Design and synthesis of bicyclic pyrimidinones as potent and orally bioavailable HIV-1 integrase inhibitors

Article abstract of DOI:10.1021/jm701164t

HIV integrase is one of the three enzymes encoded by HIV genome and is essential for viral replication, but integrase inhibitors as marketed drugs have just very recently started to emerge. In this study, we show the evolution from the N-methylpyrimidinon

Full text of DOI:10.1021/jm701164t

J. Med. Chem. 2008, 51, 861–874
861
Design and Synthesis of Bicyclic Pyrimidinones as Potent and Orally Bioavailable HIV-1
Integrase Inhibitors
Ester Muraglia,*,† Olaf Kinzel,† Cristina Gardelli,† Benedetta Crescenzi,† Monica Donghi,† Marco Ferrara,† Emanuela Nizi,†
Federica Orvieto,† Giovanna Pescatore,† Ralph Laufer,† Odalys Gonzalez-Paz,† Annalise Di Marco,† Fabrizio Fiore,†
Edith Monteagudo,† Massimiliano Fonsi,† Peter J. Felock,‡ Michael Rowley,† and Vincenzo Summa†
IRBM Merck Research Laboratories Rome, Via Pontina Km 30,600, 00040 Rome, Italy, and Department of AntiViral Research, Merck
Research Laboratories, West Point, PennsylVania
ReceiVed September 18, 2007
HIV integrase is one of the three enzymes encoded by HIV genome and is essential for viral replication, but
integrase inhibitors as marketed drugs have just very recently started to emerge. In this study, we show the
evolution from the N-methylpyrimidinone structure to bicyclic pyrimidinones. Introduction of a suitably
substituted amino moiety modulated the physical-chemical properties of the molecules and conferred
nanomolar activity in the inhibition of spread of HIV-1 infection in cell culture. An extensive SAR study
led to sulfamide (R)-22b, which inhibited the strand transfer with an IC50 of 7 nM and HIV infection in
MT4 cells with a CIC95 of 44 nM, and ketoamide (S)-28c that inhibited strand transfer with an IC50 of 12
nM and the HIV infection in MT4 cells with a CIC95 of 13 nM and exhibited a good pharmacokinetic
profile when dosed orally to preclinical species.
Introduction
from the 3′ terminus of both strands of the viral DNA generates
a processed DNA/integrase preintegration complex (PIC), which
crosses the nuclear membrane to access the host genome. The
cell DNA is then cleaved by integrase in a nonspecific way,
and the shortened strands of viral DNA are integrated into the
host DNA sequence.
Selective inhibition of the HIV-1 integrase activity causes
an interruption of the HIV-1 replication cycle and could
represent an answer to the unmet medical need for new and
improved treatments.10 Just very recently the first integrase
inhibitor (raltegravir) was approved in the U.S. for treatment
of HIV infection.11
Human immunodeficiency virus type 1 (HIV-1) is responsible
for human acquired immunodeficiency syndrome (AIDS), one
of the most urgent world health threats. Currently approved
therapies1,2 are based on inhibitors of HIV protease (PIs),3
reverse transcriptase (NRTIs and NNRTIs, nucleoside and non-
nucleoside reverse transcriptase inhibitors),4 and more recently,
fusion inhibitors (enfuvirtide).5 During the past years, the
combination of protease and reverse transcriptase inhibitors
(HAART, highly active antiretroviral therapy)6,7 has demon-
strated efficacy in strongly reducing morbidity and mortality.
Nevertheless, the rapid emergence of drug resistant viral strains
and the toxicity derived from chronic treatment remain serious
issues that highlight the need for the development of new
therapeutic strategies.
The HIV-1 genome, together with protease and reverse
transcriptase, encodes a third enzyme, integrase, which is
necessary for the viral life cycle and is an appealing target for
drug discovery for its essential function in viral replication and
the absence of a direct counterpart in the host cells.8,9 HIV-1
integrase catalyzes the incorporation of the viral DNA into the
host cell’s genome through a multistep process. In the initial
assembly step, integrase binds to specific sequences of the
double-stranded viral DNA, newly formed by reverse transcrip-
tion. An endonucleolytic cleavage of the last two nucleotides
We recently reported12–14 that dihydroxypyrimidine carboxa-
mide 1 (Figure 1) is a potent HIV integrase strand transfer15,16
inhibitor (IC50 ) 0.06 µM), but despite the high intrinsic
potency, it showed a much lower activity in the cell based assays
(CIC95 > 10 µM in inhibiting the spread of HIV-1 infection in
MT4 cell culture in the presence of 10% fetal bovine serum
(FBS) or 50% normal human serum (NHS) (spread assay).15,17
An extensive SAR study on the substitution at the 2-position
of the dihydroxypyrimidine scaffold13 demonstrated that various
substituents are tolerated, providing compounds equipotent to
1 in the enzymatic assay. This observation was interpreted as
an indication that the 2-substituent is not directly interacting
with the HIV integrase enzyme and that this position could be
exploited to modify the physical-chemical properties of the
molecule (lipophilicity, solubility, plasma protein binding) in
order to modulate the pharmacological properties.
* To whom correspondence should be addressed. Phone: +39 0691093276.
Fax: +39 06 91093654. E-mail: ester_muraglia@merck.com.
Introduction of a basic amine proved to be beneficial for
cellular activity, as in 2,14 which proved to be a potent inhibitor
both in the strand transfer and in the spread assays.
†
IRBM Merck Research Laboratories Rome.
Merck Research Laboratories.
Abbreviations: TFA, trifluoroacetic acid; TMS, tetramethylsilane;
‡
a
DMSO, dimethyl sulfoxide; DMF, dimethylformamide; DCM, dichlo-
romethane; THF, tetrahydrofuran; TEA, triethylamine; HOBt, 1-hydroxy-
benzotriazole; EDC, N-ethyl-N′-(3-dimethylaminopropyl)carbodiimide; DI-
PEA, N,N-diisopropylethylamine; PEG, poly(ethylene glycol); NBS,
N-bromosuccinimide; PK, pharmacokinetic; NADPH, nicotinamide adenine
dinucleotide phosphate, reduced form; UDPGA, uridine 5′-diphosphoglu-
curonic acid; PPB, plasma protein binding; HPLC, high-performance liquid
chromatography; RP-HPLC, reverse-phase high-performance liquid chro-
matography; UPLC, ultraperformance liquid chromatography; HRMS, high-
resolution mass spectrometry.
Cyclization of the tertiary amine of 2 as in 3 provided a
further enhancement in the spread activity, and the introduction
of a methyl on the 1-nitrogen of the pyrimidine led to 1-Me-
pyrimidinone structure 4,18 which was more than 2 orders of
magnitude more potent than 1 in the spread assay in the presence
of 50% normal human serum (NHS).
Capitalizing on the above observations of the importance of
installing a ꢀ-amino substituent in the 2-position of the
10.1021/jm701164t CCC: $40.75
2008 American Chemical Society
Published on Web 01/25/2008

862 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 4
Muraglia et al.
Figure 1. Evolution from dihydroxypyrimidine to N-methylpyrimidinones.
Figure 2. Strategic approach from N-methylpyrimidinones to bicyclic pyrimidinones.
pyrimidine scaffold and the beneficial effect of the 1N-
methylation, we envisaged the possibility of constraining the
1N-Me of the 1N-methylpyrimidinone scaffold 5 into a saturated
cycle as in 6 (n ) 0, 1, 2) (Figure 2).
(n ) 1), which is equally (or less as in 7b) potent as the
corresponding five-membered (n ) 0) one. Unfortunately, all
the above compounds show lower inhibitory effect on the spread
of HIV infection in cell culture (CIC95 g 1 µM in the presence
of 50% NHS). Nevertheless, these observations confirmed the
potential of the bicyclic pyrimidinone series as HIV-1 integrase
inhibitors and prompted us to undertake a further investigation
on the 2-ꢀ-nitrogen in 6, aimed at modifying the physical-
chemical properties of the cyclized structures, in order to gain
activity in the cell based assays.
Results and Discussion
In order to probe the hypothesis summarized in Figure 2,
our initial investigations focused on the evaluation of structure
6 where R1 and R2 are alkyls, which should provide the closest
cyclized analogues of 3–4. We were pleased to see that
dimethylamino derivatives 7a-c, the closest analogues of 2,
indeed displayed intrinsic activity (IC50 ) 0.007, 0.069, and
0.55 µM, respectively) comparable to that for 1–4 for n ) 0–1
and lower activity than 1-4 for n ) 2. Substitution of the
dimethylamino moiety with the cyclic amine pyrrolidine (8b)
provided a compound that displayed the same activity as 7b,
but the introduction of more bulky cyclic amines (piperidine as
in 9b, morpholine as in 10b,c) and the more lypophilic
benzylmethylamine as in 11b,c gave a 1 order of magnitude
increase of the potency in the enzymatic assay. The positive
influence of the benzyl moiety on integrase inhibition has also
been suggested by a pharmacophore model previously reported
by the Chimirri research group.19
The initial efforts concentrated on the exploration of the amide
SAR, as shown in Table 2. Changing one of the two nitrogen
alkyls into an acetyl group as in 13a-c proved to be well
tolerated for n ) 0–1 and very favorable for n ) 2, providing
equipotent low nanomolar inhibitors in the strand transfer assay.
When n ) 2 (13c), activity was also observed in the cell based
assay. A large variety of acyl groups was accepted: small acyl
groups as in 14b and more elaborate residues as in 15b and
16b. We were very pleased to discover that the introduction of
a sulfonamide (as in 17b) or a sulfone (as in 18b,c) moiety in
the ꢀ position with respect to the amide carbonyl resulted in
very active inhibitors of the viral spread. The low shift in activity
displayed in the low serum conditions (10% fetal bovine serum)
with respect to the intrinsic enzymatic activity (less than 2-fold
for 17b and 3- to 4-fold for 18b,c) confirmed the ability of the
compounds to cross the cellular membrane. Moreover, the very
low shift between the low and high serum (50% normal human
serum) assay conditions can be rationalized as the presence of
a significant unbound fraction of compound in human plasma,20
Interestingly, the unsubstituted derivatives 12a-c also showed
very high enzymatic activity (IC50 ) 0.008, 0.005, 0.019 µM,
respectively), comparable to that of 9 and 10. The activities
displayed in Table 1 seem to follow a trend according to the
size of the saturated ring in the bicyclic system, the seven-
membered cycle (n ) 2) being less active than the six-membered

