Substituted γ‐lactones. XXX . Reactions of α‐Keto‐β‐Subtituted‐γ‐butyrolactones with diamines

The condensation reaction between α‐keto‐β‐aroyl (or acyl) ‐γ‐butyrolactones, 4a‐4e and o ‐phenylenediamine or 2, 3‐diaminonaphthalene leads under retrograde aldol condensation involving loss of formaldehyde to formation of 3‐substituted‐3, 4‐dihydro‐2 (1 H ) quinoxalinones or benzo [ g ] quinoxalinones, 7a‐7g , respectively as a new convenient synthesis of this type of heterocyclic systems. The reaction of type 4 compound with 4, 5‐diaminopyromidine, 8 , was found to proceed differently. 2‐[(4‐Amino‐5‐pyrimidinyl)amine]‐4‐oxo‐3‐(hydroxymethyl)‐4‐phenyl‐2‐butenoic acid 9 was the only product formed when the reaction between 4a and 8 was run in ethanol. The same reaction in glacial acetic acid proceeds with loss of formaldehyde, to afford 7‐phenacylidene‐7,8‐dihydro‐6 (1 H )‐pteridione 10 . The reaction between type 4 compounds and ethylenediamine or 1, 4‐phenylenediamine leads to the formation of the bis‐condensation products 13–15 , respectively.