Richard N. Loeppky

The synthesis of N-arylcyclopropylamines via palladium-catalyzed C–N bond formation

Abstract A variety of N-arylcyclopropylamines has been prepared in one step, by the Pd2(dba)3/BINAP/NaOtBu-catalyzed amination of an aryl bromide with cyclopropylamine. Compounds bearing the N-aryl substitutent (phenyl, 4-methylphenyl, 2-methoxyphenyl, 3-methoxyphenyl, 4-chlorophenyl, 1-napthyl, 9-anthryl, 9-phenanthryl, and 3-pyridyl) were prepared in isolated yields ranging from 43 to 99%. Overall, this chemistry represents a vast improvement over the previous multi-step procedures for the synthesis of compounds of this type.

Rapid nitrosamine formation from a tertiary amine: The nitrosation of 2-(N,N-Dimethylaminomethyl)pyrrole

Abstract 2-(N,N-Dimethylaminomethyl)pyrrole reacts instantaneously with nitrous acid at 25° to produce diemthylnitrosamine, maleimidemonooxine, formaldehyde and other products. The data implicate new mechanisms of tertiary amine nitrosation.

The nitrosation of imidazolines and oxazolines

Abstract Nitrosation ( HOAc NaNO 2 ) of 1-methyl-2-phenyl-2-imidazoline 8 results in cleavage of only the CN single bond and production of N-(2-methylnitrosaminoethyl)-N-nitrosobenzamide 10. In contrast, 2-phenyl-2-oxazoline 9 nitrosates very rapidly to give products (13–16) derived from a diazonium ion arsing from the exclusive cleavage of the CN.

The synthesis of highly reactive, multi-functional α,β-epoxy- and α-acetoxy-nitrosamines

Abstract The synthesis of the reactive acetates, trans -3-acetoxy-2-hydroxy- N -nitrosomorpholine 3 and N -(1-acetoxy-2-hydroxyethyl)- N -nitrosoethanolamine 12, of two α-hydroxynitrosamines has been accomplished through the ring opening of the corresponding epoxides, NEMOR and 10 which were prepared by dimethyldioxirane oxidation of the vinyl nitrosamines.

Studies towards the synthesis of medermycin via Dötz benzannulation.

The C-arylglycosides are available in enantiomerically pure form via the Dötz benzannulation reaction between Fischer alkenyl chromium carbene complexes and alkynes; it also could be converted to a precursor of medermycin by O-carbamate directed ipso bromination and nitrile substitution in good overall yields.