Synthesis of novel functionalized 4-aza-2,3-didehydropodophyllotoxin derivatives with potential antitumor activity

Article abstract of DOI:10.1002/jhet.467

Novel arylamino alcohols were synthesized and these alcohols were used to prepare 12 novel N-(2-hydroxy-ethyl)-2,3-didehydroazapodophyllotoxins, in one step, by simple reflux in ethanol. Isolated yields in the range of 50-70% were obtained.

Full text of DOI:10.1002/jhet.467

November 2010
Synthesis of Novel Functionalized 4-Aza-2,3-
didehydropodophyllotoxin Derivatives with Potential Antitumor
Activity
1275
Ajay Kumar and Antonio E. Alegria*
Department of Chemistry, University of Puerto Rico, Humacao, Puerto Rico
*E-mail: antonio.alegria1@upr.edu
Received February 12, 2010
DOI 10.1002/jhet.467
Published online 20 August 2010 in Wiley Online Library (wileyonlinelibrary.com).
Novel arylamino alcohols were synthesized and these alcohols were used to prepare 12 novel N-(2-
hydroxy-ethyl)-2,3-didehydroazapodophyllotoxins, in one step, by simple reflux in ethanol. Isolated
yields in the range of 50–70% were obtained.
J. Heterocyclic Chem., 47, 1275 (2010).
such as Nippon-Kayaku’s NK-611 [2], GL-331 and Tai-
ho’s TOP-53 [3,4]. Podophyllotoxin derivatives also dis-
play anti-HIV-1 [5,6] and antibacterial [7] activities.
Currently, the commercial sources of podophyllotoxin
are the rhizomes and roots of plants, such as Podophyl-
lum peltatum, Podophyllum emodi, and American
mayapple. Podophyllum emodi is an endangered species
from the Himalayas [8]. Synthesis of podophyllotoxin is
a multistep process, involving multicomponents and ex-
pensive reagents. The latest reported method for the syn-
thesis of podophyllotoxin involves 5 steps and 20
reagents with 7.6% overall yield [9]. This tedious syn-
thesis limits the new derivatives research of podophyllo-
toxin core. Podophyllotoxin contains 5 rings denoted as
A, B, C, D, and E (Fig. 1). The basic structure of podo-
phyllotoxin with rings A, B, C, D, and E was modified
in different but limited ways since decades, in search of
new chemical entities for drug discovery [10,11]. Deriv-
atives of 4-aza-2,3-didehydropodophyllotoxin derivatives
have also been synthesized as a strategy to develop
podophyllotoxin analogs aimed at improving biological
activity (Fig. 2) [12–14]. Some of those derivatives
showed twice the cytotoxicity against P-388 leukemia
cells as compared with podophyllotoxin [13].
INTRODUCTION
Podophyllotoxin (Fig. 1) is the starting material for
the semi-synthesis of the anticancer drugs etoposide,
etopophos and tenoposide. These antineoplastic pharma-
ceuticals block DNA topoisomerase II and have been
used for the treatment of small and large cell lung, re-
fractory testicular, stomach and pancreatic cancers, as
well as myeloid leukemias [1a]. The podophyllotoxin
core structure possesses a dual mode of action, i.e., inhi-
bition of DNA topoisomerase II and of microtubule as-
sembly through binding to tubulin, both of which are
considered to be responsible for its antitumor activity.
Podophyllotoxin is the precursor to a new derivative,
R
CPH-82 or ReumaconV, which is being used to treat
active rheumatoid or psoriatic arthritis in Europe. It is
used to reduce inflammation. Podophyllotoxin is also
the precursor of other derivatives used for the drug de-
velopment of psoriasis and malaria [1b]. Several podo-
phyllotoxin preparations are in the market for dermato-
logical use to treat genital warts, e.g., imiquimod. Sev-
eral new members of the podophyllotoxin derivatives
have emerged as potentially superior chemotherapeutics,
displaying improved water solubility and bioavailability,
C
V
2010 HeteroCorporation

1276
A. Kumar and A. E. Alegria
Vol 47
Figure 1. Structures of podophyllotoxin and etoposide.
Figure 2. Structures of 4-aza-2,3-didehydropodo-phyllotoxin deriva-
tives [13].
Many cytotoxic drugs have been conjugated to car-
riers for the selective targeting of organs and tissues
[15]. To our best knowledge, no podophyllotoxin deriva-
tive has been conjugated to carriers for selective tissue
targeting. In this work we report a facile and high-yield-
ing synthetic procedure for the preparation of N-(2-
hydroxy-ethyl)-2,3-didehydroazapodophyllotoxin deriva-
tives with the potential to be conjugated to tissue-target-
ing carriers.
mino alcohols are not stable for long periods of time at
room temperature and, thus, were synthesized freshly
before used. Compounds AP-101 to AP-304 were pre-
pared following the procedure reported by Tratrat et. al.
[14] by reacting novel arylamino alcohol with tetronic
acid and substituted aldehyde in ethanol (Fig. 3). Iso-
lated yields were in the order of 60%. This is a straight-
forward one-step multicomponent synthesis, which
involves simple isolation of the products by filtration
and recrystallization. Isolated yields were in the 50–70%
range.
