Carlos A. González-González

Aluminium Chloride Hexahydrate (AlCl3 · 6H2O): An Efficient, Facile, Mild, And Highly Chemoselective Catalytic Deprotection of Tert-Butyldimethylsilyl (TBS) Ethers

Abstract tert-Butyldimethylsilyl (TBS) phenyl / alkyl ethers were cleaved to the corresponding efficiently parent hydroxyl compounds in good yields using catalytic amounts of AlCl3 · 6H2O by conventional or microwave-assisted heating in methanol or isopropanol solution. Intramolecular and competitive experiments demonstrated the chemoselective deprotection of TBS ethers in the presence of triisopropylsilyl and tert-butyldiphenylsilyl ethers. GRAPHICAL ABSTRACT

Synthesis of caffeine from theobromine: Bringing back an old experiment in a new setting

Caffeine is one of the most widely consumed, naturally occurring, mild, and central nervous system stimulants. Its synthesis, by the N-methylation (SN2 substitution) of theobromine is described as an experiment for the undergraduate organic chemistry laboratory. The N-methylation of theobromine is rapid and efficient and its progress is monitored by TLC using authentic standards. The undergraduate student also is able to observe the effect of temperature on the rate of the N-methylation reaction.

A Novel and Chemoselective Process of N-Alkylation of Aromatic Nitrogen Compounds Using Quaternary Ammonium Salts as Starting Material

The process of N-alkylation of several pyrroles, indoles, and derivative heterocycles is herein described, using quaternary ammonium salts as the source of an alkylating agent. These reactions were carried out on several heterocyclic rings with triethylbenzylammonium chloride or tetradecyltrimethylammonium bromide and an NaOH solution at 50%, leading to a chemoselective N-alkylated product and an average yield of 73%. This is an alternative process to the traditional benzylation and methylation of N-heterocycles with direct handling of alkyl halides.