Heterocyclization of acetamidine adducts with N-(2,2-dichloroethenyl) benzamides

Full text of DOI:10.1007/s11176-008-2031-9

ISSN 1070-3632, Russian Journal of General Chemistry, 2008, Vol. 78, No. 2, pp. 332 333.
Pleiades Publishing, Ltd., 2008.
Original Russian Text
B.A. Demidchuk, V.S. Brovarets, B.S. Drach, 2008, published in Zhurnal Obshchei Khimii, 2008, Vol. 78, No. 2, pp. 349 350.
LETTERS
TO THE EDITOR
Heterocyclization of Acetamidine Adducts
with N-(2,2-Dichloroethenyl)benzamides
B. A. Demidchuk, V. S. Brovarets, and B. S. Drach
Institute of Bioorganic and Petroleum Chemistry, National Academy of Sciences of Ukraine,
ul. Murmanskaya 1, Kiev, 02660 Ukraine
e-mail: brovarets@bpci.kiev.ua
Received July 20, 2007
DOI: 10.1134/S107036320802031X
It was shown previously [1, 2] that accessible
chlorine-containing enamides I readily react with
primary and secondary amines to give 1:1 adducts.
Here, an important role is likely to be played by
N-acylimino tautomers II which are highly electro-
philic, and therefore they readily take up an amine
molecule at the electron-deficient C=N bond [1]. We
have found that reactions of tautomers II with acet-
amidine result in the formation of 2:1 adduct which
readily undergo regioselective cyclization in the
presence of sodium methoxide (transformation
sequence II III IV V shown in the scheme
below). The fact that the cyclization involved two
acylamino groups and two dichloromethyl moieties in
The scope of application of the revealed cyclocon-
densation IV V and related transformations will be
considered elsewhere.
N,N -Bis(1-acylamino-2,2-dichloroethyl)ethan-
imidamides IVa and IVb (general procedure). En-
amide Ia or Ib [2, 3], 0.02 mol, was dissolved in
40 ml of tetrahydrofuran, 0.01 mol of acetamidine
hydrochloride and 0.06 mol of triethylamine were
added, the mixture was stirred for 48 h at 20 C, the
precipitate was filtered off, the filtrate was evaporated
under reduced pressure, and the residue was treated
with water and purified by recrystallization from
aqueous ethanol (2:1). Yield of IVa 84%, mp 189
190 C. Found, %: Cl 28.50; N 11.09. C20H20Cl4N4O2.
Calculated, %: Cl 28.93; N 11.43. Yield of IVb 91%,
mp 186 187 C. Found, %: Cl 27.53; N10.50.
C22H24Cl4N4O2. Calculated, %: Cl 27.36; N 10.81.
1
compounds IV was confirmed by IR and H NMR
spectroscopy. The molecular weights of new oxazole
derivatives V was determined by mass spectrometry.
+
H
H
NH2Cl
, Et3N
Me
N
Ar
N
Ar
N
N
NH2
Me
Ar
H
NH2
H
~~
~
)
(
)
O
O
O
CHCl2
CHCl2
Cl
Cl
Ia, Ib
IIa, IIb
IIIa, IIIb
H
N
H
N
H
H
N
N
N
N
Ar
Ar
N
N
IIa, IIb
MeONa, MeOH,
Ar
Ar
Me
Va, Vb
O
Me
O
CHCl2
CHCl2
O
O
IVa, IVb
Ar = Ph (a), 4-MeC6H4 (b).
332

HETEROCYCLIZATION OF ACETAMIDINE ADDUCTS
333
N,N -Bis(2-aryl-1,3-oxazol-4-yl)ethanimidamides
Va and Vb (general procedure). Compound IVa or
IVb, 0.005 mol, was added to a solution of 0.015 mol
of sodium methoxide in 50 ml of anhydrous methanol,
the mixture was heated for 4 h under reflux, the
precipitate was filtered off, the solvent was removed
from the filtrate under reduced pressure, and the
residue was recrystallized from isopropyl alcohol.
71.03; H 5.60; N 14.84. C22H20N4O2. Calculated, %:
C 70.95; H 5.41; N 15.04.
The IR spectrum of Va was recorded in KBr on a
UR-20 spectrometer. The 1H NMR spectra were
measured on a Varian VXR-300 instrument from solu-
tions in DMSO-d6 using tetramethylsilane as internal
reference. The mass spectrum of Va was obtained on
an Agilent 1100 LC/MSD system.
Yield of Va 54%, mp 178 179 C. IR spectrum,
,
1
1
cm : 1660 (C=N), 3000?3200 (NH assoc.). H NMR
spectrum, , ppm: 2.53 s (3H, CH3), 7.43 7.56 m
(6H, Harom), 7.72 s (1H, 5-H, oxazole), 8.04 8.06 m
(4H, Harom), 8.54 s (1H, 5-H, oxazole), 10.80 s (1H,
NH). Mass spectrum, m/z: 345 [M+], 255, 214, 159,
124, 106. Found, %: C 70.19; H 4.70; N 16.18.
C20H16N4O2. Calculated, %: C 69.75; H 4.68;
N 16.27.
REFERENCES
1. Drach, B.S., Sviridov, E.P., Kisilenko, A.A., and Kir-
sanov, A.V., Zh. Org. Khim., 1973, vol. 9, no. 9,
p. 1818.
2. Atavin, A.S., Mirskova, A.N., and Zorina, E.F., Zh.
Org. Khim., 1972, vol. 8, no. 4, p. 708.
3. Shainyan, B.A., Mirskova, A.N., and Atavin, A.S., Zh.
Org. Khim., 1975, vol. 11, no. 2, p. 245.
Yield of Vb 67%, mp 214 216 C. Found, %: C
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 2 2008