Bicyclic Pyrimidinones HIV1-Integrase Inhibitors
Journal of Medicinal Chemistry, 2008, Vol. 51, No. 4 863
Table 1. Effect of Amino Substituents on Activity of Bicyclic
rate by oxidation and glucuronidation. (S)-17b displayed moder-
ate stability in the presence of NADPH (turnover; rat 51, dog
15, human 36 %/h) and UDPGA (turnover; rat 47, dog 24,
human 46 %/h).22 The same pharmacokinetic profile was
observed also for the enantiomer (R)-17b (data not shown). This
finding, together with the low values of plasma protein binding
measured in all the species investigated ((S)-17b plasma protein
binding; rat 74, dog 71, human 78% bound), were consistent
with the high plasma clearance observed in vivo (rat). The same
profile observed for (R)-17b and (S)-17b was also observed for
the enantiomers of derivative 18b (data not shown).
Pyrimidinonesa
We then turned our attention to sulfonamide derivatives
(Table 3). Sulfonamides 20b,c proved to be potent compounds
both on the enzyme and in the cellular assays. Pharmacokinetic
evaluation of 20b in rat (Table 4) showed that, though
characterized by a good oral bioavailability (F ) 47%), the
compound presents similar relatively high plasma clearance (Clp
48 (mL/min)/kg) already observed in the amide series. Metabolic
stability studies in liver microsomes in the presence of UDPGA,
in agreement with the observed in vivo data, showed high
turnover in all species and in particular in rat and human
(turnover; rat 88, dog 29, human 74 %/h).22 Structurally more
complex sulfonamides, such as 21b, displayed similar high
potency both on the enzyme and in the cell based assays and
even lower metabolic stability in liver microsomes (turnover;
rat 94, dog 78, human 90 %/h, in the presence of UDPGA).22
A significant improvement was obtained by modification of
the sulfonamide moiety into a tetrasubstituted sulfamide as in
22a-c. Compound 22b was a low nanomolar inhibitor of HIV
integrase strand transfer (IC50 ) 0.005 µM), displaying only a
4-fold shift in activity in the spread assay in the presence of
50% human plasma serum (CIC95 ) 0.021 µM). The corre-
sponding analogue with n ) 2 (22c), though only 2-fold less
potent than 22b in the enzymatic assay, showed a lower activity
in the high serum cell based assay (CIC95 ) 0.125 vs 0.021
µM). Surprisingly, the corresponding analogue for n ) 0 (22a)
was 9-fold less potent than 22b in the strand transfer assay and
not active up to 1 µM in both the cell based assays.
Further studies on the effects of different alkylation patterns
on the sulfamide nitrogen were performed. Internal cyclization
of the sulfamide as in 23b,c provided compounds equipotent
with the corresponding open derivatives 22b,c. Replacement
of the two methyls of 22b with cycloalkyls as in 24b and 25b
lowered activity in the cell based assay (50% NHS). Activity
could be restored to previous levels by introduction of the more
polar morpholine (26b), obtaining a compound that is essentially
equipotent with 22b in the cell based assays. This observation
prompted us to further increase polarity by introducing a
protonable nitrogen in the sulfamide moiety; the change of
morpholine into N-methylpiperazine gave an extremely potent
compound (27b), and interestingly, it was characterized by a
higher stability toward glucuronidation with respect to 22b (data
not shown).
The two enantiomers (S)- and (R)-27b were profiled in vitro
and in vivo showing that the (S)-enantiomer was 3-fold more
potent than the (R)-enantiomer in the high serum spread assay
(CIC95 ) 0.006 µM for (S)-27b vs CIC95 ) 0.020 µM for (R)-
27b). (S)-27b thus proved to be the most active compound in
the series.
Metabolic stability of (S)-27b in liver microsomes in the
presence of both NADPH and UDPGA showed a moderately
low turnover (turnover; rat 10, dog 8 (mL/min)/mg P),23 but
plasma protein binding was also low, consistent with a positively
charged molecule24 (PPB; rat 76, dog 82% bound), and the
a Results are the mean of at least three independent experiments. b Assays
were performed with recombinant HIV-1 integrase (0.1 µM) preassembled
on immobilized oligonucleotides. Inhibitors were added after assembly and
washings. For details, see ref 15 and references therein.
which was confirmed by a low value of human plasma protein
binding (81% and 70% bound to human plasma proteins,
respectively, for 17b and 18b).21 Removal of one of the R2 alkyl,
as in 19b, produced no change in the intrinsic potency but
produced a marked drop of activity in the cell based assays.
The two enantiomers of 17b, (R)-17b and (S)-17b, were
prepared and further profiled in vitro and in vivo. Although
showing the same in vitro enzymatic activity, enantiomer (S)-
17b was 2-fold more potent in the spread assays (CIC95: 10%
FBS, 0.016 µM; 50% NHS, 0.031 µM) than (R)-17b. The
pharmacokinetic profile in rat of (S)-17b, as reported in Table
4, was characterized by high plasma clearance (Clp ) 55 (mL/
min)/kg) and modest oral bioavailability (F ) 17%). The
metabolic stability in liver microsomes was studied in the
presence of NADPH and UDPGA to evaluate the metabolism

864 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 4
Table 2. Effect of Amide Substitutiona
Muraglia et al.
a Results are the mean of at least three independent experiments. b Assays were performed with recombinant HIV-1 integrase (0.1 µM) preassembled on
immobilized oligonucleotides. Inhibitors were added after assembly and washings. For details, see ref 15 and references therein. c Cell culture inhibitory
concentrations (CIC95) are defined as those that inhibited by g95% the spread of HIV-1 infection in susceptible cell culture MT-4 human T-lymphoid cells.
For details see ref 15 and references therein.
compound presented a rat and dog PKa profile (Table 4)
characterized by high plasma clearance (98 and 23 (mL/min)/
kg, respectively, in rat and dog).
identical for the two enantiomers, the oral bioavailability was again
higher for (R)-22b (F ) 42%) than for (S)-22b (F ) 16%). Rhesus
monkey PK profile of (R)-22b displayed a plasma clearance of 27
(mL/min)/kg and 9% oral bioavailability.
22b and its two enantiomers ((S)-22b and (R)-22b) were
also evaluated in vitro and in vivo in preclinical species; they
displayed almost the same potency in the enzymatic and in
the cell based assays and similar moderately low human PPB
((S)-22b, 87% bound, (R)-22b, 81% bound). Pharmacokinetic
profiles of the two enantiomers (Table 4) showed significant
differences; in rat, (R)-22b showed a 1.8 (mL/min)/kg plasma
clearance value, while the corresponding value for (S)-22b
was almost 8-fold higher (Clp ) 14 (mL/min)/kg). Further-
more, oral bioavailability was higher for (R)-22b (F ) 63%)
than for (S)-22b (F ) 49%). Comparison of the dog PK
parameters revealed that although the plasma clearance was
The stability of (R)-22b was also investigated in liver
microsomes in the presence of NADPH and UDPGA,
revealing that the compound was not subject to significant
oxidative metabolism and was metabolized mainly by glu-
curonidation. Despite the low (rat and dog) and moderate
(rhesus) plasma clearance in vivo (Table 4), (R)-22b dis-
played unexpectedly high turnover in liver microsomes in
the presence of UDPGA (turnover; rat 81, dog 46, rhesus 84
%/h).25 The high plasma protein binding values observed
(PPB; rat 99, dog 89, rhesus 86% bound) may partially

Bicyclic Pyrimidinones HIV1-Integrase Inhibitors
Journal of Medicinal Chemistry, 2008, Vol. 51, No. 4 865
Table 3. SAR of Sulfonamides and Sulfamidesa
a Results are the mean of at least three independent experiments. b Assays were performed with recombinant HIV-1 integrase (0.1 µM) preassembled on immobilized
oligonucleotides. Inhibitors were added after assembly and washings. For details, see ref 15 and references therein. c Cell culture inhibitory concentrations (CIC95) are de-
fined as those that inhibited by g 95% the spread of HIV-1 infection in susceptible cell culture MT-4 human T-lymphoid cells. For details, see ref 15 and references therein.

866 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 4
Table 4. Pharmacokinetics
Muraglia et al.
Table 6. Pharmacokinetics Data for Ketoamides Derivatives
Clpb T1/2 AUCd C max
compd species F (%)a ((mL/min)/kg) (h)c (µM·h) (µM) (L/kg)
e
f
compd
species
F (%)a
Clpb ((mL/min)/kg)
Vdss
(S)-17b
20b
(S)-22b
ratc
17
47
49
16
63
42
9
55
48
14
3.8
1.8
3.8
27
98
23
ratd
(S)-28b ratg
47
39
64
61
31
11
15
7
7.5
8
14
1.7
7.4 37
2.1 31
2.6 14
2.5
3.8
2.0
2.5
27
25
10
3.0
1.2
0.7
0.9
0.7
ratd
dogh
doge
ratd
(S)-28ci ratj
dogk
(R)-22b
(S)-27b
doge
rhesusf
ratg
rhesusl
a Oral bioavailability. b Plasma clearance. c Plasma half-life after iv
administration. d Area under the curve after po administration. e After PO
administration. f Volume of distribution. g Dose: iv ) po, 3 mg/kg.
Formulation: iv, DMSO/PEG400/H2O (20%-40%-40%); po, 1% meth-
ylcellulose suspension. h Dose: iv, 1 mg/kg; po, 4 mg/kg. Formulation: iv,
DMSO/PEG400/H2O (20%-40%-40%); po, 1% methylcellulose suspension.
i Dosed as potassium salt. j Dose: iv, 3 mg/kg; po, 10 mg/kg. Formulation:
iv, DMSO/PEG400/H2O (20%-60%-20%); po, 1% methylcellulose
suspension. k Dose: iv, 1 mg/kg; po, 2 mg/kg. Formulation: iv, DMSO/
PEG400/H2O (20%-60%-20%); po, 1% methylcellulose suspension.
l Dose: iv, 2 mg/kg; po, 10 mg/kg. Formulation: iv, DMSO; po, 0.5%
methylcellulose suspension.
15
dog
a Oral bioavailability. b Plasma clearance. c Dose: iv ) po, 3 mg/kg.
Formulation: iv, DMSO/PEG400/H2O (60%-20%-20%); po, 1% methyl-
cellulose. d Dose: iv ) po, 3 mg/kg. Formulation: iv, DMSO/PEG400/H2O
(20%-40%-40%); po, 1% methylcellulose. e Dose: iv, 1 mg/kg; po, 2 mg/
kg. Formulation: iv, DMSO/PEG400/H2O (20%-40%-40%); po, 1%
methylcellulose. f Dose: iv, 1 mg/kg; po, 6.5 mg/kg. Formulation: iv, DMSO;
po, 0.5% methylcellulose. g Dose: iv ) po, 3 mg/kg. Formulation: iv,
DMSO/PEG400/H2O (20%-60%-20%); po, 1% methylcellulose.
Table 5. Ketoamides: Effect of Ring Size on Activitya
spread CIC95 (µM)c
compd
n
strand transfer IC50 (µM)b
10% FBS
50% NHS
28a
28b
(R)-28b
(S)-28b
28c
(R)-28c
(S)-28c
0
1
1
1
2
2
2
0.020
0.007
0.019
0.012
0.013
0.035
0.012
>1
>1
0.038
0.067
0.033
0.094
0.021
0.010
0.040
0.098
0.043
0.063
0.042
0.013
Figure 3. Rat oral administration of (S)-28c, exposure dose
proportionality.
µM in the presence of 50% NHS). In order to further evaluate
the series, the enantiomers of both compounds were tested and,
in both cases, they shared the common feature of the (S)-
enantiomers (S)-28b and (S)-28c, being about 2-fold more active
than the corresponding (R)-enantiomers (R)-28b and (R)-28c
in the enzyme assay and in the cell based assay in high serum
conditions. Plasma protein binding values for (S)-28c (PPB; rat
94, dog 76, rhesus 88, human 81% bound) were higher in all
species tested with respect to (S)-28b (PPB; rat 84, dog 66,
human 63% bound).
a Results are the mean of at least three independent experiments. b Assays
were performed with recombinant HIV-1 integrase (0.1 µM) preassembled
on immobilized oligonucleotides. Inhibitors were added after assembly and
washings. For details, see ref 15 and references therein. c Cell culture
inhibitory concentrations (CIC95) are defined as those that inhibited by g
95% the spread of HIV-1 infection in susceptible cell culture MT-4 human
T-lymphoid cells. For details, see ref 15 and references therein.
account for this apparent discrepancy by reducing the in vivo
turnover, thus resulting in a low plasma clearance.
Further profiling of (R)-22b demonstrated that it does not
inhibit human DNA polymerases R, ꢀ, and γ (IC50 > 200 µM),
Rat PK profiles of both (S)-28b and (S)-28c were then
evaluated (Table 6). Both compounds proved to be orally
bioavailable, and (S)-28c showed a lower plasma clearance with
respect to (S)-28b (7 vs 11 (mL/min)/kg). The Cmax of (S)-28c
was 13-fold higher than that for (S)-28b (25 vs 2 µM). The
same behavior was also observed after administration to dog,
when (S)-28c showed a 2-fold lower plasma clearance and 10-
fold higher Cmax than (S)-28b.
Because of the above results, (S)-28c was further profiled. A
PK study in rhesus monkey showed a moderately low plasma
clearance (8 (mL/min)/kg), acceptable oral bioavailability (F
) 31%), and also in this species a high Cmax (10 µM).
In rat the compound displayed dose proportionality of plasma
exposure after oral administration of the compound (dose: 1, 4,
16, 48 mg/kg) as reported in Figure 3.
HIV-RNase-H (IC50 > 25 µM), or HCV polymerase (IC50
>
50 µM), and when tested for hERG-channel activity, it showed
IC50 ) 20 µM. It was not an inhibitor of CyP450 (1A2, 2C19,
2C9, 2D6, and 3A4, IC50 > 100 µM)).
In order to further optimize the pharmacological properties
of our inhibitors, we turned our attention to other possible
nitrogen functionalizations to improve metabolic stability and
maintain the high potency.
In other series of HIV-1 integrase inhibitors26,27 that had been
developed in our company, it had been found that the introduc-
tion of a ketoamide functionality had positive effects on activity
and pharmacological profile. We thus investigated the ketoamide
derivatization in the bicyclic series (Table 5).
As already observed in the amide and sulfonamide series,
when n ) 0, compound 28a, though active in the enzymatic
assay (IC50 ) 0.020 µM), displayed no significant activity up
to 1 µM in the cell based assays. The enlargement of the
saturated ring as in 28b (n ) 1) and 28c (n ) 2) resulted in
potent inhibitors both of the strand transfer and of the viral
spread in cells (spread CIC95: 28b 0.040 µM and 28c 0.063
Plasma concentration in the three preclinical species studied
(rat, dog, rhesus) was monitored after a 10 mg/kg oral
administration, revealing that up to 24–30 h after administration,
all species tested maintained concentration values that are higher
than the CIC95 (Figure 4).
Metabolic stability of (S)-28c in liver microsomes in the
presence of NADPH showed no appreciable turnover in dog

