Of carbohydrazide

The IR spectra of carbohydrazide 9 showed absorption bands at 3317 cm (OH,Hydrazide NH2), 3269 cm (aromatic CH), 1711 cm (CO stretching), and 1621-1640 cm (CO-NH-NH2 groups). The H NMR spectra exhibited a singlet due to the CONHNH2, NH proton at 9.32 ppm. Methylene protons resonated as a singlet at 4.23 ppm. The structures of the products lOa-1 were inferred from their analytical and spectral data. Thus, their IR spectra showed characteristic absorption bands at 3400-3240 cm (NH,OH), 1710-1700 cm (lactone CO), and NHCO at 1650-1600 cm . ... 

A protocol for the use of carbohydrazide in the modification of aldehyde or carboxylate functional groups can be found in Chapter 1, Section 4.5. 

Typically, the incorporation of carbohydrazide obtained with antibody A5B7 was about 0.5 molecules of carbohydrazide per F(ab )2 as determined by incorporation of 55Fe-labeled aldehyde 201 ESI-MS after reduction of disulfide bridges by dialysis in 10 mM DTT confirmed that the light chain was not modified by this procedure. On the other hand, the heavy-chain mass was 26 489 Da in the F(ab )2-carbohydrazide and only 26 416 in the F(ab )2. The 73 Da difference between the two heavy chains is in agreement with the 72 Da increment expected by the incorporation of one carbohydrazide group. 

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.)... 

C0(N,)3 was first prepd in 1894 by Curtius Heindenreich (Refs 1 2) by the action of sodium nitrite on the hydrochloride of carbohydrazide, C0(NH NH3HC1)3. Resting (Ref 3) found that this reaction did not always proceed homogenously and that hy-drazidicarboxyazide, (NHCON,), was always formed as a by product in ca 20% yield. The two compds could be separated by carrying out the diazotization under benz. Resting (Ref 3) obtd CO(N,)a in about 70% yield from CO(OEt)3 refluxed for 2 days on a w bath with 99% NaH4-Ha0... 

Oxovanadium(IV) complexes have also been prepared with the carbohydrazones and thiocarbohydrazones formed in the condensation of carbohydrazide or thiocarbohydrazide with benzaldehyde, o-nitrobenzaldehyde, anisaldehyde, cinnamaldehyde, acetophenone and 2-acetylpyridine.845 file values are 1.68-1.72 BM and v(V=0) is at 960-980 cm-1. The compounds, [V0(L)2(H20)j (147), were suggested to be of structure (12) (p. 487).845... 

Sol in benz and eth. Prepn is by diazotization of carbohydrazide chlorohydrate. The product explds on rapid heating above its mp Refs 1) Beil 16, 691 (404) 2) L. Wolff ... 

Many of the iV-alkyl and iV-aryl derivatives of urazine have been synthesized and characterized, but the parent substance is not well known. In the past, urazine has been prepared by thermal deammonation of carbohydrazide-iV-carboxamide [eq. (I)],1 fusion of hydrazidicarbamide with hydrazinium hydrogen sulfate [eq. (2)],2 fusion of earbohy-drazide with urea [eq. (3)],3 action of sodium hypobromite on semicarbazide [eq. (4)],4 reaction of dichlorourea with concentrated ammonia [eq. (5)],5 and the reaction between 1,2 hydrazine carboxylic ester and hydrazine hydrate... 

Preparation from Carbohydrazide. One hundred seventeen grams of carbohydrazide (1.3 mols) and 108 ml. of 12 M hydrochloric acid (1.3 mols) are" mixed in a 400-ml. beaker equipped with a mechanical stirrer and a 360° thermometer. The mixture is heated slowly on a hot plate with constant stirring. At first, there is vigorous effervescence, which may cause spattering, but this gradually subsides as evaporation continues. The temperature rises to about 215° and remains there for approximately an hour. Heating is stopped when the temperature rises above 220°. The over-all time of reaction is 4 hours. To the cooled melt, 125 ml. of water is added, and the mixture is heated to effect solution of soluble by-products (principally hydrazine hydrochloride). After the solution has cooled to room temperature, the urazine is filtered and washed with water, ethanol, and ether. The yield of dry product is 55 g. (73%)- The product melts with decomposition at 271 to 272°. 

Twenty-six and six-tenths grams of carbohydrazide-lV-carboxamide (0.2 mol) and 16.7 ml. of 12 M hydrochloric acid (0.2 mol) are heated together in a 200-ml. beaker until the temperature of the mixture rises to 210°. This usually requires between 60 and 90 minutes. The melt is then cooled and treated with 35 ml. of water. The suspension is heated briefly to effect complete solution and is then cooled to room temperature. The crystalline urazine is filtered and washed with water, ethanol, and ether. The product weighs about 11.5 g. (50% yield) and melts with decomposition at 270 to 272°. Purification is effected by recrystallization from 0.1 M hydrochloric acid, as described above. 

