Month 2014
Synthesis of Pyrimidine, Dihydropyrimidinone, and Dihydroimidazole
Method C.
A
mixture of o-aminothiophenol (1 mol),
(2E)-2-(1,3-Benzothiazol-2-ylimino)-6-hydroxy-2,3-dihydro-
dicyandiamide (1 mol), eight drops of concentrated hydrochloric
acid, and ethanol (15 mL) was heated under reflux for 3 h.
The reaction mixture was allowed to cool down and treated
with 10% NaOH to afford the product 1 with 98% yield.
General procedure for the synthesis of compounds (2–12):
Synthesis of compound (2) as a typical example. A mixture
of compound 1 (50 mmol) and 10 mL of acetylacetone in
addition to few drops of catalytic glacial acetic acid was
refluxed at 200ꢀC. The solid product was observed after 15–
20 min. The reaction was allowed to proceed with reflux for
further 1 h. After cooling down, the solid was collected by
filtration, washed with cold ethanol, and recrystallized from
ethanol to afford the bright crystals of 2 with 92% yield.
N-[(2E)-4,6-Dimethylpyrimidin-2(1H)-ylidene]-1,3-benzothiazol-
2-amine (2). This compound was obtained as bright crystaÀls1 (ethyl
alcohol), white color, yield 92%, mp 240ꢀC; IR: cm 3200
(NH); 1H NMR: d 12.19 (s, 1H, NH), 7.32–6.91 (br, 5H,
arom), 5.55 (s, 1H, CH), 2.49 (s, 6H, 2CH3); MS m/z (%):
M+ 256 (100), 215 (38.40), 175 (10.50), 67 (37.30). Anal.
Calcd for C13H12N4S (256.33): C (60.91%), H (4.72%), N
(21.86%), S (12.51%). Found: C (60.81%), H (4.28%), N
(21.05%), S (12.01%).
pyrimidine-4(1H)-one (7). This compound was obtained as
powder (ethyl alcohol), white color, 90% yield, mp 330ꢀC; IR:
cmÀ1 3431 (OH), 3278, 3155 (2NH), 1666 (CO); 1H NMR: d
12.17 (s, 1H, NH), 10.58 (s, 1H, OH), 7.77–7.07 (br, 5H,
arom+ NH), 5.05 (s, 1H, CH); MS m/z (%): M+ 260 (100), 215
(70.10), 177 (18.30), 134 (47.12), 69 (23.31). Anal. Calcd for
C17H12N4OS (260.27): C (50.76%), H (3.10%), N (21.53%), S
(12.32%). Found: C (50.44%), H (3.19%), N (21.11%), S (12.19%).
N-[(2Z)-4-Phenyl-1,5-dihydro-2H-imidazol-2-ylidene]-1,3-
benzothiazol-2-amine (8). This compound was obtained as
powder (ethyl alcohol), white color, 88% yield, mp 188ꢀC; IR:
cmÀ1 3237, 3175 (2NH); 1H NMR: d 09.66 (s, 1H, NH),
7.76–7.04 (br, 10H, 2arom+ NH), 6.66 (s, 1H, CH); MS m/z
(%): M+ 292 (04.80), 192 (75.20), 175 (100), 150 (53.52), 123
(32.10), 96 (48.90). Anal. Calcd for C16H12N4S (292.36): C
(65.73%), H (4.14%), N (19.16%), S (10.97%). Found: C
(65.42%), H (3.98%), N (19.00%), S (10.27%).
N-[(2Z)-4-Methyl-1,5-dihydro-2H-imidazol-2-ylidene]-1,3-
benzothiazol-2-amine (9). This compound was obtained as bright
crystals (ethyl alcohol), white color, 83% yield, mp 350ꢀC; IR:
1
cmÀ1 3257, 3187 (2NH); H NMR: d 11.74 (s, 1H, NH), 7.62–
7.11 (br, 5H, arom + NH), 6.85 (s, 1H, CH), 2.5 (s, 3H, CH3); MS
m/z (%): M+ 230 (28.40), 192 (26.90), 106 (80.60), 67 (100).
Anal. Calcd for C11H10N4S (230.29): C (57.37%), H (4.38%), N
(24.33%), S (13.92%). Found: C (57.59%), H (4.09%), N
(24.01%), S (13.70%).
(2E)-6-Amino-2-(1,3-benzothiazol-2-ylimino)-2,3-dihydro-
pyrimidine-4(1H)-one (3). This compound was obtained as
powder (ethyl alcohol), white color, yield 87%, mp 185ꢀC; IR:
1
cmÀ1 3368, 3250, 3177 (2NH, NH2), 1680 (CO); H NMR: d
11.67 (s, 1H, NH), 9.12 (s, 1H, NH), 7.76–7.04 (br, 4H, arom),
6.27 (s, 1H, CH), 4.11 (s, 2H, NH2); MS m/z (%): M+ 259
(38.40), 217 (58.24), 128 (13.52), 67 (38.40). Anal. Calcd for
C11H9N5OS (259.29): C (50.95%), H (3.50%), N (27.01%), S
(12.37%). Found: C (50.72%), H (3.11%), N (26.95%), S
(12.03%).
(2Z)-2-(1,3-Benzothiazol-2-ylimino)imidazolidin-4-ol (10).
