Malonates tert-butyl

The oxidation of acetate by peroxodisulphate is much slower than that of formate. Glasstone and Hickling showed that the products, which include carbon dioxide, methane, ethane, and ethylene, are similar to those produced by the anodic oxidation of acetate ions (Kolbe electrolysis), and they inferred that the same organic radicals are formed as intermediates. Similar results are reported by Eberson et al. for the oxidations of ethyl terf.-butyl-malonate, tert.-butyl-cyanoacetate, and ferl.-butyl-malonamate ions. The oxidations of these ions and of acetate by peroxodisulphate are first order with respect to peroxodisulphate and zero order with respect to the substrate. Mechanisms involving hydroxyl radicals are excluded because the replacement of peroxodisulphate by Fenton s reagent leads to different products, so Eberson et al. infer that the initial attack on the substrate is by sulphate radical-ions. Sengar and Pandey report that the rate of the silver ion-catalysed oxidation of acetate is independent of the peroxodisulphate concentration. 

CO) and 2273 (C=N) but not OH band (co 3500 broad) cm If it does not have the last named band then fractionally dist, otherwise dissolve in Et20, wash with satd aq NaHCOa, dry over K2CO3, evap Et20, and dist residue under a vacuum (see tert-butyl ethyl malonate for precautions to avoid decomposition during distn). [J Chem Soc 423 7955 Helv Chim Acta 42 1214 7959],... 

A gas ehromatographic analysis on the produet by the submitter, using an 0.3 x 80 cm. column packed with 10% silicone rubber (SE-30) supported on acid-washed, 60-80 mesh Chromasorb P at 80°, exhibited a single peak. The retention times of di-ter(-butyl malonate, di-fert-butyl diazomalonate, and p-toluenesulfonyl azide were 2, 6, and 9 minutes, respectively. The purity of the product obtained by the checkers was estimated from proton magnetic resonance spectra to be ca. 94%, the remainder being di-tert-butyl malonate. 

The diazo transfer reaction between p-toluenesulfonyl azide and active methylene compounds is a useful synthetic method for the preparation of a-diazo carbonyl compounds. However, the reaction of di-tert-butyl malonate and p-toluenesulfonyl azide to form di-tert-butyl diazomalonate proceeded to the extent of only 47% after 4 weeks with the usual procedure." The present procedure, which utilizes a two-phase medium and methyltri-n-octylammonium chloride (Aliquat 336) as phase-transfer catalyst, effects this same diazo transfer in 2 hours and has the additional advantage of avoiding the use of anhydrous solvents. This procedure has been employed for the preparation of diazoacetoacetates, diazoacetates, and diazomalonates (Table I). Ethyl and ten-butyl acetoacetate are converted to the corresponding a-diazoacetoacetates with saturated sodium carbonate as the aqueous phase. When aqueous sodium hydroxide is used with the acetoace-tates, the initially formed a-diazoacetoacetates undergo deacylation to the diazoacetates. Methyl esters are not suitable substrates, since they are too easily saponified under these conditions. 

Di-terf-butyl malonate, 59, 66 Di-tert-butyl peroxide, 55, 61... 

Successful results have been obtained (Renfrow and Chaney, 1946) with ethyl formate methyl, ethyl, n-propyl, iso-propyl, n-butyl, i o-butyl, sec.-butyl and iso-amyl acetates ethylenegl3rcol diacetate ethyl monochloro- and trichloro-scetates methyl, n-propyl, n-octyl and n-dodecyl propionates ethyl butyrate n-butyl and n-amyl valerates ethyl laurate ethyl lactate ethyl acetoacetate diethyl carbonate dimethyl and diethyl oxalates diethyl malonate diethyi adipate di-n-butyl tartrate ethyl phenylacetate methyl and ethyl benzoates methyl and ethyl salicylates diethyl and di-n-butyl phthalates. The method fails for vinyl acetate, tert.-butyl acetate, n-octadecyl propionate, ethyl and n-butyl stearate, phenyl, benzyl- and g aicol-acetate, methyl and ethyl cinnamate, diethyl sulphate and ethyl p-aminobenzoate. 

B. Di-tert-hutyl malonate. A 1-1. three-necked flask is fitted with a thermometer, a mercury- or rubber sleeve-sealed mechanical stirrer, a reflux condenser protected by a calcium chloride guard tube, and a dropping funnel (either pressure-equalized or protected by a calcium chloride guard tube). A mixture of 100 ml. (about 1 mole) of tert-butyl alcohol, dried by distillation from sodium,2 and 80 ml. (0.63 mole) of dry dimethylanilinc (Note 5) is placed in the flask, the stirrer is started, and a solu-... 