Bicyclic Pyrimidinones HIV1-Integrase Inhibitors
Journal of Medicinal Chemistry, 2008, Vol. 51, No. 4 867
Figure 4. The po dosing of (S)-28c (potassium salt) at 10 mg/kg in three preclinical species.
Scheme 1. Synthesis of Unsubstituted Bicyclic Pyrimidinonesa
resulting bromides (31a-c) were displaced with the appropriate
secondary amine, which provided also O-deprotection (32–37).
Treatment with 4-fluorobenzylamine, upon heating in MeOH,
afforded amino substituted compounds 7b,c, 8–9b, 10b,c, 11b,c.
Compounds 36a-c and 37b, where R1 (or both R1 and R2 as
in 37b) was a benzyl, gave access to further functionalized
compounds by removal of the benzyl group(s) by Pd-catalyzed
hydrogenation to 38a-c and 39b that, when treated with
4-fluorobenzylamine as before, furnished the versatile advanced
intermediates 40a-c and 41b, which allowed the synthesis of
the racemic compounds by reductive amination (7a) or func-
tionalization with acyl chlorides or carboxylic acids to give the
amide derivatives shown in Table 2, or with sulfonyl and
sulfamoyl chlorides to give the sulfonamide and sulfamide
derivatives shown in Table 3 and with methyl chlorooxoacetate,
followed by in situ amidation with dimethylamine, to provide
ketoamides shown in Table 5. To facilitate the purification of
the advanced intermediates 40, N-Boc derivatization can be
performed, followed by flash chromatography and Boc depro-
tection in acidic conditions, as described in the Experimental
Section for 40b.
The syntheses of the chiral derivatives present in Tables 2,
3, and 5 were performed, as described for the corresponding
racemic compounds in Scheme 2 (step e), by functionalizing
the chiral benzylamide intermediates (R)- or (S)-43b,c (Scheme
3). Chiral advanced intermediates 43b (n ) 1) were obtained
by treatment with 4-fluorobenzylamine of the corresponding
chiral esters 42b,29 while 43c (n ) 2) had been prepared as
recently described.30 The amide derivatives (R)/(S)-17b were
obtained by conventional amide coupling with [(dimethyl-
amino)sulfonyl]acetic acid,31 and the sulfamides (R)/(S)-22b and
(R)/(S)-27b were obtained by reaction with the appropriate
sulfamoyl chlorides in the presence of TEA. (R)/(S)-28b,c could
be obtained by a two-step one-pot procedure by acylating the
pyrimidone N-methylamine derivatives (R)/(S)-43b,c with methyl
chlorooxoacetate, followed by addition of a THF solution of
dimethylamine ((R)/(S)-28b) or alternatively by conventional
amide coupling with potassium (dimethylamino)(oxo)acetate
((R)/(S)-28c).
a Reagents and conditions: (a) benzoic anhydride, pyridine or THF; (b)
4-fluorobenzylamine, MeOH, 60 °C.
and human and only minor oxidative metabolism in rat and
rhesus. In the presence of both NADPH and UDPGA the
compound exhibited low turnover (turnover; rat 11, dog 4,
human 3 (mL/min)/mg P) and was cleared mainly by 5-O-
glucuronidation.28 Likewise, glucuronide formation was ob-
served in human hepatocytes, while no significant disappearance
of (S)-28c was detected from three different donors during a
4 h incubation with 106 cells/mL.
Selectivity of (S)-28c was demonstrated by testing it for
inhibition of human DNA polymerase R, ꢀ, and γ (IC50 > 10
µM), HIV RNaseH (IC50 > 50 µM), and it was also counter-
screened on a panel of 170 enzymes (MDS Pharma Services-
Panlabs) to evaluate potential off-target activities, resulting in
no significant notable responses. It did not significantly inhibit
the main isoforms of CyP450 (3A4, 2D6, 2C19; IC50 > 100
µM; 2C9, IC50 ) 75 µM), and when tested for hERG-channel
activity, it showed IC50 > 10 µM.
Chemistry
The synthesis of the bicyclic scaffolds was performed as
shown in Scheme 1. Treatment of pyrimidinones 29a-c29,30 or
the corresponding O-benzoyl protected 30a-c (more easily
isolated and purified) with 4-fluorobenzylamine provided ben-
zylamides 12a-c.
To obtain the functionalized derivatives shown in Tables 1-3
and 5, the synthetic pathway shown in Scheme 2 was followed.
Most of the steps could also be performed in one pot or
sequentially without isolating the intermediate steps (as de-
scribed in Experimental Section). The O-benzoyl protected
pyrimidinones 30a-c were brominated with NBS,29 and the
Conclusions
Design and synthesis of bicyclic analogues of N-methylpy-
rimidinones led to a new class of HIV-1 integrase inhibitors.
Prompted by the results of the unsubstituted bicyclic compounds
12a-c, which were nanomolar inhibitors of the strand transfer
of the integration process, we undertook a wide study on the
substitutions on the saturated ring of the bicyclic structures.
Amine, amide, sulfonamide, sulfamide, and ketoamide deriva-

