Unusual reaction of 5-benzoyl-3-ethoxycarbonyl-6-methylthio-1-R-1,2- dihydropyridin-2-ones with 1,3-diaminopropane

Full text of DOI:10.1007/s10593-008-0054-0

Chemistry of Heterocyclic Compounds, Vol. 44, No. 3, 2008
LETTERS TO THE EDITOR
UNUSUAL REACTION OF 5-BENZOYL-
3-ETHOXYCARBONYL-6-METHYLTHIO-
1-R-1,2-DIHYDROPYRIDIN-2-ONES
WITH 1,3-DIAMINOPROPANE
V. N. Britsun1, E. I. Mayboroda2, and M. O. Lozinskii1
Keywords: 5-benzoyl-3-ethoxycarbonyl-6-methylthio-1-R-1,2-dihydropyridin-2-ones, 6-(R-amino)-
5-benzoyl-3-(1,4,5,6-tetrahydro-2-pyrimidinyl-2H-2-pyranones, 1,3-diaminopropane, recyclization.
We have recently developed a preparative method for the selective synthesis of 5-benzoyl-
3-ethoxycarbonyl-6-methylthio-1-R-1,2-dihydropyridin-2-ones 1a,b from available starting materials and
showed that these products readily condense with nitrogen-containing 1,2- and 1,3-dinucleophiles to give bi- and
tricyclic heterosystems [1].
In a continuation of this study, we have found that 1,2-dihydropyridin-2-ones 1a,b react with
1,3-diaminopropane 2 with recyclization to give 6-(R-amino)-5-benzoyl-3-(1,4,5,6-tetrahydro-2-pyrimidinyl)-
2H-2-pyranones 3a,b.
Ph
O
Ph
N
O
NH2
H2N
2
O
EtO
O
N
H
–MeSH
–EtOH
–H2O
NHR
O
N
SMe
O
R
1a,b
3a,b
1, 3 а R = Me, b R = Et
Three broad multiplets of the tetrahydropyrimidine ring at 2.04-2.06, 3.52-3.53, and 3.98-3.99 ppm, a
doublet for CH3NH (3a, δ 2.75 ppm, J = 4.5 Hz), a quartet or triplet for the AlkNH groups (8.92-9.05 ppm), and
1
singlets of the tetrahydropyrimidine NH groups are characteristic signals in the H NMR spectra for confirming
the formation of compounds 3a,b. The strong deshielding of the NH protons indicates the existence of
intramolecular NH···O hydrogen bonds in 3a,b. The existence of the aroyl fragment carbonyl group in
compounds 3a,b was indicated by 13C NMR spectroscopy since the Ph–C=O carbon signals at 191.0-194.1 ppm
in the starting 1,2-dihydropyridines 1a,1b [1] and product 3a are extremely characteristic.
__________________________________________________________________________________________
1Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Kiev 02660, Ukraine;
2
e-mail: bvn1967@rambler.ru and Kiev National University of Technology and Design, Kiev 01011, Ukraine;
e-mail: eleschenko@mail.ru. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 473-473,
March, 2008. Original article submitted February 1, 2008.
366
0009-3122/08/4403-0366©2008 Springer Science+Business Media, Inc.

The IR spectra of 2H-2-pyranones 3a,b show characteristic stretching bands for the NH group at
3300 cm-1 and for the carbonyl group at 1670 cm-1.
The composition of products 3a,b was supported by elemental analysis.
This recyclization may be seen as a new synthetic method for the preparation of previously unknown
2H-2-pyranones.
The 1H and 13C NMR spectra were taken on a Varian-300 spectrometer at 300 and 75 MHz, respectively,
in DMSO-d6 with TMS as the internal standard. The IR spectra were taken on a UR-20 spectrometer for KBr
pellets.
5-Benzoyl-6-(methylamino)-3-(1,4,5,6-tetrahydro-2-pyrimidinyl)-2H-2-pyranone (3a). A solution of
1,2-dihydropyridin-2-one 1a (0.331 g, 1 mmol) and 1,3-diaminopropane 2 (0.222 g, 3 mmol) in 2-propanol
(4 ml) was heated at reflux for 2 h and cooled. A precipitate of compound 3a was filtered off. Yield of 3a was
0.134 g, (43%); mp 253-256°C (nitromethane). IR spectrum, ν, cm-1: 3300, 3100, 2950, 1670, 1640, 1590, 1550,
1
1510, 1440, 1400, 1380. H NMR spectrum, δ, ppm (J, Hz): 2.04 (2H, br. m, 5'-CH2); 2.75 (3H, d, J = 4.5,
NHCH3); 3.52 (2H, br. m, 6'-CH2); 3.99 (2H, br. m, 4'-CH2); 7.39-7.65 (5H, m, C6H5); 8.31 (1H, s, H-4); 8.92
(1H, q, J = 4.5, NHCH3); 10.88 (1H, br. s, 1'-NH). 13C NMR spectrum, δ, ppm: 18.7 (5'-CH2); 26.1 (NCH3); 38.7
(6'-CH2); 39.9 (4'-CH2); 98.8 (C-4); 104.6 (C-5); 128.5, 128.9, 131.1, 140.0 (CAr); 146.8 (C-3); 155.0 (C-2');
161.4 (C-6); 164.4 (C-2); 194.1 (Ph-C=O). Found, %: C 65.73; H 5.32; N 13.74. C17H17N3O3. Calculated, %:
C 65.58; H 5.50; N 13.50.
5-Benzoyl-6-(ethylamino)-3-(1,4,5,6-tetrahydro-2-pyrimidinyl)-2H-2-pyranone (3b) was obtained in
39% yield analogously to 3a, mp 257-259°C (nitromethane). IR spectrum, ν, cm-1: 3300, 3100, 3000, 1670,
1
1640, 1580, 1540, 1510, 1470, 1380. H NMR spectrum, δ, ppm (J, Hz): 1.07 (3H, t, J = 6.6, NCH2CH3); 2.06
(2H, br. m, 5'-CH2); 3.47 (2H, br. m, NCH2Me); 3.53 (2H, br. m, 6'-CH2); 3.98 (2H, br. m, 4'-CH2); 7.40-7.61
(5H, m, C6H5); 8.32 (1H, s, H-4); 9.05 (1H, br. t, NHCH2Me); 10.87 (1H, br. s, 1'-NH). Found, %: C 66.64;
H 5.68; N 13.15. C18H19N3O3. Calculated, %: C 66.45; H 5.89; N 12.91.
REFERENCES
1.
V. N. Britsun, A. N. Esipenko, A. N. Chernega, E. B. Rusanov, and M. O. Lozinskii, Khim. Geterotsikl.
Soedin., 1660 (2007). [Chem. Heterocycl. Comp., 43, 1411 (2007)].
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