Synthesis of ranolazine derivatives containing the (1S,4S)-2,5- diazabicyclo[2.2.1]heptane moiety and their evaluation as vasodilating agents

Article abstract of DOI:10.1111/cbdd.12285

Two diazabicyclic analogues of ranolazine, (S,S,S)-5 and (S,S,R)-5, and their epimeric mixture were synthesized. Furthermore, their vasomotor effects on rat aorta rings precontracted with phenylephrine were analyzed. These compounds showed vasodilating effects significantly greater than ranolazine. The vasodilating activities of these analogues have two components, one that depends on the endothelium, due to the release of NO, and another one due to a direct effect on the vascular smooth muscle. The compounds [(S,S,S)(S,S,R)]-5 and (S,S,R)-5 induce, in a manner similar to ranolazine, the release of a prostanoid from the cyclooxygenase pathway, whose vasoconstrictor effect is masked by the predominant vasodilation induced by these compounds. Two diazabicyclic analogues of ranolazine, (S,S,S)-5 and (S,S,R)-5, and their epimeric mixture showed a vasodilating effect significantly greater than ranolazine. This vasodilating activity has two components, one of them endothelium dependent, due to the release of NO, and the other one due to a direct effect on the vascular smooth muscle. In a manner similar to ranolazine, [(S,S,S)(S,S,R)]-5 and (S,S,R)-5 induce the release of a prostanoid, whose vasoconstrictor effect is masked by the predominant vasodilation induced by these compounds.

Full text of DOI:10.1111/cbdd.12285

Chem Biol Drug Des 2014; 83: 710–720
Research Article
Synthesis of Ranolazine Derivatives Containing the
(1S,4S)-2,5-Diazabicyclo[2.2.1]Heptane Moiety and
Their Evaluation as Vasodilating Agents
1
1
ꢀ
The (1S,4S)-2,5-diazabicyclo[2.2.1]heptane (DBH) system,
described for the first time in 1966 (4), is structurally equiv-
Manuel Lopez-Ortiz , Ivan Monsalvo , Patricia
Demare1, Cristina Paredes2, Dieter Mascher2,
Carlos Hernandez , Marcos Hernandez and
2
3
alent to
a piperazine, but it has a conformationally
ꢀ
ꢀ
Ignacio Regla1,*
restricted equilibrium. This system has been incorporated
to some compounds of medicinal character, that is, ben-
zothiazoles A and B, with antianginal activity (Figure 1; 5).
1Facultad de Estudios Superiores Zaragoza, Universidad
ꢀ
Nacional Autonoma de Mexico (UNAM), Batalla del 5 de Mayo
y Fuerte de Loreto, Iztapalapa, 09230, Mexico, D.F., Mexico
ꢀ
ꢀ
ꢀ
In the search for improving the quality of life of patients
with cardiovascular diseases, the development of more
efficient pharmacological treatments takes a greatly impor-
tant role due to the need of new and more active cardio-
vascular drugs with fewer side-effects.
2
ꢀ
Departamento de Fisiologıa, Facultad de Medicina,
ꢀ
Universidad Nacional Autonoma de Mexico, 04510,
ꢀ
ꢀ
Mexico, D.F., Mexico
Instituo de Quımica, UNAM, Circuito Exterior, Ciudad
ꢀ
3
ꢀ
ꢀ
Universitaria, 04510, Mexico, D.F., Mexico
*Corresponding author: Ignacio Regla, regla@unam.com
ꢀ
In WO 01/62744 A2, Zablocki et al. (6) described the
preparation of a wide number of ranolazine analogues,
including some bicyclic compounds such as (S,S,S)-5,
although they do not include any physical or spectroscopic
data, nor the pharmacological assessment. Our research
group, which has found interesting results in the substitu-
tion of the piperazine ring on diverse drugs by the dia-
zabicyclic moiety (7), synthesized and evaluated the
pharmacological activity, as antianginal agents, of the epi-
meric mixture of the ranolazine analogue in which the
piperazine ring is replaced by the (1S,4S)-2,5-diazabicyclo
[2.2.1]heptane moiety (Figure 2B), and of both epimers of
this compound (Figure 2C).
Two diazabicyclic analogues of ranolazine, (S,S,S)-5
and (S,S,R)-5, and their epimeric mixture were synthe-
sized. Furthermore, their vasomotor effects on rat aorta
rings precontracted with phenylephrine were analyzed.
These compounds showed vasodilating effects signifi-
cantly greater than ranolazine. The vasodilating activi-
ties of these analogues have two components, one that
depends on the endothelium, due to the release of NO,
and another one due to a direct effect on the vascular
smooth muscle. The compounds [(S,S,S)(S,S,R)]-5 and
(S,S,R)-5 induce, in a manner similar to ranolazine, the
release of a prostanoid from the cyclooxygenase path-
way, whose vasoconstrictor effect is masked by the pre-
dominant vasodilation induced by these compounds.
Experimental Section
Key words: chemical structure, chirality relationship to biol-
ogy, drug discovery, ranolazine
Synthesis
Received 24 August 2013, revised 20 November 2013 and
accepted for publication 6 January 2014
General experimental conditions
All starting materials were purchased from Aldrich, while
the solvents used were purified by distillation prior to use.
Solvent mixtures employed in chromatography were
reported as volume-to-volume ratios.
Ranolazine (Figure 2A) is a compound employed in the treat-
ment for chronic stable angina pectoris. It was approved by
the FDA in 2006 and was the first drug authorized over
20 years in USA for this disease (1). The mechanism of
action of this drug involves the inhibition of the entrance of
Na+ through the Na+ slow channels, thus avoiding the intra-
cellular overload of Ca2+ and avoiding damage to the myo-
cardial cells, dysfunction, and instability of the electrical
activity (2). Recently, Paredes-Carbajal and co-workers
(3) reported that this drug has a vasodilating effect on rat
aorta rings, which is mostly endothelium independent.
Melting points were determined in open capillaries in a
Buchi SMP 20 melting point apparatus. The products were
characterized by 1H and 13C NMR in a 300-MHz JEOL
Eclipse equipment using tetramethylsilane as an internal
standard and CDCl3 as a solvent; the chemical shifts (d) are
reported in parts per million (ppm) from tetramethylsilane;
the signals were assigned according to the following
710
ª 2014 John Wiley & Sons A/S. doi: 10.1111/cbdd.12285

Synthesis of Diazabicyclic Ranolazine
A
B
Figure 1: Chemical structures of
diazabicyclic benzothiazoles A and
B.
A
B
C
Figure 2: (A) Ranolazine, (B)
epimeric mixture of the ranolazine
analogue 5, and (C) epimers of
ranolazine analogue.
abbreviations: s = singlet, d = doublet, dd = doublet of
doublets, t = triplet, m = multiplet, br = broad singlet.
