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779
spectrometer. Combustion microanalyses were performed on a
Carlo Erba CNH 1106 analyzer, and were within 0.4% of calculated
values and confirmed >95% purity for the final products.
resulting solution was washed successively with 10% citric acid
(2 ꢂ 25 mL), 10% NaHCO3 (2 ꢂ 25 mL), and water (2 ꢂ 25 mL), dried
over Na2SO4, and evaporated to dryness. Intermediate 10 was ob-
tained after flash chromatography using n-hexane/ethyl acetate 2/1
as ratio with 63% yield. Substitution with propyl group of indolic N1
was carried out using the same conditions described elsewhere, to
give compound 11 with 44% yield. Mannich reaction performed on
position 3 of intermediate 11 follows the procedure previously
described yielded final compound 12 in 24% yield.
4.1.1. General procedure for the synthesis of N-alkylated indole
intermediates (2, 3, 6, 11, 13 and 14)
Indole (1, 1.0 eq) or 1H-indole-5-carbaldehyde (5, 1.0 eq), or N-
(1H-indol-5-yl)benzamide (10, 1.0 eq), or 3-(2-Bromoethyl)indole
(13, 1.0 eq.) were dissolved in a mixture of anhydrous DCM/DMF
(2/1 v/v) under magnetic stirring and the temperature was set to
0
ꢁC. To this solution, 1.5 equivalents of NaH were added por-
4.1.6. General procedure for the synthesis of derivatives 15, and
16a-i
tionwise and the mixture was allowed to react for 30 min. Then,
1.5 equivalents of alkyl iodide [methyl iodide, or n-propyl iodide,
or 4-(phenyl)iodomethylbenzene] in DCM were added dropwise
and the reaction was warmed to room temperature and main-
tained under stirring for further 12 h. The reaction was then
quenched by a 10% aqueous solution of citric acid and washed
with brine. The organic layer was separated, dried over anhydrous
Na2SO4, filtered and evaporated in vacuo. Crude products were
purified by column chromatography using n-hexane/ethyl acetate
(4:1 v:v) as mobile phase. N-alkylated compounds were obtained
in 75% yield (derivative 2); 80% yield (derivatives 3 and 13); 67%
yield (derivative 6); 55% yield (derivative 11) and 50% yield (de-
rivative 14).
One equivalent of intermediate 14a or 14b was dissolved in THF
and 1.5 eq of the proper amine,1.5 eq of TEA, 1.5 eq of NaI and 0.3 eq
of (CH3COO)2Pd were added to this solution. The reaction was
conducted under m
W, at 100 ꢁC, for 20 min. The resulting mixture
was filtered through Celite, dried in vacuo and reconstituted in
DCM. The organic phase was washed with water (3 ꢂ 50 mL), dried
over anhydrous Na2SO4, filtered, concentrated and purified by
column chromatography using DCM/MeOH (9:1 v/v) as mobile
phase giving derivative 15 in 38% yield and intermediates 16a-i in
55e75% yield.
4.1.7. General procedure for the synthesis of derivatives 17a-i and
18a-c
4.1.2. Synthesis of derivative 4a
One equivalent of intermediate 16a-i was dissolved in DCM and
1.5 eq of the proper acyl chloride and 1.5 eq of TEA, were added to
the solution. The reaction was conducted for 20 min at room
temperature. The organic phase was washed with water
(3 ꢂ 50 mL), dried over anhydrous Na2SO4, filtered, concentrated
and purified by column chromatography using n-hexane/ethyl ac-
etate (2:1 v/v) as mobile phase. Final derivatives 17a-i and 18a-
d were obtained as an atropisomer mixtures in 42e58% yield.
To a solution of 1-propyl-1H-indole (2) in dry CH3CN was added
aluminium trichloride (15 eq) and benzoyl chloride (10 eq), the
reaction was stirred at room temperature overnight. The resulting
mixture was dried in vacuo and reconstituted in DCM. The organic
phase was washed with water (3 ꢂ 50 mL), dried over anhydrous
Na2SO4, filtered, concentrated and purified by column chroma-
tography using n-hexane/ethyl acetate (3/2) as mobile phase.