868 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 4
Scheme 2. Synthesis of Substituted Bicyclic Pyrimidinonesa
Muraglia et al.
a Reagents and conditions: (a) NBS, benzoyl peroxide, CCl4, reflux; (b) R1R2NH, DMF; (c) 4-fluorobenzylamine, MeOH, 60 °C; (d) H2 atmospheric
pressure, 10% Pd/C, MeOH; (e) appropriate acyl chloride (or sulfonyl chloride or sulfamoyl chloride), base or carboxylic acid, coupling reagent; (f) for 40a,
to obtain 7a, 37% HCHO, NaCNBH3, AcONa, MeOH; (g) (1) Boc2O, dioxane; (2) 4 M HCl/dioxane.
under reduced pressure, and the crude material was dissolved in
methanol (0.5 mL). 4-Fluorobenzylamine (0.084 mL, 0.75 mmol)
was added, and the mixture was stirred for 1.5 h at 65 °C. The
solvent was removed under reduced pressure, and the product was
purified by preparative RP-HPLC and isolated as the trifluoroacetate
salt unless otherwise indicated.
(()-9-(Dimethylamino)-N-(4-fluorobenzyl)-3-hydroxy-4-oxo-
6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidine-2-carboxamide
(7b). A solution 2 N in MeOH of dimethylamine was used as amine.
Yield: 26%. 1H NMR (300 MHz, DMSO-d6) δ 12.51 (s, 1H), 10.69
(s, 1H), 10.59 (t, J ) 3.6 Hz, 1H), 7.50–7.40 (m, 2H), 7.22–7.10
(m, 2H), 4.79–4.68 (m, 1H), 4.60–4.38 (m, 2H), 4.13–4.03 (m, 1H),
3.61–3.48 (m, 1H), 2.97 (d, J ) 5.1 Hz, 3H), 2.66 (d, J ) 5.1 Hz,
3H), 2.34–2.17 (m, 2H), 2.00–1.79 (m, 2H). MS m/z: 361 (M +
H)+.
tives were evaluated as well as the size of the saturated ring
(Tables 1-3 and 5). A number of low nanomolar inhibitors of
the HIV-1 infection spread in cell culture could be identified
and further profiled in vitro and in vivo, leading to the ketoamide
(S)-28c, which proved to be a very potent and selective HIV
integrase inhibitor and orally biovailable and with good
pharmacological profile in preclinical species (rat, dog, rhesus
monkey) and was taken into further development.
Experimental Section
Reagents and solvents were obtained from commercial suppliers
and were used as obtained without further purification. Flash
chromatography purifications were performed on a Biotage system
using prepacked silica gel (200–400 mesh) cartridges. Analytical
HPLC-MS (X-Terra C18 column, 4.6 mm × 50 mm, 5 µm) and
UPLC-MS (Acquity UPLC BEH C18 column, 2.1 mm × 50 mm,
1.7 µm) were performed on a Waters Alliance 2795 apparatus
equipped with a diode array and a ZQ mass spectrometer (solvent
system acetonitrile/water + 0.1% HCOOH). Purity of final com-
pounds was more than 98% by area. Preparative RP-HPLC was
performed on a Waters Delta Prep 4000 connected to a dual-
wavelength absorbance detector 2487 (gradient of CH3CN/H2O +
0.1% TFAa, flow rate of 20 mL/min), typically using a Waters
Symmetry preparative column C18, 5 µm, 19 mm × 300 mm. After
RP-HPLC, the final compounds were isolated by lyophilization.
Enantiomeric excesses were determined by chiral HPLC using a
Chiralpak AD column, mobile phase n-hexane/ethanol + 0.2% TFA
+ 3% methanol, or or n-hexane + isopropanol + 0.2% TFA.
Nuclear magnetic resonance spectra (1H NMR recorded at 300,
400, or 500 MHz; 13C NMR recorded at 100 or 75 MHz) were
obtained on Bruker AMX spectrometers and are referenced in ppm
relative to TMS. Unless otherwise indicated, spectra were acquired
at 300 K. Microwave irradiation was performed in a Personal
Chemistry (now Biotage) Optimizer.
(()-10-(Dimethylamino)-N-(4-fluorobenzyl)-3-hydroxy-4-oxo-
4,6,7,8,9,10-hexahydropyrimido[1,2-a]azepine-2-carboxamide
(7c). A solution 2 N in MeOH of dimethylamine was used as amine.
1
Yield: 18%. H NMR (300 MHz, pyridine-d5) δ 10.01 (bs, 1H),
7.52 (dd, J ) 8.6, 5.7 Hz, 2H), 7.13 (t, J ) 8.6 Hz, 2H), 5.12–4.91
(m, 1H), 4.79 (dd, J ) 14.4, 6.2 Hz, 1H), 4.68 (dd, J ) 14.7, 5.9
Hz, 1H), 4.42 (t, J ) 11.8 Hz, 1H), 2.95 (bs, 1H), 2.00 (m, 6H),
1.92–1.61 (m, 3H), 1.60–1.10 (m, 3H). MS m/z: 375 (M + H)+.
(()-N-(4-Fluorobenzyl)-3-hydroxy-4-oxo-9-pyrrolidin-1-yl-
6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidine-2-carboxamide
(8b). Yield: 22%. 1H NMR (400 MHz, DMSO-d6) δ 12.44 (s, 1H),
11.14 (s, 1H), 10.66 (t, J ) 6.4 Hz, 1H), 7.47–7.40 (m, 2H),
7.18–7.10 (m, 2H), 4.85–4.74 (m, 1H), 4.55–4.37 (m, 2H),
4.07–4.00 (m, 1H), 3.76–3.65 (m, 1H), 3.65–3.52 (m, 1H),
3.42–3.25 (m, 2H), 3.22–3.15 (m, 1H), 2.37–2.29 (m, 1H),
2.25–2.15 (m, 1H), 2.10–1.76 (m, 6H). MS m/z: 387 (M + H)+.
(()-N-(4-Fluorobenzyl)-3-hydroxy-4-oxo-9-piperidin-1-yl-
6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidine-2-carboxamide
(9b). Yield: 17%. 1H NMR (300 MHz, DMSO-d6) δ 12.32 (s, 1H),
10.45 (t, J ) 5.4 Hz, 1H), 10.07 (s, br, 1H), 7.52–7.40 (m, 2H),
7.22–7.11 (m, 2H), 4.83–4.70 (m, 1H), 4.62–4.40 (m, 2H),
4.13–4.02 (m, 1H), 3.60–3.15 (m, 4H), 2.98–2.82 (m, 1H),
2.65–2.50 (m, 1H), 2.44–2.22 (m, 2H), 2.00–1.67 (m, 6H),
1.56–1.37 (m, 1H). MS m/z: 401 (M + H)+.
General Procedure for the Synthesis of Amines 7b-11c. To
a solution of bromide 3129,30 (0.245 mmol) in DMF (0.5 mL) (or
MeOH), the appropriate amine (0.75 mmol) was added. The mixture
was stirred at room temperature for 1 h. The solvent was removed

Bicyclic Pyrimidinones HIV1-Integrase Inhibitors
Journal of Medicinal Chemistry, 2008, Vol. 51, No. 4 869
Scheme 3. Synthesis of Chiral Pyrimidinone Benzylamidesa
(()-10-[Benzyl(methyl)amino]-N-(4-fluorobenzyl)-3-hydroxy-
4-oxo-4,6,7,8,9,10-hexahydropyrimido[1,2-a]azepine-2-carboxa-
mide (11c). Yield: 36%. 1H NMR (400 MHz, pyridine-d5) δ 9.85
(bs, 1H), 7.51 (dd, J ) 8.3, 5.6 Hz, 2H), 7.43–7.25 (m, 5H), 7.10
(t, J ) 8.7 Hz, 2H), 5.13 (dd, J ) 13.2, 6.1 Hz, 1H), 4.61–4.82
(m, 3H), 3.42–3.11 (m, 3H), 1.98–1.75 (m, 6H), 1.62–1.22 (m, 3H).
MS m/z: 451 (M + H)+.
(()-8-(Dimethylamino)-N-(4-fluorobenzyl)-3-hydroxy-4-oxo-
4,6,7,8-tetrahydropyrrolo[1,2-a]pyrimidine-2-carboxamide (7a).
The title compound was prepared using the following five-step
procedure. Step a: A mixture of methyl 3-(benzoyloxy)-4-oxo-
4,6,7,8-tetrahydropyrrolo[1,2-a]pyrimidine-2-carboxylate 30a31
(0.095 g, 88% w/w, 0.26 mmol), NBS (0.061 g, 0.35 mmol),
and catalytic dibenzoylperoxide in CCl4 (1.6 mL) was stirred
under reflux for 6 h. The mixture was cooled to room temperature
and filtered over silica gel (petroleum ether/ethyl acetate, 65:
35) to afford methyl 3-(benzoyloxy)-8-bromo-4-oxo-4,6,7,8-
tetrahydropyrrolo[1,2-a]pyrimidine-2-carboxylate 31a (MS m/z,
393/395 (M + H)+), which was used as such in the next step.
Step b: To a stirred solution of the above bromide in anhydrous
DMF (0.3 mL) was added N-benzyl-N-methylamine (0.064 mL,
0.5 mmol). The mixture was stirred for 2 h at room temperature
and then concentrated to dryness under reduced pressure to
provide crude methyl 8-[benzyl(methyl)amino]-3-hydroxy-4-oxo-
4,6,7,8-tetrahydropyrrolo[1,2-a]pyrimidine-2-carboxylate 36a (MS
m/z, 330 (M + H)+), which was used as such in the next step.
Step c: A solution of crude as above in methanol (0.9 mL),
containing palladium on charcoal (6 mg, 10% w/w), was stirred
under hydrogen at atmospheric pressure for 1.5 h. The catalyst
was filtered off, and the solution was concentrated to dryness
under reduced pressure. Crude methyl 3-hydroxy-8-(methyl-
amino)-4-oxo-4,6,7,8-tetrahydropyrrolo[1,2-a]pyrimidine-2-car-
boxylate 38a (MS m/z, 240 (M + H)+) was used as such in the
next step. Step d: To a solution of the above crude and TEA
(0.023 mL, 0.16 mmol) in dry methanol (0.7 mL) was added
4-fluorobenzylamine (0.028 mL, 0.25 mmol). The mixture was
stirred and heated to 65 °C overnight. After the mixture was
cooled to room temperature, the solvent was removed under
reduced pressure and the crude N-(4-fluorobenzyl)-3-hydroxy-
8-(methylamino)-4-oxo-4,6,7,8-tetrahydropyrrolo[1,2-a]pyrimi-
dine-2-carboxamide 40a (MS m/z, 333 (M + H)+) obtained was
used as such. Step e: To a solution of the above crude in
methanol (2 mL) were added formaldehyde (37% aqueous
solution, 0.03 mL, 0.33 mmol), sodium acetate (0.022 g, 0.27
mmol), and sodium cyanoborohydride (0.014 g, 0.23 mmol). The
mixture was stirred for 16 h at room temperature. The mixture
was concentrated under reduced pressure, and 8-(dimethy-
lamino)-N-(4-fluorobenzyl)-3-hydroxy-4-oxo-4,6,7,8-tetrahydro-
pyrrolo[1,2-a]pyrimidine-2-carboxamide 7a was isolated by
preparative RP-HPLC as the trifluoroacetate salt. Yield: 5%. 1H
NMR (400 MHz, DMSO-d6 + 2% TFA, 340 K) δ 9.03 (bs, 1H),
7.42–7.33 (m, 2H), 7.20–7.09 (m, 2H), 4.96 (t, J ) 8.3 Hz, 1H),
4.55 (ddd, J ) 6.3, 15.0, 35.9 Hz, 2H), 4.21–4.09 (m, 1H),
4.00–3.89 (m, 1H), 2.96 (s, 6H), 2.72–2.59 (m, 1H), 2.47–2.39
(m, 1H, partially under solvent signal). MS m/z: 347 (M + H)+.
a Reagents and conditions: (a) 4-fluorobenzylamine, MeOH, 65 °C, 3 h.
(b) For (R)/(S)-17b: HOBt, EDC, DIPEA, [(dimethylamino)sulfonyl]acetic
acid, DMF, room temperature, 24 h. (c) For (R)/(S)-22b and (R)/(S)-27b:
appropriate sulfamoyl chloride, DCM, TEA, room temperature, 90 min.
(d) For (R)/(S)-28b: (1) methyl chlorooxoacetate, TEA, DCM, room
temperature, 50 min; (2) 2 M N,N-dimethylamine/THF, 55 °C, 16 h. (e)
For (R)/(S)-28c: potassium (dimethylamino)(oxo)acetate, HOBt, EDC, TEA,
DCM, room temperature overnight.
(()-N-(4-Fluorobenzyl)-3-hydroxy-9-morpholin-4-yl-4-oxo-
6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidine-2-carboxamide
(10b). Yield: 9%. The trifluoroacetate salt obtained after RP-HPLC
was dissolved in 1 N HCl, the solvent was removed under reduced
pressure, and the residue was lyophilized from water/acetonitrile
to afford N-(4-fluorobenzyl)-3-hydroxy-9-morpholin-4-yl-4-oxo-
6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidine-2-carboxamide 10b
as the hydrochloride salt. 1H NMR (400 MHz, DMSO-d6) δ 12.34
(s, 1H), 10.99 (s, 1H), 10.47 (s, 1H), 7.44 (m, 2H), 7.16 (m, 2H),
4.85 (m, 1H), 4.60–4.40 (m, 3H), 4.10–3.85 (m, 4H), 3.60–3.05
(m, 5H), 2.35–2.15 (m, 2H), 2.03–1.80 (m, 2H). MS m/z: 403 (M
+ H)+.
(()-N-(4-Fluorobenzyl)-3-hydroxy-10-morpholin-4-yl-4-oxo-
4,6,7,8,9,10-hexahydropyrimido[1,2-a]azepine-2-carboxamide
(10c). Yield: 31%.1H NMR (300 MHz, pyridine-d5) δ 10.04 (bs,
1H), 7.52 (dd, J ) 8.3, 5.6 Hz, 2H), 7.14 (t, J ) 8.7 Hz, 2H), 5.13
(dd, J ) 13.2, 6.1 Hz, 1H), 4.81 (dd, J ) 14.4, 6.6 Hz, 1H), 4.69
(dd, J ) 14.5, 6.5 Hz, 1H), 4.41 (t, J ) 12.1 Hz, 1H), 3.77–3.57
(m, 4H), 2.96 (d, J ) 5.3 Hz, 1H), 2.42–2.19 (m, 2H), 2.00–1.64
(m, 5H), 1.56–1.23 (m, 3H). MS m/z: 417 (M + H)+.
(()-9-[Benzyl(methyl)amino]-N-(4-fluorobenzyl)-3-hydroxy-
4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidine-2-carboxa-
mide (11b). Yield: 26%.1H NMR (300 MHz, DMSO-d6) δ 12.64
(s, 0.4H), 12.34 (s, 0.6H), 10.92 (t, J ) 6.2 Hz, 0.4H), 10.77 (s,
0.4H), 10.32 (s, 0.6H), 10.17 (t, J ) 6.3 Hz, 0.6H), 8.00 (m, 1H),
7.53–7.11 (m, 9H), 4.93–4.82 (m, 0.6H), 4.82–4.73 (m, 0.4H),
4.65–4.49 (m, 2H), 4.45–4.32 (m, 1H), 4.23–4.05 (m, 1.6H),
3.98–3.85 (m, 0.4H), 3.52–3.45 (m, 1H), 2.96 (d, J ) 4.8 Hz, 1.8H),
2.89 (d, J ) 4.8 Hz, 1.2H), 2.49–1.60 (m, 4H). MS m/z: 438 (M +
H)+.
N-(4-Fluorobenzyl)-3-hydroxy-4-oxo-4,6,7,8-tetrahydropyr-
rolo[1,2-a]pyrimidine-2-carboxamide (12a). To a solution of 30a
(0.100 g, 88% w/w, 0.28 mmol) in dry methanol (1.0 mL) was
added 4-fluorobenzylamine (0.11 g, 0.84 mmol). The mixture was
irradiated in a sealed vessel in a microwave apparatus (140 °C,
500 s). After the mixture was cooled, the solvent was removed
under reduced pressure and the product was isolated by preparative
RP-HPLC (0.070 g, 82%). 1H NMR (400 MHz, DMSO-d6) δ 12.74
(bs, 1H), 8.96 (bs, 1H), 7.94–7.89 (m, 2H), 7.66–7.60 (m, 2H),
5.06 (d, J ) 6.6 Hz, 2H), 4.56 (t, J ) 7.2 Hz, 2H), 3.47 (t, J ) 7.9
1
Hz, 2H), 2.77 (m, partially overlapped by H2O). H NMR (300
MHz, DMSO-d6 + 2% TFA) δ 9.41 (t, J ) 6.2 Hz, 1H), 7.38–7.31
(m, 2H), 7.19–7.07 (m, 2H), 4.42 (d, J ) 6.2 Hz, 2H), 3.98 (t, J )
7.4 Hz, 2H), 2.97 (t, J ) 7.8 Hz, 2H), 2.14 (q, J ) 7.4 Hz, 2H).
13C NMR (75 MHz, DMSO-d6) δ 168.6, 161.2 (d, J ) 242 Hz),

