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Allylic Displacement Reactions of a 2-Acetamido-D-glucal Derivative with Acids and Phenols

N. Pravdić ; Department of Organic Chemistry and Biochemistry, "Rud.er Boskovic« Institute, Zagreb, Yugoslavia
B. Židovec ; Department of Organic Chemistry and Biochemistry, "Rud.er Boskovic« Institute, Zagreb, Yugoslavia
H. G. Fletcher ; National Institute of Arthritis and Metabolic Diseases, National Institutes of Health, Public Health Service, U.S. Department of Health, Education and Welfare, Bethesda, Maryland 20014, U.S.A.

Sažetak

Fusion of 3,4,6-tri-O-acetyl-2-(N-acetylacetamido)-1,2-dideoxy-
o-arabino-hex-1-enopyranose [I, 2-(N-acetylacetamido)-o-glucal
triacetate] with various acids and phenols in the presence of. a
trace of p-toluenesulfonic acid causes loss of the acetoxy group at
C-3, shift of the double bond to the C-2-C-3 position, and entry
of an acyloxy or aryloxy group at C-1 to give esters and glycosides,
respectively, of 4,6-di-0-acetyl-2-(N-acetylacetamido)-2,3-dideoxy-
a-o-erythro-hex-2-enopyranose (compounds III, V, VI, and
VII). In each case, the main product is accompanied by 1,4,6-tri-O-
acetyl-2- (N-acetylacetamido) -2,3-dideoxy-a-o-erythro-hex-2-enopyranose
(IV), a substance which is found to be readily accessible
through the deliberate rearrangement of I under acidic conditions.
While IV reacts with benzoic acid when boiled in benzene solution
containing hydrogen chloride, I is recovered unchanged after treatment
in this fashion. On the basis of these facts, a mechanism for
the acid-catalyzed reaction of I with carboxylic acids and phenols
is proposed. An improved preparation of I from 2-acetamido-2-deoxy-omannose via 2-acetamido-1,3,4,6-tetra-O-acetyl-2-deoxy-a-o-mannopyranose (II) is described. Phenyl 4,6-di-0-acetyl-2-(N -acetylacetamido )-2,3-dideoxy-a-D- eryth ro-hex-2-enopyranoside (VI) may be reduced by catalytic hydrogenation to the corresponding cyclohexyl glycoside (VIII), the double bond remaining unaffected.

Ključne riječi

Hrčak ID:

197519

URI

https://hrcak.srce.hr/197519

Datum izdavanja:

10.2.1971.

Posjeta: 580 *