Hydrazide anion

The ionic hydrazides are extremely sensitive and explode on contact with ak or upon heating. The alkaline-earth hydrazides, which have the general formula M(N2H2), appear to be less sensitive (15). Hydrazides such as aluminum hydrazide [25546-96-7] Al(N2H2)3, have also been made (16). The hydrazide anion is more nucleophilic than hydrazine and undergoes reactions not possible using hydrazine itself (17). Thus, styrene in ethyl ether solution at 0°C is... 

Fig. 1.47. Myers synthesis of atkanes from aldehydes via the sulfonylated hydrazones B and their silyl derivatives C. This procedure provides a skeletongenerating three-step synthesis of alkanes from aldehydes. In terms of Figure 1.2, the chain reaction F —> I involved is a "substitution reaction by fragmentation." (The sulfonylated hydrazide anion, which here results from the addition of R3-Li to the sulfonyl hydrazone C, does—at this reaction s temperature of-78 °C—not release toluene sulfinate. Compare the different behavior of the sulfonylated hydrazide anion C in the reaction of Figure 17.69, where a mesitylene sulfinate residue is eliminated at a temperature that is higher by 160 °C).

Tosylhydrazones can be reduced to the corresponding alkanes under milder conditions compared to the reduction of carbonyl compounds by the Wolff-Kishner method. This is illustrated in Figure 14.60 by the reduction of the aldhydrazone A (for a possible preparation, see Table 7.2) to the alkane C. The reduction is carried out with NaBH4 in MeOH.The effective reducing agent, formed in situ, is NaBH(OMe)3. This reductant delivers a hydride ion for addition to the C=N double bond of the tosyl-hydrazone A. Thereby the hydrazide anion B is formed. Much as in the second step... 

Because the alkyllithium compound used as catalyst is consumed within the time of mixing, the actual catalyst for most of the reaction is hydrazide anion. Letting one isomer by AH and the other BH, the reaction sequence can be summarized as in Eq. (9). The equilibration... 

A small number of mixed anion complexes containing lithiated hydrazides have also been identified. 

In DMS0/tert.Bu0K/02 quantum yields found were 3 x I0 4 for 50 and 5 X 104 for 49. These values are not regarded as maximum values, as a strong influence of the reaction conditions was noted 104). Whereas, in luminol-type compounds, any substitution in the cyclic hydrazide ring system renders the compound non-chemiluminescent 105>, this is not the case with these open-chain hydrazides the methylated compounds 49, 50 (R=N(CH3)NH2) and 50 (R=N(CH3)NH(CH3)) were also found to be chemiluminescent, though less so than the unsubstituted hydrazide. E. H. White and coworkers 104> therefore suggest a mechanism via acyl anions for the non-cyclic hydrazides (see Section VI. C.). 

Dialkylamino phthalic acids resulting from the chemiluminescence reaction of 4-dialkylamino-phthalic hydrazides cannot easily form a tris anion because deprotonation of the amino group is impossible. They should therefore not exhibit such a strong decrease in fluorescence efficiency at higher pH values. This can actually be concluded from the pH dependence of the chemiluminescence of the 4-dialkylamino-phthalic hydrazides and related compounds 97>. 

The question is whether diazaquinones are in fact in the main stream 2> of cyclic diacyl hydrazide chemiluminescence or whether they are only one of the possible intermediates or, finally, whether diazaquinone chemiluminescence is a special type of chemiluminescence reaction although very closely related to the chemiluminescence of the corresponding hydrazides. E. H. White and D. F. Roswell 2> point out that the respective diazaquinone may actually be one of the possible intermediates formed either from the hydrazide dianion (essential in aprotic solvents) or from a hydrazide radical anion (which is the usual species in aqueous media). This is outlined in the following scheme ... 

The importance of radical ions and electron-transfer reactions has been pointed out in the preceding sections (see also p. 128). Thus, in linear hydrazide chemiluminescence (p. 103) or acridine aldehyde or ketone chemiluminescence, the excitation steps consist in an electron transfer from a donor of appropriate reduction potential to an acceptor in such a way that the electron first occupies the lowest antibonding orbital, as in the reaction of 9-anthranoyl peroxide 96 with naphthalene radical anion 97 142> ... 

Nucleophilic attack at substituted ring carbon is probably the most common reaction of 1,3,4-oxadiazoles. However, few examples have been reported of nucleophilic attack at unsubstituted carbon since such compounds (19a) are relatively uncommon. The mechanism of the well-known conversion of 2-amino-oxadiazoles (in aqueous alkali) into triazoles has been studied in the case of the reaction where (19a R = NHPh) is converted to (20). This proceeds via the anion of semi-carbazide PhNHCONHNHCHO and is initiated by hydroxide attack at C-5 <84JCS(P2)537>. A similar nucleophilic attack by hydroxide on oxadiazole (19a R = 5-pyrazolyl) was followed by cyclization to the pyrazolo-triazine (21). Hydrolytic cleavage of 2-ary 1-1,3,4-oxadiazoles to aroyl-hydrazides allows use of the former as protected hydrazides. Oxadiazole (19a R = 4-... 

The magnitude of K value for this self-ionization is in the order of which is greater than that for anhydrous ammonia ionizing to ammonium (NR4+) and amide (NH2 ) ions (K 10-33). Anhydrous hydrazine thus forms salts with hahde and other anions of the composition N2H5 X which are acids. Similarly, metallic hydrazides, M N2H3, are bases in anhydrous hydrazine. Most hydrazine salts are unstable and are sensitive to heat and... 

Reaction of phthalic anhydride (70-1) with the ylide from ethyl triphenylphos-phoniumacetate leads to the condensation product (70-2), which in effect consists of a cyclic enol anhydride. Treatment of this product with hydrazine leads to the hydrazone-hydrazide (70-3). Alkylation of the anion from removal of the hydrazide proton with the substituted benzyl bromide (70-4) affords the alkylation product (70-5). Saponification then leads to the aldose reductase inhibitor ponalrestat (70-6) [79]. 

The reaction of alkyl isothiocyanates, RNCS, with diphenylphosphinic hydrazide (338) in benzene has been reported.308 The bis(diethylamino)[(methylthio)thiocarbon-yl]carbenium salts (339 X = I or BF4) display ambident reactivity and can react either at carbenium carbon (hard nucleophiles) or at the thiocarbonyl sulfur atom (soft nucleophiles).309 Electrochemically generated superoxide reacts with dithioic S,S -diesters (dicarbothiolates) (340 Ar = C5H3N or C6H4) to give the monocarboxylate anions in 100% yield before giving the dicarboxylate anions.310... 

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