PART I. A NEW TYPE OF SUBSTITUTION AT A SATURATED CARBON ATOM. PART II. A NEW METHOD FOR PROTECTING CARBOXYLIC ACIDS, PHENOLS, THIOPHENOLS, MERCAPTANS, AMINES, AND ALCOHOLS

ALLEN SCOTT, Purdue University

Abstract

Part I. Preliminary mechanistic experiments involving substitution reactions of the 9-anthrylmethyl system are described. The reaction of 9-anthrylmethyltrimethylammonium chloride with lithium 2-propanenitronate is found to be unaffected by the addition of oxygen, m-dinitrobenzene, di-t-butylnitroxide, or anthraquinone-2-sulfonic acid sodium salt. A brief survey of leaving groups and entering groups is discussed and the generality of the multi-stage substitution process is demonstrated. The rapidity of the reaction of 9-anthrylmethyl phenyl sulfide with the sodium salt of methyl mercaptan in HMPA suggests that the 9-anthrylmethyl group may find application as a protective group for a wide variety of functional groups. Part II. The 9-anthrylmethyl group is shown to be a satisfactory protecting group for six different functional groups. Carboxylic acids are effectively protected as 9-anthrylmethyl esters. Phenols, thiophenols, and mercaptans may be conveniently blocked as the 9-anthrylmethyl ethers or thioethers. Amines and alcohols are protected as the corresponding 9-anthrylmethyl carbamates or carbonates, respectively. The blocking group, is, in each case, selectively removed at low temperature with the sodium salt of methyl mercaptan in DMF. In contrast to the lability of this group in the presence of CH(,3)SNa the blocked compounds are found to be resistant to the action of various acids and bases. As a consequence of the ease of attachment, stability, and mild, selective removal the 9-anthrylmethyl protecting group should find broad application as a synthetic tool in many areas of organic synthesis.

Degree

Ph.D.

Subject Area

Organic chemistry

COinS