No abstract

Acid-catalyzed cyclocondensation in a three component system of dichloromethylacetylbenzoylmethanes, urea, and aromatic aldehydes occurred regio-and stereoselectively to give polyfunctional derivatives of perhydropyrimidine.

No abstract

Three component condensation of diethyl isophthaloyldiacetate, aromatic aldehyde, and urea as a new method for the synthesis of 1,3 bis(2 oxo 1,2,3,4 tetrahydropyrimidin 6 yl)benzenesCondensation of diethyl isophthaloyldiacetate, aromatic aldehyde, and urea in the presence of Me 3 SiCl proceeds efficiently and faster than in the absence of the latter to form 1,3 bis(2 oxo 1,2,3,4 tetrahydropyrimidin 6 yl)benzene derivatives capable to give inclusion complexes with DMF.

Cyclocondensation of 5 aroyl 4 dichloromethyl 4 hydroxy 6 phenylperhydropyrimidin 2 ones with 85% hydrazine hydrate in boiling toluene afforded pyrimido[4,5 d]pyridazines.Tetraazanaphthalene derivatives play a substantial part in vital functions and are drug components. Compounds containing the pyrazino[2,3 d]pyrimidine (pteridine) system 1,2 are leaders in the number of natural and syn thetic drugs derived therefrom. In addition, other tetra azanaphthalenes such as pyrimido[5,4 d]pyrimidines, 3 pyrimido[4,5 c]pyridazines, 4 and pyrimido[4,5 d]pyrid azines 3,5-10 attract attention because of their cardiotonic and hypotensive effects and diuretic properties that in hibit phosphodiesterase (PDE) and its subtypes (PDE1-PDE11) responsible for erectile dysfunctions. Never theless, simple methods for the synthesis of such hetero cyclic systems are lacking. Known routes to pyrimido pyridazines involve expensive pyrimidine 3,7,8,11 or pyrid azine derivatives. 4Here we present a new simple and efficient method for the preparation of pyrimido[4,5 d]pyridazines from accessible starting materials. We found that 6 aryl 5 ben Scheme 1 R = H (a), Br (b), OMe (c)