Benzyl -nitrobenzoate, preparation

Other syrupy, benzylated bromides bearing O-acetyl or O-p-nitro-benzoyl groups were also prepared and characterized,86-84 as well as a partially benzylated chloride.85 Acid hydrolysis of 22 gave crystalline 2-O-benzyl-a-L-fucose, which was acylated with p-nitrobenzoyl chloride-pyridine. Treatment84 of the resulting tris(p-nitrobenzoate) with hydrogen bromide-dichloromethane led to precipitation of p-nitrobenzoic acid and formation of syrupy 2-0-benzyl-3,4-di-0-(p-nitro-benzoyl)-a-L-fucopyranosyl bromide (33). 

Attempts to demethylate himbacine with a variety of reagents under several conditions were unsuccessful but dihydrohimbacine was readily converted by cyanogen bromide into the cyanamide (XXVI). This was stable to acid and only slowly hydrolyzed by alkali but catalytic hydrogenation afforded dihydrohimbeline in good yield. By standard methods the following iV-substituted derivatives were prepared ethyl, p-hydroxyethyl (p-nitrobenzoate and trimethylgallate), allyl, m-butyl, ethoxycarbonylmethyl, cyclohexyl, benzyl, /3-phenylethyl, y-phenyl-propyl, and phenylcarbamido. 

On account of the activity of benzyl alcohol, its derivatives which contain substituents in the ring are prepared indirectly. Thus, m-nitrobenzyl alcohol is not formed when benzyl alcohol is treated with nitric acid. It is prepared by the action of sodium hydroxide on m-nitrobenzoic aldehyde. 

The 2-, 3-, and 6-0-(2-hydroxyethyl) ethers of o-glucose have been obtained by way of treatment of appropriately protected derivatives (e.g. l,2 3,5-di-0-methylene-a-D-glucofuranose) with sodium and then with 2-bromoethanol. Allyl 3-0-benzyl-4,6-0-benzylidene-o -D-glucopyranoside has been used as the starting material in preparations of 2-0-allyl-3,4,6-tri-0-benzyl-D-gluco-pyranose and 2-0-allyl-3,4-di-0-benzyl-D-glucopyranose, the l-(4-nitrobenzoates) of which are potential intermediates for the synthesis of glycolipids that occur in the cytoplasmic membranes of Streptococci. Allyl ethers can be cleaved on... 

---