Dimethylformamide acid esters

The transesterification of sucrose has been performed with a fatty acid ester of a volatile alcohol in the presence of an alkaline catalyst in a dipolar, aprotic solvent.142 The reaction of sucrose (293 mmoles) with methyl dodecanoate (293 mmoles) in A/,N-dimethylformamide in the presence of sodium methoxide in a pressure bomb for 8 h at 130° gave, after solvent extraction and crystallization, sucrose mono(dodecanoate) (m.p. 72-80° [a]D+52°) in 50% yield.142 Commercialization of these sucrose esters has so far been limited, in part because of the use of expensive solvents, and, in part, because solvent remaining in the product makes it unsuitable for use as a food emulsifier. In view of this situation, methods have been developed in which the use of toxic and expensive solvents has been avoided. 

Among the great number of different approaches for the synthesis of phthal-ideisoquinoline alkaloids the application of Reissert compounds, developed first by Kerekes et al. (42,43), proved to be one of the most efficient and suitable methods (Scheme 24). Treatment of isoquinoline Reissert compounds 26 or 28 with sodium hydride in dimethylformamide resulted in the formation of the corresponding Reissert anions, which were reacted with dimethoxy- or meth-ylenedioxy-substituted o-formylbenzoic acid ester derivatives 178 and 179, respectively. The presumed mechanism of this reaction involves an initial reaction... 

Dimethylformamide was suggested for the GC detection of microgram amounts of formic acid [182]. After esterification of acids with diazomethane the sample was treated with a dimethylamine—water mixture (1 2). Dimethylformamide was thus produced from formic acid ester, while other acids present were analysed as methyl esters. 

The major problem associated with the enzymatic acylation of sucrose is the incompatibility of the two reactants sucrose and a fatty acid ester. Sucrose is hydrophilic and readily soluble in water or polar aprotic solvents such as pyridine and dimethylformamide. The former is not a feasible solvent for (trans)esterifi-cations, for obvious thermodynamic reasons, and the latter are not suitable for the manufacture of food-grade products. The selective acylation of sucrose, as a suspension in refluxing tert-butanol, catalyzed by C. antarctica lipase B, afforded a 1 1 mixture of the 6 and 6 sucrose monoesters (Fig. 8.39) [208]. Unfortunately, the rate was too low (35% conversion in 7 days) to be commercially useful. 

One of the most popular methods of single-stage amino acid derivatization at present is their conversion to N,0 S) err-butyldimethylsilyl derivatives [the reagent rert-butyldimethylsilyl trifluoroacetamide (MTBSTFA) or its A-Me analog]. Another way, which was proposed at the beginning of the 1970s is based on amino acid interaction with dimethylformamide di-alkylacetals (CH3)2NCH(OR )2 (R = Me, Et, Pr, iso-Pr, Bu, Am) with formation of A-dimethylaminometh-ylene derivatives of amino acids esters ... 

The cyanomethyl-substituted pyrido[2,l-i ]quinazolinones 211 (R = CH2CN) can be transformed by chain elongation into the propionic acid and propionic acid ester derivatives. Reactions were effected by heating the cyanomethyl derivatives for 2 hr in diethyl carbonate in the presence of sodium hydride, followed by evaporation and treatment with methyl iodide and sodium hydride in dimethylformamide at 0°C, and finally by stirring of the evaporated oily residue in a mixture of isopropanol and coned, sodium hydroxide to obtain the acids,and in 0.5 N aqueous acetic acid to obtain the esters. ... 

A new development is biphasic hydrogenation using solvent-stabilized colloid (SSCs) catalysts [39-41]. Palladium colloid systems, especially, were proven to give high reactivity and selectivity. Best solvents are dimethylformamide and particularly the two cyclic carbonic acid esters, ethylene carbonate and 1,2-propene carbonate. In these solvents sodium tetrachloropalladate - stabilized by a sodium carbonate buffer - is reduced with hydrogen to yield the solvent-stabilized palladium colloid. Transmission electron microscopy of the palladium colloid demonstrates that the colloid particles are spherical with an average diameter of 4 nm. 

The acrylic acid ester side chain may also be introduced by the Wittig reaction of 6-chloro-l,3-dimethyl-2,4-dioxo-l,2,3,4-tetrahydropyrimidine-5-carbaldehyde with the appropriate ylide. Subsequent conversion to a 6-amino compound and ring closure in the presence of triethyl-amine gives 8-alkyl-l,3-dimethylpyrido[2,3-t/]pyrimidine-2,4,7(l//,3//,8W)-triones 9. 45 146 Exclusive formation of pyrido[2,3-t/]pyrimidines is achieved by refluxing the acrylic acid esters in a mixture of triethylamine and dimethylformamide in the presence of l,5-diazabicyclo[4.3.0]-non-5-ene (DBN).147 55t... 

