A convenient method for the synthesis of 4,6,7,8-tetrahydropyrrolo[1,2-a] thieno-[2,3-d]pyrimidin-4-ones [11]

Full text of DOI:10.1007/s10593-006-0276-y

Chemistry of Heterocyclic Compounds, Vol. 42, No. 11, 2006
A CONVENIENT METHOD FOR THE SYNTHESIS
OF 4,6,7,8-TETRAHYDROPYRROLO[1,2-a]THIENO-
[2,3-d]PYRIMIDIN-4-ONES
V. K. Vasilin, Mokhamed Abdel-Moneim Makhmud, and G. D. Krapivin
Keywords: butyrolactone, 2-amino-3-cyanothiophenes, thieno[2,3-d]pyrrolo[1,2-a]pyrimidin-5-ones.
A method is known for preparing 3,4,5,7,8,9-hexahydro-1H-pyrrolo[1,2-a]thiopyrano[4',3':4,5]-
thieno[2,3-d]pyrimidin-5-one (1) by treatment of the 2-amino-3-ethoxycarbonylthiophene derivative 2 with
pyrrolidone via refluxing in dichloroethane in the presence of phosphorus oxychloride [1]:
O
O
O
N
POCl3
O
+
S
S
N
H
CH2ClCH2Cl
NH2
N
S
S
2
1
We propose the preparation of a pyrrolothienopyrimidinone structure (compound 3) by another route via
the reaction of the 2-amino-3-cyanothiophene derivative 4 with an excess of butyrolactone in the presence of
sulfuric acid:
O
R'
CN
R1
N
H2SO4
+
O
O
N
R
NH2
R
S
S
4a,b
3a,b
3, 4 a R = COOEt, R1 = Me; b R + R1 = (CH2)4
IR spectra were taken on a Specord-M80 instrument as a suspension in vaseline oil and 1H NMR spectra
on a Bruker AM-300 instrument (300 MHz) using DMSO and with TMS as internal standard. Mass spectra were
recorded on a Varian CH-6 instrument (EI, 70 eV).
__________________________________________________________________________________________
Kuban State Technological University, Krasnodar 350072, Russia, e-mail: krapivin@kubstu.ru. Translated
from Khimiya Geterotsiklicheskikh Soedinenii, No 11, pp. 1745-1746, November, 2006. Original article submitted
July 13, 2006.
0009-3122/06/4208-1101©2006 Springer Science+Business Media, Inc.
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Ethyl 3-methyl-4-oxo-4,6,7,8-tetrahydropyrrolo[1,2-a]thieno[2,3-d]pyrimidine-2-carboxylate (3a).
Yield 52% with mp 270°C (from a mixture of ethyl acetate and petroleum ether). IR spectrum, ν, cm-1:
1745 (COOEt); 1635 (amide). 1H NMR spectrum, δ, ppm (J, Hz): 1.32 (3H, t, J = 6.7, OCH2CH3); 2.31 (2H, m,
7-CH2); 2.82 (3H, s, 3-CH3); 3.01 (2H, t, J = 7.2, 8-CH2); 4.15. (2H, br s, 6-CH2); 4.31 (2H, q, J = 6.7,
OCH2CH3). Found, %: 56.23; H 5.24; N 9.91. C13H14N2O3S. Calculated, %: C 56.10; H 5.07; N 10.07.
1,2,3,5,6,7,8,9-Octahydrobenzo[4,5]thieno[2,3-d]pyrrolo[1,2-a]pyrimidin-5-one (3b). Yield 57%
with mp 290oC (decomp.) (from a mixture of ethyl acetate and petroleum ether). IR Spectrum, ν, cm-1:
1
1637 (amide). H NMR Spectrum, δ, ppm (J, Hz): 1.73-1.81 (4H, m, 7-CH2 and 7-CH2); 2.23-2.33 (2H, m,
2-CH2); 2.72-2.73 (2H, m, 6-CH2); 2.87-2.88 (2H, m, 9-CH2); 2.97 (2H, t, J = 7.47, 1-CH2); 4.08 (2H, t,
J = 6.99, 3-CH2). Mass spectrum, m/z (Irel, %): 246 (70), 245 (100), 231 (25), 218 (20), 151 (12), 111 (25),
91 (25), 65 (15), 43 (20). Found, %: C 63.66; H 5.75; N 11.45, C13H14N2OS. Calculated, %: C 63.39; H 5.73;
N 11.37.
The fragmentation of the molecular ion for compound 3b is characterized by three decomposition routes:
O
O
.
+
.
– H
N
N
+
N
H
N
S
S
Ф1, m/z 245 (100)
M+, m/z 246 (70)
.
– CH3
(-28)
O
H
.
+
+
N
N
N
N
S
S
Ф3, m/z 231 (25)
Ф ,
m/z 218 (20)
2
.
+
O
+
N
H
N
N
S
Ф
4 , m/z 151 (12)
m/z 111 (25)
Ф5,
REFERENCES
1.
F. Sauter, J. Froehlich, and E. R. Ahmed, Monatsh. Chem., 127, 319 (1996).
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