Brian E. Love

Isolation and synthesis of polyoxygenated dibenzofurans possessing biological activity

Reports from the past ten years describing the isolation and/or synthesis of bioactive dibenzofurans possessing three or more oxygen-containing substituents are reviewed. Dibenzofuranoquinones are included in the review.

FACILE SYNTHESIS OF BINOL IN THE ABSENCE OF SOLVENT

ABSTRACT A new synthesis of BINOL is reported, which proceeds by the oxidation of 2-naphthol by iron(III) chloride when the two reagents are co-adsorbed on alumina. The method allows easy isolation of the product in high yield and in a high state of purity and does not require the use of specialized catalysts or large volumes of high-boiling organic solvents. Some derivatives of BINOL can also be prepared by this method.

An Improved Synthesis of Camphorquinone-3-Oxime

Abstract Camphorquinone 3-oxime is prepared in 77% yield in one step from camphor. The synthesis avoids the use of toxic selenium reagents, and provides the syn compound as the major stereoisomer.

Oxidation of Alcohols by Bromine on Alumina

Abstract Bromine adsorbed on neutral alumina is an effective reagent for the oxidation of secondary alcohols to ketones.

SYNTHESIS OF CAMPHOR-BASED CHIRAL QUINOLINES

Abstract Several chiral quinolines are prepared by the cyclization of imines derived from camphor.

SYNTHESIS OF VINYL SULFONES FROM 1,3-DITHIOLANE TETRAOXIDES

Abstract Vinyl sulfones are prepared in high yield by the treatment of 1,3-dithiolane tetraoxides with a catalytic amount of N, N-diisopropylethylamine in ethanol.

Preparation of Re-Usable Glass-Supported Acid/Base Indicators

It is often necessary to determine whether a given aqueous solution is acidic or basic. Electronic devices (such as pH meters) as well as litmus paper or pH paper may be used to make such determinations. If contamination of the solution is not a concern, any of a number of acid/base indicators can be added to provide a readily observed signal as to when the solution has reached a specific pH range. Immobilization of acid/base indicators on organic polymers or glass has also been reported. Such immobilized indicators are especially attractive since they do not contaminate solutions as the free indicators do, yet are re-usable. However, they do not appear to enjoy widespread use, perhaps due to the sometimes lengthy synthetic operations required for their preparation. We sought to develop a rapid and efficient method to obtain a glass-bound indicator using inexpensive materials, and herein we report our progress toward that goal. Over 40 years ago, Harper reported functionalization of glass surfaces with (3-aminopropyl)triethoxysilane. Its amino group was either covalently bound to an acid/base indicator or converted into an acid/base indicator. We followed a similar approach by attaching phenolphthalein to an aminopropyl-functionalized glass surface through formation of a 2H-1,3-benzoxazine derivative, as shown in Figure 1.