Acetone hydrazones

The hydrazone structure 40 can be eliminated at once many examples of this class of compounds are known and their properties are completely different from the diaziridines. For example, 3,3-dimethyldiaziridine has a heat of combustion of about 35 kcal higher than the isomeric acetone hydrazone. Further pairs of isomers of diaziridines and hydrazones are known. The spectrum eliminates both the hydrazone structure and the betaine structure 41. The diaziridines do not absorb in the UV range. In the infrared spectrum, absorption is completely absent in the double-bond region. - The NMR spectrum of 3,3-dimethyldiaziridine is in agreement with a formulation that has two equivalent iV-protons. ... 

The hydrazinium nicotinate group on these reagents commonly is protected against reaction with the active ester by the addition of acetone to form the acetone hydrazone derivative. This hydrazone protective group is readily reversible at neutral or mildly acidic pH and will immediately exchange with a benzaldehyde on the corresponding chemoselective partner to form a stable hydrazone linkage. 

Acetic anhydride, with 2-hep-tanone to give 3-n-butyl-2, 4-pentanedione, 51, 90 ACETIC FORMIC ANHYDRIDE, 50, 1 Acetone azine, 50, 2 ACETONE HYDRAZONE, 50, 2, 28 Acetophenone, 54, 93 as sensitizer for irradiation of bicyclo[2.2.1]hepta-2,5-diene to give quadricyclane,... 

B. Acetone, hydrazone. Anhydrous hydrazine is prepared by heating under reflux 100% hydrazine hydrate with an equal weight of sodium hydroxide pellets for 2 hours, followed by distillation in a slow stream of nitrogen introduced through a capillary leak. (Caution Distillation in air can lead to explosion.) The distillate boils at 114-116° and the yield is 95-97% (Note 6). 

The distillation gives a small forerun, b.p. 120-128°, containing hydrazine and acetone hydrazone. There is virtually no distillation residue. The submitters carried out the preparation of both acetone azine and acetone hydrazone on a fourfold scale with comparable results. 

The forerun contains hydrazine. Material boiling above 126° contains much acetone azine. With a slow rate of distillation, disproportionation occurs and the yield of acetone hydrazone is reduced. If the forerun and material boiling above 126° are combined and reheated at 100° for 12-16 hours, they give more acetone hydrazone on redistillation. With further repetitions of this procedure, the yield is almost quantitative. 

The procedure for acetone azine is essentially that of Curtius and Thun.5 The method for acetone hydrazone is adapted from that of Staudinger and Gaule.8 The hydrazone has been prepared directly from acetone and hydrazine, but this is much less satisfactory.6... 

Acetone hydrazone is produced in good yield by the method described, and inferior product is obtained without the precautions noted. The compound is used for the preparation of 2-diazopropane.8 lu... 

A stock solution of potassium hydroxide in ethanol was prepared and stored under nitrogen. Old stocks are brown and contain a dark sediment, but they are apparently just as effective as the freshly prepared reagent. Methanolic potassium hydroxide has also been used by the submitters this remains clear and colorless for long periods but offers no other advantage over the ethanolic solution. In absence of the basic solution, the acetone hydrazone is not oxidized by mercuric oxide. 

Examples of the oxidation of aliphatic hydrazones are the conversion of acetone hydrazone into 2-diazopropane [386, 392], of hexafluoroacetone hydrazone into 2-diazohexafluoropropane [445], of 4-octanone hydrazone into 4-diazooctane [386], and of the hydrazone of diethyl mesoxalate into diethyl diazomalonate [935] (equations 457 and 458). 

The formation of azine is not a means of trapping the hydrazine formed in the Raschig process with acetone, the reaction proceeding by way of two distinct intermediates dimethyl oxazirane and acetone hydrazone, as follows ... 

Diazopropane in EtjO [from acetone hydrazone (2 g) and yellow HgO (15 g) ] was added dropwise to a stirred ice-cooled solution of 3,3,5,5-tetramethyl-4,5-dihydro-3ff-pyrazole-4-thione (23, 1 g, 6.4mmol) - - ° in EtjO (25 mL) until a permanent pale-pink color was observed. The mixture was... 

A mixture of 112 g. (1.0 mole) of acetone azine and 32 g. (1.0 mole) of anhydrous hydrazine is placed in a 300-ml. round-bottomed flask fitted with a reflux air condenser and drying tube, and kept at 100° for 12-16 hours. Caution This reaction and the subsequent distillation should be carried out behind a protective screen.) The crude product is then rapidly distilled through a water-cooled condenser and the colorless fraction boiling at 122-126° collected, n D 1.4607 (Note 7). It weighs 111-127 g. (77-88%, Notes 7 and 8) and is essentially pure acetone hydrazone (Note 9). 

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