870 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 4
Muraglia et al.
156.3, 153.7, 147.0, 134.8 (d, J ) 3 Hz), 129.5 (d, J ) 8 Hz),
126.6, 115.0 (d, J ) 21 Hz), 46.8, 41.4, 31.1, 19.3. MS m/z: 304
(M + H)+.
m/z: 447 (M + H)+. Step e: A solution of the above tert-butyl
(2-{[(4-fluorobenzyl)amino]carbonyl}-3-hydroxy-4-oxo-6,7,8,9-tet-
rahydro-4H-pyrido[1,2-a]pyrimidin-9-yl)methylcarbamate (1.62 g,
3.62 mmol) in 4 M HCl/1,4-dioxane (31 mL) was stirred at room
temperature for 3 h. The solvents were removed under reduced
pressure and the residue was triturated with Et2O, filtered, and left
under high vacuum to afford 40b as the hydrochloride salt as a
yellow solid (1.37 g, 99%). 1H NMR (300 MHz, DMSO-d6) δ 12.38
(s, 1H), 10.39 (t, J ) 6.2 Hz, 1H), 9.90 (s, br, 1H), 9.43 (s, br,
1H), 7.49–7.05 (m, 4H), 4.60–4.43 (m, 3H), 4.06–3.99 (m, 1H),
3.70–3.60 (m, 1H), 2.64 (s, 3H), 2.35–2.25 (m, 1H), 2.20–2.11 (m,
1H), 1.96–1.73 (m, 2H). MS m/z: 347 (M + H)+.
N-(4-Fluorobenzyl)-3-hydroxy-4-oxo-6,7,8,9-tetrahydro-4H-
pyrido[1,2-a]pyrimidine-2-carboxamide (12b). A solution of 29b
(0.050 g, 0.22 mmol) and 4-fluorobenzylamine (0.055 g, 0.44 mmol)
in methanol (0.5 mL) was stirred and heated to 65 °C for 22 h.
After the mixture was cooled, the solvent was removed under
reduced pressure and the product was isolated by preparative RP-
1
HPLC. Yield: 45%. H NMR (400 MHz, DMSO-d6) δ 12.12 (s,
1H), 9.35 (m, 1H), 7.36 (m, 2H), 7.15 (m, 2H), 4.44 (m, 2H), 3.84
(t, J ) 6.4 Hz, 2H), 2.80 (t, J ) 6.8 Hz, 2H), 1.90–1.73 (m, 4H).
MS m/z: 318 (M + H)+.
(()-N-(4-Fluorobenzyl)-3-hydroxy-10-(methylamino)-4-oxo-
4,6,7,8,9,10-hexahydropyrimido[1,2-a]azepine-2-carboxamide
(40c). 40c was prepared as described for 40b, steps a-c, starting
from methyl 10-bromo-3-hydroxy-4-oxo-4,6,7,8,9,10-hexahydro-
pyrimido[1,2-a]azepine-2-carboxylate 31c. The compound was used
as a crude for the next reactions or isolated by RP-HPLC as the
N-(4-Fluorobenzyl)-3-hydroxy-4-oxo-4,6,7,8,9,10-hexahydro-
pyrimido[1,2-a]azepine-2-carboxamide (12c). 12c was prepared
as described for 12b. The product was isolated by preparative RP-
HPLC (yield 54%). 1H NMR (500 MHz, DMSO-d6 + 2% TFA) δ
9.35 (bs, 1H), 7.36 (dd, J ) 8.4, 5.6 Hz, 2H), 7.14 (t, J ) 8.9 Hz,
2H), 4.44 (d, J ) 6.4 Hz, 2H), 4.33–4.20 (m, 2H), 3.05–2.90 (m,
2H), 1.78–1.62 (m, 6H). MS: m/z: 332 (M + H)+.
1
trifluoroacetate salt (yield 49%). H NMR (400 MHz, DMSO-d6)
δ 12.33 (s, 1H), 9.52 (s, 1H), 9.22 (bs, 1H), 8.82 (bs, 1H), 7.39 (t,
J ) 7.12 Hz, 2H), 7.21 (t, J ) 8.6 Hz, 2H), 4.94 (dd, J ) 14.3, 4.6
Hz, 1H), 4.71 (m, 1H), 4.63–4.51 (m, 2H), 3.50 (dd, partially
overlapped by water, 1H), 2.69 (s, 3H), 2.23 (d, J ) 12.7 Hz, 1H),
1.97 (d, J ) 11.5 Hz, 1H), 1.91–1.80 (m, 2H), 1.70–1.60 (m, 1H),
1.45–1.30 (m, 1H). MS m/z: 361 (M + 1)+.
General Procedure for the Synthesis of Amides 13c, 14–17b,
18b,c. Compound 40b or crude 40c (0.052 mmol) was dissolved
in DMF (0.5 mL) or DCM (1 mL). DIPEA (0.030 mL, 0.15 mmol),
HOBt (0.009 g, 0.068 mmol), EDC (0.038 g, 0.16 mmol), and the
appropriate carboxylic acid (0.16 mmol) were added, and the
mixture was stirred for 24 h at room temperature. The mixture was
diluted with 0.5 mL of DMF and filtered, and the product was
isolated by preparative RP-HPLC.
(()-2-{[(4-Fluorobenzyl)amino]carbonyl}-3-hydroxy-N-meth-
yl-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-9-amin-
ium chloride (40b). The title compound was prepared using the
following five-step procedure. Step a: To a stirred solution of methyl
3-(benzoyloxy)-9-bromo-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-
a]pyrimidine-2-carboxylate 31b (5.9 g, 14.43 mmol) in DMF (25
mL) at room temperature were added N-methyl-N-benzylamine
(4.03 mL, 30.3 mmol) and TEA (2.21 mL, 16.0 mmol). The mixture
was stirred for 75 min, and Et2O (900 mL) and 2 M HCl/Et2O
(23.6 mL) were added. The formed yellow precipitate was filtered
off, washed with Et2O, and dried under high vacuum to afford a
yellow solid (9.3 g). Crude methyl 9-[benzyl(methyl)amino]-3-
hydroxy-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidine-2-
carboxylate hydrochloride 36b was used as such without further
purification (MS m/z: 344 (M + H)+). Step b: The above crude
material was dissolved in MeOH (160 mL), palladium on charcoal
(0.980 g, 10% w/w) was added, and the mixture was stirred under
a hydrogen atmosphere for 3.5 h. The catalyst was filtered off, and
the solution was concentrated to dryness under reduced pressure
to afford crude methyl 3-hydroxy-9-(methylamino)-4-oxo-6,7,8,9-
tetrahydro-4H-pyrido[1,2-a]pyrimidine-2-carboxylate 38b as the
hydrochloride salt (6.9 g), which was used as such in the next step
without further purification (MS m/z: 254 (M + H)+). Step c: An
amount of 4.72 g of this crude material was dissolved in MeOH
(60 mL). 4-Fluorobenzylamine (1.15 mL, 10 mmol) and TEA (2.78
mL, 20 mmol) were added, and the mixture was stirred at 60 °C
for 14 h. The mixture was concentrated to dryness. The residue
was triturated with Et2O, and the residue was dried under vacuum
to afford 6.4 g of crude N-(4-fluorobenzyl)-3-hydroxy-9-(methyl-
amino)-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidine-2-car-
boxamide 40b as a yellow solid, which was used without further
purification (MS m/z: 347 (M + H)+). Step d: An amount of 5.9 g
of this crude material was suspended in a mixture of water (52
mL) and 1,4-dioxane (67 mL). Di-tert-butyl dicarbonate (11.0 g,
50.7 mmol), and NaHCO3 (4 g, 22.5 mmol) were added, and the
mixture was stirred at 62 °C for 3.5 h. After cooling to room
temperature, the mixture was partitioned between EtOAc (400 mL)
and 0.3 M aqueous HCl (200 mL). The organic phase was separated,
and the aqueous phase was extracted with EtOAc (200 mL). The
combined organic phases were dried over Na2SO4, filtered, and
concentrated to dryness under reduced pressure. The crude product
was purified by flash chromatography on silica gel, using EtOAc/
petroleum ether (4:1) as eluent. The pooled product fractions were
concentrated to dryness under reduced pressure to afford tert-butyl
(2-{[(4-fluorobenzyl)amino]carbonyl}-3-hydroxy-4-oxo-6,7,8,9-tet-
rahydro-4H-pyrido[1,2-a]pyrimidin-9-yl)methylcarbamate as a light-
pink oil (1.67 g, 3.74 mmol, 41% from 31b). 1H NMR (400 MHz,
DMSO-d6) δ 12.02 (s, 0.6H), 11.86 (s, 0.4H), 8.60 (s, 0.6H), 8.24
(s, 0.4H), 7.40–7.08 (m, 4H), 4.80–4.75 (m, 0.4H), 4.60–4.40 (m,
2.6H), 4.16–7.00 (m, 1H), 3.67–3.45 (m, 1H), 2.93 (s, 1.8H), 2.78
(s, 1.2H), 2.18–1.75 (m, 4H), 1.25 (s, 3.6H), 1.14 (s, 5.4H). MS
(()-10-[Acetyl(methyl)amino]-N-(4-fluorobenzyl)-3-hydroxy-
4-oxo-4,6,7,8,9,10-hexahydropyrimido[1,2-a]azepine-2-carboxa-
mide (13c). Yield: 17% from 31c. 1H NMR (400 MHz, DMSO-d6
+ 2% TFA) δ 8.13 (bs, 1H), 7.41–7.36 (m, 2H), 7.16 (t, J ) 8.8
Hz, 2H), 5.61 (bs, 1H), 5.00 (dd, J ) 14.4, 5.4 Hz, 1H), 4.61–4.49
(m, 2H), 3.63–3.50 (m, 1H), 3.05 (bs, 2H), 2.09–1.77 (m, 9H),
1.44–1.29 (m, 1H). MS m/z: 403 (M + H)+.
(()-9-[(Difluoroacetyl)(methyl)amino]-N-(4-fluorobenzyl)-3-
hydroxy-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidine-
1
2-carboxamide (14b). Yield: 19%. H NMR (300 MHz, DMSO-
d6) δ 12.20–11.90 (m, 1H), 8.67 (t, J ) 6.0 Hz, 0.7H), 8.57 (t, J )
6.0 Hz, 0.3H), 7.39–7.25 (m, 2H), 7.21–7.10 (m, 2H), 6.92–6.55
(m, 1H), 5.26–5.02 (m, 1H), 4.50 (d, J ) 6.0 Hz, 2H), 4.18–4.02
(m, 1H), 3.80–3.59 (m, 1H), 3.02 (s, 2.1H), 2.73 (s, 0.9H),
2.18–1.82 (m, 4H). MS m/z: 425 (M + H)+.
(()-N-(4-Fluorobenzyl)-3-hydroxy-9-[methyl(1H-pyrazol-1-
ylacetyl)amino]-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyri-
1
midine-2-carboxamide (15b). Yield: 44%. H NMR (300 MHz,
DMSO-d6) δ 12.16 (bs, 1H), 9.07 (t, J ) 6.7 Hz, 0.44H), 8.81 (t,
J ) 6.7 Hz, 0.56H), 7.68 (d, J ) 2.0 Hz, 0.44H), 7.56 (d, J ) 2.2
Hz, 0.56H), 7.41–7.28 (m, 3H), 7.22–7.06 (m, 2H), 6.28–6.21 (m,
1H), 5.48 (d, J ) 16.1 Hz, 0.44H), 5.29–5.10 (m, 2.56H), 4.65–4.51
(m, 2H), 4.20–4.05 (m, 1H), 3.72–3.55 (m, 1H), 3.00 (s, 1.68H),
2.66 (s, 1.32 H), 2.18–1.85 (m, 4H). MS m/z: 455 (M + H)+.
(()-N-(4-Fluorobenzyl)-3-hydroxy-9-[methyl([1,2,4]triazolo[1,5-
a]pyrimidin-2-ylcarbonyl)amino]-4-oxo-6,7,8,9-tetrahydro-4H-
1
pyrido[1,2-a]pyrimidine-2-carboxamide (16b). Yield: 68%. H
NMR (300 MHz, DMSO-d6) δ 12.20–11.5 (m, 1H), 9.60–9.50 (m,
0.6H), 9.45–9.40 (m, 0.6H), 9.35–9.23 (m, 0.8H), 7.56–7.38 (m,
3H), 7.21–7.03 (m, 2H), 5.57–5.50 (m, 0.6H), 5.25–5.15 (m, 0.4H),
4.80–4.60 (m, 2H), 4.15–3.90 (m, 1H), 3.76–3.55 (m, 1H), 2.89
(s, 1.2H), 2.85 (s, 1.8H), 2.23–1.71 (m, 4H). MS m/z: 493 (M +
H)+.
(()9-[{[(Dimethylamino)sulfonyl]acetyl}(methyl)amino]-N-(4-
fluorobenzyl)-3-hydroxy-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-
1
a]pyrimidine-2-carboxamide (17b). Yield: 53%. H NMR (300
MHz, DMSO-d6) mixture of two rotamers in ratio 4/1: δ 12.07 (s,
1H), 8.90 (t, J ) 6.3 Hz, 0.8H), 8.53 (t, J ) 6.3 Hz, 0.2H),

