Carbohydrazide, oxidation

Recently ureas have been obtained by the oxidation of carbohydrazide (oxidative carbamylation) [78] with 4 moles of iodine in the presence of 10 moles of amine (or 2 moles of the amine and 8 moles of triethylamine) using dimethylacetamide as solvent (Eq. 55). (See Table IX.)... 

Ring synthesis via the transformation of 3-amino-277-pyran-2-ones (including fused derivatives) have been further investigated <2006H(70)235, 2006T9718>. 3-Amino-2//-pyran-2-ones could be transformed into the corresponding pyridazine-3-carboxylates via reaction with hydrazine followed by oxidation of the carbohydrazide moiety and 1,4-dihydropyridazine nucleus with CAN. 

Several methods have been introduced which express the degree of oxidation deterioration in terms of hydroperoxides per unit weight of fat. The modified Stamm method (Hamm et at 1965), the most sensitive of the peroxide determinations, is based on the reaction of oxidized fat and 1,5-diphenyl-carbohydrazide to yield a red color. The Lea method (American Oil Chemists Society 1971) depends on the liberation of iodine from potassium iodide, wherein the amount of iodine liberated by the hydroperoxides is used as the measure of the extent of oxidative deterioration. The colorimetric ferric thiocyanate procedure adapted to dairy products by Loftus Hills and Thiel (1946), with modifications by various workers (Pont 1955 Stine et at 1954), involves conversion of the ferrous ion to the ferric state in the presence of ammonium thiocyanate, presumably by the hydroperoxides present, to yield the red pigment ferric thiocyanate. Newstead and Headifen (1981), who reexamined this method, recommend that the extraction of the fat from whole milk powder be carried out in complete darkness to avoid elevated peroxide values. Hamm and Hammond (1967) have shown that the results of these three methods can be interrelated by the use of the proper correction factors. However, those methods based on the direct or indirect determination of hydroperoxides which do not consider previous dismutations of these primary reaction products are not necessarily indicative of the extent of the reaction, nor do they correlate well with the degree of off-flavors in the product (Kliman et at. 1962). 

Carbon tetrafluoride, 1 34 3 178 Carbon tetraiodide, 3 37 Carbonyl azide, formation of, by carbohydrazide, 4 35 Carbonyl fluoride, 6 155 Carbonyls, metal, 2 229 metal, nomenclature of, 2 264 structure of, 2 232 Catalysts, beryllium chloride, 5 25 boron fluoride, 1 23 chromium(III) oxide gel, 2 190... 

Pyridine and picoline addition compounds of chromium (VI) oxide, synthesis 33 Biurea, synthesis 8 Urazine, synthesis 9 Carbohydrazide, synthesis 10... 

Aminopyridine-4-carbohydrazide (5),55 as well as 3-aminopyridine-4-carboxamide 1-oxide, 420 can be cyclized thermally with triethyl orthoformate to give the corresponding pyri-do[3,4-r/]pyrimidinc, e.g. 6. 

Folsome, C. Brittain, A. Smith, A. Chang, S. Hydrazines and carbohydrazides produced from oxidized carbon in Earth s primitive environment. Nature 1981, 294, 64-65. 

Carbonic dihydrazide. See Carbohydrazide Carbonic ether. See Diethyl carbonate Carbonic oxide. See Carbon monoxide 4,4 -Carbonimidoylbis (N,N-dimethylbenzenamine monohydrochloride. 

The ferric thiocyanate method for peroxide value is based on the oxidation of ferrous to ferric ions, which are determined colorimetrically as ferric thiocyanate. This method is more sensitive and requires a smaller sample (about 0.1 g) than does the iodometric method (Table 5.3). However, the values obtained by the ferric thiocyanate method are higher by a factor of 1.5 to 2 relative to those of the iodometric method. The peroxide values obtained by both methods are of only relative significance. The ferric thiocyanate method is commonly applied to dairy products, which undergo oxidative deterioration at relatively low peroxide values. Other colorimetric methods for peroxide values include the determination of the blue starch-iodine complex in the iodometric method, the red color developed with 1,5-diphenyl-carbohydrazide, the color developed with ferric ions and xylenol orange, ferrous chloride and 2,6-dichlorophenolindophenol, titanium dichloride, and xylenol orange. 

Electrochemical oxidation of catechol in the presence of carbohydrazide in aqueous solution using carbon electrode resulted in benzimidazole derivatives by cyclic voltammetry and controlled-potential coulometry techniques [20] (Scheme 49). A direct electron transfer mechanism occurred during the process on the surface of carbon. The investigators proposed that the Michael adduct formed between the carbohydrazide and o-quinone (Eqn (2)) leads to the formation of l,3-diamino-5,6-dihydroxy-lH-benzo[d]imidazole-2(3H)-one 52. 

Apart from the above applications, hydrazine hydrate is also used in preparing organic derivatives, like hydrazones and hydrazides such as carbohydrazide (CH), oxalyl dihydrazide (ODH), malonic acid dihydra-zide (MDH), tetra formal tris azine (TFTA) and so on, from the corresponding ketones and aldehydes. Hydrazones have been investigated as solid fuels in hybrid rockets [40]. The hydrazides have been exploited as combustible fuels with metal nitrate oxidizers in the preparation of nanocrystalline oxide materials [41]. 

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