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Polycyclic Pyrazoles: Routes to New Pyrazoloazines

 

作者: Abdel M. Hussein,  

 

期刊: Journal of Chemical Research, Synopses  (RSC Available online 1998)
卷期: Volume 0, issue 1  

页码: 20-21

 

ISSN:0308-2342

 

年代: 1998

 

DOI:10.1039/a703809g

 

出版商: RSC

 

数据来源: RSC

 

摘要:

N N Me CHO Ph NH2 1 N N Me Ph 11 N CN NH2 N N Me Ph NH2 3 OH H H CONHY C N NCCH2CONHY N N Me Ph 4 N CONHY NH H H OH H 2a 2a,b N N Me Ph 5a,b N CONHY NH2 –H2O 2,5 a b H NH2 Y N N Me Ph 12 N CN Ph N N Me Ph 13 N NHCOPh O H N N Me Ph 14 NHCO2Et CHO 1 PhCOCH2CN (8) ClCO2Et (10) PhCONHCH2CO2H (2) CH2(CN)2 (7) N N Ph Me NH CN O 6 N N Me Ph N CN X OH H N N Me Ph NH EtO CN X 1 + 11 X = CN X = CO2Et –HCN N N Me Ph N X OH CHO CH C CN X 18a X = CO2Et b X = CN 15,16 a b X CO2Et CN CN X Ar 1 + N N Me Ph N X OH 20 X = CO2Et X = CN 11 6 X = CO2Et, CN 19 Ph p-anisyl p-ClC6H4 2-furyl 2-thienyl Ph p-anisyl p-ClC6H4 2-furyl 2-thienyl CN CN CN CN CN CO2Et CO2Et CO2Et CO2Et CO2Et a bc def gh ij Ar X Ar 19 16 17 15 20 J.CHEM. RESEARCH (S), 1998 J. Chem. Research (S), 1998, 20–21 J. Chem. Research (M), 1998, 0231–0241 Polycyclic Pyrazoles: Routes to New Pyrazoloazines Abdel M. Hussein*a and T. I. El-Emaryb aChemistry Department, Faculty of Science, Al-Azhar University, Assiut 71524, Egypt bChemistry Department, Faculty of Science, Assiut University, Assiut 71516, Egypt A number of substituted pyrazolo[3,4-b]pyridines and pyrazolo[4p,3p:5,6]pyrido[2,3-d]-pyrimidinones and -1,2,3 -triazinones have been made, starting from 5-amino-3-methyl-1-phenylpyrazole-4-carbaldehyde. Pyrazoles have been found to be excellent precursors for the syntheses of condensed polyfunctionally substituted pyrazoles. 10–11 We report here the facile synthesis of some new pyrazolo[3,4-b]pyridines from 5-amino-3-methyl-1-phenylpyrazole- 4-carbaldehyde (1) which was first described by H�aufel and Breitmaier.12 Cyclocondensation of 1 with cyanoacetamide (2a) in refluxing ethanolic piperidine yielded a product which could have been either the cyano-pyridone 6 or the amino-amide 5a (Scheme 1).Structure 5a was considered to be the only reaction product on the basis of spectroscopic data. Compound 1 also reacted with cyanoaceto hydrazide 2b to yield the pyrazolo[3,4-b]pyridine 5b.Similarly 1 reacted with malononitrile (7) in refluxing ethanolic piperidine to yield the corresponding pyrazolopyridine 11 via addition followed by elimination of water. In analogy, cyclocondensation of 1 with benzoylacetonitrile (8) afforded the pyrazolopyridine derivative 12. The reaction of 1 with hippuric acid was also investigated. Thus, cyclocondensation of 1 with hippuric acid (9) in glacial acetic acid afforded the pyrazolopyridine 13. Also, the reaction of 1 with ethyl chloroformate 10 in ethanolic piperidine yielded the urethane 14.Compound 1 reacted with ethyl ethoxymethylidenecyanoacetate (15a) to yield the substitution product 16 (Scheme 2). Efforts to cyclize 16 under various reaction conditions failed. Also, ethoxymethylidenemalononitrile (1b) failed to yield 18 in reaction with 1, compound 11 instead being formed under the reaction conditions. Efforts to cyclize 1 with arylmethylidenes 19a–j to afford 20a–j were not successful; instead, 6 and 11 were isolated.12 Synthetic approaches to aminocarboxamide derivatives have been extensively studied, and many syntheses using aminocarboxamides as starting materials have been reported.13–16 We found that the aminocarboxamide 5a reacted with urea derivatives to yield the pyrazolopyridopyrimidine derivatives 22a,b (Scheme 3).Similarly, formic acid, acid chlorides, aryl aldehydes and phenyl isothiocyanate reacted with 5a to give *To receive any correspondence.Scheme 1 Scheme 2N N N N NH Me O X H Ph 22a X = O b X = S N N N N NH Me O Ph 25a R = H b R = Me c R = CH2Cl R N N N N NH Me O Ph Ar Ar a bc Ph p-ClC6H4 p-anisyl 26,27 N N N N NH Me O Ph NHPh 29 N N N N N NH Me O Ph 30 NH2C(X)NH2 (21) HCO2H (23) RCOCl (24a R = Me b R = CH2Cl) ArCHO (26) PhNCS (28) NaNO2 AcOH 5a 27 J. CHEM. RESEARCH (S), 1998 21 the corresponding pyrazolopyridopyrimidine derivatives 25, 27 and 29 respectively. Treatment of the aminocarboxamide 5a with sodium nitrite in acetic acid at room temperature afforded the 1,2,3-triazinone derivative 30.Techniques used: IR, NMR (1H, 13C), mass spectrometry, microanalysis References: 16 Table 1: Mps, yields and elemental analysis of 5a–c, 11, 12, 13, 14, 16, 22a,b, 25a–c, 27a–c, 29 and 30 Table 2: IR and 1H NMR of 5a,b, 11, 12, 13, 14, 16, 22a,b, 25a–c, 27a–c, 29 and 30 Table 3: 13C NMR of 22a and 27b Received, 2nd June 1997; Accepted, 29th September 1997 Paper E/7/03809G References cited in this synopsis 10 C. R. Hardy, Adv. Hetrocycl. Chem., 1984, 36, 343. 11 M. H. Elnagdi, G. E. H. Elgemeie and R. M. H. El-Moghayar, Adv. Heterocycl. Chem., 1987, 41, 319. 12 J. H�aufel and E. Breitmaier, Angew. Chem., Int. Ed. Engl., 1974, 13, 604. 13 G. M. Coppola and M. J. Shapiro, J. Heterocycl. Chem., 1980, 17, 1163. 14 Y. Imai, S. Sato, R. Takasawa and M. Ueda, Synthesis, 1981, 35. 15 J. Clark and G. Hitiris, J. Chem. Soc., Perkin Trans. 1, 1984, 2005. 16 T. M. Stevenson, F. Kazmierczak and N. J. Leonard, J. Org. Chem., 1986, 51, 616. Sche

 



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