3-Nitrobarbituric acid

Unless the product is dried before recrystallization it is difficult to remove all the nitric acid, and the final product will have a strong odor of nitric acid. 

If a clear yellow solution is not obtained, decolorizing carbon (Norit) should be added before filtering. 

This yield is slightly above the theoretical yield of 139 g., but this is probably due to a greater degree of hydration than is indicated in the formula. 

Nitrobarbituric acid has been prepared by oxidation of vio-luric acid,1 and by treatment of barbituric acid with fuming nitric acid.2 

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Nitrobarbituric acid. Place 72 ml. of fuming nitric acid, sp. gr. 1 52, in a 1-litre flask equipped with a mechanical stirrer and surrounded by an... 

There are many synthetic routes to alloxan. Probably the best is direct oxidation of barbituric acid (1004 R = H) with chromium trioxide (5208(32)6) but it may be made from barbituric acid via its benzylidene derivative by direct or indirect oxidation of uric acid from 5-chlorobarbituric acid (1004 R = C1) by nitration or from 5-nitrobarbituric acid (1004 R = N02) by chlorination, both via the intermediate (1005) (64M1057) or by permanganate oxidation of uracil (1006) under carefully controlled conditions (73BSF1167). 

Uramil (aminobarbituric acid) (III) may be prepared by the oxidation of barbituric acid (I) to nitrobarbituric acid (II), followed by reduction of the latter ... 

Methyl Benzoxazone 3,4-Methylenedioxy compounds (any) N-Methylmescaline N-Methyl Formamide Monoethanolamine 5-Nitrobarbituric Acid Nitroethane... 

The IR spectrum suggests that the compound exists partly in the enolic form, just like the anhydrous 5-nitrobarbituric acid 121). 

In a 5-I. flask are placed 100 g. (0.44 mole) of nitrobarbituric acid (p. 58) and 600 cc. of concentrated hydrochloric acid, and the mixture is heated on a boiling water bath. To the hot mixture are added 250 g. (2.1 moles) of mossy tin and about 400 cc. of hydrochloric acid over a period of about thirty minutes heating is continued until there is no yellow color in the liquid (Note 1). The solution is treated with about 3 1. more of concentrated hydrochloric acid, and heated until all the white solid is in solution. Decolorizing carbon (Norit) is added, and the hot mixture is filtered through a sintered-glass funnel (Note 2). The filtrate is allowed to stand in an ice box overnight, and then the precipitate (Note 3) of uramil is collected on a filter and washed with liberal quantities of dilute hydrochloric acid and finally with water (Note 4). The filtrate is concentrated under reduced pressure to about 1 1. and cooled overnight. The additional uramil thus obtained is collected on a Buchner funnel and added to the first product (Notes 5 and 6). The uramil is dried in a desiccator over concentrated sulfuric acid, and finally over... 

Nitrobarbituric acid forms a yellow aqueous solution, but as the color is weak in concentrated hydrochloric acid solution, no trace of it should show at the end of the reaction. 

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