Malonic reduction

Extremely dry (or super-dry ) ethyl alcohol. The yields in several organic preparations e.g., malonic ester syntheses, reduction with sodium and ethyl alcohol, veronal synthesis) are considerably improved by the use of alcohol of 99-8 per cent, purity or higher. This very high grade ethyl alcohol may be prepared in several ways from commercial absolute alcohol or from the product of dehydration of rectified spirit with quicklime (see under 4). 

The carbopalladation is extended to homoallylic amines and sulfides[466. Treatment of 4-dimethylamino-l-butene (518) with diethyl malonate and Li2PdCl4 in THF at room temperature leads to the oily carbopalladated complex 519, hydrogenation of which affords diethyl 4-(dimethylamino) butylmalonate (520) in an overall yield of 91%. Similarly, isopropyl 3-butenyl sulfide (521) is carbopalladated with methyl cyclopentanonecarboxylate and Li2PdCl4. Reduction of the complex affords the alkylated keto ester 522 in 96% yield. Thus functionalization of alkenes is possible by this method. 

Based on the above-mentioned stereochemistry of the allylation reactions, nucleophiles have been classified into Nu (overall retention group) and Nu (overall inversion group) by the following experiments with the cyclic exo- and ent/n-acetales 12 and 13[25], No Pd-catalyzed reaction takes place with the exo-allylic acetate 12, because attack of Pd(0) from the rear side to form Tr-allyl-palladium is sterically difficult. On the other hand, smooth 7r-allylpalladium complex formation should take place with the endo-sWyWc acetate 13. The Nu -type nucleophiles must attack the 7r-allylic ligand from the endo side 14, namely tram to the exo-oriented Pd, but this is difficult. On the other hand, the attack of the Nu -type nucleophiles is directed to the Pd. and subsequent reductive elimination affords the exo products 15. Thus the allylation reaction of 13 takes place with the Nu nucleophiles (PhZnCl, formate, indenide anion) and no reaction with Nu nucleophiles (malonate. secondary amines, LiP(S)Ph2, cyclopentadienide anion). 

Reaction of (T)-(-)-2-acetoxysuccinyl chloride (78), prepared from (5)-mahc acid, using the magnesiobromide salt of monomethyl malonate afforded the dioxosuberate (79) which was cyclized with magnesium carbonate to a 4 1 mixture of cyclopentenone (80) and the 5-acetoxy isomer. Catalytic hydrogenation of (80) gave (81) having the thermodynamically favored aH-trans stereochemistry. Ketone reduction and hydrolysis produced the bicycHc lactone acid (82) which was converted to the Corey aldehyde equivalent (83). A number of other approaches have been described (108). 

Snyder and Smith prepared diethyl acetamidomalonate in 40% yield by reduction of diethyl isonitrosomalonate in ethanol over palladium on charcoal followed by direct acetylation of diethyl aminomalonate in the filtrate with acetic anhydride. Ghosh and Dutta used zinc dust instead of palladium. A modification using Raney nickel is described by Akabori et al. Shaw and Nolan reported a 98% yield by conversion of diethyl oximino-malonate-sodium acetate complex. 

Tabushi and Fujiyoshi have prepared alkylated cyclam derivatives for the purpose of suspending these systems from a polymer backbone. They have utilized a malonic ester alkylation reaction followed by cyclization and reduction to accomplish this end. ... 

Properties. — It is soluble m water and alcohol, but not in ether. On heating, it loses water and is converted into fumaiic and maleic acids (see p. 125). On o.xidation it gives malonic acid and on reduction succinic acid. 

The same methodology was also used starting from the ethyl 6-amino-7-chloro-l-ethyl-4-oxo-l,4-dihydroquinoline-3-carboxylate, prepared by reduction of the nitro derivative. The requisite nitro derivative was prepared by nitration of ethyl 7-chloro-l-ethyl-4-oxo-l,4-dihydroquinoline-3-carboxylate. A second isomer was prepared from 4-chloro-3-nitroaniline by reaction with diethyl ethoxymethylene-malonate, subsequent thermal cyclization, and further ethylation because of low solubility of the formed quinolone. After separation and reduction, the ethyl 7-amino-6-chloro-l-ethyl-4-oxo-l,4-dihydroquinoline-3-carboxylate 32 was obtained. The ort/io-chloroaminoquinolones 32,33 were cyclized to the corresponding 2-substituted thiazoloquinolines 34 and 35, and the latter were derivatized (Scheme 19) (74JAP(K)4, 79CPB1). 

