الفهرس 
Summary
Tautomeric rearrangementOnly 14 pages are availabe for public view
 |  | from | 142 |  |  |
| | | from | 142 | | |
Abstract
The chemical behaviour of 1,5-diary1-2,3-dioxopyrrolidine (1amb) towards different reagents has been studied. Thus compounds (1a,b) were treated with α-cyanocinnamonitriles (2a-c) and ethyl α -cyanocinnamates (2e-f) to give the 4H-pyrano[2,3-c]pyrrole derivatives (4a-f) and (6a-f) respctively (Scheme 1). In order to obtain an authentic samples of (4d-f) and (6e) the 4-arylidene-5-anisy1-1-pheny1-2,3-dioxopyrrolidines (8) could be synthesized from the precourser (1b) and the corresponding aldehyde. Then, the ylidenes (8) were reacted with malononitrile and ethy1 cyanoacetate but the reaction products were identified as the isoindole derivaties (10a-c) and (13) respectively (Schemes2,3). The condensation of (8) with cyanoacetamide under the conditions of Michael additioin reaction led to the formation of the pyrrole[3,4-d]pyridine derivatives (15a-d) (Scheme 4). The pyrrole[3,4-d] pyrimidine systemes (16) and (17) could be obtained by treating 4-benzylidene-1,5-dipheny1-2,3-dioxopyrrolidine with urea and thiourea respectively (Scheme 5). Moreover, 1,5-dipheny1-2,3-dioxopyrrolidine (1a) was condensed with malononitrile to give the benzylidene pyruvic acid derivative (19) instead of the 3-dicyanomethylidene-1,5-dipheny1-2-oxopyrrolidine (18). The structure of (19) was confirmed by its behaviour towards the arylidenes (2a-f), hydrazine and pyridin-2-y1 diazonium chloride which led to the formation of (20a-c), (21a-c), (22) and (23) respectively (Scheme 6). Also, compound (1b) was treated with malononitrile and elemental sulfur in ethanolic sodium ethoxide as a base to afford the thieno[3,2-c]pyrrole derivative (25). Following the same reaction conditions, compounds (1a,b) were refluxed with ethyl cyanoacetate and S in ethanolic sodium ethoxide to give the thieno[3,2-c]pyrrole derivatives (27a,b) (Scheme 7). Scheme (8) described the reaction of (1a)with hydrazoic acid under Schmidt reaction conditions to afford the piperazine derivative (31) in one pot reaction. In addition, Mannich bases (32), (34) and (36) could be obtained by treatment of (1a,b) with formaldehyde and piperidine, morpholine or diphenylamine respectively. Compounds (32). (34) and (36) were subjected to Schmidt reaction with sodium azide and sulphuric acid to produce the piperazines (33),(35) and (37) respectively (Scheme 8).