RESULTS AND DISCUSSION
Although there is an NAH bond at position 4 in the
‘‘C’’ ring of 4-aza-2,3-didehydropodophyllotoxin deriva-
tives, nucleophilic substitution to electrophiles, such as
acetic anhydride or an acyl chloride to form amides was
not successful in our laboratory. Furthermore, attempts
to use a strong base such as NaH or LDA to abstract the
proton of the amine was not effective. Therefore, for the
synthesis and biological activity studies of OH-function-
alized derivatives of 4-aza-2,3-didehydropodophyllo-
toxin at the N atom in ring ‘‘C,’’ we synthesized some
new arylamino alcohols (AP-100 to AP-300, Scheme 1)
to prepare N-(2-hydroxy-ethyl)-2,3-didehydroazapodo-
phyllotoxins in one step, by simple refluxing in ethanol
as reported previously [14]. The novelty in our work is
the preparation of hydroxy-functionalized 2,3-didehy-
droazapodophyllotoxin derivatives, in two simple steps,
which have a functional group which is available for
further modifications. The novel arylamino alcohols
were prepared by reacting commercially-available sub-
stituted anilines with 2-chloroethylchloroformate in dry
dichloromethane in the presence of pyridine followed by
reacting with KOH in ethanol (Scheme 1). These aryla-
Structures were corroborated with the help of 1H,
COSY, 13C, DEPT45, DEPT90, DEPT135, HETCOR
NMR, as well as 1H-NMR coupled with deuterium
exchange experiments, FTIR spectroscopy, HRMS and
elemental analyses.
Scheme 1. Synthesis of arylamino alcohols. Structures of three exam-
ples of N-(2-hydroxy-ethyl)-2,3-didehydroazapodophyllotoxins are
shown to indicate the structural variation of the arylamino alcohol pre-
cursor used.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

November 2010
Synthesis of Novel Functionalized 4-Aza-2,3-didehydropodophyllotoxin
Derivatives with Potential Antitumor Activity
1277
Figure 3. Structures of 4-aza-2,3-didehydropodo-phyllotoxin derivatives prepared in this work.
Compounds AP-101 to AP-304 were prepared follow-
ing the procedure reported by Tratrat et al. [14] by
reacting novel arylamino alcohol with tetronic acid and
substituted aldehyde in ethanol (Fig. 3). The mechanism
for the formation of AP-101 is shown in Scheme 2.
When the final ring closure is completed, the carbon
atom, here assigned as 9, has a unique 13C-NMR chemi-
cal shift of ca. 39 ppm (Fig. 5). The proton attached to
this carbon also has a unique chemical shift (s, 1H, 4.8
ppm, Fig. 4). Both types of chemical shifts for this car-
bon and proton were found uniform in the entire azapo-
dophyllotoxin derivatives synthesized in this work.
Some other specific carbons also corroborate the struc-
ture of the cyclisized scaffold, i.e. 8a at 95 ppm and 5a
at 160 ppm. These chemical shifts were also uniformly
found in the entire series of the azapodophyllotoxins
synthesized in this work.
the same enantiomeric form like podophyllotoxin,
showed the same IC50 value of 0.0050 lg/mL against
P388 leukemia cells. But interestingly, when strain
between ring ‘‘C’’ and ‘‘D’’ was eliminated in 4-aza-
2,3-didehydropodophyllotoxin analogue by dehydration
at the 2,3 positions, the enhanced IC50 against P388 leu-
kemia cells was observed, i.e., 0.0018 lg/mL as com-
pare to 0.0043 lg/mL for podophyllotoxin [13]. There-
fore, the synthesis of 4-aza-2,3-didehydro podophyllo-
toxin analogues with hydroxyl functionality, as in podo-
phyllotoxin, has an excellent potential for the develop-
ment of new drug entities not only as anti-tumor drugs
but also for the treatment of psoriatic arthritis, HIV-1,
genital warts, malaria, and bacterial infections as well.
In this work we have further modified the 4-aza-2,3-
didehydropodophyllotoxin core by functionalizing posi-
tion 4 at the ‘‘C’’ ring in a similar fashion as that occur-
ring in podophyllotoxin derivatives. Libraries of these
new heterocyclic compounds should be accessible by
this straightforward one-step multicomponent synthesis,
which involves simple isolation of the products by filtra-
tion and recrystallization and requires no further purifi-
cation steps. Although the new compounds are racemic,
we hope that the separation and testing of individual
enantiomers may lead to more potent compounds.
HETCOR NMR studies reveal other interesting find-
ings (Fig. 5). Protons at carbon 200 of all the azapodo-
phyllotoxin derivatives are expected to be equivalent but
these are not. One of them appears at ꢀ3.6 ppm and the
other at ꢀ3.8 ppm and the latter may be interacting
with protons at carbons 6 (Fig. 5). In fact, protons at
position 6 are showing a broad peak probably due to
that interaction. Also, protons at carbon 100 are expected
to be splitted into a triplet by two equal protons. How-
ever, these are unusually shaped as a doublet of doublets
with J values of ꢀ22 Hz and ꢀ15 Hz, as protons at 200
are not equivalent.
This work will open a new area of 4-aza-2,3-didehy-
dropodophyllotoxin analogues having almost similar
structural functionalities to podophyllotoxin and will
help to develop a library of new bioactive chemical enti-
ties which could be conjugated to carriers for tissue
targeting. Whether these compounds may exert their
Itokawa and Takeya [12] have previously shown that
(-)-4-aza-4-deoxypodophyllotoxin, which possess exactly
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A. Kumar and A. E. Alegria
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Scheme 2. Synthesis of AP-101.
