On November 30, 1991, Buckle, Derek R.; Eggleston, Drake S.; Houge-Frydrych, Catherine S. V.; Pinto, Ivan L.; Readshaw, Simon A.; Smith, David G.; Webster, Richard A. B. published an article.Application of 138801-92-0 The title of the article was Conformational and steric modifications of the pyran ring of the potassium channel activator cromakalim. And the article contained the following:
The syntheses of analogs of the novel smooth muscle relaxant cromakalim, (I), in which the C-2 Me groups have been successively replaced by hydrogen, are described and the relative stereochem. of the two corresponding, isomeric monomethyl compounds, unambiguously assigned by 1H NMR spectroscopic techniques. Single-crystal x-ray anal. of the 2伪-monomethyl compound showed that it existed in a distorted half-chair conformation in the solid state and confirmed the relative orientation of the C-2, C-3 and C-4 substituents. The 2尾-Me isomer appeared to exist in a single conformation in solution, with the pyran ring adopting a half-chair conformation and with all the substituents in this ring occupying a pseudoequatorial position. The solution behavior of the 2伪-Me isomer is more complex, however, although it seems likely to exist as a distorted half-chair conformer similar to that found in the solid state. The syntheses of two related benzoxepines are also described. All compounds were less potent than cromakalim itself, which is consistent with the view that di-Me substitution at C-2 is essential for optimal activity. The experimental process involved the reaction of 4-Oxochroman-6-carbonitrile(cas: 138801-92-0).Application of 138801-92-0
The Article related to cromakalim analog preparation conformation, Heterocyclic Compounds (One Hetero Atom): Benzopyrans (Including Coumarins, Isocoumarins, Chromones, Benzopyrones, Dibenzopyrans, and Other Arenopyrans) and other aspects.Application of 138801-92-0
Referemce:
Nitrile – Wikipedia,
Nitriles – Chemistry LibreTexts