Synthesis and biological activities of meribendan and related heterocyclic benzimidazolo-pyridazinones

Molecular structure, vibrational spectra, natural bond orbital and thermodynamic analysis of 3,6-dichloro-4-methylpyridazine and 3,6-dichloropyridazine-4-carboxylic acid by dft approach

“…Pyridazine is a privileged structure in medicinal chemistry and can be used in isosteric replacement of phenyl or heteroaromatic rings [5]. The pyridazine nucleus, which has been known for more than a century, is of considerable interest because of its various synthetic [6,7] and biological uses [8][9][10][11][12]. Pyridazines are rare in nature, possibly reflecting the scarcity of naturally occurring hydrazines, a common building block for the synthesis of these heterocycles.…”

Five‐Membered Heterocycles: 1,2‐Azoles. Part 1. Pyrazoles

“…Many different structural variations have been devised in this series and, related to pyrazoles, the most interesting compound from a series of heterocyclic benzimidazolyl-pyridazinones is meribendan (22). It inhibited myocardial PDE3, showed an interesting calcium sensitizing effect and was selected for development as a positive inotrope [56].…”

Energetics and molecular structure of alkyl 1-methylpyrrolecarboxylates (alkyl=methyl or ethyl)

“…Pyrrole moiety is the structural core of the naturallyoccurring porphyrins, the tetrapyrrolic ''pigments of life'', which include the hemoglobin, porphyrins, corrins, vitamin B 12 , the bile pigments and chlorophyll, playing an important role in respiration and photosynthesis processes [14][15][16][17][18]. Moreover, pyrrole and derivatives scaffolds are widely used as precursors in the synthesis of drugs with high therapeutical potential [19][20][21][22][23][24][25][26][27][28][29][30], polymers and new materials [31][32][33][34][35][36][37]. In this context, the knowledge of the molecular energetics of the core units is of great importance to understand the activity and the chemical behaviour of larger molecules involving them.…”