2-[5-Benzyl-(1S,4S)-2,5-diazabicyclo[2.2.1]heptan-
2-yl]-N-(2,6-dimethylphenyl) acetamide [(S,S)-3]
In a 250-mL round-bottom flask equipped with magnetic
stirring were dissolved 5 g (21 mmol) of 2, 3.9 g
(21 mmol) of 2-benzyl-DBH, and 3.3 mL (2.5 g, 21 mmol)
of Et3N in 100 mL of CH2Cl2; the mixture was then stirred
for 24 h. It was rinsed with water (3 9 50 mL); the organic
phase was dried over anhydrous sodium sulfate and con-
centrated under reduced pressure to give 7.8 g of crude
product which was heated under reflux, with stirring, in
hexane (40 mL) for 1 h, allowed to cool to room tempera-
ture and filtered to give 6.5 g (90% yield) of (S,S)-3 as
High-resolution mass spectra (HRMS) were determined in a
MStation JMS-700 equipment. The infrared spectra were
obtained in an infrared Bruker tensor 27 spectrometer. Opti-
cal rotations were determined in a Perkin-Elmer 341 polarim-
eter using a 1-dm cell length. Measurements were carried out
using the sodium D-line (589 nm), at a sample compartment
temperature of 20 °C and a concentration of 1% m/v. The
specific rotations are reported along with the solvent used.
20
white crystals. Mp: 126–128 °C; ½aꢁD = +2.6 (c 1, MeOH);
2-Bromo-N-(2,6-dimethylphenyl)acetamide (2)
IR (KBr, cmꢀ1) mmax: 3240, 2972, 2844, 1662, 1496, 762,
721, 696, 501; 1H RMN (300 MHz, CDCl3, d, ppm): 1.73
(d, 1H, J = 9.9 Hz), 1.86 (d, 1H, J = 9.9 Hz), 2.23 (s, 6H),
2.73–2.78 (m, 2H), 2.81 (d, 1H, J = 2.4 Hz), 3.05 (d, 1H,
J = 9.6 Hz), 3.33 (d, 1H, J = 16.8 Hz), 3.4 (s, 2H), 3.45
(d, 1H, J = 16.8 Hz), 3.72 (d, 1H, J = 2.4 Hz), 7.05–7.10
(m, 3H), 7.21–7.37 (m, 5H), 8.72 (br, 1H); 13C RMN
(75 MHz, CDCl3, d, ppm): 18.5, 33.9, 57.7, 58.1, 58.4,
59.4, 61.5, 63.8, 126.9, 127.1, 128.1, 128.3, 128.4,
133.7, 135.1, 139.4, 169.4; HRMS (FAB+): m/z calculated
for C22H28N3O [M+H]+: 350.2232, found: 350.2216.
In a 500-mL round-bottom flask equipped with magnetic
stirrer, 19.2 g (158 mmol) of 1 was dissolved in 200 mL of
CHCl3 and 25.2 mL (16 g, 158 mmol) of Et3N was added.
The reaction mixture was cooled to ꢀ10 °C, stirred for
15 min and then 14.1 mL (32 g, 158 mmol) of bromoace-
tyl bromide, previously dissolved in 80 mL of CHCl3, was
added slowly (for 2 h). Stirring was continued for 15 min,
and the mixture was washed with water (3 9 50 mL) and
with 1N HCl (2 9 20 mL) until acidic pH in the aqueous
phase. The organic phase was dried over anhydrous
sodium sulfate and concentrated under reduced pressure
on a rotary evaporator. A solid product weighing 39 g was
obtained and crystallized in five parts of MeOH to give
33.8 g (88% yield) of 2 as white crystals. Mp: 158–
160 °C; IR (KBr per cm) v: 3212, 3041, 2973, 1637,
1527, 1469, 1213, 1119, 758, 512; 1H RMN (300 MHz,
CDCl3, d, ppm): 2.22 (s, 6H), 4.03 (s, 2H), 7.05–7.13 (m,
3H), 7.78 (br, 1H); 13C RMN (75 MHz, CDCl3, d, ppm):
18.2, 29.0, 127.8, 128.3, 132.9, 135.3, 164.0.
2-[(1S,4S)-5-H-2,5-diazabicyclo[2.2.1]heptan-2-yl]
-N-(2,6-dimethylphenyl) acetamide [(S,S)-4]
In a 500-mL hydrogenation flask, 6.5 g (19 mmol) of (S,S)-3
was dissolved in 38 mL (38 mmol) of 1N HCl; then 62 mL of
H2O, 100 mL of MeOH and 650 mg of 10% Pd/C were
added. Hydrogenation at 60 psi was carried out for 2 h.
MeOH was evaporated under vacuum and 38 mL (38 mmol)
Chem Biol Drug Des 2014; 83: 710–720
711

ꢀ
Lopez-Ortiz et al.
of 1N NaOH was added; the mixture was extracted with
CH2Cl2 (3 9 25 mL); the organic phase was dried over
anhydrous sodium sulfate and concentrated under reduced
pressure to obtain 4.8 g (99% yield) of (S,S)-4 as white crys-
obtained 555 mg of (S)-7, as a light yellow solid (90% yield).
20
Mp: 56–57 °C; ½aꢁD = ꢀ14.2 (c 1, MeOH), {Lit. (8) Mp: 59–
20
60 °C; ½aꢁD = ꢀ12.9 (c 0.53, EtOH)}; 1H RMN (300 MHz,
CDCl3, d, ppm): 2.72 (dd, 1H, J2 = 4.9 Hz, J1 = 2.6 Hz),
2.87 (dd, 1H, J2 = 4.9 Hz, J1 = 4.3 Hz), 3.35-3.40 (m, 1H),
3.86 (s, 3H), 4.03 (dd, 1H, J2 = 11.4 Hz, J1 = 5.5 Hz), 4.23
20
tals. Mp: 131–132 °C; ½aꢁD = +25.1 (c 1, MeOH); IR (KBr
1
per cm) mmax: 3208, 2962, 2856, 1658, 1492, 767, 518; H
RMN (300 MHz, CDCl3, d, ppm): 1.68 (d, 1H, J = 9.9 Hz),
1.83 (d, 1H, J = 9.9 Hz), 2.22 (s, 6H), 2.76 (d, 1H,
J = 10.2 Hz), 2.84 (br, 1H), 2.96 (dd, 1H, J2 = 10.5 Hz,
J1 = 2.1 Hz), 3.01 (dd, 1H, J2 = 9.9 Hz, J1 = 2.4 Hz),
3.13 (dd, 1H, J2 = 10.5 Hz, J1 = 0.6 Hz), 3.31 (d, 1H, J =
16.8 Hz), 3.42 (d, 1H, J = 16.8 Hz), 3.47 (s, 1H), 3.65 (s,
1H), 7.05–7.09 (m, 3H), 8.65 (br, 1H); 13C RMN (75 MHz,
CDCl3, d, ppm): 18.5, 36.0, 49.7, 57.1, 59.2, 62.7, 63.2,
127.1, 128.1, 133.6, 135.0, 169.2; HRMS (FAB+): m/z cal-
culated for C15H22N3O [M+H]+: 260.1763, found: 260.1773.
