Reactivity of condensed thiophenes in the Diels-Alder reaction: The reactivity of 3-aminothieno [3,4:3`,4`] benzo [b] pyranone; 3-aminothieno [3,4-c] quinoline and of 5-amino-7-substituted thieno [3,4-d] pyridazinone toward electron-poor olefins and acetylenes

Studies with condensed amino‐thiophenes: Further investigation of reactivity of amino‐thieno‐coumarines and amino‐thieno‐benzo[h]coumarines toward electron‐poor olefins and acetylenes

“…In the light of this last finding and in the light of well-accepted thermal instability of thiepins [5], we have decided to look further into the structure of thiepins claimed to be formed in the previous work [6] as a part of continued investigation on reactivity of condensed thiophenes toward olefins and acetylenes.…”

“…Later our group has reported as well the formation of similar thiepins [6] 3b-c by reaction of condensed thiophenes 2b-c with acetylenic esters. Al-Omran et al [7,8] also claimed the formation of thiepins on reacting with other condensed aminothiophenes and dimethyl acetylenedicarboxylate (Scheme 2).…”

Synthesis of 3‐arylazo‐6‐oxopyridazin‐5‐carbonitriles: A versatile precursor for condensed arylazopyridazin‐6‐ones

“…Alternately reacting 3 with 5 has afforded 6. Reactions of this type has been recently utilized by other groups, thus established their general nature [12][13][14] (Scheme 1).…”

Alkylazinylcarbonitriles as building blocks in organic synthesis: synthesis of 3-amino-7-arylhyrazonothieno-7H-[3,4-c]-pyridine-4,6-diones and pyrido-[3,4-c]-pyridazine-5-carbonitrile

“…This methodology has been utilized by Elnagdi et al [1][2][3][4][5][6][7][8] and Döpp et al 9,10 as precursors to thienopyridazines, thienocoumarines and thienoquinolines, which were subsequently reacted with dienophiles yielding benzofused heteroaromatics. The scope of this approach for the synthesis of phthalazines as well as condensed benzopyrans has been defined by the recent work of Döpp and coworkers as well as Elnagdi et al (Scheme 1).…”