TABLE 1. P r im a r y Nitr oa lk a n es 2
probably because of the prevalent formation of side
produts, as previously reported.19
Compared with the standard procedures, our method
offers a series of important advantages such as (i) the
minimization of the formation of the undesidered alkyl
nitrites, (ii) better yields, (iii) easier workup, and (iv)
shorter reaction times.
In conclusion, we have reported the first eco-friendly pro-
cedure for the conversion of primary alkyl halides to nitro-
alkanes under aqueous medium, and this result can be of
great interest due to the large need of aliphatic nitro com-
pounds as the key building blocks in organic synthesis.
Exp er im en ta l Section
To a water solution (2 mL) of the iodoalkane (1 mmol) was
added AgNO2 (4 mmol) and the reaction flask was wrapped with
silver paper to protect the reaction mixture from light. After
being stirred at the appropriate temperature (see Table 1), the
reaction mixture was filtered, extracted with EtOAc, and dried
over Na2SO4 and the solved was evaporated under reduced
pressure. The crude products were purified by column chroma-
tography (hexane:EtOAc, 95:5). To verify the efficiency of the
reaction in a larger scale, we tested, as a representative example,
the conversion of 1h (20 mmol) to 2h , without significant
changes of both the reaction time and yield. As a criterion of
purity, 1H NMR or 13C NMR spectra of the compounds prepared
are reported in the Supporting Information.
1-Nitr ou n d eca n e (2i): oil; 1H NMR (300 MHz, CDCl3) δ 0.88
(t, J ) 6.9 Hz, 2H), 1.28 (m, 16H), 1.99 (m, 2H), 4.38 ppm (t, J
) 7.1 Hz, 2H); 13C NMR (75 MHz, CDCl3) δ 14.3, 22.9, 26.4,
27.6, 29.0, 29.45, 29.48, 29.6, 29.7, 32.1, 75.9 ppm; GC-MS m/z
154 (M+ - HNO2), 138,124,110, 97, 83, 69, 55, 43; IR (neat) 2928,
a
Yield of pure, isolated product.
2855, 1555, 1468, 1381 cm-1
.
SCHEME 2
2-(4-Nitr obu tyl)-1H-isoin d ole-1,3(2H)-d ion e (2k ): white
solid, mp 69-72 °C; 1H NMR (300 MHz, CDCl3) δ 1.79 (m, 2H),
2.05 (m, 2H), 3.74 (t, J ) 7.0 Hz, 2H), 4.44 (t, J ) 7.0 Hz, 2H),
7.72 (dd, J ) 5.5, 3.4 Hz, 2H), 7.84 ppm (dd, J ) 5.5, 3.4 Hz,
2H); 13C NMR (75 MHz, CDCl3) δ 24.7, 25.6, 36.9, 75.0, 123.5,
132.1, 134.3, 168.5 ppm; GC-MS m/z 213, 200, 160, 148, 130,
104, 76; IR (neat) 2940, 1772, 1713, 1548, 1438, 1377, 725, 714,
666 cm-1
.
3-Nitr o-1-p h en ylp r op a n -1-on e (2m ): white solid, mp 72-
74 °C; 1H NMR (300 MHz, CDCl3) δ 3.69 (t, J ) 6.2 Hz, 2H),
4.85 (t, J ) 6.2 Hz, 2H), 7.52 (m, 2H), 7.65 (m, 1H), 8.00 ppm
(m, 2H); 13C NMR (75 MHz, CDCl3) δ 24.7, 25.6, 36.9, 75.0, 123.5,
132.1, 134.3, 168.5 ppm; GC-MS m/z 179, 132, 120, 105, 77, 51;
formation of R,ω-diiodo structures 3 to the corresponding
dinitroalkanes 4 (Scheme 2, 61-64%).
