Indian Journal of Chemistry Vol. 438, March 2004, pp. 667-669 Note Synthesis of triazolo-pyrimidine, tetrazolo- pyrimidine and pyrimido-triazepine C S Andotra* & Sukhbinder Kaur Department of Chemistry, University of Jammu, Jammu 180006 Received 13 March 2002; accepted (revised) 24 June 2003 Some 4-substituted aryl-6-(2,4-dialkoxypheyl) 1,2,4-triazolo- [4,3-aJ-pyrimidine, 4-substitutedaryl-6-(2,4-dialkoxyphenyl)-tet- razolo-[I ,S-aJ-pyrimidine and 4-substitutedaryl-6-(2,4-dialkoxy- phenyl) pyrimido-[2, l-cJ-[ I ,2,4J-triazepine have been synthesized from 4-substi tu tedary 1-6-(2,4-d ialkox y phen y 1)-2-h ydrozi nopyr i- midine. IPC: InLCL 7 C 07 0253/00 Numerous pyrimidine derivatives are well known drugs for variety of diseases. Some pyrimidines are physiologically as well as pharmacologically impor- tant. Literature survey reveals that compounds having 1,2, 4-triazole, tetrazole nucleus and seven membered ring with one or more hetero atoms in them have at- tracted considerable attention as they are endowed with wide range of pharmaceutical activities like anti- b . 112 . 34 ·f 1 5 - 7 h b· ·d 1 89 actena· anticancer·, anti unga , er ICI a ., . HIY IO II·h . 121 3 d .. fl antl- . , anti ypertenslve . , an antl-1I1 am- matory 14 etc. Because of the importance of 1, 2, 4- triazole nucleus and in continuation of our earlier work 15·20 on the synthesis of 1, 2, 4-triazole nucleus and our search for biologically active new heterocy- cles, we report herein the synthesis of some tria- zolopyrimidine, tetrazolo pyrimidine and pyrimido- triazepine. It has been reported that hydrazino pyrimidimes can be considered as key starting materials for the synthesis of diverse nitrogen bridgehead compounds. Thus the hydrazino pyrimidine reacted with formic acid and acetic acid giving triazolo [4, 3-a] pyrimidine derivative 1. Also when reacted with ni- trous acid and acetyl acetone gave the tetrazolo [1, S- a] pyrimidine derivative 2 and pyrimido [2, I-c] [1 , 2, 4] triazepine derivative 3 respectively. The IH NMR spectra of triazolo-pyrimidine showed signal at 1.2- lA as singlet for IH, 3-methyl triazo·lopyrimidine showed a signal at 1.3-1.4 as singlet for 3H which confirmed the triazole ring proton. In tetrazolo- pyrimidine no signal was recorded as there is no pro- ton in the tetrazole ring. Primido-triazepine spectra showed two singlet at lA-I.5 for 2CH 3 present at po- sitions 3 and 5 which are interchangeable with CH 3 of the OCH 2 CH 3 group and C-H at positions 4 appeared as singlet at 3.5 for 1H which confirmed primido- triazepine ring proton. Experimental Section All the melting points were determined in Bucchi melting point apparatus and are uncorrected. IR spec- 2
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Indian Journal of Chemistry Vol. 438, March 2004, pp. 667-669
Note
Synthesis of triazolo-pyrimidine, tetrazolopyrimidine and pyrimido-triazepine
C S Andotra* & Sukhbinder Kaur
Department of Chemistry, University of Jammu , Jammu 180006
Received 13 March 2002; accepted (revised) 24 Jun e 2003
Some 4-substituted aryl-6-(2,4-dialkoxypheyl) 1,2,4-triazolo[4,3-aJ-pyrimidine, 4-substitutedaryl-6-(2,4-dialkoxyphenyl)-tetrazolo-[I ,S-aJ-pyrimidine and 4-substitutedaryl-6-(2 ,4-dialkoxyphenyl) pyrimido-[2, l-cJ-[ I ,2,4J-triazepine have been synthesized from 4-substi tu tedary 1-6-(2,4-d i al kox y phen y 1)-2-h ydrozi nopyrimidine.