35.37 mmol) was slowly added. The mixture was stirred at
room temperature (25ꢁC) for 2.5 h and washed with water (5.0
mL ꢂ 4), dried over anhydrous magnesium sulphate and con-
centrated under vacuum. The residue was dissolved in ethanol
(100 mL), treated with potassium hydroxide (8.6 g, 141.48
mmol) and heated at 90ꢁC for 4 h. The mixture was dried
under vacuum and the residue was dissolved in dichlorome-
thane (150 mL), the precipitate was washed with dichlorome-
thane twice (25 mL each). The combined organic phases were
washed with water (5ꢂ mL) and brine. The organic phase was
dried over anhydrous magnesium sulphate and concentrated
under vacuum. The solid was purified by silica gel (120 g)
flash chromatography with hexane-ethylacetate gradient to give
compound AP-100 (3.89 g, 61%) as brown needles. MP: 53–
54ꢁC, IR (cmꢃ1); 3283, 3162, 2869, 16360, 1496, 1232, 1190,
1122, 1073, 1031, 931, 883, 847, 782, 720, 692; 1H-NMR
(DMSO-d6, 400 MHz): d (ppm) 3.01 (q, J ¼ 11.84 Hz and
5.9 Hz, 2H), 3.54 (q, J ¼ 11.64 Hz and 5.78 Hz, 2H), 4.64
(t, J ¼ 5.71 Hz, 1H), 5.17 (t, J ¼ 5.76 Hz, 1H), 5.82 (s, 2H),
6.00 (dd, J ¼ 8.58 Hz and 2.16 Hz, 1H), 6.30 (d, J ¼ 2Hz,
1H), 6.65 (d, J ¼ 8.58 Hz, 1H); 13C-NMR (DMSO-d6, 100
MHz): d 59.42, 94.85, 99.65, 102.88, 108.18, 137.63, 144.66,
147.51; HRMS m/z: 182.0818 found (Calculated for
C9H11NO3, [MþH]þ requires 182.0812).
cytotoxic effect through podophyllotoxin-like antitubulin
mechanism, target topoisomerase II, or have a totally in-
dependent mode of action, constitutes the subject of fur-
ther investigation, which will be reported in due course.
EXPERIMENTAL
Melting points were determined on a MEL-TEMP instru-
ment and are uncorrected. IR spectra were recorded on a Per-
kin Elmer Spectrum 100 FTIR Spectrometer on ATS mode.
1H, COSY, 13C, DEPT45, DEPT90, DEPT135 and HETCOR
NMR spectra were measured on a Bruker 400 Ultra shield
Spectrometer using DMSO-d6 as solvent. All chemical shifts
are reported in parts per million relative to tetramethylsilane.
Coupling constants (J) are reported in Hz. HRMS analyses
were performed at the University of Florida (Gainesville)
Mass Spectrometry facility. Absorption spectra were obtained
in DMSO, using DMSO as blank, with an Agilent 8453
absorption spectrometer. Elemental analysis were performed at
Atlanta Microlab GA.
Synthetic procedure for compounds AP-100 to AP-300.
2-[(3,4-Methylenedioxy)anilino]ethanol (AP-100). To a solu-
tion of 3,4-(-methylenedioxy)-aniline (5 g, 35.37 mmol) in dry
dichloromethane (100 mL) and pyridine (3.6 mL, 44.57 mmol)
at room temperature 2-chloroethylchloroformate (3.8 mL,
2-(Indan-5-ylamino)-ethanol (AP-200). 2-(Indan-5-ylamino)-
ethanol (AP-200) was synthesized from a similar reaction
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DOI 10.1002/jhet

November 2010
Synthesis of Novel Functionalized 4-Aza-2,3-didehydropodophyllotoxin
Derivatives with Potential Antitumor Activity
1279
Figure 4. 1H-NMR spectrum of AP-101 in DMSO-d6.
between 5-aminoindan (9.04 gm, 64.50 mmol) and 2-chloroe-
thylchloroformate (6.86 mL, 64.50 mmol). After flash chroma-
tography, AP-200 was obtained (6.79 g, 59% yield) as a dark
brown oil showing: IR (cmꢃ1); 3345, 2940, 2837, 1615, 1494,
1456, 1329, 1290, 1260, 1212, 1157, 1119, 1058, 949, 840,
802, 703; 1H-NMR (CDCl3, 400 MHz),: d (ppm) 2.01 (m,
2H), 2.78 (q, J ¼ 15.43 Hz, and 7.72 Hz, 4H), 3.20 (t, J ¼
5.20 Hz, 2H), 3.27 (s, 2H), 3.74 (t, J ¼ 5.22 Hz, 2H), 6.42
(dd, J ¼ 8.03 Hz and 2.27 Hz, 1H), 6.53 (s, 1H), and 6.99 (d,
J ¼ 8.11 Hz, 1H); 13C-NMR (CDCl3, 100 MHz): d 25.44,
31.69, 32.87, 46.56, 60.91, 109.43, 111.65, 124.53, 133.56,
145.22, 146.58; HRMS m/z: 178.1229 found (Calculated for
C11H15NO, [MþH]þ requires 178.1226).
400 MHz): d (ppm) 3.10 (t, J ¼ 5.19 Hz, 2H), 2.80 (m, 4H),
3.20 (t, 2H), 3.27 (br, 2H), 3.74 (t, J ¼ 5.18 Hz, 2H), 6.43 (d,
J ¼ 2.0 Hz), 6.65 (d, J ¼ 8.58 Hz, 1H); 13C-NMR (CDCl3,
100 MHz): d 47.00, 61.09, 64.21, 64.76, 102.21, 107.37,
117.69, 136.03, 143.15, 144.06; HRMS m/z: 196.0968 found
(calculated for C10H13NO3, [MþH]þ requires 196.0980).
General synthesis of 4-aza-2,3-didehydropodophyllotoxin
derivatives. An equimolar mixture of tetronic acid, a substi-
tuted aniline and an aromatic aldehyde dissolved in the mini-
mum volume of ethanol was refluxed for 30 to 90 min. After
cooling, the precipitate was filtered off, washed with minimal
cold ethanol and then recrystallized from ethanol.
5-(2-Hydroxyethyl)-9-(3,4,5-trimethoxyphenyl)-6,9-dihy-
dro-[1,3]dioxolo[4,5-g]furo[3,4-b]quinolin-8(5H)-one (AP-
101). Reaction time: 30 min. The product was washed with
cold ethanol and dried under high vacuum, recrystallization
from ethanol yielded 70% as a white crystalline powder, MP:
241–243ꢁC; UV–Vis kmax (nm): 261, 322; IR (mmax, cmꢃ1);
3498, 2936, 1727, 1652, 1589, 1504, 1476, 1320, 1232,
1192, 1117, 1033, 1011, 931, 787, 760, 686; 1 H-NMR
(DMSO-d6, 400 MHz): d 3.59 (s, 3H, 40CAOCH3), 3.64 (m,
3H, 6CAH and 200CAH), 3.70 (s, 6H, 30-OCH3 and 50-OCH3)
3.92 (m,1H, 200CAH), 4.81 (s, 1H, 9CAH), 4.95 (t, 1H, OH),
2-(2,3-Dihydro-benzo[1,4]dioxin-6-ylamino)-ethanol (AP-
300). 2-(2,3-Dihydro-benzo[1,4]dioxin-6-ylamino)-ethanol
(AP-300) was synthesized from a similar reaction between
1,4-benzodioxan-6-amine (9.33 gm, 61.11 mmol) and 2-chlor-
oethylchloroformate (6.5 mL, 61.11 mmol). The solid crude
product was purified by silica gel (200 g) flash chromatogra-
phy with hexane-ethyl acetate gradient to give the title com-
pound (7.68 g, 64%) as a dark brown oil showing IR (cmꢃ1);
3373, 2928, 2876, 1625, 1595, 1502, 1460, 1325, 1276, 1205,
1171, 1062, 961, 919, 883, 828, 794, 745; 1H-NMR (CDCl3,
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A. Kumar and A. E. Alegria
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Figure 5. HETCOR spectrum of AP-101.
5.07 (d, J ¼ 15.89 Hz, 1H, 100CAH), 5.13 (d, J ¼ 15.89 Hz,
1H, 100CAH), 5.99 (d, J ¼ 22.75 Hz, 2H, 2CAH), 6.519 (s,
2H, 20CAH and 60-H), 6.77 (s, 1H, 10CAH), 6.97(s, 1H,
4CAH); 13C-NMR (DMSO-d6, 100 MHz): d 40.34, 48.44,
56.17, 56.29, 58.47, 60.22, 66.15, 95.23, 96.59, 101.73,
104.95, 104.95, 110.37, 119.80, 131.13, 136.38, 143.40,
143.62, 147.29, 153.19, 160.99, 172.67;HRMS m/z: 442.1491
found (calculated for C23H23NO8, [MþH]þ requires
442.1496); Anal. Calcd. For [C23H23NO8]; C, 62.58; H, 5.25;
N, 3.17; O, 29.00. Found C, 62.55; H, 5.26; N, 3.20; O,
29.03
95.89, 101.09, 109.85, 111.14, 111.60, 119.04, 119.39, 130.62,
139.88, 146.58, 147.10, 148.40, 160.04, 172.07; HRMS m/z:
412.1383 found (calculated for C22H21NO7, [MþH]þ requires
412.1391). Anal. Calcd. For [C22H21NO7]; C, 63.23; H, 5.14; N,
3.40. Found C, 64.19; H, 5.04; N, 3.38.
5-(2-Hydroxyethyl)-9-(3-methoxyphenyl)-6,9-dihydro-[1,3]
dioxolo[4,5-g]furo[3,4-b]quinolin-8(5H)-one (AP-103). Reaction
time: 30 min. The crude product was washed with cold ethanol
and dried under high vacuum. A white crystalline powder was
obtained, which was purified by recrystallization from ethanol;
yield 54%, MP: 140–141ꢁC; UV–Vis kmax (nm): 261, 322; IR
(mmax, cmꢃ1); 3422, 2924, 1743, 1654, 1593, 1507, 1473,
1425, 1327, 1230, 1209, 1121, 1041, 1014, 988, 876, 848,
808, 759, 680; 1H-NMR (DMSO-d6, 400 MHz),: d 3.68 (m,
6H, 30CAOCH3, 100CAH and 200CAH), 3.85 (m,1H, 200CAH),
4.87 (s, 1H, 9CAH), 5.01 (t, J ¼ 4.85 Hz, 1H, OH), 5.03 (d, J
¼ 15.48 Hz, 1H, 100CAH), 5.10 (d, J ¼ 15.48 Hz, 1H,
100CAH), 5.92 (s, 1H, 2CAH), 5.98 (s, 1H, 2CAH), 6.65 (s,
1H, 20CAH), 6.71 (br, 1H, 10CAH), 6.78 (d, J ¼ 8.26Hz, 1H,
40CAH), 6.78 (d, J ¼ 8.15 Hz, 1H, 50CAH ) 6.80 (s, 1H,
60CAH), 6.95 (s, 1H,4CAH), 7.15(t, J ¼ 8.08Hz, 1H); 13C-
NMR (DMSO-d6, 100 MHz): d 39.95, 48.12, 54.85, 57.96,
65.72, 94.77, 96.18, 101.33, 110.04, 111.30, 113.49, 119.04,
119.76, 129.30, 130.99, 143.16, 146.88, 148.66, 159.23,
160.39, 172.18; HRMS m/z: 382.1288 found (calculated for
C21H19NO6, [MþH]þ requires 382.1285). Anal. Calcd. For
9-(3,4-Dimethoxyphenyl)-5-(2-hydroxyethyl)-6,9-dihydro-[1,3]
dioxolo[4,5-g]furo[3,4-b]quinolin-8(5H)-one (AP-102). Reaction
time: 30 min. The crude product was washed with cold ethanol
and dried under high vacuum. Recrystallization from ethanol
yielded 63% as a white crystalline powder; MP: 204–205ꢁC;
UV–Vis kmax (nm): 261, 322; IR (mmax, cmꢃ1); 3418, 2929,
1742, 1654, 1593, 1508, 1473, 1425, 1363, 1327, 1230, 1209,
1
1122, 1040, 1014, 989, 876, 847, 808, 759, 680; H-NMR
(DMSO-d6, 400 MHz),: d 3.68 (m, 9H, 20,30CAOCH3, 100CAH
and 200CAH), 3.85 (m,1H, 200CAH), 4.81 (s, 1H, 9CAH), 4.99
(t, 1H, OH), 5.07 (d, J ¼ 15.68 Hz, 1H, 100CAH), 5.14 (d, J ¼
15.68 Hz, 1H, 100CAH), 5.92 (s, 1H, 2CAH), 5.98 (s, 1H,
2CAH), 6.68 (s, 1H, 10CAH), 6.69 (dd, 1H J ¼ 8.37 Hz and 2.4
Hz, 60CAH), 6.79 (d, J ¼ 8.15 Hz, 1H, 50CAH ) 6.86 (d, J ¼
7.5Hz, 1H, 20CAH), 6.95 (s, 1H,4CAH); 13C-NMR (DMSO- d6,
100 MHz): d 39.10, 47.86, 55.17, 55.27, 57.80, 65.48, 94.85,
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Synthesis of Novel Functionalized 4-Aza-2,3-didehydropodophyllotoxin
Derivatives with Potential Antitumor Activity
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[C21H19NO6]; C, 66.13; H, 5.02; N, 3.67. Found C, 66.09; H,
5.00; N, 3.81.
172.27; HRMS m/z: 438.1903 found (calculated for
C25H27NO6, [MþH]þ requires 438.1911). Anal. Calcd. For
[C25H27NO6]; C, 68.63; H, 6.22; N, 3.20. Found C, 68.51; H,
6.31; N, 3.16.
5-(2-Hydroxyethyl)-9-phenyl-6,9-dihydro-[1,3]dioxolo[4,5-
g]furo[3,4-b]quinolin-8(5H)-one (AP-104). Reaction time:
30 min. The crude product was washed with cold ethanol and
dried under high vacuum yielding a white crystalline powder
which was purified by recrystallization from ethanol; yield 62
4-(2-Hydroxyethyl)-10-(3-methoxyphenyl)-3,4,6,7,8,10-hex-
ahydro-1H-cyclopenta[g]furo[3,4-b]quinolin-1-one (AP-
203). Reaction time: 30 min. The crude product was washed
with 1:1 ethylacetate-hexane (V/V) and dried under high vac-
uum yielding a white crystalline powder which was purified
by recrystallization from ethanol: ethylacetate mixture 1:1;
yield 51%, MP: 158–159ꢁC; UV–Vis kmax (nm): 261, 322; IR
(mmax, cmꢃ1); 3378, 2933, 1718, 1643, 1597, 1476, 1431,
1366, 1347, 1321, 1262, 1243, 1202, 1172, 1161, 1095, 1020,
1001, 877, 845, 813, 780, 765, 746, 699, 671; 1H-NMR
(DMSO-d6, 400 MHz),: d 1.95 (m, 2H, 7CAH), 2.68 (m, 2H,
6CAH), 2.81 (m, 2H, 8CAH), 3.66 (m, 6H, 30CAOCH3,
100CAH and 200CAH one), 3.84 (m, 1H, 200CAH one), 4.90 (s,
1H, 10CAH), 5.01 (t, J ¼ 4.85 Hz, 1H, OH), 5.04 (d, J ¼
13.32 Hz, 1H, 100CAH), 5.12 (d, J ¼ 13.32 Hz, 1H, 100CAH),
6.69 (m, 1H, 40CAH), 6.78 (m, 2H, 20and 60CAH), 6.95 (s,
1H, 9CAH), 7.08 (s, 1H, 5CAH), 7.12(t, 1H, 50CAH); 13C-
NMR (DMSO-d6, 100 MHz): d 25.66, 31.98, 32.82, 40.23,
48.32, 55.33, 58.25, 66.22, 95.77, 110.42, 111.57, 114.15,
120.35, 124.96, 126.99, 129.79, 135.26, 139.28, 143.89,
149.46, 159.68, 161.08, 172.69; HRMS m/z: 378.1700 found
(calculated for C23H23NO4, [MþH]þ requires 378.1700). Anal.