(dd, 1H, J2 = 11.4 Hz, J1 = 3.6 Hz), 6.85–6.98 (m, 4H); 13
C
RMN (75 MHz, CDCl3, d, ppm): 44.8, 50.2, 55.8, 70.2,
112.0, 114.4, 120.8, 121.9, 148.0, 149.7.
General procedure for the synthesis of
analogues 5
In a round-bottom flask were dissolved (S,S)-4 and the cor-
responding oxirane 7 in MeOH. The reaction mixture was
stirred under reflux for 12 h, it was concentrated under
reduced pressure on the rotary evaporator, one equivalent
of 1N HCl was added, and the aqueous solution was
washed with AcOEt. One equivalent of 1N NaOH was
added to the aqueous solution and it was extracted with
AcOEt; the organic phase was dried over anhydrous sodium
sulfate and concentrated on the rotary evaporator to obtain
the crude product, which was recrystallized from AcOEt or
purified by column chromatography (20 parts of flash silica,
CH2Cl2/MeOH 95:5) to afford the pure product.
General procedure for the synthesis of
compounds 7
In a round-bottom flask, equipped with a magnetic stirrer,
a 0.7 M solution of 6 in epichlorohydrin was stirred at room
temperature for 24 h. The excess epichlorohydrin was dis-
tilled off (30 °C/0.005 mmHg); the residue was suspended
in AcOEt and rinsed with water. The organic phase was
dried over anhydrous sodium sulfate and concentrated on
a rotary evaporator, affording the crude product which
was purified by column chromatography (20 parts of flash
silica, hexane/AcOEt 9:1).
2-{(1S,4S)-5-[3-(2-methoxyphenoxy)-2-hydroxypropyl]
-2,5-diazabicyclo[2.2.1] heptan-2-yl}-N-(2,6-dimethyl
phenyl)acetamide {[(S,S,S)(S,S,R)]-5}. According to the
general procedure, 6.1 g (13.9 mmol) of [(S,S,S)(S,S,R)]-
5 was obtained from 4.7 g (18 mmol) of (S,S)-4 and 3.2 g
(18 mmol) of rac-7, as a white powder (77% yield). The
reaction was purified by recrystallization with AcOEt. Mp:
135-136 °C; IR (KBr, cmꢀ1) mmax: 3253, 2864, 1633,
1504, 1253, 1230, 1025, 769, 734; 1H RMN (300 MHz,
CDCl3, d, ppm): 1.76-1.82 (m, 2H), 2.23 (s, 6H), 2.61-2.89
(m, 4H), 2.93 (dd, 1H, J2 = 9.9 Hz, J1 = 2.4 Hz), 3.01 (dd,
1H, J2 = 10.2 Hz, J1 = 4.5 Hz), 3.31 (d, 1H, J = 16.5 Hz),
3.41 (s, 2H), 3.42 (d, 1H, J = 16.5 Hz), 3.59 (br, 1H), 3.83
(s, 3H), 3.93–4.07 (m, 3H), 6.87–6.95 (m, 4H), 7.05-7.09
(m, 3H), 8.64 (br, 1H); 13C RMN (75 MHz, CDCl3, d, ppm):
18.5, 34.3, 34.9, 55.8, 57.3, 57.5, 58.0, 58.6, 58.7, 59.4,
63.0, 63.2, 63.6, 67.7, 72.0, 72.1, 111.9, 114.7, 120.9,
121.8, 127.1, 128.2, 133.7, 135.0, 148.2, 149.8, 169.1.
( )-2-[(2-Methoxyphenoxy)methyl]oxirane (rac-7). Acc-
ording to the general procedure, from 30 mL of 0.7 M solu-
tion of 6 (21 mmol) in (ꢂ)-epichlorohydrin was obtained
3.5 g of rac-7, as a light yellow solid (95% yield). Mp: 38 °C,
[Lit. (9) Mp: 38–40 °C]; 1H RMN (300 MHz, CDCl3, d, ppm):
2.73 (dd, 1H, J2 = 5.1 Hz, J1 = 2.4 Hz), 2.86–2.89 (m, 1H),
3.35–3.40 (m, 1H), 3.86 (s, 3H), 4.03 (dd, 1H, J2 = 11.4 Hz,
J1 = 5.4 Hz), 4.23 (dd, 1H, J2 = 11.4 Hz, J1 = 3.6 Hz),
6.88–6.95 (m, 4H); 13C RMN (75 MHz, CDCl3, d, ppm):
44.8, 50.1, 55.8, 70.1, 112.0, 114.3, 120.8, 121.8, 148.0,
149.6.
(S)-2-[(2-Methoxyphenoxy)methyl]oxirane [(S)-7]. Acc-
ording to the general procedure, 4.9 mL of 0.7 M solution of
6 (3.4 mmol) in (R)-epichlorohydrin afforded 530 mg of
(S)-7, as a slightly yellow solid (86% yield). Mp: 55–56 °C;
2-{(1S,4S)-5-[(2S)-3-(2-methoxyphenoxy)-2-hydroxypro-
pyl]-2,5-diazabicyclo [2.2.1]heptan-2-yl}-N-(2,6-dimeth-
ylphenyl)acetamide [(S,S,S)-5]. According to the
general procedure, 748 mg (1.7 mmol) of (S,S,S)-5 was
obtained from 548 mg (2.1 mmol) of (S,S)-4 and 378 mg
(2.1 mmol) of (S)-7, as a white powder (81% yield). The
20
½aꢁD = +15.9 (c 1, MeOH), {Lit. (8) Mp: 59–60 °C;
20
½aꢁD = +13.0 (c 0.61, EtOH)}; 1H RMN (300 MHz, CDCl3, d,
ppm): 2.72 (dd, 1H, J2 = 4.9 Hz, J1 = 2.6 Hz), 2.87 (dd,
1H, J2 = 4.9 Hz, J1 = 4.1 Hz), 3.35–3.40 (m, 1H), 3.86 (s,
3H), 4.03 (dd, 1H, J2 = 11.4 Hz, J1 = 5.5 Hz), 4.23 (dd,
1H, J2 = 11.4 Hz, J1 = 3.6 Hz), 6.85–6.98 (m, 4H); 13C
RMN (75 MHz, CDCl3, d, ppm): 44.8, 50.1, 55.8, 70.4,
112.0, 114.4, 120.8, 121.9, 148.0, 149.7.
