Adam Shih-Yuan Lee

A simple and highly efficient deprotecting method for methoxymethyl and methoxyethoxymethyl ethers and methoxyethoxymethyl esters

Abstract A series of methoxyethoxymethyl (MEM)- and methoxymethyl (MOM)-ethers and MEM-esters were hydrolyzed to their corresponding alcohols and carboxylic acids by a catalytic amount of CBr4 (10%) in iPrOH under refluxing reaction condition. The chemoselective hydrolysis between R3Si- and MEM-protected alcohols can be achieved by using different steric bulkness solvents such as MeOH or iPrOH.

A simple and highly efficient synthesis of β-amino-α, β-unsaturated ester via sonochemical Blaise reaction

Abstract β-Amino-α,β-unsaturated ester is produced by a sonochemical Blaise reaction of nitrile, zinc powder, zinc oxide and ethyl bromoacetate in THF in a commercial ultrasonic cleaning bath.

Determination of Binding Constant and Stoichiometry for Antibody-Antigen Interaction with Surface Plasmon Resonance

A surface plasmon resonance (SPR) biosensor technology has recently been applied biochemically and clinically to the study of immunologic recognition and the evaluation of binding parameters for various interactions between antibodies (Abs) and antigens (Ags) at liquid-solid interface. The simple interaction between hapten and Ab fragment, e.g., variable single-chain fragment and antigen- binding fragment, can be described sufficiently by a 1:1 stoichiometry in SPR. However, the determination of the binding constant of an anti-protein Ab is usually complicated by the multivalence of the protein Ag. The SPR-based method enables direct determination of binding constants for a variety of specific Ab-Ag interactions in real-time. It also allows estimation of the binding stoichiometry and binding ratio for low-, intermediate-, and high-affinity Ab-Ag interaction systems. The present review is designed to indicate the theo- retical background of SPR-based biosensor technology as well as to present the great variety of measurement modes of interaction kinet- ics that can be performed with these techniques. Quantitative aspects of the Ab-Ag interaction kinetics are reviewed, focusing especially on mono- and multi-valent Ab-Ag interaction modes using a SPR biosensor. Four model binding systems developed recently for use with SPR biosenser are described with principles and examples: (i) one to one interaction mode, (ii) nonequivalent two-site interaction mode, (iii) multiple equivalent-site interaction mode and (iv) multisite interaction mode. This article closes with two descriptions of the deter- minations of the binding stoichiometry and maximum binding ratio of Ab-Ag interactions.

A novel, highly efficient and selective desilylating method for trialkylsilyl ethers

Abstract A series of tert-butyldimethylsilyl, tert-butyldiphenylsilyl and triisopropylsilyl ethers are hydrolyzed to theirs corresponding alcohols in CBr 4 CH 3 OH ( 0.1 eq. 10mL ) reaction system under refluxing condition. The chemoselectivity can be achieved between primary and secondary triisopropylsilyl ethers when more hindered 2-propanol is used instead of methanol.

Synthesis of 3,4-disubstituted α-methylene-γ-lactones via sonochemical Barbier-type reaction

Abstract A series of 3,4-disubstituted α-methylene-γ-lactones were synthesized by the addition reaction of allylic bromide with aldehyde via sonochemical Barbier-type reaction condition and then followed by the in situ intramolecular esterification. The α-methylene-γ-lactone was produced as the sole product when THF/PhH solvent mixture was used whereas the allylation adduct was generated as the major product when solvent DMF was used.

A simple and highly chemoselective desilylation of tert-butyldimethylsilyl ethers

The use of a 0.25M CH3OH CCl4(1:1) solvent mixture under ultrasound for the selective deprotection of tert-butyldimethlysilyl ethers of benzyl alcohols is described. This method enables to deprotect tert-butyldimethlysilyl ethers of primary alcohols, whereas tert-butyldimethlysilyl ethers of secondary and tertiary alcohols were stable under the reaction condition.

A facile and highly efficient sonochemical synthesis of organostannane via Barbier reaction

Abstract Aryl-, alkenyl-, and alkylstannanes are produced by a sonochemical reaction of the corresponding bromides, magnesium powder, 1,2-dibromoethane and bis(tributyltin) oxide via Barbier reaction in a commercial ultrasonic cleaning bath (39 kHz).

An unprecedented and highly chemoselective esterification method

Abstract A series of carboxylic acids was transformed to their corresponding methyl esters under CBr 4 /CH 3 OH (0.05 eq., 5 ml) reaction conditions. The rate of esterification is decreased with increasing bulkiness of the alcohol. Chemoselectivity can be achieved between phenylacetic and benzoic acids, sp 3 -C and sp 2 -C acids as well as between sp 3 -C and sp -C tethered carboxylic acids.

A NOVEL AND SELECTIVE METHOD FOR HYDROLYSIS OF ACETALS AND KETALS

Abstract A series of cyclic and acyclic acetals and ketals were hydrolyzed to their corresponding carbonyl compounds by a catalytic amount of CBr4 (20%) in CH3CN/H2O solvent mixture under different energy sources, thermal or ultrasound. The highly chemoselective hydrolysis can be achieved under ultrasonic reaction condition.

Synthesis of allyl ketone via Lewis acid promoted Barbier-type reaction

A series of allyl ketones were synthesized from the mixture of zinc, nitrile and allyl bromide in the presence of AlCl3 via Barbier-type reaction condition. When crotyl bromide was used for the allylation, only the g-adduct was produced via the SE2% pathway under the reaction condition.