Thiophosphorylated derivatives of meta- and ortho-hydroxybenzaldehydes in one-step syntheses of novel calix[4]resorcinols

Thiophosphorylated derivatives of meta- and ortho-hydroxybenzaldehydes take part in one-step, acid-catalyzed condensations with resorcinol and its derivatives. As a result, new calix[4]resorcinols, which contain four 2-thioxo-1,3,2-dioxaphosphorinane fragments on the aromatic substituents of the calixarene matrix, have been synthesized. In this case, macrocyclic products are formed as rccc- (cone or boat conformation) and/or rctt- (chair conformation) diastereomers, the ratio of which depends on the structure of the starting reagents. The obtained products have been isolated and their structures determined by NMR methods and single-crystal X-ray diffraction. The spectral differences of conformational isomers of the prepared macrocycles have been demonstrated.