Reaction of o-toluidine with chloral hydrate in presence of hydroxylamine hydrochloride and subsequent treatment with H2SO4 gave the isatin derivative 337. Bromination of 337 followed by reaction with sodium diethyl malonate gave 338. Catalytic reduction with Pd/C gave the oxoindole derivative 339 that upon hydrolysis with aqueous NaOH followed by... 

Catalytic reduction of the nitrile 79 in the presence of semicarbazide affords initially the semicarbazone of 80. Hydrolysis-interchange, for example in the presence of pyruvic acid, gives the aldehyde 80. Condensation with the half ester of malonic acid leads to the acrylic ester 81 the double bond is then removed by means of catalytic reduction (82). Base catalyzed reaction of the... 

Amino acids can be synthesized in racemic form by several methods, including ammonolysis of an a-bromo acid, alkylation of diethyl acetamido-malonate, and reductive amination of an cv-keto acid. Alternatively, an enantio-selective synthesis of amino acids can be carried out using a chiral hydrogenation catalyst. 

The synthesis of the right-wing sector, compound 4, commences with the prochiral diol 26 (see Scheme 4). The latter substance is known and can be conveniently prepared in two steps from diethyl malonate via C-allylation, followed by reduction of the two ethoxy-carbonyl functions. Exposure of 26 to benzaldehyde and a catalytic amount of camphorsulfonic acid (CSA) under dehydrating conditions accomplishes the simultaneous protection of both hydroxyl groups in the form of a benzylidene acetal (see intermediate 32, Scheme 4). Interestingly, when benzylidene acetal 32 is treated with lithium aluminum hydride and aluminum trichloride (1 4) in ether at 25 °C, a Lewis acid induced reduction takes place to give... 

Electrochemical reduction of 5-acetyl-10-bromo-5/f-dibenz[ >,/]azepine in the presence of quinoxalinc as a moderator and diethyl malonate as a proton donor, effects rapid and quantitative hydrodebromination without loss of the acetyl group.183... 

Ilydriodic acid in reduction of m-nitro-benzenesulfonyl chloride to m-nitrophenyl disulfide, 40, 80 Hydrogenation, of diethylisonitroso-malonate to diethyl aminomalo-nate over palladium-on-charcoal, 40, 24... 

The cz5-aziridine substrate shows, as expected on the basis of this model, predominant formation of the trans-cyclopropane product. The starting materials for this MIRC reaction can readily be obtained from the aziridine esters by reduction to the corresponding aldehyde and a subsequent Knoevenagel reaction with malonate ester (Scheme 25) [34]. 

Answer This is clearly a reduction product of a malonate ester (24) (cf p T 110 ) which can be dis-... 

Sengupta and Aditya ° find the usual reactivity sequence for Ce(IV) salts, viz. CIO4" > NOj" > S04 , but note that plots of log (Ce(lV)] versus time are linear even when equal molar concentrations of Ce(IV) and malonic acid are taken. This implies a first-order dependence on [Ce(IV)] and zero-order dependence on malonic acid concentration. Kemp , however, has found a clear first-order dependence on malonic acid concentration for the Ce(IV) sulphate oxidation, using an excess of reductant and making a four-fold variation in reductant concentration. Moreover, consumption of Ce(lV) was intermediate between first- and second-order. Further work is needed to resolve this discrepancy. 

Ito et al.40 examined the electrochemical reduction of C02 in dimethylsulfoxide (DMSO) with tetraalkylammonium salts at Pb, In, Zn, and Sn under high C02 pressures. At a Pb electrode, the main product was oxalic acid with additional products such as tartaric, malonic, glycolic, propionic, and n-butyric acids, while at In, Zn, and Sn electrodes, the yields of these products were very low (Table 3), and carbon monoxide was verified to be the main product even at a Pt electrode, CO was mainly produced in nonaqueous solvents such as acetonitrile and DMF.41 Also, the products in propylene carbonate42 were oxalic acid at Pb, CO at Sn and In, and substantial amounts of oxalic acid, glyoxylic acid, and CO at Zn, indicating again that the reduction products of C02 depend on the electrode materials used. 

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