Compound 4a was obtained in 32% yield.
4.1.8. Synthesis of derivative 18d
4.1.3. Synthesis of derivatives 4b-d
To a mixture of 16a (1.0 eq.) in DCM, (Boc)2O (3.0 eq.) was added
followed by TEA (1.5 eq.). The mixture was allowed to stir at room
temperature for 12 h. Afterward, the reaction mixture was diluted
with dichloromethane (20 mL), and the resulting solution was
washed with 10% citric acid (2 ꢂ 25 mL). The organic phase was
dried over Na2SO4, and evaporated to dryness. Compound 17 k was
obtained as atropisomer mixture after flash chromatography using
n-hexane/ethyl acetate 2/1 in 58% yield.
A solution of formaldehyde (2 eq.), trifluoroacetic acid (2 eq.)
and 2 equivalents of the proper amine (piperidine or bifenylethil-
amine) was added portionwise to a solution of the intermediate 2
or 3 (1 eq.) in DCM. The mixture was stirred for 3 h at room tem-
perature, then was washed with water (3 ꢂ 50 mL), dried over
anhydrous Na2SO4, filtered, concentrated and purified by column
chromatography using DCM/MeOH (9:1 v/v) as mobile phase.
Compounds 4b-d were obtained in 25%e38% yield.
4.2. Antiviral assays
4.1.4. Synthesis of derivatives 8a-b
The intermediate 7a or 7b (1.0 eq) was dissolved in a solution of
DCM:CH3COOH (5:1 v/v) at room temperature. To this solution 2.0
equivalents of 4-chloroaniline was added and the mixture was
warmed to reflux for 1.5 h. Then, 1.8 equivalents of sodium tri-
acetoxyborohydride were added portionwise and the mixture was
allowed to reflux for further 3e5 h. After cooling to room tem-
perature, NaOH 1 N was added. The organic phase was separated
and extracted one more time with the alkaline solution. Then it was
dried over Na2SO4, filtered and concentrated in vacuo. The crude
products were purified by column chromatography using mixtures
of DCM/MeOH as eluent giving desired compounds 8a and 8b in
24% and 30% yield respectively.
The compounds were evaluated against different herpes viruses,
including varicella-zoster virus (VZV) strains Oka and YS, TKꢀ VZV
strains 07-1 and YS-R, herpes simplex virus type 1 (HSV-1) strain
KOS, thymidine kinase-deficient (TKꢀ) HSV-1 KOS strain resistant
to ACV (ACVr), herpes simplex virus type 2 (HSV-2) strain G, human
cytomegalovirus (HCMV) strains AD-169 and Davis as well as feline
herpes virus (FHV), the poxvirus vaccinia virus (Lederle strain),
adenovirus-2, parainfluenza-3 virus, reovirus-1, Sindbis virus,
Coxsackie virus B4, Punta Toro virus, respiratory syncytial virus
(RSV), feline coronavirus (FIPV) and influenza A virus subtypes
H1N1 (A/PR/8), H3N2 (A/HK/7/87) and influenza B virus (B/HK/5/
72) and human immune deficiency virus (HIV-1 (IIIB) and HIV-2
(ROD)). The antiviral assays were based on inhibition of virus-
induced cytopathicity (CPE) or (VZV) plaque formation in human
embryonic lung (HEL) fibroblasts, African green monkey kidney
cells (Vero), human epithelial cervix carcinoma cells (HeLa), human
CDþ4 T-lymphocyte cells (CEM), Crandell-Rees feline kidney cells
(CRFK), or Madin Darby canine kidney cells (MDCK). Confluent cell
cultures in microtiter 96-well plates were inoculated with 100
4.1.5. Synthesis of derivative 8c
To a solution of 5-amino indole (9, 1.0 eq) in dichloromethane/
DMF (20 mL/5 mL) were successively added benzoic acid (1.1 eq),
HBTU (1.2 eq), HOBt (1.2 eq), and DIEA (2.4 eq), and stirring was
continued at room temperature for 24 h. Afterward, the reaction
mixture was diluted with dichloromethane (20 mL), and the
Musella, Simona
