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Studies Of The Cleavages And Stabilities Of Carbohydrate Epoxides And Epimines

Author

Curtis Alvin Johnson, University of the Pacific

Date of Award

1971

Document Type

Dissertation

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Chemistry

First Advisor

Emerson G. Cobb

First Committee Member

Paul Gross

Second Committee Member

Donald K. Wedegaertner

Third Committee Member

CM Roscoe

Fourth Committee Member

FW Sawyer

Fifth Committee Member

Herschul Juyl

Abstract

A novel epoxide ring opening of benzyl 3,4-anhydro-2-benzylox-carbonylamido-2-deoxy-β-D-allopyranoside(I) was affected by phenylboronic anhydride in toluene. One of the products was demonstrated to be benzyl 2-benzyloxycarbonylamido-2-deoxy-4,6-0-phenylboronate-β-D-gulopyranoside. Another product isolated, while not identified, had the properties of an anhydro-sugar different from the starting compound(I). Benzyl 6-0-acetyl-2-benzyloxycarbonylamido-2-deoxy-β-D-allopyranoside(II) also underwent epoxide ring opening in a reaction with phenylboronic acid. An isolated product had the properties of a benzyl 2-benzyloxycarbonyiamido-2-deoxy-D-hexoside different from compounds isolate in the reaction of I with the phenyboronate. This indicated the necessity for an unsubstituted 6-OH group in order for the boron compound to be involved in the ring opening. Supporting this view is the lack of reaction between the blocked benzyl 2,3-anhydro-4,6-0-benzylidene-α-D-allopyranoside and phenylboronic anhydride.

The 2,3-epoxide ring of benzyl 2,3-anhydro-4,6-0-benzylidene-α-D-allopyranodie(III) was shown to be remarkably stable in a reaction with boron acetate in nitromethane. The product had retained the 2,3-epoxide ring under conditions that removed the benzylidene group.

Trimethylsilyl azide was prepared in good yield in a mild and direct method. The azide was then used to prepare a new, low-melting, compound by dilation of the 6-OH group of I. The epoxide ring remained stable under these conditions

The epimine ring of benyl 4,6-0-benzylidene-2,3-dideoxy-2,3-epimino-α-D-allopyranodie(IV) was found to be unreactive with phenylboronate. However IV was deaminated with HNO₂ to give the 2,3-unsaturated to give benzyl 4,6-0-benzylidene-α-D-mannopyranoside. The purpose of this study was to test the reactivity of sugar epoxides toward novel, ring-opening reagents. The study is especially concerned with the opening of the epoxide ring of benzyl 3,4-anhydro-2-benzyloxycarbonylamido-2-deoxy-β-D-allopyranoside, which has been found to be quite stable.¹ These reagents were also used in a comparative study of the reactivity of epimino rings of sugars. Epimino rings react in a manner analogous to eposice rings. They have also been found to be quite stable in sugars.^2,15

Pages

103

Recommended Citation

Johnson, Curtis Alvin. (1971). Studies Of The Cleavages And Stabilities Of Carbohydrate Epoxides And Epimines. University of the Pacific, Dissertation. https://scholarlycommons.pacific.edu/uop_etds/2820