The 3f/-pyrazole-3,5(4//)-diones (7), prepared by lead tetraacetate,29,30 or tert-butyl hypochlorite31,32 oxidation of malonic acid cyclic hydrazides, are generally less stable than the triazoles 5, and are not isolable. The monocarbonyl derivatives (8-10) have been reported.33-36 The unstable 1,3,4-thiadiazole-2,5-dione (11) has been generated and reacted in situ.31,3 ... 

Ethyl tert-butyl malonate has been prepared by adding tert-butyl acetate and ethyl carbonate to sodium triphenylmethyl,3 and from ethyl malonyl chloride and fer/-butyl alcohol.4 The present procedure is an adaptation of that for the preparation of di-fer(-butyl malonate.2... 

Ethyl 3-oxoalkanoates when not commercially available can be prepared by the acylation of tert-butyl ethyl malonate with an appropriate acid chloride by way of the magnesium enolate derivative. Hydrolysis and decarboxylation in acid solution yields the desired 3-oxo esters [59]. 3-Keto esters can also be prepared in excellent yields either from 2-alkanone by condensation with ethyl chloroformate by means of lithium diisopropylamide (LDA) [60] or from ethyl hydrogen malonate and alkanoyl chloride usingbutyllithium [61]. Alternatively P-keto esters have also been prepared by the alcoholysis of 5-acylated Mel-drum s acid (2,2-dimethyl-l,3-dioxane-4,6-dione). The latter are prepared in almost quantitative yield by the condensation of Meldrum s acid either with an appropriate fatty acid in the presence of DCCI and DMAP [62] or with an acid chloride in the presence of pyridine [62] (Scheme 7). 

Ice-acetone bath. The bottle is closed with a rubber stopper which is clamped or wired securely in place (Note 3) and is shaken mechanically at room temperature until the suspended malonic acid dissolves (Note 4). The bottle is chilled in an ice-salt bath and opened then the contents are poured into a separatory funnel containing 250 ml. of water, 70 g. of sodium hydroxide, and 250 g. of ice. The mixture is shaken (carefully at first), the layers are separated, and the aqueous portion is extracted with two 75-ml. portions of ether. The organic layers are combined, dried over anhydrous potassium carbonate, and filtered into a dropping funnel attached to the neck of a 125-ml. modified Claisen flask (Note 5). The flask is immersed in an oil bath at about 100°, and the excess isobutylene and ether are removed by flash distillation effected by allowing the solution to run in slowly from the dropping funnel. The dropping funnel is then removed, and the residue is distilled at reduced pressure. The fraction boiling at 112—115°/31 mm. is collected. The yield of colorless di-tert-butyl malonate is 60.0 62.0 g. (58-60%), 1.4158-1.4161,... 

This procedure is a modification 2 of the method of Altschul3 for preparing tert-butyl esters. Di-ferf-butyl malonate has been prepared by the reaction of malonyl chloride with tert-butyl alcohol in the presence of a tertiary amine.4... 

A 250-mL, one-necked, round-bottomed flask is equipped with a magnetic stirrer and a reflux condenser protected by a calcium chloride drying tube. Into the flask are placed 30.0 g (0.14 mol) of di-tert-butyl malonate (Note 1) 8.4 g (0.28 mol) of paraformaldehdye (Note 2), 1.4 g (0.014 mol) of potassium acetate, 1.4 g (0.007 mol) of cupric acetate monohydrate, and 70 mL of glacial acetic acid. The resulting green-white suspension is placed in an oil bath preheated to 90-100°C and stirred for 2 hr (Note 3). The reaction mixture is allowed to cool to room temperature, and the reflux condenser is replaced with a short-path distillation apparatus, the vacuum outlet of which 1s connected in sequence to a trap cooled in acetone-dry ice, a potassium hydroxide trap, another trap cooled in acetone-dry ice, and a vacuum pump. The receiving flask 1s cooled in acetone-dry 1ce, and the system is evacuated over approximately 1 hr to remove acetic acid and other volatile material... 

Di-tert-butyl malonate was prepared according to the procedure of Johnson see Org. Synth., Collect, vol. IV 1963, 261. 

The bath temperature should not exceed 100°C in order to prevent contamination of the product with the his(hydroxymethyl) derivative of di-tert-butyl malonate. The product exhibits single peaks in the H Will spectrum (CDClj, 250 MHz at 1.51 and 5.25 ppm and contains approximately 6% of di-tert-butylmalonate as indicated by a peak at 1.47 ppm. Contamination by the bis(hydroxymethyl) derivative is Indicated by a peak at 1.48 ppm. 