This compound was obtained as powder (ethyl alcohol), white
color, 88% yield, mp 205ꢀC; IR: cmÀ1 3268, 3177 (2NH); 1H
NMR: d 10.06 (s, 1H, NH), 7.87–7.03 (br, 5H, arom + NH), 6.60
(s, 1H, CH); MS m/z (%): M+ 232 (53.10), 192 (40.60), 175
(50.00), 163 (65.60), 82 (100). Anal. Calcd for C10H8N4OS
(232.26): C (51.71%), H (3.47%), N (24.12%), S (13.81%).
Found: C (51.85%), H (3.08%), N (24.03%), S (13.77%).
N-[(2Z)-4-Amino-1,5-dihydro-2H-imidazol-2-ylidene]-1,3-benzo-
thiazol-2-amine (11). This compound was obtained as powder
(ethyl alcohol), white color, 82% yield, mp 265ꢀC; IR: cmÀ1
(2E)-2-(1,3-Benzothiazol-2-ylimino)-1,2-dihydropyrimidine-4,6-
diamine (4). This compound was obtained as light crystÀal1s (ethyl
alcohol), white color, 95% yield, mp 198ꢀC; IR: cm 3391,
1
3277, 3182 (NH, 2NH2); H NMR: d 12.03 (s, 1H, NH), 7.90–
7.04 (br, 5H, arom), 5.45 (s, 4H, 2NH2), 5.41 (s, 1H, CH); MS m/
z (%): M+ 258 (100), 216 (21.04), 177 (18.33), 67 (37.30). Anal.
Calcd for C11H10N6S (258.30): C (51.15%), H (3.90%), N
(32.54%), S (12.41%). Found: C (51.34%), H (3.26%), N
(32.13%), S (12.10%).
(2E)-2-(1,3-Benzothiazol-2-ylimino)-6-methyl-2,3-dihydro-
pyrimidine-4(1H)-one (5). This compound was obtained as
powder (ethyl alcohol), buff color, 82% yield, mp 305ꢀC; IR:
cmÀ1 3303, 3184 (2NH), 1691 (CO); 1H NMR: d 11.45
(s, 1H, NH), 7.67–7.05 (br, 5H, arom + NH), 5.18 (s, 1H,
CH), 2.50 (s, 3H, CH3); MS m/z (%): M+ 258 (100),
210 (40.75), 128 (24.91), 76 (60.80). Anal. Calcd for
C12H10N4OS (258.30): C (55.80%), H (3.90%), N (21.69%),
S (12.41%). Found: C (55.61%), H (3.23%), N (21.01%), S
(12.03%).
1
3371, 3236, 3177 (2NH, NH2); H NMR: d 09.86 (s, 1H, NH),
7.67–7.04 (br, 5H, arom + NH), 5.64 (s, 1H, CH), 4.73 (s, 2H,
NH2); MS m/z (%): M+ 231 (34.40), 192 (25.00), 163 (50.30), 139
(75.20), 82 (100). Anal. Calcd for C10H9N5S (231.28): C
(51.93%), H (3.92%), N (30.26%), S (13.86%). Found: C
(51.58%), H (3.77%), N (30.01%), S (13.53%).
(2Z)-4-Amino-2-(1,3-benzothiazol-2-ylimino)-2,5-dihydro-1H-
imidazole-5-carbonitrile (12). This compound was obtained as
light crystal (ethyl alcohol), brown color, 93% yield, mp 250ꢀC;
IR: cmÀ1 3382, 3278, 3177 (2NH, NH2), 2221 (CN); 1H NMR: d
10.19 (s, 1H, NH), 7.88–7.02 (br, 5H, arom+ NH), 5.33 (s, 2H,
NH2); MS m/z (%): M+ 256 (47.80), 192 (32.10), 170 (39.10),
148 (65.20), 107 (43.50), 60 (100). Anal. Calcd for C11H8N6S
(256.27): C (51.55%), H (3.15%), N (32.79%), S (12.51%).
Found: C (51.24%), H (2.99%), N (32.60%), S (12.29%).
(2E)-2-(1,3-Benzothiazol-2-ylimino)-6-phenyl-2,3-dihydro-
pyrimidine-4(1H)-one (6).
This compound was obtained as
Acknowledgments. The authors are deeply grateful to Manchester
Metropolitan University in England and Sohag University in
Egypt for supporting and facilitating this study. Also, we extend
our thanks to Dr Attash Gurbanove in Baku State University,
Azerbaijan, for measuring the X-ray crystallography and to
Dr Rehab Mostafa Mohamed or Miss Dalia ahmed Abd
El Raheem in the Botany Department, Faculty of Science, Sohag
University in Egypt, for the evaluation of bacterial inhibiting effects.
light crystals (eÀth1yl alcohol), creamy color, 88% yield, mp
1
<360ꢀC; IR: cm 3393, 3177 (2NH), 1661 (CO); H NMR: d
12.34 (s, 1H, NH), 7.78–7.04 (br, 10H, 2arom + NH), 6.34
(s, 1H, CH); MS m/z (%): M+ 320 (100), 292 (8.60), 251
(5.24), 176 (39.72), 69 (30.00). Anal. Calcd for
C17H12N4OS (320.37): C (63.73%), H (3.78%), N (17.49%),
S (10.01%). Found: C (63.46%), H (3.18%), N (17.01%), S
(09.89%).
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet