Azo coupling of cyclopropyldiazonium ion
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 4, April, 2003
1039
propylazo)ꢀ2ꢀnaphthol (2) was obtained in a yield of 0.44 g
(∼60%) (see Ref. 3), Rf 0.75; 1ꢀnitrosoꢀ2ꢀnaphthol (3) was obꢀ
tained in a yield of 13 mg (∼2%), Rf 0.40, and 1ꢀnitrosoꢀ2ꢀ
(cyclopropylamino)naphthalene was obtained as greenish crysꢀ
tals (m.p. 129.5—130.5 °С) in a yield of 10 mg (>1%), Rf 0.35.
1Н NMR (CDCl3), δ: for compound 4: 1.05 and 0.85 (both m,
2×2 Н, СН2СН2); 2.85 (m, 1 Н, СН); 7.40 (d, 1 Н, Н(3), J =
9.5 Hz); 7.50 (m, 1 Н, Н(5)); 7.71 (m, 2 Н, Н(6) and Н(7));
7.85 (d, 1 Н, Н(4), J = 9.5 Hz); 9.10 (d, 1 Н, Н(8), J = 8.0 Hz);
14.4 (br.s, 1 Н, NH). The partial mass spectrum, m/z (Irel (%)):
212 (70) [M]+, 182 (56), 181 (67), 180 (53), 167 (56), 155 (100),
140 (73).
Analogously, in the reaction with 1ꢀnaphthol 0.21 g of the
mixture of 2ꢀcyclopropylazoꢀ (5) and 2,4ꢀdi(cyclopropylazo)ꢀ
1ꢀnaphthols (7) in molar ratio of about 1 : 1 (see Ref. 3), Rf 0.85
and 0.22 g (∼30%) of 4ꢀcyclopropylazoꢀ1ꢀnaphthol (6) (see
Ref. 3), Rf 0.75, and 43 mg (7%) of 4ꢀnitrosoꢀ1ꢀnaphthol, Rf 0.35
and 18 mg (∼3%) of 2ꢀnitrosoꢀnaphthol, Rf 0.30 was isolated.
tive 2, but into izomeric compound 4. On heating in the
aqueous medium4 or in the presence of the excess of
nitrosonaphthol, this process accelerates apparently due
to the salt destruction and reaction of releasing cycloꢀ
propylamine with ketoimine form of nitrosonaphthol.
Similarly to 2ꢀnaphthol, the reaction of 1ꢀnaphthol
with cyclopropylamine and isoamylnitrite under the same
conditions leads to 2ꢀ(cyclopropylazo)ꢀ (5), 4ꢀ(cycloꢀ
propylazo)ꢀ (6), and 2,4ꢀdi(cyclopropylazo)naphthols in
a ratio of about 1 : 2.4 : 1 and a total yield of ∼55%. The
byꢀproducts are 2ꢀ and 4ꢀnitrosoꢀ1ꢀnaphthols (∼10%),
and, as in the previous case, their reaction with cycloꢀ
propylamine does not lead to azo compounds 5 and 6. It
should be noted, that direct nitrosation of cyclopropylꢀ
amine and azo coupling reaction of forming diazonium
ion 1 with 1ꢀnaphthols lead to the same azo adducts in
about the same ratio as upon generation of cyclopropylꢀ
diazonium ion 1 from NꢀcyclopropylꢀNꢀnitrosourea.3
Thus, based on the results obtained, one could conꢀ
sider that, in fact, cyclopropylazonaphthols are formed
upon nitrosation of cyclopropylamine with isoamyl niꢀ
trite, the former evidently existing as an associate with
naphthols, and subsequent reaction of the formed cycloꢀ
propyldiazonium ion with naphthols. Besides, side nitrosaꢀ
tion of the initial naphthols is probable, but this process is
not responsible for the formation of corresponding azo
This work was financially supported by the Russian
Foundation for Basic Research (Project No. 02ꢀ03ꢀ33365)
and the Research Program of the Russian Academy of
Sciences "Theoretical and experimental investigation of
nature of chemical bond and mechanisms of the most
important chemical reactions".
References
compounds.
1. I. Szele and H. Zollinger, Top. Curr. Chem., 1983, 112, 6.
2. W. Kirmse, Angew. Chem., 1976, 88, 273.
3. Yu. V. Tomilov, I. V. Kostyuchenko, E. V. Shulishov, and
O. M. Nefedov, Mendeleev Commun., 2002, 104.
4. E. Toja, D. Selva, and P. Schiatti, J. Med. Chem., 1984,
27, 610.
Direct generation of cyclopropyldiazonium cation and its azo
coupling reaction with 2ꢀnaphthol. A solution of isoamylnitrite
(0.58 g, 5 mmol) in СHCl3 (5 mL) was added to a stirred soluꢀ
tion of 2ꢀnaphthol (0.50 g, 3.5 mmol) and cyclopropylamine
(0.29 g, 5 mmol) in СHCl3 (10 mL) at 5 °С for 20 min. The
reaction mixture was kept at 5 °С for 13—16 h. The solvent and
iꢀC5H11OH formed were removed in vacuo. Reaction prodꢀ
ucts were isolated by preparative TLC (silica gel (Merck),
0.040—0.063 mm, benzene—ether as the eluent, 5 : 1). 1ꢀ(Cycloꢀ
5. E. Bamberger, Ber., 1896, 29, 102.
Received February 5, 2003;
in revised form March 6, 2003