Novel approach to the synthesis and optical absorption properties of 2-(2-oxo-1,2-dihydro-3H-pyrrole-3-ylidene)malononitriles

A novel three-position molecular switch based on the transformations of a cyano-substituted pyrrol-2-one derivative

“…2). 21 They contain an ylidenemalononitrile fragment, as well as a methyl group in the fourth position of the pyrrole ring. We decided to develop an approach to the synthesis of novel oxotricyanopyrrole ( OTCP , Scheme 1), which is an analogue of pyrroles F but differs in the presence of a cyano group instead of methyl in the fourth position.…”

The first example of unusual reversible nucleophilic addition to 2-(5-aryl-2-oxo-3H-pyrrol-3-ylidene)malononitriles – a new tool for the creation of thermosensitive molecular switches

“…It should be noted that there is no single example of reactions of structures A and B with nucleophiles at the C5 atom in the literature. Studies of the possibility to engage this reaction center in transformations are also promising because of the recently reported 18 intense color of compounds 1 . As a result of the reactions occurring at the C5 atom, the conjugation between the aryl substituent and the ylidenemalononitrile fragment in the donor–acceptor structures 1 can be broken, which will lead to a contrasting color change of the reaction product compared to the starting material.…”

“…In the starting compounds 1 the bands of conjugated CN groups appeared at 2214–2220 cm −1 . 18 Bands below 2200 cm −1 in the IR spectra are a characteristic of the cyano groups attached to the carbanion. 28,29…”

“…Non-fused pyrrole derivatives B are significantly less available. [18][19][20] According to literature data, compounds A and B are characterized by reactions with nucleophiles at the electrophilic C2 and C3 atoms of the pyrrole ring. Reactions of compounds A and B at the C3 atom led to biologically active spiroindoles 21,22 and spiropyrroles, respectively.…”

“…DCAA-pyrroles 1 recently became available, 18 and were chosen as the objects of the presented study. Morpholine was used as a model reagent showing pronounced nucleophilic properties.…”