Calcd. For [C23H23NO4]; C, 73.19; H, 6.14; N, 3.71. Found C,
72.88; H, 6.14; N, 3.76.
4-(2-Hydroxyethyl)-10-phenyl-3,4,6,7,8,10-hexahydro-1H-
cyclopenta[g]furo[3,4-b]quinolin-1-one (AP-204). Reaction
time: 30 min. The crude product was washed with 1:1 ethyla-
cetate-hexane (V/V) and dried under high vacuum yielding a
white crystalline powder which was purified by recrystalliza-
tion from ethanol: ethylacetate mixture 1:1; yield 52%, MP:
191–192ꢁC;); UV–Vis kmax (nm): 261, 322; IR (mmax, cmꢃ1);
3386, 2952, 2857, 1730, 1637, 1477, 1444, 1413, 1355, 1323,
1203, 1059, 1034, 1015, 994, 880, 852, 812, 754, 737, 701;
1H-NMR (DMSO-d6, 400 MHz),: d 1.95 (m, 2H, 7CAH), 2.68
(m, 2H, 6CAH), 2.81 (m, 2H, 8CAH), 3.69 (m, 3H, 100CAH
and 200-H), 3.86 (m, 1H, 200CAH), 4.94 (s, 1H, 10CAH), 5.04
(t, J ¼ 4.85 Hz, 1H, OH), 5.09 (d, J ¼ 15.55 Hz, 1H,
100CAH), 5.15 (d, J ¼ 15.55 Hz, 1H, 100CAH), 6.92 (s, 1H,
9CAH), 7.09 (s, 1H, 5CAH), 7.15(m, 4H, 20,30,40and 60CAH);
13C-NMR (DMSO- d6, 100 MHz): d 25.65, 31.96, 32.82,
40.31, 48.33, 58.25, 66.23, 95.77, 110.44, 125.09, 126.63,
127.07, 128.06, 128.74, 135.35, 139.31, 143.88, 147.92,
161.08, 172.69; HRMS m/z: 348.1597 found (calculated for
C22H21NO3, [MþH]þ requires 348.1594). Anal. Calcd. For
[C22H21NO3]; C, 76.06; H, 6.09; N, 4.03. Found C, 75.73; H,
6.06; N, 4.06.
%, MP: 180–181ꢁC; UV–Vis kmax (nm): 261, 322; IR (mmax
,
cmꢃ1); 3278, 2880, 1709, 1641, 1480, 1438, 1369, 1339, 1242,
1198, 1020, 936, 876, 742, 700; 1H-NMR (DMSO-d6, 400
MHz),: d 3.64 (m, 3H, 100CAH and 200CAH), 3.79 (m,1H,
200CAH), 4.88 (s, 1H, 9CAH), 5.01 (t, J ¼ 4.84 Hz, 1H, OH),
5.05 (br 2H, 100CAH), 5.90 (s, 1H, 2CAH), 5.96 (s, 1H,
2CAH), 6.59 (s, 1H, 10CAH), 6.94 (s, 1H, 4CAH) 7.14 (br,
1H, 40CAH), 7.21(br, 4H, 20CAH, 30CAH, 50CAH and
60CAH); 13C-NMR (DMSO- d6, 100 MHz): d 40.43, 48.62,
58.43, 66.24, 95.35, 96.71, 101.83, 110.60, 119.65, 126.75,
127.99, 128.77, 131.54, 143.67, 147.36, 147.60, 160.88,
172.69; HRMS m/z: 352.1178 found (calculated for
C20H17NO5, [MþH]þ requires 352.1179).
9-(4-Hydroxy-3,5-dimethoxyphenyl)-5-(2-hydroxyethyl)-6,9-
dihydro-[1,3]dioxolo[4,5-g]furo[3,4-b]quinolin-8(5H)-one (AP-
105). Reaction time: 30 min. The crude product was washed
with cold ethanol and dried under high vacuum yielding a
white crystalline powder which was purified by recrystalliza-
tion from ethanol; yield 69%, MP: 237–238ꢁC; UV–Vis kmax
(nm): 261, 322; IR (mmax, cmꢃ1); 3551, 3345, 2940, 1708,
1638, 1605, 1509, 1481, 1456, 1367, 1322, 1242, 1198, 1108,
1068, 1016, 919, 860, 818, 763, 687; 1H-NMR (DMSO-d6,
400 MHz),: d 3.66 (m, 9H, 50and 30CAOCH3, 100CAH and
200CAH), 3.92 (m, 1H, 200CAH), 4.75 (s, 1H, 9CAH), 4.95 (t,
J ¼ 4.85 Hz, 1H, OH), 5.02 (d, J ¼ 15.43 Hz, 1H, 100CAH),
5.12 (d, J ¼ 15.43 Hz, 1H, 100CAH), 5.92 (s, 1H, 2CAH),
5.98 (s, 1H, 2CAH), 6.48 (s, 2H, 20and 60 CAH), 6.74 (s, 1H,
10CAH), 6.95 (s, 1H,4CAH), 8.10(s, 1H, 40CAOH); 13C-
NMR (DMSO-d6, 100 MHz): d 40.16, 48.50, 56.40, 58.53,
66.15, 95.50, 96.56, 101.75, 105.27, 110.47, 120.35, 131.13,
134.58, 138.19, 143.60, 147.21, 148.32, 160.86, 172.79;
HRMS m/z: 428.1345 found (calculated for C22H21NO8,
[MþH]þ requires 428.1340).; Anal. Calcd. For [C22H21NO8];
C, 61.82; H, 4.95; N, 3.28. Found C, 61.74; H, 4.84; N, 3.24.
