Aldehyde compounds

The rather labile Schiff base interaction can be chemically stabilized by reduction. The addition of sodium borohydride or sodium cyanoborohydride to a reaction medium containing an aldehyde compound and an amine-containing molecule will result in reduction of the Schiff... 

H Hydrazide Compound H Aldehyde Compound H Hydrazone Linkage ... 

By Far the simplest bifunctional crosslinking agent is formaldehyde. Although structurally a mono-functional aldehyde compound, formaldehyde reacts with proteins via a two-step reaction... 

The reaction of these aldehydes, derived from periodate oxidation, with carbonyl reagents has also been investigated. Studies 147 148 were made on oxidized laminarin, a (1 —> 3)-linked polysaccharide, in which only the terminal residues had been oxidized. The addition of phenylhydrazine acetate detached the remainder of the terminal residue as glyoxal phenyl-osazone. When the aldehydic compounds derived from the periodate oxidation of raffinose and trehalose818a were reacted with p-nitrophenylhydrazine, the authors were surprised to find that one molecule of oxidized raffinose, containing six aldehydic functions, reacts with only three molecules of the reagent, and that the four aldehydic functions of the oxidized trehalose molecule react with only two. The reactions of periodate-oxidized carbo-... 

Figure 3 Luciferase-catalyzed bioluminescent reaction with (A) luciferin and (B) an aldehyde compound and FMNH2.

Fig. 2.9.15. APCI-FIA-MS-MSMS-MS(+) (CID) product ion mass spectrum of selected [M + NH4]+ parent ion (m/z 266) compound was identified as metabolite (aldehyde compound) of degradation product of non-ionic surfactant compound PPG (general formula H0-(CH(CH3)-CH2-0)x-CH(CH3)-CH0 ( = 3) fragmentation behaviour under CID presented in the inset [22].

To circumvent this problem, several methods have been developed (157). Probably, the most prominent method is treatment with sodium boro-hydride (0.1% in PBS, 30 minutes prior to staining). NaBILi is known to neutralize Schiff s bases through reduction of amine-aldehyde compounds into nonfluorescent salts. 

Saeo, M.K., Abdulmalik, O., Danso-Danquah, R., Burnett, J.C., Nokuri, S., Joshi, G.S., Musayev, F.N., Asakura, T., and Abraham, D.J. Structural basis for the potent antisickling effect of a novel class of five-membered heterocyclic aldehydic compounds./. Med. Chem., 2004. 

Ibert arc alntiml endless vtmeliev of aldehyde compounds that can be produced Muuv of them arc products used in specialty applications or us jmcmicdutcs m the production of other compounds This chapter presents the physical properties of lour typical compounds that have achieved cominci-cud importance... 

Various hyposulphite compounds are used for industrial purposes including stable aldehyde compounds. Of these the formaldehyde compound (Formosul) is tie most important, since it is the reducing agent almost universally employed in applying vat dyes by printing methods to textile materials. The less stable sodium hydrosulphite is used in dyeing with vat dyes. Stable zinc compounds (Rongalite) are also on the market. 

Amino groups on proteins may be reacted with the bis-aldehyde compound glutaraldehyde to form activated derivatives able to cross-link with other proteins. The reaction mechanism for this modification proceeds by one of several possible routes. In the first option, one of the aldehyde ends can form a Schiff base linkage with e-amines... 

The preparation of (83) (Expt 8.29) is an example of the Hantzsch pyridine synthesis. This is a widely used general procedure since considerable structural variation in the aldehydic compound (aliphatic or aromatic) and in the 1,3-dicarbonyl component (fi-keto ester or /J-diketone) is possible, leading to the synthesis of a great range of pyridine derivatives. The precise mechanistic sequence of ring formation may depend on the reaction conditions employed. Thus if, as implied in the retrosynthetic analysis above, ethyl acetoacetate and the aldehyde are first allowed to react in the presence of a base catalyst (as in Expt 8.29), a bis-keto ester [e.g. (88)] is formed by successive Knoevenagel and Michael reactions (Section 5.11.6, p. 681). Cyclisation of this 1,5-dione with ammonia then gives the dihydropyridine derivative. Under different reaction conditions condensation between an aminocrotonic ester and an alkylidene acetoacetate may be involved. 

When a twofold molar excess of an aldehyde, ketone, ketonitrile, or vinyl acetate (the latter provides formaldehyde oxide +CH2-0-0 ) is co-ozonolyzed with various cycloalkene derivatives, three main products are obtained (1) an ozonide 83 with an aldehydic group tethered via an -carbon chain (2) a bicyclic tetraoxepane compound 84 formed from the above dipolar chain and the added carbonyl derivative and (3) a diozonide 85 resulted from the formaldehyde oxide and the aldehydic compound 83. Structures and yields of these products are presented in Scheme 25 and Table 9. 

Figure 1 illustrates the fact that resins and adhesives formed by the possible combinations of a phenolic compound, a nitrogenous compound, an aldehyde compound, and a carbohydrate have been reported in the literature. The exact conditions used to formulate the resins and adhesives represented in Figure 1 vary considerably. For example, additional circles representing acidic, basic, and neutral reaction conditions could be added. In most instances, the exact chemistry that occurs during the formulation of resins at each intersection is not known. Indeed, in many cases, the component actually reacting into the resin or adhesive system may not be the original carbohydrate added at the start. In this and other respects, these formulations will overlap with those discussed in the next section. 

Highly diastereoselective acetate aldol additions using chlorotitanium enolates of mesityl-substituted JV-acetylthiazolidinethione 136 has been documented <07OL149>. These aldol reactions proceed in high yields and diastereoselectivities (94/6 to 98/2) for aliphatic, aromatic, and a,P-unsaturated aldehydes. Compound 136 also undergoes double diastereoselective aldol additions with chiral aldehyde 139 to give adduct 140 in high yields. 

Amine Compound Aldehyde Compound Schiff Base Secondary Amine Bond... 

Scheme 4 Synthesis of hydrazone linkages from hydrazide and aldehyde compounds...

To prepare dynamic cyanohydrin systems under mild conditions, a range of aldehyde compounds and cyanide sources was evaluated. As a result, benzaldehydes 23A-E were selected due to their diverse substitution patterns and their inability to generate any side reactions. Even though there are many cyanide sources, acetone cyanohydrin 24 was chosen as cyanide source in presence of triethylamine base, resulting in smooth cyanide release. Dynamic cyanohydrin systems (CDS-3) were thus generated from one equivalent of each benzaldehyde 23A-E and acetone cyanohydrin 24 in chloroform- at room temperature (Scheme 10). One equivalent of triethylamine was added to accelerate the reversible cyanohydrin reactions and this amount was satisfactory to force the dynamic system to reach equilibrium even at low temperature. 

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