SYNTHESIS OF 4-ARYL-1,5-BENZODIAZEPINE-2-CARBOXAMIDES
1537
group is less sensitive to acid catalysis than the attack
on the amide carbonyl. This is quite probable, for
resonance stabilization of the amide carbonyl un-
doubtedly requires stronger catalysis, as compared to
the -carbonyl group. Correspondingly, when the reac-
tion time is not long (0.5 1.0 h), compounds III can
be isolated as kinetically controlled products. Increase
of the reaction time to 5 6 h even at pH 5.8 leads to
accumulation of quinoxalin-2-ones II, while benzodi-
azepines III cannot be isolated.
pound IIIa was filtered off and recrystallized. Yield
0.155 g. Compounds IIIb and IIIh were obtained in
a similar way.
c. A solution of 0.325 g (1 mmol) of amide Ie and
0.629 g (1 mmol) of N,N -bis(triphenylphosphorane-
diyl)-o-phenylenediamine in 7 ml of dry toluene was
refluxed for 12 h. The solvent was removed, the
residue was dissolved in 5 ml of alcohol, and the pre-
cipitate of compound II was filtered off. The filtrate
was evaporated, and the residue was recrystallized
from acetonitrile. Yield of compound IIIe 0.08 g
(21%), mp 194 195 C. Compounds IIIj and IIIm
were synthesized in a similar way.
EXPERIMENTAL
1
The IR spectra were recorded on UR-20 and
The yields, melting points, and IR and H NMR
1
Specord M-80 spectrometers in mineral oil. The H
spectra of the products are collected in Table 1, and
Table 2 contains their elemental analyses.
NMR spectra were obtained on a Bruker WR-80-SY
instrument (80 MHz) using HMDS as internal refer-
ence and chloroform-d and DMSO-d6 as solvents.
The UV spectra were measured on a Specord UV-Vis
REFERENCES
5
spectrophotometer in ethanol (c = 1 10 M). The
1. Bodforss, S., Justus Liebigs Ann. Chem., 1957,
progress of reactions and the purity of products were
monitored by TLC on Silufol UV-254 plates using
the solvent system diethyl ether benzene acetone
(10:9:1), development with iodine vapor.
4-Aryl-1,5-benzodiazepin-2-carboxamides IIIa
IIIo. a. A solution of 2.97 g (0.01 mol) of amide Ia,
1.08 g (0.01 mol) of o-phenylenediamine, 6 ml of
acetate buffer (pH 5.8), and 0.8 ml of a 1.68 M al-
coholic solution of HCl in 100 ml of ethanol was
refluxed for 0.5 h. The solvent was evaporated, and
the residue was recrystallized from acetonitrile. Yield
3.06 g. Compounds IIIb IIIo were synthesized in
a similar way.
vol. 609, pp. 103 125.
2. Mondelli, R. and Merlini, L., Tetrahedron, 1966,
vol. 22, no. 10, pp. 3253 3273.
3. Andreichikov, Yu.S., Pitirimova, S.G., Saraeva, R.F.,
Gein, V.L., Plakhina, G.D., and Voronova, L.A.,
Khim. Geterotsikl. Soedin., 1978, no. 3, pp. 407 410.
4. Andreichikov, Yu.S., Pitirimova, S.G., Tendryako-
va, S.P., Saraeva, R.F., and Tokmakova, T.N.,
Zh. Org. Khim., 1978, vol. 14, no. 1, pp. 169 172.
5. Andreichikov, Yu.S., Kozlov, A.P., and Kurdina, L.N.,
Zh. Org. Khim., 1984, vol. 20, no. 4, pp. 826 831.
6. Bogatskii, A.V., Andronati, S.A., and Goloven-
ko, N.Ya., Trankvilizatory. 1,4-Benzdiazepiny i rod-
stvennye struktury (Tranquilizers. 1,4-Benzodiazepines
and Related Structures), Kiev: Naukova Dumka, 1980,
pp. 90 98.
b. A mixture of 0.297 g (1 mmol) of amide Ia and
0.108 g (1 mmol) of o-phenylenediamine was heated
for 0.25 h at 120 130 C. The melt was heated in
15 ml of boiling acetonitrile, the mixture was filtered,
the filtrate was cooled, and the precipitate of com-
7. Mannschreck, A., Rissman, G., Fogtle, F., and
Wild, D., Chem. Ber., 1967, vol. 100, p. 335.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 38 No. 10 2002