Dibenzo[b,f]oxepin‐10(11H)‐one and dibenzo[b,f]thiepin‐10(11H)‐one as useful synthons in the synthesis of various dibenzo[e,h]azulenes

Abstract

The present review focuses on dibenzo[b,f]oxepin‐10(11H)‐one (I, X = O) and dibenzo[b,f]thiepin‐10(11H)‐one (I, X = S) as common synthons in the efficient synthesis of various dibenzoxepino[4,5‐ and dibenzothiepino[4,5]‐fused five‐membered heterocycles: [2,3] fused thiophene (II), [3,4] fused thiophene (III), furan (IV), pyrrole (V), imidazole (VI), pyrazole (VII), oxazole (VIII), and thiazole (IX). The potential of I to be converted into reactive intermediates that readily undergo heteroaromatic annulation reactions by cyclocondensation with proper binucleophiles allows formation of a range of enumerated functionalized dibenzo[e,h]azulene [4] structures (II, III, IV, V, VI, VII, VIII, IX). Dibenzo[e,h]azulenes as heterotetracyclic scaffold can be exploited in further modifications to obtain compounds with altered physicochemical and biological profile. J. Heterocyclic Chem., (2012).

The Recycling of Substandard Rocket Fuel N,N-Dimethylhydrazine via the Involvement of Its Hydrazones Derived from Glyoxal, Acrolein, Metacrolein, Crotonaldehyde, and Formaldehyde in Organic Synthesis

“…Attempts have been made to synthesize inhibitors of p38 MAP kinases (mitogenactivated protein kinases) based on DMHG [49][50][51], aiming to reduce the production of pro-inflammatory cytokines, which contribute to tissue destruction in diseases such as rheumatoid arthritis, an inflammatory joint disease. In one method [49] (Figure 6), the authors propose a DMHG-based condensation in an alkaline medium, alcohol solution, without the use of organometallic reagents.…”

“…This approach is chosen because the original aldehydes 32a,b do not hinder enolization due to the arrangement of atoms. The authors of [49,50] performed cyclization of hydrazones 33a,b followed by N-N bond cleavage using a sodium dithionite aqueous alcohol solution, similar to the method described above [39] (Figure 6). The resulting heterocycle 35a, when interacting with bromosuccinimide (NBS), underwent further chemical transformations (Figure 6) into 2-bromopyrrole 36.…”