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Syntheses and NMR, MS and X‐ray investigations of homoadamantane‐fused pyridopyrimidinones
Author(s) -
Gyarmati Zsuzsanna Cs.,
Csomós Péter,
Bernáth Gábor,
Valtamo Pauliina,
Kivelä Henri,
Klika Karel D.,
Pihlaja Kalevi,
Argay Gyula,
Kálmán Alajos
Publication year - 2004
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570410208
Subject(s) - chemistry , x ray , nuclear physics , physics
Abstract The reactions of ethyl 5‐oxotricyclo[4.3.1.1 3,8 ]undecane‐4‐carboxylate (2) with methyl‐substituted 2‐aminopyridines in polyphosphoric acid (PPA) gave two products, linearly‐condensed pyridopyrimidinones 4a‐c and 2‐pyridylcarboxamides 5a‐c , whereas the reactions with amino, hydroxy and nitro derivatives of 2‐aminopyridine furnished only linearly‐condensed pyridopyrimidinones (4g‐j). Use of a mixture of PPA and phosphorus oxychloride as solvent afforded both linearly‐ (4a‐c,e,f) and angularly‐condensed (6a–c,e,f) pyridopyrimidinones. In toluene, with p ‐toluenesulfonic acid as catalyst, 2‐pyridylcarboxamides 5a‐f were obtained. In a mixture of PPA and phosphorus oxychloride at 80–120 °C, 5a‐f yielded angularly‐condensed pyridopyrimidinones 6a‐f. All the products exhibited characteristic features, as determined by NMR and electron ionization mass spectrometry and X‐ray crystallography.