IPC: InLCL7 C 07 0253/00
Numerous pyrimidine derivatives are well known drugs for variety of diseases. Some pyrimidines are physiologically as well as pharmacologically important. Literature survey reveals that compounds having 1,2, 4-triazole, tetrazole nucleus and seven membered ring with one or more hetero atoms in them have attracted considerable attention as they are endowed with wide range of pharmaceutical activities like anti-b . 112 . 34 ·f 15-7 h b· ·d 189 actena· anticancer·, anti unga , er ICI a .,
. HIY IO II·h . 121 3 d .. fl antl- . , anti ypertenslve . , an antl-1I1 am-matory 14 etc. Because of the importance of 1, 2, 4-triazole nucleus and in continuation of our earlier work 15·20 on the synthesis of 1, 2, 4-triazole nucleus
and our search for biologically active new heterocycles, we report herein the synthesis of some triazolopyrimidine, tetrazolo pyrimidine and pyrimidotriazepine.
It has been reported that hydrazino pyrimidimes can be considered as key starting materials for the synthesis of diverse nitrogen bridgehead compounds. Thus the hydrazino pyrimidine reacted with formic acid and acetic acid giving triazolo [4, 3-a] pyrimidine derivative 1. Also when reacted with nitrous acid and acetyl acetone gave the tetrazolo [1, Sa] pyrimidine derivative 2 and pyrimido [2, I-c] [1 , 2, 4] triazepine derivative 3 respectively . The IH NMR spectra of triazolo-pyrimidine showed signal at 1.2-lA as singlet for IH, 3-methyl triazo·lopyrimidine showed a signal at 1.3-1.4 as singlet for 3H which confirmed the triazole ring proton . In tetrazolopyrimidine no signal was recorded as there is no proton in the tetrazole ring. Primido-triazepine spectra showed two singlet at lA-I.5 for 2CH3 present at positions 3 and 5 which are interchangeable with CH3 of the OCH2CH3 group and C-H at positions 4 appeared as singlet at 3.5 for 1 H which confirmed primidotriazepine ring proton .
Experimental Section All the melting points were determined in Bucchi
melting point apparatus and are uncorrected. IR spec-
2
668 INDIAN J. CHEM., SEC B, MARCH 2004
tra were recorded using KBr disc on Pye unicam SP-2000, 'H NMR spectra in CDCb DPX-200 (200 MHz) (chemical shi fts in 8ppm) and mass spectra on Ion trap Brker-3000 Ms spectrometer.
4-Substituted aryl-6-(2, 4-dialkoxyphenyl)-I, 2, 4-triazolo[4, 3-a]pyrimidine 1. A solution of 4-substituted aryl-6-(2, 4-dialkoxyphenyl)-2-hydrazi nopyrimidine (0.01 mole) in 25 mL formic ac id or 25 mL acetic acid was allowed to stand at 25°C for 24 hr. To this mixture were added few drops of PPA and it was refluxed for 3 hr. The product was decomposed on crushed ice and the resultant precipitates were filtered off, washed with cold water and crysta l-
li zed from proper solvents. The IR spectra showed peaks at 3216 (N-H), 3000 (C-H), 1672 (N=N), 1356 (C-N). The 'H NMR spectra of Ie showed signals at 81.28 (lH, s, H-3) 1.47 (3H, t, 1=7.02 Hz, -OCH2 CHr 4" ). 1.67 (3H, t, 1=6.9 Hz, -OCH2 CH3-2"), 4. 15 (2H, g, 1=7.02 Hz, -OCH2-4") 4.28 (2H, g, 1=6.9 Hz, -OCHz-2") 6.64 (2H, dd, 1=8.85, 2.2 Hz, H-6' H-6"), 7.48 (lH, s, H-5), 7.S3 (3H, unresolved dd, 1=7. 12, 4.33 Hz, H-3' HA' H-5 '), 7.8 1 (lH, d 1=8.8Hz, B-2') 8.18 (2H, dd, 1=1.59 Hz, H-3"-H-S"). MS: mlz 360 (M+), 330 (100%), 301, 287, 272, 245, 204. The melting points and yields of con.pounds prepared are given in Table I.
