Malonaldehyde derivative

The theoretical yield of carbon dioxide was obtained in about 10 hours from lactose by oxidation with 0.06 M sodium metaperiodate in acetate buffer at pH 5.0 and 50°. On the other hand, the use of phosphate buffer at pH 5.0 led to extensive over-oxidation of the products, giving carbon dioxide far in excess of one mole per mole. The concentration of periodate in the reaction mixture has a profound effect on the rate of oxidation of malonaldehyde derivatives and, in <0.01 M periodate, the reactions are very slow. ... 

The results of the above procedure, when applied to the malonaldehyde derivatives [158], evidence some important peculiarities (Table 2). A good linear correlation between the ir-delocalization energy versus Ehb (Fig. 6b) is found only if the values deduced from full planarity imposition to the open form are... 

Table 2. Grabowski Tr-delocalization energies (kJ/mol) and resonance parameters for the O-H- O bridges of some malonaldehyde derivatives, calculated at B3LYP/6-31G level (reprinted from Ref. 158 with permission from Elsevier)...

Table 6. OH and NO2 rotation barriers (kJ/mol) in some malonaldehyde derivatives (B3LYP/6-311 ++G(d,p)), (Table 10 in Ref. 159, partially reprinted with permission from Elsevier)...

Scheme 4. Labeling of bonds and substituents in malonaldehyde derivatives.

Scheme 5. Closed and open conformation of malonaldehyde derivatives.

There are not many Vilsmeier reactions reported for alkynes. Ethoxyacetylene gives the malonaldehyde derivative 75 (Eq. 68)/" and arylalkynes give chlorocin-namaldehydes such as 76 (Eq. 69). The use of the unusual reagent Ph3P Br2 with... 

A -Acylureas or thioureas such as 167a react with elimination of the urea and formation of malonaldehyde derivatives, isolated as perchlorates (Eq. 138a). A-Acetylurea does not react. 

GrabowskP estimated the strength of 0-H... 0 intramolecular HBs via AIM operating on MP2/6-31H-+G wavefunetions of malonaldehyde derivatives. Correlations between the HB strength and topological parameters are discussed. 

The addition of phenylisocyanate to aldehyde-derived enamines resulted in the formation of aminobutyrolactams (438,439). As aminal derivatives these produets can be hydrolyzed to the linear aldehyde amides and thus furnish a route to derivatives of the synthetically valuable malonaldehyde-acid system. With this class of reactions, a second acylation on nitrogen becomes possible and the six-membered cyclization products have been reported (440). Closely related to the reactions of enamines with isocyanates is the condensation of cyclohexanone with urea in base (441). 

Penicilloic acid 5, the substrate for the projected lactamization reaction, could be derived from the suitably protected intermediate 6. Retrosynthetic disassembly of 6, in the manner illustrated, provides D-penicillamine hydrochloride (7) and tert-butyl phthalimido-malonaldehydate (8) as potential building blocks. In the synthetic direction, it is conceivable that the thiol and amino groupings in 7 could be induced to converge upon the electrophilic aldehyde carbonyl in 8 to give thiazolidine 6 after loss of a molecule of water. 

MALONALDEHYDE, NITRO-, SODIUM DERIVATIVE, 32, 95 Malonic acid, 31, 35 33, 20, 62 Malonic acid, ethylidene, diethyl ESTER, 32, 54... 

Substituted pyridinium salts of this nature were difficult to obtain by other methods. This sequence is initiated with condensation of the anions of imine 50 with malonaldehyde monoacetals 51 to access glutaconaldehyde monoacetals 52. The monoacetal-aldehyde was then reacted with primary amines ( -BuNH2) to give 3-substituted pyridinium salts 49. When the silylimino derivative (R1=Si(CH3)3) was used, substantially higher yields of intermediate glutaconaldehydes were obtained. 

The parent compound (i), (7), is very difficult to prepare by the standard method from malonaldehyde and ethylenediamine [68JCS(B)1536], although it is one of the most stable, but can be prepared readily from imines of malonaldehyde and ethylenediamine under nonaqueous conditions (73S791). This is apparently because, despite its thermodynamic stability, it is hydrolyzed readily in aqueous solution. (Thus chromatographic separations, successful with many dihydrodiazepines, can result in progressive loss of material.) In contrast, derivatives substituted at positions 5 and 7 are hydrolyzed only very slowly, if at all, nucleophilic attack at these positions being sterically inhibited by the substituents. 

The remaining [3 4-3] reaction proceeds directly to form derivatives of the quinolizinium cation (75CHE467). The perchlorate (212 Scheme 112) of 2-pyridylacetonitrile was allowed to react with malonaldehyde (as its diacetal), or with a /3-diketone (213) to give 1-cyanoquinolizinium derivatives (214). 

SODIUM NITROMALONALDEHYDE MONOHYDRATE (Malonaldehyde, nitro-, sodium derivative)... 

All four isomeric selenolopyridines which can be derived from benzoselenophene (423— 426 Scheme 123) have been described. Ethyl 3-hydroxyselenolo[2,3-fe]pyridine-2-carboxy-late (429) has been prepared as shown in Scheme 124 (73BSF704). Treatment of ethyl 2-chloropyridine-3-carboxylate with methaneselenol yields (427). Nucleophilic displacement of bromine in bromoacetic acid with subsequent loss of methyl bromide yields (428), which after esterification is cyclized under Dieckmann conditions to give (429). The parent compound (423 colorless oil with b.p. 92 °C/1 mmHg) is prepared either by cyclization of compound (430) and subsequent decarboxylation of the intermediate acid (equation 57) or by reduction of 2-nitroselenophene and subsequent condensation of the amino compound with malonaldehyde bis(diethyl acetal) in the presence of zinc chloride (equation 58) (76BSF883). Selenolo[3,2-6]pyridine (426 b.p. 127-129°C/10 mmHg m.p. 35.5-37.0°C) has been obtained in an analogous manner. 

Similarities in the spectrofluorometric and chemical behavior of the malonaldehyde and Maillard adducts and the constraints of the rather precise geometry of the available amine groups in microcrystalline polyamide are consistent with a possible carbohydrate-substituted amino-iminopropene derivative for the sugar-amine fluorophore. The malonaldehyde product with amino acids and amines has been demonstrated by others to have an amino-iminopropene moiety. 

Pyrimidine derivatives are frequently used as functional materials or are found in their partial structures. A great number of methods for construction of pyrimidine skeleton have been reported in which the majority is the condensation of a C - C - C unit (e.g., malonaldehyde, malononitrile, diethyl malonate) and an N-C-N unit (e.g., urea, guanidine) [46]. On the other hand, the general method involving a combination ofC-N-C, C-C and N units is not known to our best of knowledge. Thus, the present TCRT will be an alternative method for the preparation of 4,5-disubstituted pyrimidines, however, this reaction suffers from limited scope of ketones. When cyclohexanone is employed, tetrahydroquinazoline 26d is effectively formed... 

The cycloaddition of two equivalents of chlorsulfonyl isocyanate (297) with (arylmethyl-ene)malonaldehydes (296) affords the fused l,3-oxazin-2-one derivatives (298) which can be hydrolysed to the derivatives (299) (Scheme 44) <92T(48)455i>. 

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