PubMed Health⌕ Search

Biomedical subjects

Mark Mascal

Publications and source records attributed to Mark Mascal.

10 recordsLinked to original sources
PubMed2006

Synthesis of the G-C DNA base hybrid with a functional tail.

Molecules which possess the hydrogen bonding codes of both guanine and cytosine ("G-C DNA base hybrids") are known to organize in a hexagonal array both in solution and the solid state. Including an easily derivatizable functional group in the molecule allows the co-organization of virtually any species in the hexagonal periphery. Simple 5- and 6-step procedures are described for the synthesis of DNA base hybrids with tail groups which are terminated by electrophilic (primary bromide) and nucleophilic (primary alcohol) functions, respectively.

Cytosine↗
PubMed2005

The azaacepentalenide anion: a new aromatic, bowl-shaped heterocycle.

The bowl-shaped aromatic azaacepentalenide anion and its perchloro analogue were derived from 10-azatriquinacene and 2,3,5,6,8,9-hexachloro-10-azatriquinacene via the N-oxides. Spectroscopic and computational studies, as well as chemical derivitization experiments, were used to confirm the structural assignments.

Journal Article↗
PubMed2002

The energetics of shooting ions into the dodecahedrane cage.

The activation barriers and energy profiles along the inclusion coordinate for the penetration of H+, He, Li+, Be+, Be2+, and Mg2+ into dodecahedrane 1 vary considerably with the nature of the projectile. Using Hartree-Fock and MP2 derived structures and energies, the overall process of creating endohedral X n+@1 complexes is examined in detail.

Journal Article↗
PubMed2002

Anion-aromatic bonding: a case for anion recognition by pi-acidic rings.

The basis for unprecedented noncovalent bonding between anions and the aryl centroid of electron-deficient aromatic rings has been demonstrated by an ab initio study of the interaction between 1,3,5-triazine and the fluoride, chloride, and azide ion at the MP2 level of theory. Minima are also located corresponding to C[bond]H...X(-) hydrogen bonding, reactive complexes for nucleophilic attack on the triazine ring, and pi-stacking interactions (with azide). Trifluoro-1,3,5-triazine also participates in aryl centroid complexation and forms nucleophilic reactive complexes with anions. This novel mode of bonding suggests the development of new cyclophane-type receptors for the recognition of anions.

Journal Article↗
PubMed1998

Azatriquinanes: Synthesis, Structure, and Reactivity.

Azatriquinane, a tricyclic amine with rigid, hemispherical topology, is synthesized in six steps from pyrrole. This first example of a [2.2.2]cyclazine can be oxidatively dimerized to a novel, highly strained heptacycle or oxidized with chlorine to give an azatriquinacene, a theoretical precursor to diazadodecahedrane via Woodward dimerization.

Journal Article↗