Synthesis of 3-Alkyl Oxazolidines, Derived from 2-Hydroxymethyl Piperidine, as Analytical Standards for the Analysis of Volatile Aldehydes in the Workplace.

Hexahydro-3-alkyl-3-oxazolo[3,4-]pyridines for the quantitative analysis of various aldehydes were obtained in good yield the condensation reaction of 2-hydroxymethylpiperidine (2-HMP) with aldehydes under mild conditions. When acrolein was used, the bicyclic was obtained. This novel compound has suitable physical characteristics for an analytical standard.

Bis(Iminophosphorano)-Substituted Pyridinium Ions and their Corresponding Bispyridinylidene Organic Electron Donors.

Optimized synthetic procedures for pyridinium ions featuring iminophosphorano (-N=PR ; R=Ph, Cy) π-donor substituents in the 2- and 4- positions are described. Crystallographic and theoretical studies reveal that the strongly donating substituents severely polarize the π-electrons of the pyridyl ring at the expense of aromaticity. Moreover, the pyridinium ions are readily deprotonated to generate powerful bispyridinylidene (BPY) organic electron donors.

Iminophosphorano-Substituted Bispyridinylidenes: Redox Potentials and Substituent Constants from Tolman Electronic Parameters.

Bispyridinylidenes (BPYs) have emerged as an important class of neutral organic electron donors, with redox potentials that vary widely with choice of substituent. Methods to predict the effect of substitution on the redox potential are therefore highly desirable. Here we show that the redox potential of BPYs featuring iminophosphorano substituents (R P=N-), which represent the most reducing class of BPYs, can be predicted based on the well-known Tolman electronic parameter (TEP) for the respective phosphine fragment (R P).

Accessing the Ene-Imine Motif in 1-Isoindole, Thienopyrrole, and Thienopyridine Building Blocks.

A pathway to a range of diverse heterocycles was developed using a nucleophilic cyclization strategy. Lactams and ene-imines are accessed in a few steps from a common precursor, and these moieties are further elaborated to directly provide pyrroles or pyridines with extended conjugation. Reaction conditions are mild, and a broad range of structural types are available within a few steps.

Guanahanolide A, a Meroterpenoid with a Sesterterpene Skeleton from Coral-Derived sp.

A meroterpenoid, guanahanolide A (), was purified from a fermentation extract of sp. RKBH-B7. The planar structure of guanahanolide A () was elucidated by NMR spectroscopy, revealing a meroterpenoid comprised of an unprecedented sesterterpene skeleton.