Acetolysis reagents

The synthesis of HMX from the nitrolysis of hexamine with conventional reagents is far more problematic. However, HMX (25) is synthesized in high yield from the nitrolysis of l,3,5,7-tetraacetyl-l,3,5,7-tetraazacyclooctane (TAT) (23) and l,5-diacetyl-3,7-dinitro-1,3,5,7-tetraazacyclooctane (DADN) (24) with dinitrogen pentoxide in nitric acid. DADN (24) is readily synthesized from the acetolysis of hexamine followed by mild nitration with mixed acid. The synthesis of HMX (25) via the nitrolysis of DADN (24) is now a pilot plant... 

Various techniques have been utilized for sequencing the glycosyl residues of polysaccharides and oligosaccharides. These techniques are elaborations of the commonplace procedure of converting polysaccharides, by partial hydrolysis, into structurally analyzable oligosaccharides. This conversion is generally achieved by partial hydrolysis with acid, by acetolysis,131 or by formolysis.62 These reagents may differ in the... 

The method most likely to provide information concerning the nature of the reaction intermediates is that of detailed, kinetic analysis under a variety of carefully controlled conditions. It is evident that, in the application of this method, there is an extensive field of investigation to be surveyed, not only of the action of acyl trifiuoroacetates on hydroxylic compounds under the influence of different media and catalysts, but also of the peculiar differences between the ring-opening reactions of cyclic acetals with this type of reagent and with that which is employed in the Hudson acetolysis procedure. 

The reactivity of 120 is much less than that of either a normal alkene or a dithioacetal. Attempts to hydrogenolyze (see Section IV,3) or reduce 120 with Raney nickel, to hydrolyze the dithioacetal (see Section IV,1) with mercury(II) chloride (even in the presence of an overwhelming excess of the reagent), and to ozonize the double bond at —78°, produce only the starting material an analytical sample was prepared by extended treatment of the crude product with a concentrated, aqueous, alkaline solution of potassium permanganate at the reflux temperature.20 Acetolysis, ozonolysis, or brominolysis of 120 at room temperature affords diphenyl disulfide, and extended oxidation with hydrogen peroxide in acetone, with peroxypropionic acid, and with peroxyacetic acid, produces benzene-sulfonic acid, methyl phenyl sulfone, and an uncharacterized explosive, respectively the products occur as intractable mixtures, and the yields are invariably low. 

Conventional reduction of C-4 keto function with L-Selectride, followed with acetylation proceeds with high stereoselectivity forming only single epimer as detected by H NMR. Final deprotection by removal of 1,6-anhydro ring with tandem reagents trifluoroacetic acid/acetic anhydride via conventional acetolysis produced an anomeric mixture of crystalline heptaacetates in an a/(3 ratio of 1 3. This mixture was further deprotected with aqueous methanol with catalytic amount of triethylamine solution to form crystalline inseparable anomeric mixtures of (l-2)-5 -thio-3 -deoxydisaccharides. 

Much work was conducted by Hudson and his school on the acetolysis of methylene acetals of alditols. Their principal finding was that a methylene acetal that links primary and secondary positions is cleaved readily, and preferentially, at the primary position to give the primary acetate and the acetoxymethyl ether of the secondary hydroxyl group (Scheme 1). The reagent... 

Estradiol and estrone are metabolized to an array of oxidized products, one of which consists of the 16a-hydroxy derivative 30-4. One approach to preparing that compound starts by reaction of estrone with isopropyhdene acetate, to afford the acetate of the enolic form of the ketone and also the ester of the phenol at position 3 (30-1) (Scheme 3.30). Treatment of that product with perbenzoic acid leads to the a-oxirane 30-2, formed from approach of the reagent from the less hindered backside. Acetolysis of that intermediate gives 16a-acetoxyestrone (30-3). Reaction of that product with lithium aluminum hydride leads to reduction of the 17-carbonyl and also the phenolic ester to give the trans-Aio 16a-hydroxy- 17(3-estradiol (30-4). The same product is obtained on reducing 30-2 directly also with lithium aluminum hydride. 

In the first study on the decomposition of phenyl azide in the presence of electrophilic reagents it has been shown that both thermal and photochemical reactions lead to the azepinone (2) and to disubstituted arenes such as (4). The azepinone is thought to be formed by the addition of acetic acid to the didehydroazepine intermediate (1) and subsequent acetolysis, and the disubstituted arenes are formed from the nitrenium ion (3). 

After this general discussion of the nucleophilic substitution of norbornane derivatives, we will concentrate on the deamination of exo- and eAzrfo-2-norbornyl-amine. The acetolysis of norbornanediazonium ions was first studied by Corey et al. (1963) and by Berson and Remanick (1964). Their results could not be interpreted easily either by Winstein s or by Brown s hypothesis, as seen, for example, in Bartlett s annotated reprint collection (1965), in which he emphasized the need for fully resolved reagents and for better separation methods. 

Most reagents that readily open the epoxide ring are without effect on the much more stable hydrofuran anhydro ring. The latter may be opened, however, by acetolysis under vigorous conditions 90). Halogen acids or... 

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