The NMR spectra and the GC analysis of the crude
reaction mixtures show that by our conditions the forma-
tion of alkyl nitrites, as byproducts, is strongly depressed,
since in most of the cases the nitrite could not be detected
or, in a few cases, less than 4-5% of the above side
products were observed. The reaction has also been tested
in the presence of a catalytic amount of cetyltrimethy-
lammonium bromide (CTABr) without any improvement.
The method failed with secondary halo derivatives,
IR (neat) 2927, 1773, 1718, 1551, 1054, 726, 690, 666 cm-1
.
1
1,5-Din itr op en ta n e (4a ): oil; H NMR (300 MHz, CDCl3) δ
1.50 (m, 2H), 2.06 (m, 4H), 4.40 ppm (t, J ) 6.9 Hz, 4H); 13C
NMR (75 MHz, CDCl3) δ 23.4, 26.7, 75.1 ppm; GC-MS m/z 69,
41; IR (neat) 2927, 1560, 1546, 1432, 1375 cm-1
.
1,8-Din itr oocta n e (4b): oil; 1H NMR (300 MHz, CDCl3) δ
0.63 (m, 8H), 2.00 (m, 4H), 4.38 ppm (t, J ) 7.0 Hz, 4H); 13C
NMR (75 MHz, CDCl3) δ 26.3, 27.5, 28.7, 75.8 ppm; GC-MS m/z
158, 95, 81, 69, 55, 41; IR (neat) 2922, 2859, 1551, 1436, 1383
cm-1
.
(12) Bayada, A.; Lawrence, G. A.; Maeder, M.; O’Leary, M. A. Dalton
Trans. 1994, 21, 3107-3111.
1
1,10-Din itr od eca n e (4c): oil; H NMR (300 MHz, CDCl3) δ
0.67 (m, 12H), 1.99 (m, 4H), 4.37 ppm (t, J ) 7.0 Hz, 4H); 13C
NMR (75 MHz, CDCl3) δ 26.3, 27.5, 28.9, 29.2, 75.9 ppm; GC-
MS m/z 152, 109, 95, 83, 69, 55, 41; IR (neat) 2926, 2855, 1541,
(13) Hauser, F. M.; Baghdanov, V. M. J . Org. Chem. 1988, 53, 2872-
2873.
(14) Crandall, J . K.; Reix, T. J . Org. Chem. 1992, 57, 6759-6764.
(15) Kornblum, N.; Erickson, A. S.; Kelly, W. J .; Henggeler, B. J .
Org. Chem. 1982, 47, 4534-4538.
1448, 1385 cm-1
.
Ack n ow led gm en t. This work was supported by the
University of Camerino-Italy and by MIUR-Italy
(Project “Il Mezzo Acquoso nelle Applicazioni Sintetiche
dei Nitrocomposti Alifatici”).
(16) Katritzky, A. R.; Kashmiri, M. A.; Wittmann, D. K. Tetrahedron
1984, 40, 1501-1510.
(17) Ballini, R.; Bosica, G.; Fiorini, D.; Giarlo, G. Synthesis 2001,
13, 2003-2006. The spectroscopic data are not reported in the
litterature.
(18) J ones, R. C. F.; Duller, K. A. M.; Vulto, S. I. E. J . Chem. Soc.,
Perkin Trans.1 1998, 411-416.
(19) (a) Kornblum, N.; Larso, H. O.; Blackwood, R. K.; Mooberry,
D. D.; Oliveto, E. P.; Graham, G. E. J . Am. Chem. Soc. 1956, 78, 1497-
1499. (b) Kornblum, N. Org. React. 1962, 12, 101-156. (c) Feuer, H.
The Chemistry of Nitro and Nitroso Groups; Interscience Publishers:
New York, 1969.
1
Su p p or tin g In for m a tion Ava ila ble: The H NMR or 13C
NMR spectra of the compounds prepared are reported as a
criterion of purity. This material is available free of charge
J O049048B
6908 J . Org. Chem., Vol. 69, No. 20, 2004