reaction was purified by column chromatography. Mp: 142-
20
143 °C; ½aꢁD = +8.57 (c 1, MeOH); IR (KBr, cmꢀ1) mmax
:
3388, 3254, 2865, 2805, 1634, 1505, 1253, 1026, 769,
734, 608, 457; 1H RMN (300 MHz, CDCl3, d, ppm): 1.77 (d,
1H, J = 9 Hz), 1.82 (d, 1H, J = 9 Hz), 2.22 (s, 6H), 2.75-
2.89 (m, 4H), 2.92 (d, 1H, J = 9 Hz), 3.03 (d, 1H, J = 9 Hz),
3.29 (d, 1H, J = 15 Hz), 3.42 (d, 1H, J = 15 Hz), 3.44 (d,
(R)-2-[(2-Methoxyphenoxy)methyl]oxirane [(R)-7]. Acc-
ording to the general procedure, from 4.9 mL of 0.7 M solu-
tion of 6 (3.4 mmol) in (S)-epichlorohydrin there was
712
Chem Biol Drug Des 2014; 83: 710–720

Synthesis of Diazabicyclic Ranolazine
2H, J = 18 Hz), 3.83 (s, 3H), 3.97–4.03 (m, 3H), 4.18 (br,
1H), 6.86-6.97 (m, 4H), 7.08–7.09 (m, 3H), 8.66 (br, 1H);
13C RMN (75 MHz, CDCl3, d, ppm): 18.6, 34.3, 55.9, 57.7,
58.5, 58.8, 59.4, 63.5, 63.6, 67.6, 72.0, 112.0, 114.6,
121.0, 121.9, 127.3, 128.3, 133.8, 135.2, 148.2, 149.8,
169.3; HRMS (FAB+): m/z calculated for C25H34N3O4
[M+H]+: 440.2549, found: 440.2539.
in such device, basal tension of 2 g was applied and was
allowed to stabilize for a 60-min period at a temperature of
37 °C. In this way, it was possible to maintain under the
same experimental conditions both rings and simulta-
neously record the effects produced on the vascular smooth
muscle and those in which the endothelium was involved.
As a model to study the release of NO, the relaxation
effect of carbachol (10ꢀ5 M) was utilized in the rings with
the intact endothelium and precontracted with phenyleph-
rine (10ꢀ5 M), which when contrasted with the response
to carbachol of rings without endothelium is a reliable
physiological indicator of the release of NO.
2-{(1S,4S)-5-[(2S)-3-(2-methoxyphenoxy)-2-hydroxypro-
pyl]-2,5-diazabicyclo [2.2.1]heptan-2-yl}-N-(2,6-dimeth-
ylphenyl)acetamide [(S,S,R)-5]. According to the gen-
eral procedure, 766 mg (1.7 mmol) of (S,S,R)-5 was
obtained from 548 mg (2.1 mmol) of (S,S)-4 and 378 mg
(2.1 mmol) of (R)-7, as a white powder (83% yield). The
reaction was purified by column chromatography. Mp: 110–
20
112 °C; ½aꢁD = +3.58 (c 1, MeOH); IR (KBr per cm) mmax
:
Perfusion system
1
3257, 2990, 2861, 1645, 1504, 1252, 1228, 770, 731; H
RMN (300 MHz, CDCl3, d, ppm): 1.76 (d, 1H, J = 9 Hz),
1.80 (d, 1H, J = 9 Hz), 2.22 (s, 6H), 2.72–2.90 (m, 5H), 3.01
(d, 1H, J = 9 Hz), 3.30 (d, 1H, J = 15 Hz), 3.40-3.42 (m,
3H), 3.42 (d, 2H, J = 15 Hz), 3.84 (s, 3H), 3.97–4.04 (m,
3H), 6.87-6.97(m, 4H), 7.07–7.09 (m, 3H), 8.64 (br, 1H); 13C
RMN (75 MHz, CDCl3, d, ppm): 18.5, 34.3, 55.8, 57.6,
58.7, 58.8, 59.4, 63.3, 63.6, 67.8, 72.1, 112.0, 114.8,
120.8, 121.9, 127.1, 128.2, 133.7, 135.7, 148.3, 149.9,
169.2; HRMS (FAB+): m/z calculated for C25H34N3O4
[M+H]+: 440.2549, found: 440.2566.
A peristaltic pump with polyethylene tubing was employed
to conduct the Tyrode and test solutions to the perfusion
chamber. The perfusion solutions continuously aerated
with carbogen entered through the bottom of the chamber
whose volume was 0.5 mL and were drained to the out-
side by overflow, through fluting on the upper edge of the
chamber, and provided with
a cellulose wick which
avoided sudden changes in volume.
Temperature control
The polyethylene tubes that conducted the perfusion solu-
tion passed, forming a spiral, through a thermostatic sys-
tem adjusted to bring the temperature of the solution in
the perfusion chamber to the desired value.
Biological assays
General experimental conditions
Glucose was acquired from Merck (Darmstadt, Germany).
Ranolazine was prepared according to
a
procedure
Recording system
described in the literature (9). All the other compounds
were acquired from Sigma (St. Louis, MO, USA). Indo-
methacin was dissolved in a 4% sodium carbonate solu-
tion. Ranolazine, L-phenylephrine hydrochloride, carbachol
(carbamoylcholine chloride), and the hydrochloride of Nx-
nitro-L-arginate methyl were dissolved in deionized water.
The tension developed by each ring was picked up by an
isometric force transducer (Grass FT03), and the signal
was taken to a polygraph Grass model 79.
Results and Discussion
The experiments were carried out on Wistar male adult
rats from de strain. The animals were killed by cervical dis-
location and immediate exsanguination. The thoracic aorta
was extracted by means of a thoracotomy and taken to a
dissection chamber that contained Tyrode solution, contin-
uously aerated. The connective tissue that surrounded the
vessel was eliminated under a microscope with extreme
caution so as not to touch the innermost of the vessel in
order to avoid damaging the endothelium. There were
obtained small rings approximately 2 mm wide.
Chemistry
The synthesis of the epimeric mixture of the target diazabi-
cyclic analogue is described in Scheme 1. Acetamide
(S,S)-4 was prepared from the aniline 1, which in the
presence of bromoacetyl bromide yielded the bromoaceta-
mide 2; this upon reaction with 2-benzyl-DBH [prepared
according to Melgar-Fernandez et al. (10)] afforded the
protected diamine (S,S)-3, which produced, by palladium-
catalyzed hydrogenolysis, the intermediate (S,S)-4, which
reacted with racemic epoxide 7 to give the epimeric
mixture of (S,S,S)-5 and (S,S,R)-5.
