Derivatives of a new heteroaromatic system —11-thia-4b,6,10,12-tetraazaindeno[2,1-a]-fluorene

Large‐Ring Carbocycles

“…Irradiation of 15 in acetonitrile gives a single product 18 in good yield. 22 Ring closure to the galanthan skeleton is carried out under basic conditions with piperidine to generate ketone 19 in 78% yield. Enol Esters of ß-Diketones…”

“…13 While this review focuses specifically on the dinitrile variant of the reaction, the reader's attention is directed to a wealth of literature on these related [14][15][16][17][18][19][20][21][22][23][24][25][26] reactions, commonly used in heterocycle synthesis.…”

2-Amino-3-aroyl-1-(2-benzimidazolyl)-indolizines in the synthesis of new heterocyclic systems

“…On boiling the imidazolines 3a,b in acetic anhydride or formic acid, with the addition acetic anhydride as water removing medium [2,3] we obtained the new heterocyclic systems indolizino[2′,1′:4,5]pyrimido-[1,6-a]benzimidazoles 4a-c [4]. …”

“…In a previously developed method [1] we obtained 1-(2-benzimidazolyl)indolizines 3a,b from the salts 1a,b and 2-benzimidazolylacetonitrile (2). On boiling the imidazolines 3a,b in acetic anhydride or formic acid, with the addition acetic anhydride as water removing medium [2,3] we obtained the new heterocyclic systems indolizino[2′,1′:4,5]pyrimido-[1,6-a]benzimidazoles 4a-c [4].…”