4-(2-Hydroxyethyl)-10-(3,4,5-trimethoxyphenyl)-3,4,6,7,8,10-
hexahydro-1H-cyclopenta[g]furo[3,4-b]quinolin-1-one (AP-
201). Reaction time: 30 min. The crude product was washed
with 1:1 ethylacetate-hexane (V/V) and dried under high vac-
uum yielding a white crystalline powder which was purified
by recrystallization from ethanol: ethylacetate mixture 1:1;
yield 49%, MP: 153–154ꢁC; UV–Vis kmax (nm): 261, 322; IR
(mmax, cmꢃ1); 3422, 2929, 1743, 1655, 1620, 1593, 1508,
1473, 1426, 1363, 1328, 1293, 1231, 1210, 1123, 1066, 1043,
1015, 989, 876, 848, 823, 808, 791, 759, 744, 681; 1H-NMR
(DMSO-d6, 400 MHz),: d 1.96 (m, 2H, 7CAH), 2.71 (m, 2H,
6CAH), 2.81 (m, 2H, 8CAH), 3.58 (s, 3H, 40-OCH3), 3.66 (m,
9H, 30and 50, CAOCH3, 100CAH and 200CAH), 3.98 (m, 1H,
200CH), 4.86 (s, 1H, 10CAH), 4.98 (t, J ¼ 4.85 Hz, 1H, OH),
5.05 (d, J ¼ 15.98 Hz, 1H, 100CAH), 5.15 (d, J ¼ 15.98 Hz,
1H, 100CAH), 6.53 (s, 2H, 20 and 60 CAH), 7.06 (s, 1H,
9CAH), 7.10 (s, 1H, 5CAH); 13C-NMR (DMSO-d6, 100
MHz): d 25.17, 31.52, 32.32, 39.94, 47.68, 55.74, 55.74,
57.83, 59.77, 65.73, 95.29, 104.53, 109.92, 124.76, 126.33,
134.48, 135.85, 138.83, 143.32, 143.33, 152.73, 160.81,
6-(2-Hydroxyethyl)-10-(3,4,5-trimethoxyphenyl)-2,3,7,10-
tetrahydro-[1,4]dioxino[2,3-g]furo[3,4-b]quinolin-9(6H)-one (AP-
301). Reaction time: 60 min. The crude product was washed
with cold ethanol and dried under high vacuum yielding a
white crystalline powder which was purified by recrystalliza-
tion from ethanol; yield 61%, MP: 256–257ꢁC; UV–Vis kmax
(nm): 261, 322; IR (mmax, cmꢃ1); 3506, 2936, 1733, 1650,
1591, 1506, 1474, 1367, 1295, 1203, 1120, 1065, 993, 894,
755, 686; 1H-NMR (DMSO- d6, 400 MHz): d 3.59 (s, 3H,
40CAOCH3), 3.70 (m, 9H, 30and 50, CAOCH3, 100CAH and
200CAH), 3.89 (m, 1H, 200CAH), 4.16 (m, 4H, 2and3CAH)
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

1282
A. Kumar and A. E. Alegria
Vol 47
4.80 (t, J ¼ 4.85 Hz, 1H, OH), 4.96 (s, 1H, 10CAH), 5.07
(d, J ¼ 15.29 Hz, 1H, 100CAH), 5.13 (d, J ¼ 15.29 Hz, 1H,
100CAH), 6.53 (s, 20and60CAH), 6.71 (s, 1H, 11CAH), 6.75 (s,
1H, 5CAH); 13C-NMR (DMSO-d6, 100 MHz): d 39.67, 48.32,
56.24, 58.32, 60.29, 64.42, 64.72, 66.23, 95.14, 103.38,
104.95, 119.07, 120.33, 130.49, 136.36, 139.87, 142.89,
143.52, 153.24, 161.12, 172.79; HRMS m/z: 456.1647 found
(calculated for C24H25NO8, [MþH]þ requires 356.1653). Anal.
Calcd. For [C24H25NO8]; C, 63.29; H, 5.53; N, 3.08. Found
C, 63.04; H, 5.44; N, 3.04.
