Green and efficient synthesis of 2-(4-oxo-3,4-dihydroquinazolin-2-yl)-2,3-dihydropthalazine-1,4-dione

Abstract

412-4172-Hydrazinoquinazolin-3H-4-ones 1a,b were reacts with each of the anhydrides, phthalic anhydride 2a, succinic anhydride 2b and maleic anhydride 2c independently in PEG-600 at RT to yield 2-(2-(4-oxo-3,4-dihydroquinazolin-2-yl)hydrazine-ecarbonyl)benzoic acid 3a,b, 4-oxo-4-(2-(4-oxo-3,4-dihydroquinazolin-2-yl)hydrazinyl)butanoic acid 3c,d and 4-oxo-4-(2-(4-oxo-3,4-dihydroquinazolin-2-yl)hydrazinyl)but-2-enoic acid 3e,f, respectively. 3a,b,<b style="mso-bidi-font-weight: normal"> 3c,d, 3e,f have been transformed into 2-(4-oxo-3,4-dihydroquinazolin-2-yl)-2,3-dihydrophthalazine-1,4-dione 4a,b, 1-(4-oxo-3,4-dihydroquinazolin-2-yl)piperazine-3,6-dione 4c,d and 1-(4-oxo-3,4-dihydroquinazolin-2-yl)-1,2-dihydropyridazine-3,6-dione 4e,f, respectively by heating each in PEG-600 at 100 °C for 3-3.5 hr in high yields and in high purity, involving a dehydrative ring closure. The final compounds <b style="mso-bidi-font-weight: normal">4a-f have also been prepared alternatively by reacting 1 with <b style="mso-bidi-font-weight: normal">2 in PEG-600 at 100 °C for 3.5-4 hr