Hydrazones 3- 0-methyl

This set of ARl values illustrates that the simplest alkyl hydrazones (methyl, ethyl, dimethyl, etc.) have appropriate GC retention parameters and theoretically can be recommended as the derivatives of carbonyl compounds. But in real... 

Dissolve 0 3 ml. of glacial acetic acid in 2 ml. of water in a 25 ml. conical flask, and add 0 4 ml. (0 44 g.) of phenylhydrazine. Mix thoroughly to obtain a clear solution of phenylhydrazine acetate and then add 0 2 ml. (0 21 g.) of benzaldehyde. Cork the flask securely and shake the contents vigorously. A yellow crystalline mass of the hydrazone soon begins to separate. Allow to stand for 15 minutes, with occasional shaking, and then filter the solid product at the pump, wash first with very dilute acetic acid and then with water, and finally drain thoroughly. Recrystallise the material from rectified or methylated spirit, the benzaldehyde phenylhydrazone being thus obtained in fine colourless needles, m.p. 157 yield, 0 4 g. 

Dissolve 0-2 g. of fructose in 10 ml. of water, add 0-6 g. of cw-methyl-phenylhydrazine and sufficient rectified spirit to give a clear solution. Since the fructose may not be quite pure, warm the mixture slightly, allow to stand, preferably overnight, so that any insoluble hydrazones may separate if present, remove them by filtration. Add 4 ml. of 50 per cent, acetic acid to the filtrate it will become yellow in colour. Heat the solution on a water bath for 5-10 minutes, and allow to stand in the dark until crystalUsation is complete it may be necessary to scratch the walls of the vessel to induce crystalUsation. Filter the crystals and wash with water, followed by a little ether. RecrystaUise the orange-coloured methylphenylosazone from benzene m.p. 152°. 

Benzil monohydrazone. Method 1. Boil a mixture of 26 g. of hydrazine sulphate, 55 g. of crystallised sodium acetate and 125 ml. of water for 5 minutes, cool to about 50°, and add 115 ml. of methyl alcohol. Filter off the precipitated sodium sulphate and wash with a little alcohol. Dissolve 25 g. of benzil (Section IV,126) in 40 ml. of hot methyl alcohol and add the above hydrazine solution, heated to 60°. Most of the benzil hydrazone separates immediately, but reflux for 30 minutes in order to increase the yield. Allow to cool, filter the hydrazone and wash it with a httle ether to remove the yellow colour. The yield is 25 g., m.p. 149-151° (decomp.). 

When ethyl acetoacetate is warmed with an equivalent quantity of phenyl-hydrazine, the compound (I), which is not a true hydrazone, is first formed this undergoes ring formation (II) with loss of ethyl alcohol upon further heating. The product (II) is N or l-phenyl-3-methyl-5-pyrazolone. 

Noncatalytic Reactions Chemical kinetic methods are not as common for the quantitative analysis of analytes in noncatalytic reactions. Because they lack the enhancement of reaction rate obtained when using a catalyst, noncatalytic methods generally are not used for the determination of analytes at low concentrations. Noncatalytic methods for analyzing inorganic analytes are usually based on a com-plexation reaction. One example was outlined in Example 13.4, in which the concentration of aluminum in serum was determined by the initial rate of formation of its complex with 2-hydroxy-1-naphthaldehyde p-methoxybenzoyl-hydrazone. ° The greatest number of noncatalytic methods, however, are for the quantitative analysis of organic analytes. For example, the insecticide methyl parathion has been determined by measuring its rate of hydrolysis in alkaline solutions. 

On reaction with /V-methyl- /V-phenylhydrazine, however, the hydrazone (47) can be isolated, which on further treatment with anhydrous trifluoroacetic acid gives an A/-aLkenylpyrazole (48) (eq. 9). 

The synthesis of pyrazolines and pyrazoles of the [CCNN + C] type with the creation of two bonds, N(2)-C(3) + C(3)-C(4) (or N(l)-C(5) + C(5)-C(4)), has been studied by several groups. Beam and coworkers have published a series of papers on the synthetic utility of lithiated hydrazones. Thus, the methylhydrazone of acetophenone (598) is converted by butyllithium into the dianion (599), which in turn reacts with methyl benzoate to afford the pyrazole (600) (76SC5). In earlier publications Beam et al. have used aldehydes and acyl chlorides to obtain pyrazolines and pyrazoles by the same method. 

Clean examples of diaziridine to hydrazone rearrangements are rare. Diaziridine (119) mentioned above rearranges to the isomeric enhydrazone in boiling toluene, and 2,4-dinitrophenyldiaziridine (125) under the same conditions affords the 2,4-dinitrophenylhy-drazone (145) within 4 h. On blocking this rearrangement by iV-methyl, conversion with loss of cyclohexanone occurred to give benzotriazole iV-oxide (146) (72JOC2980). 

Benzothiazoline, N-methyl-2-methylene-structure, 6, 238 Benzothiazolines aromatization, 6, 270 oxidation, 6, 272 structure, 6, 238 synthesis, 6, 323, 325 Benzothiazoline-2-thione, 3-methyl-in organic synthesis, 6, 329 Benzothiazoline-2(3 f/)-thiones tautomerism, 6, 248 Benzothiazolin-2-one alkylation, 6, 286 Benzothiazolin-2-one, 3-methyl-hydrazone... 

