Saturated Heterocycles, 75 - Preparation of Tetracyclic Thiophene Derivatives with Bridgehead Nitrogen. Synthesis of Polymethylenethienodihydropyrrolo-, tetrahydropyrido- and tetrahydroazepinopyrimidin-4-ones and -4-thiones

Article abstract of DOI:10.1007/BF00810875

The following tetracyclic ring systems and their derivatives have been synthesized for pharmacological investigations: Trimethylenethieno<2,3-d>dihydropyrrolo<1,2-a>pyrimidin-4-one and -4-thione (1a, 5a); Tetramethylenethieno<2,3-d>dihydropyrrolo<1,2-a>pyrimidin-4-one and -4-thione (1b, 1j, 5b); Pentamethylenethieno<2,3-d>dihydropyrrolo<1,2-a>pyrimidin-4-one and-4-thione (1c, 5c); Trimethylenethieno<2,3-d>tetrahydropyrido<1,2-a>pyrimidin-4-one and -4-thione (1d, 5d); Tetramethylenethieno<2,3-d>tetrahydropyrido<1,2-a>pyrimidin-4-one and -4-thione (1e, 5e);Pentamethylenethieno<2,3-d>tetrahydropyrido<1,2-a>pyrimidin-4-one and -4-thione (1f, 5f); Trimethylenethieno<2,3-d>tetrahydroazepino<1,2-a>pyrimidin-4-one and -4-thione (1g,5g); Tetramethylenethieno<2,3-dpyrimidin-4-one and -4-thione (1h, 5h); Pentamethylenethieno<2,3-d>tetrahydroazepino<1,2-a>pyrimidin-4-one and -4-thione (1i, 5i); Tetramethylenethieno<2,3-d>tetrahydroazepino<1,2-a>pyrimidin-4-one (7b); Pentamethylenethieno-<2,3-d>tetrahydropyrido<1,2-a>pyrimidin-4-one (7c).Compounds 1a-i were synthesized from 2-amino-3-ethoxycarbonyl-4,5-polymethylenethiophene 2a-c with the corresponding lactim ethers (3a-c) in chlorobenzene in the presence of polyphosphoric acid (PPA).Compounds 7b and 7c were obtained in the reaction ob β-amino acid esters 2a and 2c with 2-bromopyridine (6).The thione derivatives (5a-i) were prepared from compounds 1a-i with phosphorus(V) sulphide. - Keywords: Condensation of 2-amino-3-ethoxycarbonyl-4,5-polymethylenethiophene with lactim ethers and 2-bromopyridine; Oxo-thio exchange