Two rings were selected (the endothelium was damaged
mechanically in one of them), and they were mounted in a
perfusion chamber between two stainless steel hooks; one
of each pair of hooks was attached to the perfusion cham-
ber, and the other was attached to an isometric force trans-
ducer (Grass FT03). Once the preparations were mounted
The synthesis of pure diastereoisomers (S,S,S)-5 and (S,
S,R)-5 is described in Scheme 2. The epoxides (S)-7 and
(R)-7 were obtained by the reaction of (R)-epichlorohydrin
and (S)-epichlorohydrin, respectively, with sodium 2-meth-
oxyphenolate (6). The condensation of (S,S)-4 with (S)-7
Chem Biol Drug Des 2014; 83: 710–720
713

ꢀ
Lopez-Ortiz et al.
Scheme 1: Reagents: (A)
bromoacetyl bromide, Et3N,
CH2Cl2; (B) 2-benzyl-DBH, Et3N,
CH2Cl2; (C) H2, Pd/C, MeOH; rac-
7, MeOH.
Scheme 2: Reagents: (A) (R)-
epichlorohydrin; (B) (S,S)-4, MeOH;
(C) (S)-epichlorohydrin.
and (R)-7 afforded the respective pure epimers (S,S,S)-5
and (S,S,R)-5.
compounds at cumulatively increasing concentrations
(10ꢀ6–10ꢀ4 M) on phenylephrine (10ꢀ5 M)-precontracted
rings were analyzed. These effects were analyzed in the
absence and in the presence of either indomethacin
(10ꢀ6 M) or L-NAME (300 µM).
Pharmacology
The pharmacological evaluation of compounds [(S,S,S)-
(S,S,R)]-5, (S,S,S)-5 and (S,S,R)-5 was carried out on
aorta rings from adult male Wistar rats. For each experi-
ment, two 2-mm rings were used, one with endothelium
and another without endothelium, which was removed by
manual friction.
Data analysis: The relaxations induced by these com-
pounds are expressed as the percent of the maximal ten-
sion induced by phenylephrine (10ꢀ5 M). IC50 (ꢀlog of the
mean molar concentration of the compound producing
50% of the maximal response) was determined with the
software package GRAPH PAD PRISM (v.5; San Diego, CA,
USA). Data are expressed as mean ꢂ DS for tension
development and as mean ꢂ SE for IC50 values.
Both rings were suspended in an miniature organ bath
(vol. 0.5 mL), between a pair of stainless steel hooks, one
attached to the wall of the chamber and the other
attached to an isometric force transducer (Grass, model
FT03). The rings were continuously perfused (1 mL/min)
with an oxygenated Tyrode solution (95% O2, 5% CO2);
the pH was adjusted to 7.2, and the temperature was
maintained at 37 °C.
Comparisons of means were made by one-way analysis of
variance (ANOVA), and differences between the groups were
evaluated using Student–Newman–Keuls method [Graph
Pad Prism (v.5) software; St. Louis MO, USA)]; p value of
0.05 or less was considered significant.
At the start of each experiment, the response to phenyl-
ephrine (10ꢀ5 M) and carbachol
Effects of compound [(S,S,S)-(S,S,R)]-5
(10ꢀ5 M) was evaluated. The relaxation induced by carba-
chol on the precontracted rings with phenylephrine was
taken as evidence that those rings have the endothelium
preserved, while the absence of relaxation confirmed the
absence of a functional endothelium.
In precontracted rings with phenylephrine (10ꢀ5 M), at
successively increasing concentrations (10ꢀ6–10ꢀ4 M) of
[(S,S,S)-(S,S,R)]-5, a relaxation effect was produced that
depended on the concentration and partially on the pres-
ence of the endothelium.
To investigate a possible relaxant action of the epimeric
compound 5 and the mixture of them, the effects of these
The maximum relaxation response was observed with
10ꢀ4 M (78.61 ꢂ 5.79% in the rings with endothelium and
714
Chem Biol Drug Des 2014; 83: 710–720

Synthesis of Diazabicyclic Ranolazine
140
120
100
80
A
B
140
120
100
80
60
60
40
40
20
20
0
0
–6.20
–5.70
–5.20
–4.70
–4.20
–6.20
–5.70
–5.20
–4.70
–4.20
[(S,S,S)-(S,S,R)]-5 log [M]
[(S,S,S)-(S,S,R)]-5 log [M]
Figure 3: Concentration–response curve at successively increasing concentrations to [(S,S,S)-(S,S,R)]-5 in aorta rings with endothelium
(A) and without endothelium (B). The curves represent the relaxation response of the precontracted aorta rings with phenylephrine
(10ꢀ5 M), to [(S,S,S)-(S,S,R)]-5 (10ꢀ6–10ꢀ4 M) ( ), in the presence of indomethacin (10ꢀ6 M) (o), and in the presence of L-NAME (300 lM)
ꢃ
(♢). The data are expressed as the mean ꢂ DS, n = 5.
Table 1: IC50 and maximum tension in rat aorta rings induced by ranolazine, [(S,S,S)-(S,S,R)]-5, (S,S,S)-5 and (S,S,R)-5 in the pres-
ence and absence of indomethacin and L-NAME
With endothelium
IC50 (log[M])
Without endothelium
IC50 (log[M])
Experiment
Compounds
Max. Tension (%)
Max. Tension (%)
1
2
Ranolazine
4.61 ꢂ 0.05
5.39 ꢂ 0.17a
3.98 ꢂ 0.09a,b
4.78 ꢂ 0.03*
5.47 ꢂ 0.09a
4.53 ꢂ 0.04a,b
4.85 ꢂ 0.03*
4.75 ꢂ 0.04a,*
3.96 ꢂ 0.09a,b
4.47 ꢂ 0.07
56.78 ꢂ 6.81
66.05 ꢂ 10.70
34.94 ꢂ 9.88a,b
78.61 ꢂ 5.79*
81.53 ꢂ 5.28
74.47 ꢂ 6.33
76.65 ꢂ 3.42*
74.14 ꢂ 9.67
33.81 ꢂ 15.14a,b
60.69 ꢂ 3.42
72.66 ꢂ 8.28
46.53 ꢂ 3.08a,b
4.27 ꢂ 0.02
4.61 ꢂ 0.04a
4.42 ꢂ 0. 03a,b
4.55 ꢂ 0.03*
5.00 ꢂ 0.02a
4.53 ꢂ 0.049b,*
4.55 ꢂ 0.05
4.46 ꢂ 0.09
4.09 ꢂ 0.12a,b
4.25 ꢂ 0.02
4.69 ꢂ 0.02a
47.88 ꢂ 4.70
66.25 ꢂ 4.45a
52.38 ꢂ 9.76
63.59 ꢂ 14.40
78.39 ꢂ 2.22
60.35 ꢂ 4.76b
64.42 ꢂ 12.15
66.82 ꢂ 8.57
45.72 ꢂ 12.37b
43.53 ꢂ 11.64
70.85 ꢂ 4.50a
43.38 ꢂ 7.53b
Ranolazine + A
Ranolazine + B
[(S,S,S)-(S,S,R)]-5
[(S,S,S)-(S,S,R)]-5 + A
[(S,S,S)-(S,S,R)]-5 + B
(S,S,S)-5
3
4
5
6
7
8
(S,S,S)-5 + A
(S,S,S)-5 + B
(S,S,R)-5
9
10
11
12
(S,S,R)-5 + A
(S,S,R)-5 + B
5.09 ꢂ 0.12a
4.21 ꢂ 0.05a,b,
*
4.17 ꢂ 0.03a,b,
*
IC50: log of the mean molar concentration that causes 50% of the relaxation induced by ranolazine, [(S,S,S)-(S,S,R)]-5, (S,S,S)-5, and
(S,S,R)-5 (10ꢀ6–10ꢀ4 M). Maximum tension developed in response to phenylephrine (10ꢀ5 M). A: indomethacin (10ꢀ6 M). B: L-NAME
(300 lM). The percentage data from the maximum relaxation are presented as the mean ꢂ DS. The IC50 data are presented as the
b
mean ꢂ ES a,bdenotes significant differences between the same group (a versus. in absence of A or B, versus A) (p < 0.05). *Denotes
significant differences between the groups in their respective conditions (p < 0.05). n = 5 for all of the groups.
