The Journal of Organic Chemistry
Article
7.8 Hz), 7.19 (s, 1H), 7.96 (d, 1H, J = 7.8 Hz), 8.33 (d, 1H, J = 3.6
Hz), 10.03 (br s, 1H). 13C NMR (100 MHz, CDCl3): δ 23.3, 25.5,
39.8, 111.6, 115.6, 120.0, 122.5, 127.3, 142.9, 148.7, 170.1. FTIR (film,
cm−1): 3285, 1630. Anal. Calcd for C11H13N3O (203.11): C, 65.01; H,
6.45; N, 20.68. Found: C, 65.09; H, 6.39; N, 20.71.
ASSOCIATED CONTENT
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S
* Supporting Information
Figures giving 1H and 13C NMR spectra for all new
compounds. This material is available free of charge via the
N-(2,2-Bis(1H-indol-3-yl)ethyl)acetamide (4). This compound was
obtained and isolated as a reaction byproduct under the conditions
reported in the general procedure employing 1H-indole and N-(2-
hydroxyethyl)acetamide. Yield: 9% (7 mg, 0.02 mmol). MS (ESI): 318
AUTHOR INFORMATION
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Corresponding Author
1
[M + H]+. H NMR (200 MHz, CDCl3): δ 1.90 (s, 3H), 4.07 (m,
2H), 4.75 (t, 1H, J = 7.1 Hz), 5.60 (br s, 1H), 7.04−7.11 (m, 4H),
7.16−7.24 (m, 2H), 7.37−7.41 (m, 2H), 7.60−7.64 (m, 2H), 8.07 (br
s, 2H). The chemical and physical data are in accord with those in the
literature.32
Notes
The authors declare no competing financial interest.
2-(1H-Indol-3-yl)ethanol (5). This compound was obtained and
isolated as a reaction byproduct under the conditions reported in the
general procedure employing 1H-indole and N-(2-hydroxyethyl)-
acetamide. Yield: 6% (2 mg, 0.015 mmol). MS (ESI): 162 [M + H]+.
1H NMR (400 MHz, CDCl3): δ 3.03 (dt, 2H, J = 0.5 Hz and J = 6.3
Hz), 3.91 (t, 2H, J = 6.3 Hz), 7.07−7.26 (m, 3H), 7.38 (d, 1H, J = 8.0
Hz), 7.62 (d, 1H, J = 8.0 Hz), 8.07 (br s, 1H). The chemical and
physical data are in accord with those in the literature.33
ACKNOWLEDGMENTS
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This work was partially supported by the Italian MIUR
(Ministero dell’Istruzione, dell’Universita
University of Urbino “Carlo Bo”.
̀
della Ricerca) and
REFERENCES
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1
mmol). Yield: 40%. MS (ESI): 251 [M + H]+. H NMR (200 MHz,
CDCl3): δ 3.00 (app. s, 4H), 3.81 (s, 2H), 6.99−7.35 (m, 10H), 7.60
(d, 1H J = 7.5 Hz), 8.15 (br s, 1H). The chemical and physical data are
in accord with those in the literature.34
2-(1H-Indol-3-yl)-N,N-dimethylethanamine (6d). This compound
was prepared according to the general procedure from 1H-indole and
2-(dimethylamino)ethanol. Flash chromatography (CH2Cl2/MeOH/
TEA 93/6/1) gave 6d as a brown oil (20 mg, 0.11 mmol). Yield: 42%.
1
MS (ESI): 189 [M + H]+. H NMR (400 MHz, CDCl3): δ 2.36 (s,
6H), 2.64−2.68 (m, 2H), 2.94−2.98 (m, 2H), 7.03 (s, 1H), 7.11−7.15
(m, 1H), 7.18−7.22 (m. 1H), 7.36 (d, J = 8.0 Hz, 1H), 7.63 (d, J = 8.0
Hz, 1H), 8.11 (br s, 1H). The chemical and physical data are in accord
with those in the literature.35
General Procedure for the N-Deacetylation. Ammonium
bromide (49 mg, 0.5 mmol), ethylenediamine (0.135 mL, 2 mmol),
and N-acetyltryptamine derivative (0.5 mmol) were mixed in a suitable
vial fitted with a magnetic stirrer. The mixture was then heated to 100
°C in a microwave apparatus (250 W) for 7 h. After it was cooled to
room temperature, the crude reaction mixture was diluted with
CH2Cl2 and the desired tryptamine was extracted with an aqueous
solution of 1 M HCl. The aqueous layer was then made basic by
addition of aqueous NaOH (1 M) and then extracted with CH2Cl2.
The combined organic phases were washed with brine, dried over
Na2SO4, and concentrated by distillation at reduced pressure, giving a
crude residue which was purified by filtration on a flash chromato-
graphic column of silica gel (CH2Cl2/MeOH/TEA 90/9/1).
2-(5-Methoxy-1H-indol-3-yl)ethanamine (7b). This compound
was obtained as a colorless oil (85 mg, 0.45 mmol). Yield: 89%. MS
(ESI): 191 [M + H]+. 1H NMR (200 MHz, CDCl3): δ 1.98 (br s, 2H),
2.85−2.91 (m, 2H), 2.99−3.06 (m, 2H), 3.87 (s, 3H), 6.83−6.89 (m,
1H), 7.0 (s, 1H), 7.04−7.05 (m, 1H), 7.22−7.27 (m, 1H), 8.46 (br s,
1H). The chemical and physical data are in accord with those in the
literature.36
2-(2-Methyl-1H-indol-3-yl)ethanamine (7h). This compound was
obtained as a pale yellow amorphous solid (68 mg, 0.39 mmol). Yield:
78%. MS (ESI): 175 [M + H]+. 1H NMR (400 MHz, CDCl3): δ 1.76
(br s, 2H), 2.38 (s, 3H), 2.83−2.87 (m, 2H), 2.95−2.99 (m, 2H),
7.05−7.13 (m, 2H), 7.26 (d, J = 7.5 Hz, 1H), 7.50 (d, J = 7.5 Hz, 1H),
8.00 (br s, 1H). The chemical and physical data are in accord with
those in the literature.8a
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