Methylindole has been prepared from the a5-methylphenyl-hydrazone of pyruvic acid, by the action of sodium amide or sodium hydride on indole followed by methyl iodide at elevated temperatures,by treatment of indole with methyl p-toluene-sulfonatc and anhydrous sodium carbonate in boiling xylene, and by the action of inelhyl sulfate on indole previously treated... 

Dipping solution Dissolve 0.5 —1 g 3-methyl-2-benzothiazolinone-hydrazone hydrochloride (Besthorn s hydrazone) in 100 ml methanol — water(l + l),water[2,4 —8]ormethanol[3,11]. If precipitation occurs filter the solution before use. 

Hess and Eichel have shown that d-coniine with formaldehyde and formic acid yields an active A -methyl-d-coniine, and that methylZso-pelletierine hydrazone (see p. 57) yields ZV-methyl-dZ-coniine when heated with sodium ethoxide at 150-70°. 

Iodine fluoride is a more versatile reagent than molecular fluorine in geminal fluorination of other hydrazones and related compounds under milder reaction conditions [55] Substrates fluorinated include hydrazones of simple cyclic or steroidal ketones (e g, 4 tert butylcyclohexanone, 70%, 3 cholestanone, 70%), W methyl and A/N dimethylhydrazones [R2C=NNH(CH3) 70%, R2C=NNC(CH3)2, 50%], semicarbazones (R2C=NNHCONH2, 25-50%), and 2,4-dinitrophenylhy-drazones [R2C==NNH-C6H3-2,4(N02)2, 25-50%]... 

On reaction of methyl trifluoropyruvate with phosphorus pentachlonde 1,1,2,2 tetrachloro-3,3,3-trifluoro-l-methoxypropane IS obtained [273] Hexafluo-roacetone hydrazone is oxidized to bis(tnfluoromethyl)diazomethane upon tieat-ment with phosphorus pentachlonde [274]... 

MCPBA, DMF, —63°, 100% yield.Hydrazones of aldols are cleaved without elimination under these conditions. " An axial a-methyl group on a cyclohexanone does not epimerize under these conditions. ... 

Several thiadiazolo-triazoles 43 have been synthesized that show antifungal and cytotoxic properties. hiadiazoles 45 were prepared from hydrazones 44 by treating them neat with thionyl chloride at room temperatures. The thiadiazoles were formed regio-selectively on the methyl group of the hydrazone. 

The reduction of 2-methyl-1,2,3,4-tetrahydro-y-carboline (92) with zinc and hydrochloric acid in the presence of mercuric chloride gives the indolenine derivative, 2-methyl-l,2,3,4,4a,9b-hexahydro-y-carbo-line (93). A related compound, 4,9b-diethyl-2-methyl-l,2,3,4,4a,9b-hexahydro-y-carboline (96), was obtained by catalytic hydrogenation of 95, which was prepared by Fischer ring closure of the phenyl-hydrazone 94. The stereochemistry of the B/C ring junction in these... 

Katritzky and co-workers studied the mechanism of this reaction in detail. His work involved a NMR study of 16 reactions of methyl-, phenyl-, 1,2-dimethyl-, and l-methyl-2-phenylhydrazine with /3-keto esters. In many cases starting materials, intermediates, and products were detected simultaneously. Most reactions proceed by nucleophilic addition of the less hindered hydrazine nitrogen atom to the keto carbon of the keto ester. For example, the pathway given in Scheme 3 for the reaction of methyl 3-oxobutanoate 9 with methyl- or phenyUiydrazine 2 (R = Me or Ph) was found to be dominant. The initially formed addition product 10 dehydrates to hydrazone 11, which then isomerizes to hydrazone 12. Intermediate 12 then cyclizes to pyrazol-3-one 13, which tautomerizes to the kinetically more stable pyrazol-3-otie 14 [87JCS(P2)969]. 

Although the addition of hydrazine and its derivatives to acetylenic ketones has been studied in considerable detail, their interaction with hydrazones and mono-alkylhydrazones is less well known. Yandovskii and Klindukhova (74ZOR730) have studied the reaction between hydrazones and alkylhydrazones of aliphatic ketones with dipropynylketones and showed that hydrazones of acetone, methyl-ethylketone, and cyclohexane easily add to one of the triple bonds of dipropynylketone to form 4-methyl-1,1,3-trialkyl-2,3-diaza-l,4-nonadien-7-yn-6-ones (yields... 

The condensation of amidrazone with isonitrosoacetophenone occurs via formation of the hydrazone 136. The elimination of the ammonia molecule from intermediate 136 yields 3-methyl-6-phenyl-l,2,4-triazine 4-oxide 137 (71LA12). 

To prepare fervenulin 4-oxides 12 or toxoflavine 4-oxides 146, it is convenient to use the reaction of l,3-dimethyl-2,4-dioxopyrimidin-6-yl hydrazone 147 or N-(3-methyl-2,4-dioxopyiimidin-6-yl) iV-methylhydrazone 148 with potassium nitrate in acetic acid [75CPB1885,76CPB338,76JCS(CC)658,82JHC1309,93CPB362]. Diethyl azodicarboxylate can be used instead of potassium nitrate [76JCS(P1 )713]. 

A study of the photochemical reactions of some ylides of compound 1 showed the expected fragmentation to give, from compound 258 for example, 3-methyl-triazolopyridine and the products 259 and 260 postulated as derived from a carhene intermediate (00MI2). Ester 261 gives a hydrazone, and ylide 262 an indolizine. Thermal reactions of ylides are in Section IV. I. 

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