Bicyclic Pyrimidinones HIV1-Integrase Inhibitors
Journal of Medicinal Chemistry, 2008, Vol. 51, No. 4 871
7.46–7.32 (m, 2H), 7.26–7.13 (m, 2H), 5.56–5.44 (m, 0.8H),
5.24–5.12 (m, 0.2H), 4.64–4.04 (m, 5H), 3.80–3.64 (m, 1H), 3.10
(s, 2.4H), 2.83 (s, 6H), 2.74 (s, 0.6H), 2.19–1.90 (m, 4H). MS m/z:
496 (M + H)+.
DMSO-d6) mixture of two rotamers in ratio 4/1: δ 12.08 (s, br,
1H), 8.72 (t, J ) 6.4 Hz, 0.8H), 8.49 (t, J ) 6.4 Hz, 0.2H),
7.38–7.30 (m, 2H), 7.21–7.11 (m, 2H), 5.23–5.18 (m, 0.8H),
5.02–4.954 (m, 0.2H), 4.58 (d, J ) 6.4 Hz, 2H), 4.10–4.01 (m,
1H), 3.74–3.49 (m, 1H), 2.92 (s, 2.4H), 2.60 (s, 0.6H), 2.09 (s,
0.6H), 2.02 (s, 2.4H), 2.01–1.84 (m, 4H). MS m/z: 389 (M + H)+.
(()-9-({[(Dimethylamino)sulfonyl]acetyl}amino)-N-(4-fluo-
robenzyl)-3-hydroxy-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-
a]pyrimidine-2-carboxamide (19b). 19b was prepared from 31b
as described as for 13b, using dibenzylamine in the first step. Yield:
(R)-9-[{[(Dimethylamino)sulfonyl]acetyl}(methyl)amino]-N-
(4-fluorobenzyl)-3-hydroxy-4-oxo-6,7,8,9-tetrahydro-4H-pyri-
do[1,2-a]pyrimidine-2-carboxamide ((R)-17b). (R)-17b was pre-
pared from (R)-43b. [R]20 +89 ( 3 (EtOH), 99.5% ee. Spectral
D
properties are identical to those of the corresponding racemic
compound 17b.
1
8% from 31b. H NMR (300 MHz, DMSO-d6) δ 12.16 (s, 1H),
(S)-9-[{[(Dimethylamino)sulfonyl]acetyl}(methyl)amino]-N-(4-
fluorobenzyl)-3-hydroxy-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-
a]pyrimidine-2-carboxamide ((S)-17b). (S)-17b was prepared from
9.08 (t, J ) 6.2 Hz, 1H), 8.84 (d, J ) 7.8 Hz, 1H), 7.42–7.33 (m,
2H), 7.22–7.13 (m, 2H), 4.92–4.81 (m, 1H), 4.60–4.40 (m, 2H),
4.31 (d, J ) 13.8 Hz, 1H), 4.13 (d, J ) 13.8 Hz, 1H), 4.12–4.02
(m, 1H), 3.90–3.80 (m, 1H), 3.11 (s, 3H), 2.18–1.87 (m, 3H),
1.75–1.55 (m, 1H). MS m/z: 453 (M + H)+.
(S)-43b. [R]20 -93 ( 3 (EtOH), 96.7% ee. Spectral properties
D
are identical to those of the corresponding racemic compound 17b.
(()-N-(4-Fluorobenzyl)-3-hydroxy-9-{methyl[(methylsulfonyl)
acetyl]amino}-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimi-
dine-2-carboxamide (18b). Yield: 70%. 1H NMR (300 MHz,
DMSO-d6) mixture of two rotamers in ratio 4/1: δ 12.11 (s, 1H),
8.89 (t, J ) 6.3 Hz, 0.8H), 8.68 (t, J ) 6.3 Hz, 0.2H), 7.45–7.33
(m, 2H), 7.25–7.13 (m, 2H), 5.55–5.43 (m, 0.8H), 5.25–5.15 (m,
0.2H), 4.74–4.44 (m, 4H), 4.22–4.10 (m, 1H), 3.80–3.60 (m, 1H),
3.25 (s, 0.6H), 3.10 (s, 2.4H), 3.08 (s, 2.4H), 2.73 (s, 0.6H),
2.20–1.92 (m, 4H). MS m/z: 467 (M + H)+.
General Procedure for the Synthesis of Sulfonamides 20,
21, 22b,c, 24–27. 40b (or 40c) (0.14 mmol) was suspended in DCM
(4 mL). TEA (0.3 mL, 2.15 mmol) and the appropriate sulfonyl
(or sulfamoyl) chloride (1.86 mmol) were added, and the mixture
was stirred at room temperature for 90 min. The solvent was
removed under reduced pressure, and the product was isolated by
preparative RP-HPLC.
(()-N-(4-Fluorobenzyl)-3-hydroxy-9-[methyl(methylsulfonyl)
amino]-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidine-2-
carboxamide (20b). Yield: 39%. Prior to RP-HPLC, the residue
was suspended in a mixture of 1 M NaOH and MeOH (1:1, 20
mL), stirred at room temperature for 16 h, and neutralized with 1
N aqueous HCl. 1H NMR (400 MHz, DMSO-d6) δ 11.85 (s, 1H),
8.87 (t, J ) 6.4 Hz, 1H), 7.36–7.28 (m, 2H), 7.20–7.12 (m, 2H),
4.97–4.88 (m, 1H), 4.57–4.42 (m, 2H), 4.01–3.94 (m, 1H),
3.74–3.65 (m, 1H), 3.09 (s, 3H), 2.71 (s, 3H), 2.10–1.92 (m, 4H).
MS m/z: 425 (M + H)+.
(()-N-(4-Fluorobenzyl)-3-hydroxy-10-{methyl[(methylsulfo-
nyl)acetyl]amino}-4-oxo-4,6,7,8,9,10-hexahydropyrimido[1,2-
a]azepine-2-carboxamide (18c). To crude N-(4-fluorobenzyl)-3-
hydroxy-10-(methylamino)-4-oxo-4,6,7,8,9,10-hexahydropyrimido[1,2-
a]azepine-2-carboxamide 40c (0.33 mmol) in DCM (6 mL) were
added DIPEA (0.043 g, 0.33 mmol), HATU (0.152 g, 0.4 mmol),
methylsulfonylacetic acid (0.055 g, 0.4 mmol), and TEA (0.121 g,
1.2 mmol), and the mixture was stirred at room temperature. The
reaction mixture, diluted with DCM, was washed with 1 M HCl in
water, dried over anhydrous Na2SO4, filtered, and concentrated. The
residue was purified by RP-HPLC. Yield: 14% from 31c. 1H NMR
(400 MHz, DMSO-d6) mixture of two rotamers in ratio 4/1: δ 12.78
(bs, 1H), 8.60 (bs, 0.8H), 8.09 (bs, 0.2H), 7.34–7.30 (m, 2H), 7.14
(t, J ) 8.8 Hz, 2H), 5.58 (d, J ) 8.8 Hz, 0.8H), 5.26 (bs, 0.2H),
4.98 (dd, J ) 14.1, 5.2 Hz, 1H), 4.69 (d, J ) 14.3 Hz, 1H), 4.56
(dd, J ) 14.7, 6.7 Hz, 1H), 4.45 (dd, J ) 15.0, 6.2 Hz, 1H), 4.32
(d, J ) 14.5 Hz, 1H), 3.53 (t, J ) 12.8 Hz, 1H), 3.18 (s, 2.4H),
3.02 (s, 3H), 2.95 (s, 0.6H), 2.15–1.71 (m, 5H), 1.45–1.31 (m, 1H).
MS m/z: 481 (M + H)+.
(()-N-(4-Fluorobenzyl)-3-hydroxy-10-[methyl(methylsulfonyl)
amino]-4-oxo-4,6,7,8,9,10-hexahydropyrimido[1,2-a]azepine-2-
carboxamide (20c). 20c was treated with NaOH prior to RP-HPLC,
1
as described for 20b. Yield: 8% from 31c. H NMR (400 MHz,
DMSO-d6): δ 12.13 (bs, 1H), 8.68 (t, J ) 6.0 Hz, 1H), 7.35 (dd,
J ) 8.6, 5.7 Hz, 2H), 7.16 (t, J ) 8.9 Hz, 2H), 4.99 (d, J ) 8.8
Hz, 2H), 4.88 (dd, J ) 14.0, 5.5 Hz, 1H), 4.59–4.47 (m, 2H),
3.58–3.48 (m, partially hidden under water), 3.03 (s, 1H), 2.94 (s,
3H), 2.11–1.78 (m, 5H), 1.38–1.22 (m, 1H). MS m/z: 439 (M +
H)+.
(()-N-(4-Fluorobenzyl)-3-hydroxy-9-{methyl[(1,3,5-trimethyl-
(()-8-[Acetyl(methyl)amino]-N-(4-fluorobenzyl)-3-hydroxy-
4-oxo-4,6,7,8-tetrahydropyrrolo[1,2-a]pyrimidine-2-carboxam-
ide (13a). The compound was prepared by reacting a solution of
crude N-(4-fluorobenzyl)-3-hydroxy-8-(methylamino)-4-oxo-4,6,7,8-
tetrahydropyrrolo[1,2-a]pyrimidine-2-carboxamide 40a (prepared
as described for 7a, step d) in dry DCM (2 mL) with DIPEA (0.062
g, 0.48 mmol), HOBt (0.045 g, 0.33 mmol), EDC (0.064 mg, 0.33
mmol), and acetic acid (0.034 g, 0.56 mmol). The mixture was
stirred at room temperature for 16 h and then concentrated. The
product was isolated by preparative RP-HPLC. Yield: 2% from
1H-pyrazol-4-yl)sulfonyl]amino}-4-oxo-6,7,8,9-tetrahydro-4H-
1
pyrido[1,2-a]pyrimidine-2-carboxamide (21b). Yield: 29%. H
NMR (400 MHz, DMSO-d6 + 2% TFA) δ 9.04 (t, J ) 6.0 Hz,
1H), 7.42–7.35 (m, 2H), 7.20–7.11 (m, 2H), 5.17 (t, J ) 8.8 Hz,
1H), 4.60 (dd, J ) 7.2, 15.0 Hz, 1H), 4.44 (dd, J ) 5.6, 15.0 Hz,
1H), 4.10–4.02 (m, 1H), 3.67 (s, 3H), 3.60–3.49 (m, 1H), 2.37 (s,
3H), 2.31 (s, 3H), 2.16 (s, 3H), 2.12–1.92 (m, 4H). MS m/z: 519
(M + H)+.
(()-9-[[(Dimethylamino)sulfonyl](methyl)amino]-N-(4-fluo-
1
robenzyl)-3-hydroxy-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-
30a. H NMR (400 MHz, DMSO-d6 + 2% TFA) mixture of two
1
a]pyrimidine-2-carboxamide (22b). Yield: 32%. H NMR (300
rotamers in ratio 3/1: δ 9.02 (bs, 1H), 7.40–7.32 (m, 2H), 7.18–7.08
(m, 2H), 5.75–5.65 (m, 0.75H), 5.59–5.48 (m, 0.25H), 4.50 (ddd,
J ) 6.6, 15.0, 24.8 Hz, 2H), 4.19–4.05 (m, 1H), 3.91–3.78 (m,
1H), 2.93 (s, 2.1H), 2.71–2.64 (bs, 0.9H), 2.46–2.35 (m, 1H,
partially under solvent signal), 2.20–2.00 (m, 4H). MS m/z: 375
(M + H)+.
MHz, CDCl3) δ 11.95 (s, 1H), 9.13 (m, 1H), 7.38 (m, 2H), 7.04
(m, 2H), 4.98 (m, 1H), 4.56 (m, 2H), 4.36 (m, 1H), 3.62 (m, 1H),
2.84 (s, 6H), 2.57 (s, 3H), 2.38–1.85 (m, 4H). 13C NMR (100 MHz,
CDCl3) δ 167.53, 162.55, 160.11, 157.74, 145.76 144.11, 132.70,
128.89, 128.81, 124.82, 114.60, 114.39, 58.06, 42.93, 41.53, 37.00,
29.03, 23.89, 20.09. MS m/z: 454 (M + H)+.
(S)-9-[[(Dimethylamino)sulfonyl](methyl)amino]-N-(4-fluo-
robenzyl)-3-hydroxy-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-
a]pyrimidine-2-carboxamide ((S)-22b). (S)-22b was prepared from
(S)-43b as already described for 22b. Yield: 37%. [R]20D +33 ( 3
(EtOH), 97% ee. Spectral properties are identical to those of the
corresponding racemic compound 22b.
(()-9-[Acetyl(methyl)amino]-N-(4-fluorobenzyl)-3-hydroxy-
4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidine-2-carboxa-
mide (13b). The compound was prepared starting from 31b (0.055
g, 0.138 mmol), according to the procedure described for the
synthesis of 40b (step c) and then the following step d: Crude 40b
was dissolved in DCM (2 mL). DIPEA (0.105 g, 0.82 mmol), acetic
acid (0.029 g, 0.48 mmol), HOBt (0.081 g, 0.60 mmol), and EDC
(0.115 g, 0.60 mmol) were added, and the mixture was stirred for
4 h at room temperature. The solvent was removed under reduced
pressure, and the product was isolated by preparative RP-HPLC to
(R)-9-[[(Dimethylamino)sulfonyl](methyl)amino]-N-(4-fluo-
robenzyl)-3-hydroxy-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-
a]pyrimidine-2-carboxamide ((R)-22b). (R)-22b was prepared
from (R)-43b as already described for 22b. The pooled product
1
afford the title compound (0.020 g, 26%). H NMR (400 MHz,

