reaction manifolds
(
e.g. thiol–disulfide exchange), and is consistent with recent data
solutions containing less than 25% v/v DMSO-d
6
. Without
from Deshmukh et al., which suggests that SAMTs target a minor
sufficient amounts of DMSO, disulfide 5 precipitates before the
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Chemistry - A European Journal
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COMMUNICATION
slower disproportionation reaction can occur to form 6. In addition,
we measured the effect of 5 mol% 2 on the rate of oxidation of an
exogenous thiol [N-acetyl-L-cysteine (S6)] after exposure to 30%
hydrogen peroxide (0.5 equiv) in a deoxygenated solution (93:7)
After thorough drying, 5 was ground into a fine powder,
suspended in a solution of methanol–tetrahydrofuran (3:1), and
subjected to reduction via portion-wise addition of sodium
borohydride. Due to the poor solubility of 5 under the reaction
conditions, the high surface area afforded through grinding was
critical for achieving full conversion. Upon concentration, the
product mixture containing 2 was diluted with water and acidified
to pH 1–2 with concentrated hydrochloric acid. The resulting
precipitate was filtered, providing the mercaptobenzamide 2 in
84% yield. As a consequence of thiol pKa (5.83 ± 0.04), minimal
washing of 2 with low temperature (< 10 °C) water was critical to
avoiding excessive product loss. The thiol thus attained often
contained ~5% of the disulfide 5, resulting from re-oxidation
during the workup procedure. This contamination was
exacerbated at larger reaction scales. To address this issue, we
relied on our experimental data from the kinetics of thiol–thioester
exchange (Figure 1D) and N-acetyl-L-cysteine (S6) oxidation
2
of PBS 10X buffer/D O (pH adjusted to 7.19 ± 0.02 with 0.5 M
NaOH; Figure 1F). Due to the electrophilicity of 5, 6, and the
mixed disulfide of 2 and N-acetyl-L-cysteine (S6), we anticipated
2
would exert a catalytic influence under oxidative conditions,
furnishing the disulfide N,N’-diacetyl-L-cystine (S7) after turnover
Scheme S4). Repeated in triplicate, 2 appears to accelerate the
oxidation of N-acetyl-L-cysteine (S6) by factor of ~1.5,
(
a
suggesting that 2 is a competent catalyst for in vitro disulfide
formation, and may contribute to Gag crosslinking in cellulo.
R
SH
O
CDI (1.05 equiv)
i-Pr2EtN, ß-Ala-NH ·HCl (S2)
S
O
O
2
OH
N
H
NH2
(
Figure 1F), which suggested that the disulfide 5 may react rapidly
then 30% H2O2
91%, 50 g scale
2
with the thiol 3. Indeed, addition of 3 (0.27 equiv) to the product
mixture prior to acidification reduced reoxidation to 5 to < 1%.
Finally, acetylation of the mercaptobenzamide 2 with acetic
anhydride and triethylamine in N,N-dimethylformamide
proceeded in < 5 min to furnish SAMT-247 (1; 84%), the structure
of which was confirmed by X-ray crystallography (Scheme 2).
Notably, the triethylammonium acetate byproduct is volatile,
obviating the need for aqueous workup or column
7
5
O
RHN
O
O
NHR
R
S
N
NaBH4
84%
S
S
O
H
H
25 g scale
ORTEP (1)
8
9
O
SH
O
O
chromatography.
Despite
extensive
efforts,
N,N-
Ac2O, Et3N
84%, 20 g scale
H3C
S
O
O
N
H
NH2
dimethylformamide (~1%) could not be completely removed via
rotary evaporator (50 °C, < 10 torr). Instead, the concentrated
product mixture was sequentially diluted with toluene, followed by
a 4:1 toluene–ethanol mixture, and N,N-dimethylformamide was
removed azeotropically using a rotary evaporator after each
N
H
NH2
SAMT-247 (1)
2
Scheme 2. Synthesis of SAMT-247 (1).
dilution.