10-(3,4-Dimethoxyphenyl)-6-(2-hydroxyethyl)-2,3,7,10-tetra-
hydro-[1,4]dioxino[2,3-g]furo[3,4-b]quinolin-9(6H)-one (AP-
302). Reaction time: 90 min. The crude product was washed
with cold ethanol and dried under high vacuum yielding a
white crystalline powder which was purified by recrystalliza-
tion from ethanol; yield 65%, MP: 210–211ꢁC; UV–Vis kmax
(nm): 261, 322; IR (mmax, cmꢃ1); 3497, 2932, 1726, 1647,
1504, 1474, 1440, 1347, 1268, 1206, 1133, 1067, 1025, 1004,
892, 812, 758, 706; 1H-NMR (DMSO- d6, 400 MHz): d 3.68
(m, 9H, 30and 40, CAOCH3, 100CAH and 200CAH), 3.82 (m,
1H, 200CAH), 4.16 (m, 4H, 2and3CAH), 4.99 (t, J ¼ 4.85 Hz,
1H, OH), 4.80 (s, 1H, 10CAH), 5.06 (d, J ¼ 15.07 Hz, 1H,
100CAH), 5.10 (d, J ¼ 15.07 Hz, 1H, 100CAH), 6.61 (s, 1H,
11CAH), 6.66 (dd, J ¼ 7.99 Hz and 1.91 Hz, 1H, 60CAH),
6.73 (s, 1H, 5CAH), 6.79 (t, J ¼ 8.38 Hz, 1H, 50CAH), 6.84
(d, J ¼ 1.91 Hz, 1H, 20CAH); 13C-NMR (DMSO-d6, 100
MHz): d 39.05, 48.38, 55.90, 55.99, 58.28, 64.43, 64.73,
66.15, 95.39, 103.27, 111.86, 112.34, 119.20, 119.72, 120.55,
130.65, 139.82, 140.57, 142.80, 147.74, 149.05, 160.75,
172.78; HRMS m/z: 426.1553 found (calculated for
C23H23NO7, [MþH]þ requires 426.1547). Anal. Calcd. For
[C23H23NO7]; C, 64.93; H, 5.45; N, 3.29. Found C, 64.92; H,
5.34; N, 3.32.
der which was purified by recrystallization from ethanol; yield
68%, MP: 229–230ꢁC; UV–Vis kmax (nm): 261, 322; IR (mmax
,
cmꢃ1); 2956, 2876, 1719, 1637, 1581, 1475, 1437, 1363, 1292,
1250, 1203, 1149, 1065, 1007, 923, 893, 832, 806, 753, 734,
1
695; H-NMR (DMSO-d6, 400 MHz): d 3.66 (m, 3H, 100CAH
and 200CAH), 3.79 (m, 1H, 200CAH), 4.14 (m, 4H,
2and3CAH), 4.88 (s, 1H, 10CAH), 5.04 (br, 1H, OH), 5.08 (d,
J ¼ 15.48 Hz, 1H, 1"CAH), 5.13 (d, J ¼ 15.48 Hz, 1H,
1"CAH), 6.59 (s, 1H, 11CAH), 6.74 (s, 1H, 5CAH), 7.21 (br,
2H, 20and60CAH), 7.24 (br, 2H, 30 and 50CAH), 7.14 (t, J ¼
6.87 Hz, 1H, 40CAH); 13C-NMR (DMSO-d6, 100 MHz): d
39.57, 48.46, 58.25, 64.43, 64.72, 66.21, 95.25, 103.39,
119.30, 120.16, 126.67, 127.99, 128.75, 130.85, 139.86,
142.72, 147.60, 160.86, 172.71; HRMS m/z: 366.1338 found
(calculated for C21H19NO5, [MþH]þ requires 366.1336). Anal.
Calcd. For [C21H29NO5]; C, 69.03; H, 5.24; N, 3.83. Found
C, 68.64; H, 5.29; N, 3.84.
Acknowledgments. The authors are grateful for grants No. SO6-
GM008216 and P20 RR-016470 from NIH (USA) for financial
support of this work. They also thank Professor Margarita Ortiz-
Marciales from University of Puerto Rico for helpful suggestions.
REFERENCES AND NOTES
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303). Reaction time: 90 min. The crude product was washed
with cold ethanol and dried under high vacuum yielding a
white crystalline powder which was purified by recrystalliza-
tion from ethanol; yield 60%, MP: 175–176ꢁC; UV–Vis kmax
(nm): 261, 322; IR (mmax, cmꢃ1); 3424, 2936, 1720, 1641,
1581, 1483, 1442, 1367, 1296, 1274, 1250, 1206, 1155, 1060,
1036, 1004, 907, 868, 806, 772, 753, 713, 695; 1H-NMR
(DMSO- d6, 400 MHz): d 3.68 (m, 6H, 30CAOCH3, 100CAH
and 200CAH), 3.78 (m, 1H, 200CAH), 4.16 (m, 4H, 2 and 3
CAH), 4.85 (s, 1H, 10CAH), 5.01 (t, J ¼ 4.82 Hz, 1H, OH),
5.07 (d, J ¼ 15.63 Hz, 1H, 100CAH), 5.14 (d, J ¼ 15.63 Hz,
1H, 100CAH), 6.59 (s, 1H, 11CAH), 6.71 (br, 1H, 60CAH),
6.74 (s, 1H, 5CAH), 6.76 (s, 1H, 20CAH), 6.78 (br, 1H,
40CAH), 7.15 (t, J ¼ 8.09 Hz, 1H, 50CAH ); 13C-NMR
(DMSO- d6, 100 MHz): d 39.48, 48.45, 55.35, 58.25, 64.43,
64.73, 66.21, 95.13, 103.37, 111.65, 114.05, 119.22, 120.03,
120.26, 129.79, 130.77, 139.83, 142.91, 149.17, 159.71,
160.89, 172.72; HRMS m/z: 396.1452 found (calculated for
C22H21NO6, [MþH]þ requires 396.1442). Anal. Calcd. For
[C22H21NO6]; C, 66.83; H, 5.35; N, 3.54. Found C, 66.68; H,
5.27; N, 3.52.
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6-(2-Hydroxyethyl)-10-phenyl-2,3,7,10-tetrahydro-[1,4]diox-
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Journal of Heterocyclic Chemistry
DOI 10.1002/jhet