Synthesis of some pyridine and pyrimidine derivatives via michael-addition

الملخص EN

Synthesis of pyridine and pyrimidine analogues 4 and 6-9 were achieved by Michael-addition of compounds containing either active methylene groups like, malononitrile, ethyl cyan acetate and 1-tetra lone or compounds containing active hydrogen atoms like, guanidine in the presence of an oxidizing agent and thiourea to 2-arylmethylidine-1-tetralone and 2-arylmethylidine-6-methoxy-1-tetralone (2) (enones).

Addition of malononitrile in piperidine at room temperature to 2 gave 2-amino-3-cyano-naphtha [1, 2- b] pyran derivatives 3 which were converted to 4 upon treatment with sodium meth oxide.

Addition of malononitrile in sodium alkoxide or sodium hydroxide to 2 gave 4.

Cyclization of 3a with acetic anhydride in the presence of conc.

H2SO4 gave the naphtho-pyrano [2, 3-d] pyrimidin-8-one (5).

Condensation of the pyrimidine thione derivatives 9 with chloroacetic acid gave the 3-oxo-benzo [h] thiazolidino [2, 3-b] quinazoline derivatives (10), which were reacted through their active Methylene groups with aromatic aldehydes to give the arylidine derivatives 11.

These compounds’ were also prepared in one step by reacting 9 with chloroacetic acid and aromatic aldehydes.

Condensation of 9 with 3-bromopropanoic acid gave 4-oxo-benzo [h] 1, 3-thiazino [2, 3-b] quinazoline derivatives (12).

The structures of the prepared compounds were mainly confirmed on the basis of spectroscopic methods.