NITRATE de ZINC (French) (7779-88-6) Noncombustible, but will enhance the combustibility of other materials. Many chemical reactions can cause fire and explosions. A strong oxidizer. Violent reaction with reducing agents, strong oxidizers, combustible materials, organic substances, metallic powders, acetic anhydride, tert-butylhydroperoxide, carbon, dimethylformamide, metal cyanides, metal sulfides, phosphorus, sodium acetylide, sulfur, thiocyanates. Incompatible with amines, ammonium hexacyanoferrate(II), boranes, cyanides, citric acid, esters, hydrazinium perchlorate, isopropyl chlorocarbonate, nitrosyl perchlorate, organic azides, organic bases, sodium thiosulfate, sulfamic acid. Attacks metals in the presence of moisture. 

A soln. of guanylurea in abs. methanol treated with dimethylformamide dimethyl acetal, and allowed to stand overnight at room temp, under anhydrous conditions -> 5-azacytosine. Y 91%. Also with ethyl orthoformate in dimethylformamide and f. e. with orthocarboxylic acid esters s. A. Piskala, Coll. 32, 3966 (1967). 

A mixture of o-hydroxyacetophenone, dimethylformamide dimethyl acetal, and abs. xylene heated to 120 bath temp, with distillation of methanol, after ca. 2 hrs. the temp, raised to 150-160 for 0.5 hr., then allowed to stand overnight o-hydroxy-co-dimethylaminomethyleneacetophenone (Y 80%) heated 75 min. at 100 bath temp, with aq. H2SO4 chromone (Y 71%). B. Fohlisch, B. 104, 348 (1971) aminomethylenemalonic acid esters (cf. Synth. Meth. 25, 759) by C-dimethylaminomethylenation s. N. D. Harris, Synthesis 1971, 220. 

The reductive carbonylation of iodobenzene with triiron dodecacarbonyl in toluene gives benzophenone (Rhee et al., 1967). Reaction of pentafluoro-phenyl iodide and nickel carbonyl in dimethylformamide or toluene gives perfiuorobenzophenone and perfluorobiphenyl (Beckert and Lowe, 1967). Iodobenzene reacts with nickel carbonyl to give benzoic acid esters (in alcohols) or benzil (in tetrahydrofuran) (Bauld, 1963), possibly via a benzoyl-nickel intermediate. Reaction of this intermediate with enamines affords /f-diketones in high yields (Seki et al, 1975). 

Dimethylformamide-dialkyl sulfate Carboxylic acid esters from carboxylic acids... 

Carboxylic acid esters and phenolethers from carboxylic acids and phenols respectively with dimethylformamide acetals... 

Dithiocarboxylic acid esters. 1.5-2 moles of phosgene passed at 25-30° into a soln. of propionic acid piperidide in toluene, and the product isolated after 4-5 hrs. propionic acid piperidide chloride (Y 90-95%) suspended in abs. ether, treated at 0° with ethyl mercaptan, the ether removed, the residue treated with dimethylformamide and pyridine, HgS introduced 4 hrs. at 0°, and allowed to stand several hrs. at room temp. ethyl dithiopropionate (Y 86%). F. e., also thionocarboxylic acid esters by initial treatment with alcohol, isolation of thiolic acid esters, and f. reactions, also ring closures to hetero-cyclics, s. H. Eilingsfeld, M. Seefelder, and H. Weidinger, B. 96, 2671 (1963). 

O, -unsaturated carboxylic acids, esters, and amides are reduced easily to saturated derivatives by treating them with Sml2 in the presence of a proton source (Girard et al., 1980). The use of dimethylformamide (DMF) or A/, A/ -dimethyl acetamide (DMA) as a cosolvent with THF enhances the rates of reaction and improves yields considerably as shown in eqs. (8), (9) (Inanaga, 1990). 

Nucleotide derivatives. Dry adenosine-5 -phosphoric acid stirred with -carb-ethoxy-a-ethoxyvinyl diethyl phosphate and tri-n-butylamine in abs. dimethyl-formamide until dissolved after 2-3 days, dil. with acetone and the product precipitated with a soln. of anhydrous Nal in acetone Na P -(5 -adenosyl) P -diethyl diphosphate (Y 87 % as the monohydrate) warmed 3 hrs. at 50° in abs. methanol-pyridine, and the product isolated as the NH4-salt NH4 5 -adenosine methyl phosphate (Y 79.2% as the monohydrate).—Pyrophosphoric acid esters react with alcohols, amines, and acids so that the monoester part appears in the product. The adenosine-5 -phosphoric acid group in the intermediate triester is activated and can be easily combined with various nucleophiles. F. e. without isolation of the intermediate s. F. Cramer and R. Witt-mann. B. 9A, 328 (1961) s. a. B. 94, 322 dimethylformamide as phosphorylation catalyst s. B, 94, 989. 

Carboxylic acid esters. Butyl bromide heated 4 hrs. at 90-100° with K-acrylate in dimethylformamide butyl acrylate. Y 92%. F. e., also with Na-salts, s. S. Yoneda, Z. Yoshida, and K. Fukui, Kogyo Kagaku Zasshi 69, 641 (1966) (Japan) C. A. 66, 10537 phosphoric acid esters s. Kogyo Kagaku Zasshi 69, 644 C.A. 66, 10538. 

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