Roman Davis

Selective Alkylations of Certain Phenolic and Enolic Functions with Lithium Carbonate/Alkyl Halide

Abstract Phenolic groups with pKa ≤ 8 (due to the presence of electron withdrawing groups in the orho- or para- position) can be alkylated selectively with Li2CO3/alkyl halide/DMF; less acidic phenolic groups are unreactive. Even though chelated phenolic/enolic functions have unexpectedly high experimental pKa′s (∼10), they can be alkylated with this reagent combination.

Selective Phenol Alkylation: An Improved Preparation of Efaproxiral

Abstract An improved, two‐step synthesis of efaproxiral, used in breast cancer therapy, is described, utilizing inexpensive commodity chemicals for starting materials. Selective amide formation and O‐alkylation in the presence of multireactive functional groups is demonstrated, thus avoiding protection/deprotection steps.

Novel product ions of 2‐aminoanilide and benzimidazole Ag(I) complexes using electrospray ionization with multi‐stage tandem mass spectrometry

RATIONALE The 2-aminoaniline scaffold is of significant value to the pharmaceutical industry and is embedded in a number of pharmacophores including 2-aminoanilides and benzimidazoles. A novel application of coordination ion spray mass spectrometry (CIS-MS) for interrogating the silver ion (Ag(+)) complexes of a homologous series of these compounds using multi-stage tandem mass spectrometry is described. Unlike the ubiquitous alkali metal ion complexes, Ag(+) complexes of 2-aminoanilides and benzimidazoles were found to yield [M - H](+) ions in significant abundance via gas-phase elimination of the metal hydride (AgH) resulting in unique product ion cascades. METHODS Sample introduction was by liquid chromatography with mass spectrometry analysis performed on a hybrid linear ion trap/orbitrap instrument capable of high-resolution measurements. RESULTS Rigorous structural characterization by multi-stage tandem mass spectrometry using [M +  H](+), [M - H](-) and [M - H](+) precursor ions derived from ESI and CIS experiments was performed for the homologous series of 2-aminoanilide and benzimidazole compounds. A full tabular comparison of structural information resulting from these product ion cascades was produced. CONCLUSIONS Multi-stage tandem mass spectrometry of [M - H](+) ions resulting from Ag(+) complexes of 2-aminoanilides and benzimidazoles in CIS-MS experiments produced unique product ion cascades that exhibited complementary structural information to that obtained from tandem mass spectrometry of [M  +  H](+) and [M - H](-) ions by electrospray ionization (ESI). These observations may be broadly applicable to other compounds that are observed to form Ag(+) complexes and eliminate AgH.

General Synthesis of 1‐Substituted 2‐Methylbenzimidazoles from Ketones and 2‐Aminoacetanilide

Abstract A novel method for preparation of 1‐substituted benzimidazoles via reductive amination of ketones with N‐differentiated 1,2‐diaminobenzenes is described. The method appears to be general in application to acyclic and cyclic ketones, as well as heteroatom‐substituted cyclic ketones.

Decomposition of peracids and their salts with activated carbon

Activated carbon-mediated reductive decomposition of several commonly used peracids, peracid salts, and alkyl hydroperoxides was investigated, and oxygen release was measured. Environmentally unfriendly reagents such as dimethyl sulfide, trimethyl phosphite, and triphenyl phosphine were ineffective in reducing the peracid salts. However, the environmentally friendly and waste-minimizing activated carbon proved an effective, simple, and safe method for the decomposition of peracids, peracid salts, and alkyl hydroperoxides.