dimethylformamide,
concentration in drug formulations is ~880 ppm, with ethanol
~1%), a class 3 solvent, tolerated at concentrations of ~5000
ppm.[19] We hypothesized that since 1 proved stable in pH 7.2
buffer (Figure 1D), trace ethanol could be completely removed via
azeotropic distillation with water. However, 1 has relatively poor
aqueous solubility (5 g/L) so the scalability of this approach was
limited by the time required to remove water via a rotary
evaporator. Azeotropic distillation of 6.63 mmol 1 was successful
This
protocol
successfully
replaced
N,N-
a
class
2
solvent whose tolerated
The kinetic parameters and molecular properties described
heretofore inspired a three-step synthetic strategy (Scheme 2),
carefully optimized to avoid deleterious late-stage workup or
purification, whose merits include scalability (75 mmol), efficiency
(
(
64% overall yield), and cost-effectiveness ($4/mmol). Due to the
poor solubility and lack of disproportionation reactivity of the
disulfide 5 in water, we anticipated that initial formation of the thiol
2
, followed by oxidative workup, would provide 5 in high purity
(
2
350 mL H O; < 1 h required), but thioester hydrolysis was
after filtration. To this end, thiosalicylic acid (7) was initially
activated with carbonyldiimidazole (CDI; 1.05 equiv) and di-iso-
propylethylamine, providing the acyl imidazole in situ, followed by
amide bond formation with freshly prepared b-alanamide·HCl (S2;
see SI for synthesis). Proper stoichiometry of CDI was important
in this step as excess CDI lead to the formation of the imide 8.
Moreover, certain solvents with electrophilic functionality were
found to be non-innocent in the presence of 2 and should be
avoided; in particular, dichloromethane reacted with 2 to afford
dithioacetal 9. Under optimal conditions, the unpurified reaction
mixture was concentrated, diluted with water, and treated with
observed on larger scales.
The antiviral activity and toxicity profiles of 1 before and after
azeotropic distillation with water were evaluated in CEM-SS
cells.[20] SAMT-247 (1) of both purities was nontoxic (TC50 >100
µM) and inhibited virus-induced cytopathic effects at
concentrations comparable to previous reports[8] (EC50 values of
1
.3 ± 0.7 µM and 0.9 ± 0.3 µM, respectively). Based on these data,
we propose that 1 containing residual ethanol is sufficiently pure
for further preclinical evaluation.
Our synthetic observations, in combination with our
examination of reaction kinetics and pKa, provide new insights
into the behavior of 1 in cells (Scheme 3). On the basis of
nucleophile–thioester exchange kinetics, the lifetime of 1 in the
cellular milieu is likely low. Productive reactivity with the minor
unligated thiol of Cys-36 within the C-terminal zinc knuckle of
NCp7,[13] or unproductive reactivity with high abundance
3
2 2
0% H O (2 portions, 0.20 equiv each), precipitating the disulfide
5
; as anticipated, disproportionation to 6 was not observed. The
high aqueous solubility of all byproducts (imidazole: 633 g/L; di-
iso-propylethylammonium chloride: > 4.01 g/L[18]) enabled facile
isolation of 5 after several aqueous washes (91% overall yield).
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Chemistry - A European Journal
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COMMUNICATION
cytoplasmic thiols (such as CoA or glutathione) would rapidly
convert 1 to the major species 2, which predominantly exists as
the thiolate in cells under physiological conditions (pH 7.4). While
non-enzymatic hydrolysis is likely negligible, the slower direct
acyl-transfer to proteinogenic amines may be a viable, albeit
minor, pathway. Although 1 may be regenerated from 2 via acetyl-
CoA,[8] the formation of 1 is strongly disfavored at equilibrium, as
demonstrated by the reaction of 1 with 3.
In summary, a detailed investigation of SAMT kinetics and
molecular properties has provided insight into both productive and
unproductive SAMT reaction pathways in cells. The
predominance of thiol–thioester exchange (as compared to other
nucelophiles), the high equilibrium abundance of the thiolate 2 (as
compared to the more reactive metabolites 1, 6, and 10), and the
application of interconnected acetylative and oxidative reaction
manifolds to the mechanism of HIV inactivation, are particularly
notable. Moreover, it led to a three-step synthesis of SAMT-247
(
1), which was conducted on 75 mmol scale with 64% overall yield,
Table 1. Antiviral activity [EC50 (µM)], toxicity [TC50 (µM)], and therapeutic
index (TI) of SAMT-247 (1).
utilizes inexpensive reagents ($4/mmol), and avoids any
chromatography.