Di-tert-butyl methylenemalonate was originally prepared by phenyl-sulfenylation of di-tert-butyl methylmalonate and thermal elimination of the related sulfoxide.8 Because methylenemalonate esters are customarily prepared by Knoevenagel-type condensation of malonic esters with formaldehyde equivalents, the considerably more convenient procedure described herein was subsequently adapted from Bachman and Tanner s study using paraformaldehyde under metal ion catalysis.39 The approximately 6% di-tert-butyl malonate accompanying the product has presented no interference in the aforementioned reactions with nucleophilic alkenes under neutral or acidic conditions, but its presence should be taken into consideration in other applications. 

To a well-stirred suspension of l,2-bis(bromomethyl)benzene (34 26.4 g, 0.1 mol) and diethyl 2-(ace-tylamino)malonate (21.7 g, 0.1 mol) in MeOH (175 mL) was added 30% NaOMe in MeOH (18 mL, 0.1 mol) dropwise over 10 min at rt. The mixture was heated to reflux, treated with additional 30% NaOMe in MeOH (18 mL, 0.1 mol) over 2 h, and stirred for a further 2 h at reflux temperature. The soln was cooled to rt, concentrated, and the solid residue was distributed between H20 (100 mL) and EtOAc (150 mL). The aqueous phase was extracted with EtOAc (2 x 75 mL), and the combined organic phases were washed with brine (100mL), dried (Na2S04), and concentrated. The crude residue was recrystallized (iPrOH/tert-butyl methyl ether 1 1) to give 36 yield 21.5g (75%) mp 141-143°C. 

MALONIC ACID AND DERIVATIVES] (Vol 15) tert-Butyl mercaptan [75-66-1]... 

Preparation of mono-adducts of fullerene - for studies on electrostatic interactions - was undertaken by cyclopropanation of fullerene with appropriately functionalised malonic esters 1 (Bingel reaction) to form 2. Coupling with the tert-butyl protected oligoamide-amino-dendron 3 and subsequent hydrolysis lead to the water-soluble fullerene dendron 5, which can carry up to nine negative charges after depro to nation. After association with the zinc complex of cytochrome C, photoinduced electron transfer (PET) from the redox protein to the fullerene can be accomplished, which was studied by fluorescence spectroscopy. 

Cheap and readily available L-proline has been used numerous times for the intermediate and reversible generation of chiral iminium ions from a,/ -unsaturated carbonyl compounds. For example, Yamaguchi et al. reported in 1993 that the rubidium salt of L-proline catalyzes the addition of di-iso-propyl malonate to the acyclic Michael acceptors 40a-c (Scheme 4.13), with enantiomeric excesses as high as 77% [22], With 2-cycloheptenone and 2-cyclohexenone as substrates ca 90% yield and ee of 59% and 49% were obtained. Later the enantioselectivity of this process was increased to a maximum of 88% ee in the addition of di-tert-butyl malonate to the E-pentenone 40a in the presence of 20 mol% Rb-L-prolinate and 20 mol% CsF [23], Taguchi and Kawara employed the L-proline-derived ammonium salts 41a and... 

Cyclopropyl-3-fluoro-2-hydroxy-6-oxo-67/-pyrido[l,2-a]pyrimidine-7-carboxylates 340 were obtained in the reaction of 2-cyclopropyl-2-(5-fluoro-4-hydroxy-2-pyrimidinyl)acetaldehyde (339) and ethyl, tert-butyl and dibenzyl malonates in the presence of piperidine and AcOH (95MIP1, 96JMC3070, 96MIP4, 96USP5580872). 

Compound 45 was also obtained by a second route. We prepared the bis (tert-butyl ester) ( )-42 by transforming the DB18C6 diol 40 into bis-malonate 41,... 

Strube, R. E. Ethyl tert-butyl malonate. Org. Synth. 1963, Coll. Vol. IV, 417 119. 

Section 12.2 closes with the a-functionalization of enols with C electrophiles (Figure 12.11-12.15). Figure 12.11 presents a tert-butylation of malonic ester with tert-butyl chlo-... 

Fig. 12.11. Mechanism of the tert-butylation of malonic acid diethyl ester. From the point of view of tert-butyl chloride it is an SN1 reaction with the malonic ester enol (B) acting as the nucleophile.

Methyl vinyl ketone (entry 3) and the tert-butyl cation (entry 4) are also reactive toward complex 3. The naphthalenium complexes resulting from the addition of these electrophiles will add the conjugate base of dimethyl malonate (generated in situ from a combination of dimethyl malonate (DMM) and diisopropylethylamine (DIEA)) to complete the tandem additions. Oxidation of the resulting complexes yields cis-l,4-dihydronaphthalenes. The entire sequence of complexation, tandem addition, and demetalation employed for all entries in Table 4 can be performed using bench-top conditions (i.e., a non-inert atmosphere). 

Nucleophiles A, dibenzylamine, B, sodium diethyl malonate, C, lithium salt of tert-butyl N-(diphenylmethylene)glycinate. 

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