The pot liquor is cooled to 20° and allowed to stand for at least 1 hour. Crystals of carbohydrazide separate and are filtered and dried as completely as possible by suction. The crude product weighs approximately 165 g. (60% yield). 

Semicontinuous Procedure. The yield of carbohydrazide may be increased markedly by recycling the mother liquor with fresh reagents. 

The pH of a 1 % aqueous solution of carbohydrazide is in the neighborhood of 7.4.7 This solution is gradually decomposed when heated with acid or base. 

Ninety-nine grams of carbohydrazide (1.10 mols) is dissolved in a solution containing 120 g. of glacial acetic acid (2.00 mols) and 1000 ml. of water. To this, a solution of 81 g. of potassium cyanate (1.00 mol) in 350 ml. water is added dropwise over a period of about 2 hours. The mixture is digested at room temperature for 5 hours. The precipitate is then removed by filtration and washed very thoroughly with water, alcohol, and ether. The dry product weighs approximately 115 g. (86%) and melts with decomposition at 227 to 228°. 

Pellizzari and Roncagliolo2 prepared this compound by reaction of carbohydrazide in dilute acetic acid with 2 mols of potassium cyanate and also by condensation of carbohydrazide- A-carboxamide hydrochloride with 1 mol of cyanate. The former procedure does not give a pure product, probably because of the preferential formation of the less soluble carbohydrazide-A-carboxamide. The latter reacts wjth hydrochloric acid to form the hydrochloride, which is water-soluble. Prior condensation of carbohydrazide to form the A-carboxamide is advantageous, since the hydrochloride of this compound will undergo further reaction with cyanate to give the desired product by precipitation from water. When the procedure outlined below is followed, it is not necessary to recrystallize the carbohydrazide-A, A -dicarboxamide unless an extremely pure material is desired. 

Thirteen and three-tenths grams of carbohydrazide-A-carboxamide (0.10 mol) is dissolved in a solution of 9.2 ml. of 12 M hydrochloric acid (0.11 mol) in 100 ml. of water. The resulting solution is filtered, if necessary, and to it is added a solution of 8.9 g. of potassium cyanate (0.11 mol) dissolved in 100 ml. of water. After a short time, precipitation begins. The resulting suspension is digested at room temperature for 5 hours with constant stirring. The crystals are filtered and washed with water, alcohol, and ether. The yield of carbohydrazide-A,A -dicarboxamide thus obtained weighs about 15.0 g. (85 %). A small sample melts with decomposition at 225°, or at 232° when heated rapidly. 

Cyanate condensation products of carbohydrazide, synthesis 11 Thiosemicarbazide, synthesis 12 Dithiocarbamates of selenium(II) and tellurium (II), synthesis 32 Aluminum phosphide, synthesis 7 Phosphorus(III) fluoride, synthesis 49... 

The conversion of carbohydrazides to carboxamides in tetrahydrofuran with copper(II) chloride catalyst required only 1 mol equiv. of amine in the presence of DBU. However, if DBU was not present, 5 mol equiv. of amine was necessary (80T1311). 

The synthesis of carbohydrazides from the corresponding 1-acylimidazoles by Staab s method703,1166 proceeds under very mild conditions an equimolar mixture of carboxylic acid and l,Tcarbonyldiimidazole is heated in anhydrous tetrahydrofuran until evolution of carbon dioxide ceases and is then treated with the requisite hydrazine derivative. Hydrazine hydrate can be used to provide unsubstituted hydrazides since hydrazinolysis of the acylimidazole is faster than its hydrolysis.703,1166... 

Cyclization of carbohydrazide with carboxylic acids or ortho esters [90]. 

In situ preparation of carbohydrazide and cyclization with isobutyronitrile in the presence of a suitable tin compound as reaction auxiliary [93]. 

Silvestri et alP showed that the reduction of the nitro sulfone 49 with iron-acetic acid led to the formation of carbohydrazide 50 with extrusion of sulfone group. Further, 50 undergoes Smiles rearrangement affording an intermediate 51, which then cyclizes to give benzimidazole 52. 

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. 

If an anionic surfactant is heated anaerobically to 650 C, characteristic fragments are produced. In the case of LAS, the pyrolysis products are linear C2-C10 olefins and paraffins, benzene, toluene, and xylenes. For alcohol sulfates and ethoxysulfates, C5-C14 a-olefins are found, as well as the original alcohols. Paraffin sulfonates give primarily C5-C17 a-olefins (11). This approach can also be used for quantitative analysis, measuring either the hydrocarbon fragments or the SO2 evolved. Addition of carbohydrazide to the sample gives more complete yield of hydrocarbons (12). 

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