Propellanes. Part LXXI. Confirmation of predicted regiospecificity in Diels-Alder reactions of certain propellanes with 4-phenyl-1,2,4-triazoline-3,5-dione

Two isomeric propellane epoxides 1a and 1b containing a cyclohexadiene ring are attacked by the title dienophile as predicted, syn to the five-membered ether ring whose α-hydrogens exert less repulsion than the α-epoxy hydrogens or the epoxide oxygen, respectively, of the cyclobutane ring.     

Propellanes-li. diels-alder reactions of 12-methyl-12-aza [4.4.3] propella-2,4,7,9-tetraene with nitroso-aromatic dienophiles1

Regiospecificity in attack of the title-bis-diene by aromatic nitroso compounds as dienophilic components is lower than that of other dienophiles of the triazolinedione type.     

Ratiometric photoacoustic sensing of pH using a "sonophore"

This work describes ratiometric photoacoustic chemical sensing of pH, and describes how these measurements can be applied as a ratiometric biomedical imaging modality to image pH in intact biological tissue.     

Propellanes—XLIV: Reaction of 11-substituted-1,6-methano[10]annulenes with 4-phenyl-1,2,4-triazoline-3,5-dione

Reaction of the bridged annulene derivatives and the dienophile mentioned in the title occurs through attack by the latter from below, anti- to the bridge. The mono-adducts obtained contain a substituted cyclopropane ring. Attempted nucleophilic displacement of suitable substituents was unsuccessful.     

Experimental investigation of the strength of glass-reinforced plastics in biaxial compression in three planes of symmetry

Glass-reinforced plastics (GRP) with fiber (wound) and fabric (hot-molded textolites) reinforcement have been investigated in biaxial compression in the three planes of symmetry. The high strength in biaxial compression in the transverse plane, observed for all the GRP investigated, is explained. A method of investigating the tensile strength of the fiber components of the GRP from the results of testing a unidirectional composite in biaxial compression in the transverse plane is proposed. The possibility of a nondestructive estimation of the strength of GRP in biaxial compression at an arbitrary stress ratio is demonstrated.Translated from Mekhanika Polimerov, No. 1, pp. 63–72, January–February, 1976.     

Propellanes-XLV: Symmetry correlation of diels-alder adducts of tetraenic propellanes with their nmr spectra

Propellane derivatives having different symmetry have been prepared and their NMR spectra measured.     

Propellanes. Part LXIX. Preparation of lactones from the three isomeric [4.3.3]propellane-8,11-diols

Each of the three isomeric[4.3.3]propellane-8,11-diols was lactonized by using 1, ω-diacids of different chain lengths. The minimal chain length required to bridge the syn-syn diol is –CO(CH₂)₁₁CO–.