The research efforts in the laboratory are divided into two general areas.
Alkaloids:
The long standing interest, developed over some 50 years of study (see, e.g. Dalton, D. R., “An Approach to the Total Synthesis of Lycorine”, Ph. D. Dissertation, University of California, Los Angeles, 1962 ; Hendrickson, J.B.; Alder, R.W.; Dalton, D.R.; Hey, D.G. “Some Approaches to Total Synthesis of Lycorine”, J. Org. Chem. 1969, 34, 2667 (doi: 10.1021/jo01261a040); Dalton, D. R. “The Alkaloids, A Biogenetic Approach” M. Dekker, Inc., New York (1979), of the rich chemistry of alkaloids (Dalton, D.R.; Mascavage, L.M.; Wilson, M.L. “Kirk-Othmer Encyclopedia of Chemical Technology”, 5th edit., Vol 2., 2004, 71ff) coupled to what we continue to learn about the processes by which these compounds form and how they might be used in medicine powers current efforts in the modification of morphinane structures. So, we are looking at the less widely studied A-ring as indicated in our recent reports (Wilson, M.L.; Dalton, D.R.; Carroll, P.J. “Decoration of the Aromatic Ring of Dihydrocodeinone (Hydrocodone) and 14-Hydroxydihydrocodeinone (Oxycodone)”. J. Org. Chem. 2005, 70, 6492 (doi: 10.1021/jo050264+) and Mascavage, L.M.; Wilson, M.L.; Dalton, D.R. “Syntheses of Morphine and Codeine (1992 – 2002): Templates for Exploration of Synthetic Tools.” Current Organic Synthesis 2006 , 3, 99.
Surface Catalyzed Gas Phase Kinetics:
The second effort derives from the lust to learn the details of product forming molecular interactions. Many efforts to define such pathways or mechanisms of simple reactions between gases have demonstrated both that (a) simple pathways are rare and (b) products can form, simultaneously, by different pathways (Rettner, C.T.; Auerbach, D.J. “Distinguishing the Direct and Indirect Products of a Gas-Surface Reaction” Science, 1994, 263, 365 [doi: 10.1126/science.263.5145.365]). Indeed, the latter appears common when surfaces (which are everywhere) can participate via adsorbed species to form the same products as formed between non-adsorbed species. Our work continues along two pathways
First, we are continuing to examine the reaction between gaseous hydrogen chloride and gaseous alkenes and alkynes (Mascavage, L.M.; Zhang F.; Dalton, D.R. “The Reaction of the Gases Hydrogen Chloride and 2-Butyne.” J. Org. Chem. 1994, 59, 5048 [doi: 10.1021/jo00096a058]) with our current (and continuing efforts) directed toward vinylacetylene (buta-1-yne-3-ene). Secondly, we are now examining, surface catalyzed reactions between aldehydes and amines (Mascavage, L.M.; Sonnet. P.E.; Dalton, D.R. “On the Surface-Catalyzed Reaction between the Gases 2,2-Dimethylpropanal and Methanamine. Formation of Active-Site Imines.” J. Org. Chem. 2006, 71, 3435 [doi: 10.1021/jo052503z]) both experimentally and computationally.
Recent work (Sonnet, P.E.; Mascavage, L.M.; Dalton , D.R. “The first steps. The attack on the carbonyl carbon of pyridoxal cofactor in pyridoxal-dependent enzymes” Bioorg. Med. Chem. Let. 2008, 18, 744 [doi: 10.1016/bmcl.2007.11.051]) extends these ideas related to many examples found in the Protein Data Bank (http://www.rcsb.org/pdb/home/home.do).
Gaseous mixtures of hydrogen chloride and vinylacetylene were permitted to react in Pyrex cells (with sodium chloride windows) and the reaction observed in the infrared (IR) region of the electromagnetic spectrum. Gaseous 4-chloro-1,2-butadiene and 2-chloro-1,3-butadiene (chloroprene) were the major products. Kinetic data generated a rate expression in concert with surface catalysis. Computational studies involving surface associated water provide a view that accounts for the experimentally determined orders and a bifurcated pathway producing both products. The results are in accord with wall-absorbed reactant(s) and previously reported computational studies. See Mascavage, L.M.; Zhang-Plasket, F.; Sonnet, P.E.; Dalton, D.R. “Gas phase surface-catalyzed HCl to vinylacetylene: motion along a catalytic surface. Experiment and theory.” Tetrahedron, 2008, 64, 9357 (doi: 10.1016/j.tet.2008.07.081).
Most recently this work was expanded to include reactions of hydrogen chloride with isoprene, a volatile plant product Mascavage, L. M.; Sonnet, P. E.; Dalton, D.R. “Surface-Catalyzed Reaction between the Gases Hydrogen Chloride and Isoprene” ACS Earth Space Chem. 2017, 3, 122 (doi: 10.1021/acsearthspacechem.7b00009).