872 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 4
Muraglia et al.
fractions, lyophilized after RP-HPLC purification, afforded the title
compound as a fluffy white material (90.7% ee). The compound
was dissolved in ethanol and left standing at room temperature for
3 days. The supernatant was taken off and concentrated to dryness
under reduced pressure. The residue was redissolved in ethanol,
and the solution was left standing at room temperature for 1 day.
The supernatant was taken off and concentrated under reduced
pressure and the residue lyophilized from water/acetonitrile to afford
the title product with an enantiomeric excess of 99.4% (ee
determined by chiral HPLC Chiralpak AD, mobile phase n-hexane/
(()-8-[[(Dimethylamino)sulfonyl](methyl)amino]-N-(4-fluo-
robenzyl)-3-hydroxy-4-oxo-4,6,7,8-tetrahydropyrrolo[1,2-a]py-
rimidine-2-carboxamide (22a). The compound was prepared by
reacting a solution of crude N-(4-fluorobenzyl)-3-hydroxy-8-
(methylamino)-4-oxo-4,6,7,8-tetrahydropyrrolo[1,2-a]pyrimidine-
2-carboxamide 40a (prepared as described for 7a step d) in dry
DCM (0.5 mL) and TEA (0.04 mL, 0.29 mmol). N,N-Dimethyl-
sulfamoyl chloride (0.031 mL, 0.29 mmol) was added. The mixture
was stirred at room temperature for 16 h, then diluted with DCM
and washed with 1 N HCl and brine. The organic phase was dried
over Na2SO4 and concentrated. The product was isolated by
isopropanol + 0.2% TFA). Yield: 61%. [R]20 -33 ( 2 (EtOH).
D
1
Spectral properties are identical to those of the corresponding
preparative RP-HPLC. Yield: 2% from 30a. H NMR (400 MHz,
racemic compound 22b.
(()-10-[[(Dimethylamino)sulfonyl](methyl)amino]-N-(4-fluo-
robenzyl)-3-hydroxy-4-oxo-4,6,7,8,9,10-hexahydropyrimido[1,2-
DMSO-d6) δ 12.42 (bs, 1H), 8.78 (t, J ) 6.3 Hz, 1H), 7.42–7.35
(m, 2H), 7.23–7.15 (m, 2H), 5.27 (t, J ) 9.1 Hz, 1H), 4.51 (ddd,
J ) 6.3, 4.8, 6.8 Hz, 2H), 4.13–4.05 (m, 1H), 3.88–3.72 (m, 1H,
partially hidden under the signal of water), 2.78 (s, 6H), 2.73 (s,
3H), 2.48–2.38 (m, 1H), 2.35–2.23 (m, 1H). MS m/z: 440 (M +
H)+.
(()-N-(4-Fluorobenzyl)-3-hydroxy-9-(6-methyl-1,1-dioxido-
1,2,6-thiadiazinan-2-yl)-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-
a ]pyrimidine-2-carboxamide (23b). 23b was prepared from 31b
as described below for 23c. Yield: 30%. 1H NMR (300 MHz,
DMSO-d6) δ 11.59 (bs, 1H), 9.14 (t, J ) 6.2 Hz, 1H), 7.45–7.32
(m, 2H), 7.25–7.12 (m, 2H), 4.87–4.78 (m, 1H), 4.61–4.42 (m, 2H),
4.12–3.96 (m, 1H), 3.70–3.47 (m, 2H), 3.31–3.22 (m, 1H),
3.18–3.12 (m, 2H), 2.68 (s, 3H), 2.12–1.86 (m, 5H), 1.48–1.35 (m,
1H). MS m/z: 466 (M + H)+.
1
a]azepine-2-carboxamide (22c). Yield: 10% from 31c. H NMR
(400 MHz, DMSO-d6): δ 11.78 (bs, 1H), 8.85 (t, J ) 5.8 Hz, 1H),
7.38 (dd, J ) 8.4, 5.6 Hz, 2H), 7.18 (t, J ) 8.9 Hz, 2H), 4.96–4.85
(m, 2H), 4.61–4.48 (m, 2H), 3.49 (dd, J ) 13.8, 11.6 Hz, 1H),
2.81 (s, 3H), 2.71(s, 6H), 2.18–2.08 (m, 1H), 2.03–1.79 (m, 4H),
1.41–1.28 (m, 1H). MS m/z: 468 (M + H)+.
(()-N-(4-Fluorobenzyl)-3-hydroxy-9-[methyl(pyrrolidin-1-yl-
sulfonyl)amino]-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyri-
midine-2-carboxamide (24b). The appropriate sulfamoyl chloride
was prepared according to the literature.32 Yield: 27%. H NMR
1
(300 MHz, DMSO-d6) δ 11.64 (s, 1H), 9.15 (t, J ) 6.3, 1H),
7.40–7.27 (m, 2H), 7.20–7.10 (m, 2H), 4.95–4.82 (m, 1H),
4.50–4.40 (m, 2H), 4.10–4.05 (m, 1H), 3.62–3.48 (m, 1H),
3.30–3.11 (m, 4H), 2.53 (s, 3H), 2.15–1.91 (m, 4H), 1.90–1.79 (m,
4H). MS m/z: 480 (M + H)+.
(()-N-(4-Fluorobenzyl)-3-hydroxy-10-(6-methyl-1,1-dioxido-
1,2,6-thiadiazinan-2-yl)-4-oxo-4,6,7,8,9,10-hexahydropyrimido[1,2-
a]azepine-2-carboxamide (23c). To a solution of methyl 3-(ben-
zoyloxy)-10-bromo-4-oxo-4,6,7,8,9,10-hexahydropyrimido[1,2-
a]azepine-2-carboxylate 31c (0.100 g, 0.238 mmol) in DMF (5 mL)
were added 2-methyl-1,2,6-thiadiazinane 1,1-dioxide (0.178 g, 1.19
mmol) and Cs2CO3 (0.387 g, 1.19 mmol), and the mixture was
stirred at 0 °C for 20 min. The solvent was removed under reduced
pressure and to crude methyl 3-hydroxy-10-(6-methyl-1,1-dioxido-
1,2,6-thiadiazinan-2-yl)-4-oxo-4,6,7,8,9,10-hexahydropyrimido[1,2-
a]azepine-2-carboxylate dissolved in methanol (4 mL) was added
4-fluorobenzylamine (0.127 g, 0.952 mmol). The mixture was stirred
at reflux overnight. The solvent was removed under reduced
pressure, and the product was purified by preparative RP-HPLC.
(()-N-(4-Fluorobenzyl)-3-hydroxy-9-[methyl(piperidin-1-yl-
sulfonyl)amino]-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyri-
midine-2-carboxamide (25b). The appropriate sulfamoyl chloride
was prepared according to the literature.32 Yield: 26%. H NMR
1
(300 MHz, DMSO-d6) δ 11.64 (bs, 1H), 9.09 (t, J ) 6.4 Hz, 1H),
7.41–7.30 (m, 2H), 7.21–7.11 (m, 2H), 4.90–4.78 (m, 1H),
4.61–4.42 (m, 2H), 4.12–3.98 (m, 1H), 3.65–3.48 (m, 1H),
3.15–3.04 (m, 4H), 2.53 (s, 3H), 2.19–1.95 (m, 4H), 1.62–1.41 (m,
6H). MS m/z: 494 (M + H)+.
(()-N-(4-Fluorobenzyl)-3-hydroxy-9-[methyl(morpholin-4-yl-
sulfonyl)amino]-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyri-
midine-2-carboxamide (26b). The appropriate sulfamoyl chloride
1
Yield: 6%. H NMR (500 MHz, DMSO-d6 + 2% TFA) δ 9.02
(bs, 1H), 7.39 (dd, J ) 8.4, 5.7 Hz, 2H), 7.18 (t, J ) 8.9 Hz, 2H),
4.80 (d, J ) 8.6 Hz, 1H), 4.68 (dd, J ) 14.0, 6.1 Hz, 1H), 4.58–4.44
(m, 2H), 3.77 (t, J ) 12.2 Hz, 1H), 3.55–3.47 (m, 2H), 3.43–3.29
(m, 2H), 2.70 (s, 3H), 2.07–1.90 (m, 2H), 1.91–1.62 (m, 5H),
1.39–1.49 (m, 1H). MS m/z: 480 (M + H)+.
was prepared according to the literature.32 Yield: 43%. H NMR
1
(300 MHz, CD3CN) δ 11.90 (bs, 1H), 9.13 (bs, 1H), 7.51–7.35
(m, 2H), 7.21–7.10 (m, 2H), 5.00–4.88 (m, 1H), 4.65–4.50 (m, 2H),
4.28–4.12 (m, 1H), 3.81–3.69 (m, 4H), 3.69–3.55 (m, 1H),
3.26–3.13 (m, 4H), 2.65 (s, 3H), 2.32–1.92 (m, 4H). MS m/z: 496
(M + H)+.
(()-N-(4-Fluorobenzyl)-3-hydroxy-9-{methyl[(4-methylpiper-
azin-1-yl)sulfonyl]amino}-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-
a]pyrimidine-2-carboxamide (27b). The appropriate sulfamoyl
chloride was prepared according to the literature.32 Yield: 33%.
Isolated as the trifluoroacetate salt after RP-HPLC. 1H NMR (300
MHz, CD3CN) δ 11.67 (bs, 1H), 9.73 (bs, 1H), 8.96 (t, J ) 6.3
Hz, 1H), 7.41–7.29 (m, 2H), 7.21–7.10 (m, 2H), 4.93–4.80 (m, 1H),
4.61–4.40 (m, 2H), 4.12–4.00 (m, 1H), 3.81–3.36 (m, 5H),
3.21–2.97 (m, 4H), 2.84 (s, 3H), 2.59 (s, 3H), 2.19–1.91 (m, 4H).
MS m/z: 510 (M + H)+.
General Procedure for the Synthesis of Ketoamides 28.
Method A. To a stirred 0.1 M solution of crude 40a or 40b,c in
DCM were added TEA (or DIPEA) (6 equiv) and methyl chlo-
rooxoacetate (6 equiv). The mixture was stirred at room temperature
for 2 h, the solvent was removed under reduced pressure, and the
residue was dissolved in a solution of 2 M dimethylamine in THF
(6 equiv). The mixture was stirred at 57 °C overnight. After the
mixture was cooled to room temperature, the solvent was removed
under reduced pressure and the product was isolated by preparative
RP-HPLC.
Method B. To a stirred 0.1 M solution of 40a-c in DCM were
added TEA (3 equiv), potassium (dimethylamino)(oxo)acetate (2
equiv), EDC (2.2 equiv), and HOBt (2.2 equiv). The mixture was
stirred at room temperature overnight. The solvent was removed
under reduced pressure, and the residue was partitioned between
ethyl acetate and 1 M aqueous HCl. The aqueous phase was
extracted with ethyl acetate, and the combined organic phases were
dried over sodium sulfate, filtered, and concentrated to dryness
under vacuum. The product was isolated by preparative RP-HPLC.
(()-N-(2-{[(4-Fluorobenzyl)amino]carbonyl}-3-hydroxy-4-
oxo-4,6,7,8-tetrahydropyrrolo[1,2-a]pyrimidin-8-yl)-N,N′,N′-tri-
methylethanediamide (28a). 28a was prepared from crude 40a
(method A) (yield 2% from 30a). 1H NMR (400 MHz, DMSO-d6)
mixture of rotamers 1:1: δ 12.57 (s, 0.5H), 12.48 (s, 0.5H), 9.17
(S)-N-(4-Fluorobenzyl)-3-hydroxy-9-{methyl[(4-methylpiper-
azin-1-yl)sulfonyl]amino}-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-
a]pyrimidine-2-carboxamide ((S)-27b). (S)-27b was prepared from
(S)-42b as described for 27b. Yield: 11%. [R]20D +22 ( 3 (EtOH),
93% ee. Spectral properties are identical to those of the corre-
sponding racemic compound 27b.
(R)-N-(4-Fluorobenzyl)-3-hydroxy-9-{methyl[(4-methylpiper-
azin-1-yl)sulfonyl]amino}-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-
a]pyrimidine-2-carboxamide ((R)-27b). (R)-27b was prepared
from (R)-42b as described for 27b. Yield: 33%. [R]20 -23 ( 3
D
(EtOH), 98% ee. Spectral properties are identical to those of the
corresponding racemic compound 27b.

