Discussion of the topology of interaction of ring compounds with macromolecules and receptors requires a system for naming the faces of the cyclic compound. An α/β-face nomenclature is suggested that is based on the clockwise/counterclockwise direction of ascending numbering in the ring with the lowest numbered unshared ring atom. This system is applicable to a very broad range of compounds: sugars, cyclic bases, steroids, cyclitols, porphyrins, etc., and molecules with a single ring, fused rings, encompassing rings, and rings formed by head-to-tail polymerization.

Anew and rapid gas chromatographic / mass spectrometric analytical procedure for insect growth regulator diflubenzuron, a phenylurea-based insecticide, has been developed. Diflubenzuron is decomposed by the heat of a gas chromatograph into three reproducible fragments, 4-chlorophenyl isocyanate, 4-chloroaniline, and 2,6-difluorobenzamide, which elute separately from the GC column. The source of the

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