Harry W. Diehl

1,3,4,6-tetra-O-benzyl-d-fructofuranose and some of its derivatives

Abstract Crystalline 1,3,4,6-tetra- O -benzyl- d -fructofuranose ( 4 ) has been obtained in 60% overall yield from d -fructose through the following steps: d -fructose→methyl tetra- O -benzyl- d -fructofuranoside→ 4 . The new d -fructofuranose derivative has been further characterized through the preparation of a p -nitrobenzoate, a p -phenylazobenzoate and a benzoate — all crystalline derivatives. To confirm the structure of 4 , it was also made through the hydrolysis of octa- O -benzylsucrose and by the partial oxidation of 1,3,4,6-tetra- O -benzyl- d -mannitol ( 11 ); the preparation of 11 and of two crystalline derivatives therefrom is described.

2-Deoxy-d-ribose. I. A simplified preparation of 2-deoxy-d-ribose based on treatment of α-d-glucose monohydrate with solid calcium hydroxide

Abstract Heating α- d -glucose hydrate with an excess of solid calcium hydroxide under nitrogen at 115–120 ° for 1 hr. affords a mixture which, after removal of excess alkali, may be submitted to the Ruff degradation to give 2-deoxy- d -ribose as its anilide in a high state of purity in 8–9% yield. With these inexpensive materials and this simple procedure, relatively large quantities of 2-deoxy- d -ribose may easily be prepared using ordinary laboratory equipment.

De-O-benzylation of benzyl ethers of carbohydrate derivatives by thiols in the presence of boron trifluoride.

Abstract Based on experiments with 2,3,4,6-tetra- O -benzyl-α- D -glucopyranose ( 1 ), 1,3,4,6-tetra- O -benzyl- D -mannitol ( 9 ), and ethyl 3,5,6-tri- O -benzyl- D -glucofuranoside ( 7 ), a mixture of boron trifluoride etherate and ethanethiol or 1,2-ethanedithiol constitutes a practical reagent for the removal of O -benzyl groups from benzyl ethers of carbohydrates at room temperature. When 1,2-ethanedithiol was used, 1 and 7 afforded D -glucose ethylene dithioacetal [ 2 ; 2-( D - gluco -pentahydroxypentyl)-1,3-dithiolane], the benzyl groups appearing as benzyl sulfide ( 3 ) and tribenzylsulfonium tetrafluoroborate ( 4 ). With ethanethiol and boron trifluoride, 1 gave a mixture of the anomeric ethyl 1-thio- D -glucopyranosides ( 5 ) and dibenzylethylsulfonium tetrafluoroborate ( 6 ). The nonreducing compound 9 simply gave D -mannitol ( 10 ) under these conditions. A mechanism for this new debenzylation procedure is proposed.

The preparation and properties of some 2-acetamido-2-deoxyhexonic acids

Abstract The oxidation of 2-acetamido-2-deoxy- D -mannose (Scheme I, 1 ) with aqueous bromine in the presence of barium benzoate leads to the isolation of crystalline 2-acetamido-2-deoxy- D -mannonic acid ( 2 ). With aqueous dicyclohexylamine, 2 gives dicyclohexylammonium 2-acetamido-2-deoxy- D -mannonate ( 4 ), a crystalline salt readily distinguishable from its known D - gluco isomer ( 5 ). Both 2 and 4 are convertible into the known 2-acetamido-2-deoxy- D -mannono-1,4-lactone ( 3 ), showing that the configurations assigned to these structures are correct. As the salt ( 4 ) is stable in saturated aqueous dicyclohexylamine solution, the conversion of 3 into 5 by aqueous dicyclohexylamine, reported earlier, probably involves an inversion prior to opening of the lactone ring. The behavior of 3 with aqueous dicyclohexylamine has been reinvestigated and found to produce 4 as well as 5 . With anhydrous dicyclohexylamine, 3 slowly undergoes a β-elimination to give 6 . 2-Acetamido-2-deoxy- D -gluconic acid (Scheme II, 8 ) can be prepared through the bromine—barium benzoate oxidation of 2-acetamido-2-deoxy- D -glucose, ( 7 ) but the yield is higher when bromine—cadmium carbonate is used. The acid ( 8 ) may also be made from 5 through its silver salt. The conversion of the lactone 10 into 3 through the action of anhydrous dicyclohexylamine, reported earlier, has been confirmed; the available evidence appears to indicate that 3 and the as yet uncharacterized lactone 10 are readily interconvertible under alkaline conditions. The preparation of a crystalline hydrate of 2-acetamido-2-deoxy- D -galactonic acid ( 11 ) from the corresponding dicyclohexylammonium salt is described. On dehydration in vacuo , 11 gives the known 2-acetamido-2-deoxy- D -galactono-1,4-lactone ( 12 ) in high yield.

Dicyclohexylammonium salts for the isolation and characterization of aldonic acids

Abstract Dicyclohexylammonium salts of aldonic acids may be prepared from aldonolactones, as well as from metal aldonates and the free acids. Although accompanied by decomposition, their melting points are usually sharp, and these salts appear to have some potential utility for the isolation and characterization of aldonic acids. Dicyclohexylammonium 2-acetamido-2-deoxy- d -gluconate (1) has recently been described; in the course of the present investigation, it was converted into 2-acetamido-2-deoxy- d -glucose (3) , confirming the configuration previously assigned to it. With aqueous dicyclohexylamine, 2-acetamido-2-deoxy- d -mannono-1,4-lactone (2 ) gives 1 . The configuration of 2 was reconfirmed through reduction to 2-acetamido-2-deoxy- d -mannitol (4) , and the optical rotations of this compound and its d - gluco isomer in acidified ammonium molybdate solution were found to be useful physical constants for distinguishing these alditols. 2-Acetamido-2-deoxy- d -galactono-1,4-lactone affords a crystalline dicyclohexylammonium salt of the corresponding acid, from which the lactone may be regenerated.