Compound
EC50 (µM)
1.3 ± 0.7
0.9 ± 0.3
TC50 (µM)
>100
TC50/EC50 (TI)
>77
1
+ 1% EtOH
Acknowledgements
1
>100
>100
This research was supported by the Intramural Research
Program of NIDDK, NIH. We thank Tracy L. Hartman and Robert
W. Buckheit, Jr. of ImQuest Biosciences (Frederick, MD) for
performing antiviral assays, John Lloyd for performing mass
spectrometry, and Robert O’Connor for assistance with NMR. The
X-ray crystallographic work was supported by NIDA through
Interagency Agreement (IAA) ADA17001 with the Naval
Research Laboratory (NRL).
Alternatively, in the presence of H
2
O
2
, O
2
, or other reactive
oxygen species (ROS) in cells, 2 may be oxidized to a mixed
disulfide (10). From our experience in synthesizing 6, we propose
that direct oxidation from 2 to the benzisothiazolinone 6 is unlikely.
Although 10 may disproportionate to 6 in vitro, the high reactivity
of both 6 and 10 towards thiol nucleophiles, as demonstrated by
the mercaptobenzamide–catalyzed oxidation of N-acetyl-L-
cysteine (S6), suggests that the equilibrium concentration of 10,
and particularly 6, is also low.
Keywords: HIV • nucleocapsid • mercaptobenzamide • scalable
synthesis • antiviral mechanism • reaction kinetics
Nevertheless, fast acetylative and oxidative reaction
kinetics, in combination with the capacity of 1, 6, and 10 to
regenerate from the thiolate 2, suggest that loss of HIV infectivity
via 1–mediated NCp7 denaturation, followed by 6– or 10–
catalyzed Gag crosslinking, is a viable mechanism of action for
this class of antivirals. Moreover, low equilibrium concentrations
of active metabolites (1, 6, and 10) may explain the low toxicity
and micromolar activity of the SAMTs.
[
1] A list of currently approved inhibitors can be found on the U.S. Food and
Drug Administration website, titled: Antiretroviral drugs used in the
treatment of HIV infection. https://www.fda.gov/forpatients/illness/hivaids
/treatment/ucm118915.htm. Page last updated: 8/9/16.
[2] Estimate from "Global AIDS Update 2016," prepared by Joint United
Nations Programme on HIV/AIDS. Available at: http://www.unaids.org/
sites/default/files/media_asset/global-AIDS-update-2016_en.pdf.
accessed: 11/28/17.
Last
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Scheme 3. Proposed acetylative and oxidative mechanistic cycles for in vivo
SAMT-247 (1)–induced HIV inactivation via NCp7 denaturation and formation
of Gag crosslinks.
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Chemistry - A European Journal
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COMMUNICATION
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[18] The aqueous solubility of di-iso-propylethylamine, triethylamine, and
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1
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COMMUNICATION
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COMMUNICATION
O
SH
O
NMR spectroscopic analyses
of model reactions that mimic
the cellular environment
Dr. Herman Nikolayevskiy, Dr.
Michael T. Scerba, Dr. Jeffrey R.
Deschamps, Dr. Daniel H.
Appella*[a]
3
steps
H
C
S
O
O
3
OH
6
4% overall yield
$4/mmol (75 mmol)
N
H
NH
2
answered fundamental
Synthetic
Inspiration
Mechanistic
Understanding
questions about the antiviral
mechanism of HIV inactivator
SAMT-247 and inspired a high-
yielding (64% overall), scalable
Page No. – Page No.
vRNA
S
Reaction Kinetics Direct a
Rational Synthesis of an HIV-1
Inactivator of Nucleocapsid
Protein 7 and Provide
Gag
O
S
Zn2+
H3C
S O
R
N
H
(
(
75 mmol), and cost-effective
$4/mmol) three-step synthesis
that will enable additional
preclinical evaluation.
Mechanistic Insight into
Cellular Metabolism and
Antiviral Activity
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