2.4- Dimethyl-9-hydroxypyrido

Diorganotin(IV) complexes with 4//-pyrido[l,2-n]pyrimidin-4-ones 109 (96MI4), complexes of 2-methyl- and 2-methyl-8-nitro-9-hydroxy-4//-pyrido[l,2-n]pyrimidin-4-ones with Ag(I), Cu(II), Ni(II), Co(II), and Mn(II) ions (00MI23), 2,4-dimethyl-9-hydroxypyrido[l, 2-n]pyrimidinium perchlorate and its complexes with prasedynium, neodymium, samarium and europium (00MI24) were characterized by UV spectroscopy. 

Diorganotin(IV) complexes (109) were prepared from 4/f-pyrido[l,2-a]pyrimidin-4-ones with Me2SnCl2 and Ph2SnCl2 in dry CHCI3 (96MI4). Different complexes of 2-methyl-9-hydroxy-4//-pyrido[l, 2-n]pyrimidin-4-one and its 8-nitro derivative were prepared with Cu(I)Cl, Cu(II)Cl2, Ni(II)Cl2, Co(II)Cl2, Mn(II)Cl2, and Ag(I)N03 m EtOH (00MI23). Complexes of 2,4-dimethyl-9-hydroxypyrido[l,2-n]pyrimidinium salt were obtained with Pr(III), Nd(III), Sm(III), and Eu(III) ions in acetone (00MI24). 

Dimethyl-9-hydroxypyrido[ 1,2-a]pyrimidinium perchlorate and its metal complexes were characterized by UV and IR spectroscopy (90MI24). 

An ice-cold soln. of 2-pyridylmethyleneaminoacetaldehyde dimethyl acetal in glacial acetic acid treated with 50%-HBr-glacial acetic acid, and allowed to stand overnight -> 6,7-dihydro-6-hydroxypyrido[l, 2-a]pyrido[l, 2 3,4]imidazo[2,1-c]-pyrazine-5,8-diium dibromide. Y 90%. F. e. s. E. C. Campbell, E. E. Glover, and G. Trenholm, Soc. (C) 1969, 1987. 

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