Acetals nitro- startg

A soln. of the crude startg. m. in pyridine containing acetic anhydride kept 0.5 hr. at room temp. -> 3-0-acetyl-5,6-dideoxy-l,2-0-isopropylidene-6-nitro-a-D- y/o-hex-5-enofuranose. Y 80%. W. A. Szarek, D. G. Lance, and R. L. Beach, Carbo-hyd. Res. 13, 75 (1970). 

Almost 2 equivalents H2O2 and coned. HCl added at 5-10° to a soln. of the startg. m. in acetic acid, and kept overnight at the same temp. -> methyl 6-chloro-ll-nitro-7-oxo-O-methylpodocarpate. Y 80%. F. e. s. B. Kumar and S. Kalra, J. Indian Chem. Soc. 50, 613 (1973) with metal halides in place of HCl, a-balogeno-carbonyl compds., cf. N. Inukai et al., Chem. Pharm. Bull. 24, 820 (1976). 

Benzoxylamine and powdered anhydrous Na-acetate added to a soln. of 2-amino-4-chloro-5-nitro-6-methylpyrimidine in ethanol, and refluxed 1 hr. 2-amino-4-benzoxylamino-5-nitro-6-methylpyrimidine (startg. m. f. 20). Y 78%. E. G. Taylor and J. W. Barton, J. Org. Ghem. 24, 127 (1959). 

O-Acetylation. 1-Nitro-l-deoxy-N-acetyl-D-mannosaminol (prepn. s. 396) dissolved at 5° in 2 iV NaOH, added dropwise with shaking and cooling at 5-15° to aq. H2SO4, neutralized with warm Ba-hydroxide soln., filtered, 2 drops of acetic acid added, coned, under reduced pressure, and the crude product kept 3 days at 0° with acetic anhydride and pyridine 2-acetamido-2-deoxy-l,3,4,6-tetra-O-acetyl- -D-mannose (startg. m. f. 7). Y 84%. A. N. O Neill, Can. J. Chem. 37, 1747 (1959) Nef reaction and N-deacetylation with HCl s. J. C. Sowden and M. L. Oftedahl, Am. Soc. 82, 2303 (1960). 

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