Table 1- Characteri za tion data of compounds la-p, 2a-h and 3a-'1
Compd R RI R2 m.p. Yield (OC) (%)
la ' C6HJ(OCH3)2 C6Hs H 148 80
l b C6H)(OCH)h C6H4(OCH) H 168 79
Ie C6H)(OCH.lh C6H3(OCHJh H 190 80
Id C6H3(OCH)h Cr,H)(OCH3)(OC2Hs) H 140 82
Ie C6H)(OC2Hsh C6Hs H 188 82
If C6H~(OC2Hs)2 C6H4(OCH) H 140 84
Ig C6H3(OC2Hs)2 C6H4(OCH3h H 170 83
Ih C6HJ (OC2Hs)2 C6H4(OCH3)(OC2Hs) H 125 80
Ii C6H3(OCH1h C6Hs CH) 130 74 l' .J C6H,(OCH1h C6H4(OCH) CH) 120 73
4-Substituted aryl-6-(2, 4-dialkoxyphenyl)-tetrazolo[I,5-a]pyrimidine 2. The solution of 4-substituted aryl-6-(2,4-dialkoxyphenyl)-2-hydrazinopyrimidine (0.01 mole) in cold cone. HCI «30%, 5 mL) was treated gradually with cold cone. solution of sodium nitrite (0.015 mole in IS mL water) at 0.-5°C with stirring. The reaction mixture was left aside at room temperature for 1 hr. The precipitated solid was filtered, washed with cold water and was subjected to column chromatography, over silica gel (100-200 mesh), using petr. ether (60-80°), benzene and ethyl acetate mixture as eluants. The IR spectra showed peaks at 3160 (N-H), 1660 (N=N), 1604 (C=N) , 1304 (C-N). The I H NMR spectra of 2e showed signals at ~1.34 (3H, t, J=7 .12 Hz, CH2CH3-4") 1.52(3H, t, J=6.52Hz, CH2CH3-2"), 4.03 (2H, dd, J= 7.12 Hz, CH2 CH3-4") , 4.06 (2H, dd , J=6.52 Hz, CH2CHr 2"), 6.45 (2H unresolved dd J=8.7 , um'z, H-6', H-6"), 7.37 (3H unresolved J=5.5, 1.95Hz, H-2', HA', H-5"), 7.6 1 (2H, d, J=4.19 Hz H-3' , H-5') 7.67 (I H, s, H-5) 7.8 (I H, s, H-3"); MS: mlz 360(M+) 274(l00%)255, 163, 133, 103,66. The melting points and yields of compounds prepared are given in Table I.
4-Substituted aryl-6-(2, 4-dialkoxyphenyl)-pyrimido[2, l-e][l, 2, 4]triazepine 3. A solution of 4-substituted aryl-6-(2, 4-dialkoxyphenyl)-2-hydrazinopyrimidine (O.ot mole) in acetylacetone (20 mL), was refluxed in presence of few drops of PPA for 6 hr. The product was decomposed in cold water and extracted with ethyl acetate. The extract was dried on anhyd. Na2S04. It was then filtered off and ethyl acetate distilled off. The desired product was obtained after column chromatography using pet. ether (60-800), benzene and ethyl acetate mixtures as eluant. The IR spectra showed peaks at 3316 (N-H), 1552 (N-N), 1360 (CN). The 'H NMR spectra of 3f showed signals at ~1.20 (3H, S, CH3-3), t.41 (3H, s, CHr 5), 1.46(3H, t, J=5Hz, OCH2CHr 4,), 1.52 (3H, t, J=7.02 Hz, OCH2CHr 2"). 3.51 (I H, s, H-4), 3.85 (3H, S, -OCHr 3') 4.08 (2H, dd, )=5 , 5Hz, OCH2CH3A"), 4.12 (2H, dd, )=7.02, 7.02 Hz, -OCH2 CHr 2"), 6.4 (2H, dd, J=7 .1, 2.24, Hz H-3', H-5'), 6.91 (lH, s H-5), 8.05 (4H, br, dd, J=2.24,
4.86 Hz, H-2', 5', 6', 6"), 8.12 (lH, s H-3"). MS: mlz 444(M+), 416,398,382(100%) 365, 326. The melting points and yields of compounds prepared are given in Table I.
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