63.59 ꢂ 14.40% in the rings without endothelium; these
values were not significantly different; Figures 3A,B, experi-
ments 4–6, Table 1). Indomethacin (10ꢀ6 M) displaced the
concentration–response curve to the left (experiment 5,
Table 1).
When comparing the concentration–response curve of
[(S,S,S)-(S,S,R)]-5 with that of ranolazine, it was found
that the one from compound [(S,S,S)-(S,S,R)]-5 is dis-
placed to the left (IC50 4.78 ꢂ 0.03 versus 4.61 ꢂ 0.05,
respectively, experiments 1 and 4, Table 1). In the aortic
rings with endothelium, [(S,S,S)-(S,S,R)]-5 produced a
maximum relaxation of greater magnitude than ranolazine
(78.61 ꢂ 6.33% versus 56.78 ꢂ 6.81%, respectively,
Figure 4A, experiments 1 and 4, Table 1).
In the rings with endothelium, in the presence of L-NAME
(300 µM), when the concentrations were between 10ꢀ6 and
10ꢀ5 M of [(S,S,S)-(S,S,R)]-5, an additional increase in the
tension induced by phenylephrine was observed (experi-
ment 6, Table 1). These results show that [(S,S,S)-(S,S,
R)]-5 has primordially a direct relaxation effect over the vas-
cular smooth muscle and also acts on the endothelium
releasing NO as well as a vasoconstrictor prostanoid.
In the presence of indomethacin (10ꢀ6 M), the relaxation
responses induced by this compound on the aortic rings
with or without endothelium were not significantly differ-
ent to the ones from ranolazine in similar experimental
Chem Biol Drug Des 2014; 83: 710–720
715

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Lopez-Ortiz et al.
140
120
100
80
A
B
140
120
100
80
60
60
40
40
20
20
0
0
–6.20
–5.70
–5.20
–4.70
–4.20
–6.20
–5.70
–5.20
–4.70
–4.20
log [M]
log [M]
Figure 4: Concentration–response curve to [(S,S,S)-(S,S,R)]-5 and ranolazine at successively increasing concentrations, in aorta rings
with endothelium (A) and without endothelium (B). The curves represent the relaxation response of the aortic rings precontracted with
phenylephrine (10ꢀ5 M) to [(S,S,S)-(S,S,R)]-5 (●) and ranolazine (10ꢀ6–10ꢀ4 M) (▲), in the absence (closed symbols) and in the presence
of indomethacin (10ꢀ6 M) (open symbols). The data are expressed as the mean ꢂ DS, n = 5.
A
B
140
120
100
80
140
120
100
80
60
60
40
40
20
20
0
0
–6.20
–5.70
–5.20
–4.70
–4.20
–6.20
–5.70
–5.20
–4.70
–4.20
log [M]
log [M]
Figure 5: Concentration–response curve to [(S,S,S)-(S,S,R)]-5 and ranolazine at successively increasing concentrations, in aorta rings
with endothelium (A) and without endothelium (B). The curves represent the relaxation response to the aortic rings precontracted with
phenylephrine (10ꢀ5 M) to [(S,S,S)-(S,S,R)]-5 (●) and ranolazine (10ꢀ6–10ꢀ4
of L-NAME (300 lM) (open symbols). The data are expressed as the mean ꢂ MD)S(▲, n),=in5t.he absence (closed symbols) and in the presence
conditions (Figure 4A,B, experiments 2 and 5, Table 1).
The inhibition of the synthesis of NO with L-NAME
(300 µM) decreased the maximum relaxation induced by
ranolazine, but not the one induced by [(S,S,S)-(S,S,R)]-5.
These results show that the relaxation induced by this
compound depends less on the synthesis of NO than the
one induced by ranolazine, even though the relaxation
in the rings without endothelium, Figure 6A,B, experiment 7,
Table 1).
No effect whatsoever was observed when blocking cyclo-
oxygenase with indomethacin (10ꢀ6 M; Figure 6A,B,
experiment 8, Table 1). In the rings with endothelium, the
maximum relaxation induced by this compound decreased
significantly by the addition of L-NAME (300 µM;
76.65 ꢂ 3.42% versus 33.81 ꢂ 15.14%, respectively, Fig-
ure 7A,B experiment 9, Table 1). These results suggest
that the relaxation induced by this compound is in part
caused by the release of endothelial nitric oxide.
effect is greater (Figure 5A,B, experiments
Table 1).
3 and 6,
Effects of compound (S,S,S)-5
In phenylephrine-precontracted rings, (S,S,S)-5 induced a
relaxation dependent on the concentration and partially
dependent on the presence of the endothelium (76.65 ꢂ
3.42% in the rings with endothelium and 64.42 ꢂ 12.15%
When comparing the effects of (S,S,S)-5 with those of ra-
nolazine, it was observed that the compound (S,S,S)-5
induces on the aortic rings with endothelium a vasodilation
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Chem Biol Drug Des 2014; 83: 710–720

Synthesis of Diazabicyclic Ranolazine
A
B
120
100
80
60
40
20
0
120
100
80
60
40
20
0
–6.0
–5.5
–5.0
–4.5
–4.0
–6.0
–5.5
–5.0
–4.5
–4.0
(S,S,S)-5 log [M]
(S,S,S)-5 log [M]
Figure 6: Concentration–response curve to (S,S,S)-5 at successively increasing concentrations, in aorta rings with endothelium (A) and
without endothelium (B). The curves represent the relaxation response of the aorta rings precontracted with phenylephrine (10ꢀ5 M), to (S,
S,S)-5 (10ꢀ6–10ꢀ4 M) (●), in the presence of indomethacin (o) and in the presence of L-NAME (300 lM) (D). The data are expressed as the
mean ꢂ DS, n = 5.
B
A
120
100
80
60
40
20
0
120
100
80
60
40
20
0
–6.0
–5.5
–5.0
–4.5
–4.0
–6.0
–5.5
–5.0
–4.5
–4.0
log [M]
log [M]
Figure 7: Concentration–response curve to (S,S,S)-5 and ranolazine at successively increasing concentrations, in aorta rings with
endothelium (A) and without endothelium (B). The curves represent the relaxation response of the aortic rings precontracted with
phenylephrine (10ꢀ5 M), to (S,S,S)-5 (●) and ranolazine (10ꢀ6–10ꢀ4 M) (▲), in the absence (closed symbols) and in the presence of
indomethacin (10ꢀ6 M) (open symbols). The data are expressed as the mean ꢂ DS, n = 5.
of greater magnitude than the one from ranolazine
(76.65 ꢂ 3.42% versus 56.80 ꢂ 6.81%, respectively,
Figure 6A, experiments 1 and 7, Table 1). In the rings with
endothelium, when cyclooxygenase was blocked with
indomethacin (10ꢀ6 M), only the ranolazine curve was dis-
placed to the left (Figure 7A,B, experiments 2 and 8,
Table 1).
(S,S,S)-5, there is a greater participation of the endothelial
NO synthesis/release than in the one induced by ranol-
azine.
Effects of compound (S,S,R)-5
In the aortic rings precontracted with phenylephrine, (S,S,
R)-5 produced a relaxation response dependent on the
concentration and partially on the presence of endothelium
(60.69 ꢂ 3.42% in the rings with endothelium and
43.53 ꢂ 11.64% in the rings without endothelium,
Figure 9A,B, experiment 10, Table 1). The addition of
indomethacin (10ꢀ6 M) produced a displacement of the
concentration–response curve to the left (IC50, 4.47 ꢂ 0.07
versus 5.09 ꢂ 0.02, in the rings with endothelium and
4.25 ꢂ 0.02 versus 4.69 ꢂ 0.02 in the rings without
In the rings with endothelium, L-NAME (300 µM) dec-
reased the maximum relaxation induced by (S,S,S)-5 as
well as the induced by ranolazine (Figure 8A, experiments
3 and 9, Table 1). These results suggest that compound
(S,S,S)-5 shares with ranolazine the effect of inducing
the release of endothelial NO, but not the synthesis of
some vasoconstricting prostanoid. On the other hand,
these results show that in the relaxation induced by
Chem Biol Drug Des 2014; 83: 710–720
717

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Lopez-Ortiz et al.
A
B
120
100
80
60
40
20
0
120
100
80
60
40
20
0
–6.0
–5.5
–5.0
log [M]
–4.5
–4.0
–6.0
–5.5
–5.0
log [M]
–4.5
–4.0
Figure 8: Concentration–response curve to (S,S,S)-5 and ranolazine at successively increasing concentrations, in aorta rings with
endothelium (A) and without endothelium (B). The curves represent the relaxation response of the aortic rings precontracted with
phenylephrine (10ꢀ5 M), to (S,S,S)-5 (●) and ranolazine (10ꢀ6-10ꢀ4 M) (▲), in the absence (closed symbols) and in the presence of L-
NAME (300 lM) (open symbols). The data are expressed as the mean ꢂ DS, n = 5
A
B
120
100
80
60
40
20
0
120
100
80
60
40
20
0
–6.0
–5.5
–5.0
–4.5
–4.0
–6.0
–5.5
–5.0
–4.5
–4.0
(S,S,R)-5 log [M]
(S,S,R)-5 log [M]
Figure 9: Concentration–response curve to (S,S,R)-5 at successively increasing concentrations, in aorta rings with endothelium (A) and
without endothelium (B). The curves represent the relaxation response to aortic rings precontracted with phenylephrine (10ꢀ5 M), to (S,S,
R)-5 (10ꢀ6–10ꢀ4 M) (●), in the presence of indomethacin (10ꢀ6 M) (o) and in the presence of L-NAME (300 lM) (D). The data are expressed
as the mean ꢂ DS, n = 5.
endothelium) and an increase in the magnitude of the
maximum relaxation (60.69 ꢂ 3.42% versus 72.66 ꢂ 8.28,
in the rings with endothelium and 43.53 ꢂ 11.64% ver-
sus 70.85 ꢂ 5.50%, in the rings without endothelium,
Figure 9A,B, experiment 11, Table 1).
on the aortic rings a maximum vasodilation similar in magni-
tude to that of ranolazine (60.69 ꢂ 3.42% versus 56.80 ꢂ
6.81%, in the rings with endothelium and 43.53 ꢂ 11.64%
versus 46.67 ꢂ 46.67 ꢂ 8.01% in the rings without endo-
thelium, experiments 1 and 10, Table 1).
In the rings with endothelium, L-NAME (300 µM) decreased
the maximum relaxation induced by this compound
(60.69 ꢂ 3.42% versus 46.53 ꢂ 3.08%, respectively, Fig-
ure 9A, experiment 12, Table 1). These results suggest that
the relaxation induced by (S,S,R)-5 is attributable to a direct
effect on the vascular smooth muscle as well as to the dis-
charge of endothelial NO and that this compound induces,
in addition, the release of some vasoconstricting prostanoid.
When blocking cyclooxygenase with indomethacin
(10ꢀ6 M), no significant differences were observed with
regard to the concentration–relaxation curves of ranolazine
in similar experimental conditions (Figure 10A,B, experi-
ments 2 and 11, Table 1).
In the rings with endothelium, L-NAME (300 µM) partially
inhibited the relaxation induced by (S,S,R)-5 as well as
the one induced by ranolazine (60.69 ꢂ 3.42% versus
46.53 ꢂ 3.08 and 56.80 ꢂ 6.81% versus 34.94 ꢂ 9.88%,
Figure 11A, experiments 3 and 12, Table 1). These results
When comparing the effects of compound (S,S,R)-5 with
those of ranolazine, it was observed that (S,S,R)-5 induces
718
Chem Biol Drug Des 2014; 83: 710–720

Synthesis of Diazabicyclic Ranolazine
A
B
120
100
80
60
40
20
0
120
100
80
60
40
20
0
–6.0
–5.5
–5.0
log [M]
–4.5
–4.0
–6.0
–5.5
–5.0
log [M]
–4.5
–4.0
Figure 10: Concentration–response curve to (S,S,R)-5 and ranolazine at successively increasing concentrations, in aorta rings with
endothelium (A) and without endothelium (B). The curves represent the relaxation response of the aortic rings precontracted with
phenylephrine (10ꢀ5 M), to (S,S,R)-5 (●) and ranolazine (10ꢀ6–10ꢀ4 M) (▲), in the absence (closed symbols) and in the presence of
indomethacin (10ꢀ6 M) (open symbols). The data are expressed as the mean ꢂ DS, n = 5.
A
B
120
100
80
60
40
20
0
120
100
80
60
40
20
0
–6.0
–5.5
–5.0
log [M]
–4.5
–4.0
–6.0
–5.5
–5.0
log [M]
–4.5
–4.0
Figure 11: Concentration–response curve to (S,S,R)-5 and ranolazine at successively increasing concentrations, in aorta rings with
endothelium (A) and without endothelium (B). The curves represent the relaxation response of the aortic rings precontracted with
phenylephrine (10ꢀ5 M), to (S,S,R)-5 (●) and ranolazine (10ꢀ6–10ꢀ4 M) (▲), in the absence (closed symbols) and in the presence of
L-NAME (300 lM) (open symbols). The data are expressed as the mean ꢂ DS, n = 5.
suggest that (S,S,R)-5 shares with ranolazine the effect of
inducing the release of endothelial NO.
direct effect on the vascular smooth muscle in addition to
inducing the release of some vasoconstricting prostanoid
from the cyclooxygenase pathway, which is independent
of the endothelium.
Conclusions
The compounds (S,S,S)-5 and (S,S,R)-5 have a vasodilat-
ing effect induced by two components, one due to the
release of endothelial NO and another one due to a direct
effect on the vascular smooth muscle. On the other hand,
(S,S,R)-5 induces the release of some vasoconstricting
prostanoid from the cyclooxygenase pathway. Comparing
these effects to those of ranolazine, it may be concluded
that both the epimeric mixture [(S,S,S)(S,S,R)]-5 and
compound (S,S,S)-5 have a higher vasodilating efficiency
due to the participation of NO in the endothelium.
The diazabicyclic analogues of ranolazine [(S,S,S)(S,S,
R)]-5, (S,S,S)-5, and (S,S,R)-5, were synthesized from
commercially available starting materials and applying
simple synthetic strategies.
In view of the pharmacological results obtained, it can be
stated that the epimeric mixture [(S,S,S)(S,S,R)]-5 has a
vasodilating effect induced by two components, one due
to the release of endothelial NO and another due to a
Chem Biol Drug Des 2014; 83: 710–720
719

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Lopez-Ortiz et al.
6. Zablocki J., Elzein E., Nudelman G., Marquardt T., Var-
khedkar V., Ibrahim P.N., Palle V.P., Blackburn B.K.,
Substituted Piperazine Compounds. Palo Alto, CA: CV
Therapeutics Inc.
Acknowledgments
This work was financed by CONACyT through the project
No. 101855. M. L-O and I.M. thank CONACyT for the
ꢀ
7. Murineddu G., Asproni B., Pinna G., Curzu M.M., Dore
A., Pau A., Deligia F., Pinna G.A. (2012) Synthesis of
biologically active bridged diazabicycloheptanes. Curr
Med Chem;19:5342–5363.
scholarship grants. The authors thank Ma. de los Angeles
~
~
ꢀ
Pena, Elizabeth Huerta, and Rocıo Patino-Maya from the
Instituto de Quımica at UNAM, for obtaining the NMR and
IR spectra, Marıa Gregoria Medina-Pintor from the Centro
ꢀ
ꢀ
ꢀ
8. Bredikhin A.A., Strunskaya E.I., Zakharychev D.V., Kri-
volapov D.B., Litvinov I.A., Bredikhina Z.A. (2005) Solid
state properties of 1,2-epoxy-3-(2-methoxyphenyloxy)-
propane–valuable intermediate in non-racemic drug
synthesis. Tetrahedron Asymmetry;16:3361–3366.
9. Riise-Moen A., Karstad R., Anthonsen T. (2005)
Chemo-enzymatic synthesis of both enantiomers of the
anti-anginal drug ranolazine. Biocatal Biotransforma-
tion;23:45–51.
ꢀ
de Investigaciones Quımicas at the Universidad Autonoma
del Estado de Morelos for obtaining the HRMS. The
ꢀ
authors thank Constantino Ramırez-Miranda, Tania
Ramırez-Morales, and Ana Lilia Ocampo-Belmont for their
ꢀ
technical skills.
References
ꢀ
ꢀ
10. Melgar-Fernandez R., Gonzalez-Olvera R., Olivares-
1. Abrams J., Jones A., Kirkpatrick P. (2006) Ranolazine.
Nat Rev Drug Discov;5:453–455.
ꢀ
ꢀ
Romero L., Gonzalez-Lopez V., Romero-Ponce L.,
ꢀ
ꢀ
Ramırez-Zarate R., Demare P., Regla I., Juaristi E.
(2008) Synthesis of novel derivatives of (1S,4S)-2,5-
diazabicyclo[2.2.1]heptane and their evaluation as
potential ligands in asymmetric catalysis. European
J Org Chem;4:655–672.
2. Siddiqui M.A., Keam S.J. (2006) Ranolazine. A review
of its use in chronic stable angina pectoris.
Drugs;66:693–710.
ꢀ
ꢀ
3. Paredes-Carbajal C., Monsalvo I., Hernandez-Dıaz C.,
Regla I., Demare P., Mascher D. (2013) Effects of
ranolazine on vasomotor responses of rat aortic rings.
Arch Med Res;44:8–12.
Supporting Information
4. Portoguese P., Mikhail A. (1966) Bicyclic bases. Syn-
Additional Supporting Information may be found in the
online version of this article:
thesis of 2,5-diazabicyclo[2.2.1]heptanes.
Chem;31:1059–1062.
J
Org
5. Elzein E., Shenk K., Ibrahim P., Marquart T., Kerwar
S., Meyer S., Ahmed H., Zeng D., Chu N., Soohoo D.,
Wong S., Leung K., Zablocki J. (2004) Novel inhibitors
of fatty acid oxidation as potential metabolic modula-
tors. Bioorg Med Chem Lett;14:973–977.
Appendix S1. MS, IR, 1H NMR and 13C NMR spectra of
all synthetized compounds.
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Chem Biol Drug Des 2014; 83: 710–720