Bicyclic Pyrimidinones HIV1-Integrase Inhibitors
Journal of Medicinal Chemistry, 2008, Vol. 51, No. 4 873
(m, 0.5H), 9.01 (m, 0.5H), 7.37–7.29 (m, 2H), 7.21–7.13 (m, 2H),
5.53 (m, 0.5H), 5.18 (m, 0.5H), 4.61–4.34 (m, 2H), 4.18–4.04 (m,
1H), 3.96–3.86 (m, 0.5H), 3.81–3.71 (m, 0.5H), 2.97 (s, 1.5H), 2.91
(s, 1.5H), 2.87–2.78 (m, 6H), 2.57–2.54 (m, partially overlapped
by solvent signal), 2.37–2.16 (m, 1.5H). MS m/z: 432 (M + H)+.
Acknowledgment. We gratefully thank Steve Young and
Daria Hazuda for useful discussion. We also thank Vincenzo
Pucci for HRMS analysis, Maria Verdirame, Francesca Naimo,
and Anna Alfieri for bioanalytical work and plasma protein
binding data, Silvia Pesci for NMR analysis, Marina Taliani
for microsomal stability studies, and Isabella Marcucci for
assistance with CYP inhibition studies. This work was supported
in part by a grant from the MIUR.
(()-N1-(2-{[(4-Fluorobenzyl)amino]carbonyl}-3-hydroxy-4-
oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-9-yl)-N1,N2,N2-
trimethylethanediamide (28b). 28b was prepared from 40b
(method A). Yield: 39%. 1H NMR (400 MHz, DMSO-d6) mixture
of rotamers 4:1, δ 12.05 (s, 0.2H), 11.89 (s, 0.8H), 9.21 (m, 0.8H),
8.74 (m, 0.2H), 7.40–7.28 (m, 2H), 7.20–7.10 (m, 2H), 5.17 (m,
0.8H), 4.63–4.35 (m, 2.2H), 4.13–4.00 (m, 1H), 3.65–3.53 (m,
partially overlapped by water signal), 2.95–2.75 (m, 9H), 2.15–1.80
(m, 4H). 13C NMR (100 MHz, DMSO-d6) δ 167.87, 167.73, 165.92,
165.46, 164.51, 164.30, 162.42, 160.01, 157.50, 157.41, 146.27,
146.18, 145.76, 145.49, 134.44, 129.43, 129.35, 129.08, 129.00,
125.17, 125.05, 115.07, 114.85, 57.47, 53.60, 43.14, 41.37, 36.49,
35.95, 32.92, 32.64, 32.36, 28.19, 23.88, 22.12, 19.67, 19.35. MS
m/z: 446 (M + H)+.
Supporting Information Available: Synthesis and analytical
data for the intermediates 30a, 30c, 31c, and [(dimethylamino)sul-
fonyl]acetic acid; HPLC, UPLC, and high-resolution mass measure-
ments (HRMS) data for final compounds. This material is available
free of charge via the Internet at http://pubs.acs.org.
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(R)-N1-((9R)2-{[(4-Fluorobenzyl)amino]carbonyl}-3-hydroxy-
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JM701164T