Tert Butyl cyanoacetate

The present preparation employs a method of considerable scope which gives much better yields and is considerably less laborious than other methods for the preparation of tert-butyl cyanoacetate. The compound is of specific interest since, for example, it may be used in any reaction where ethyl cyanoacetate is used (condensation reactions, etc.), but it has the added advantage that the carbo-feri-butoxy group, which may serve in conjunction with the a-cyano group to activate the a-hydrogens (for cyanoethylations, etc.), may be later removed simply by pyrolysis of the compound. 

Chloro-l,10-phenanthroline (69) reacts with the sodium salt of tert-butyl cyanoacetate to give the intermediate 105, which with cold hydrochloric acid affords 2-cyanomethyl-1,10-phenanthroline (106).345 2-Chloro-1,10-phenanthroline also participates in the Ullmann reaction to afford 2,2 -bi-(l,10-phenanthroline) (I07).346 5,5 -Bi-(l,10-phenanthroline) was also prepared, but by a different route starting from 8,8 -diamino-6,6 -biquinoline. 

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. 

Common synthetic methods for the preparation of cyclic 8-enamino esters are the condensation between a lactim ether and benzyl cyanoacetate followed by hydrogenolytic decarboxylation, or the imino ester carbon-carbon condensation with tert-butyl cyanoacetate followed by a trifluoroacetic acid treatment. The use of a thiolactam condensed with ethyl bromoacetate gives, after sulfur extrusion by triphenylphosphine, cyclic 8-enamino esters. Compared with these methods, the Meldrum s acid condensation followed by the monodecarboxylating transesterification described here is more convenient and practical. An extension of this procedure permits preparation of smaller... 

A double Michael addition has been observed in the intermolecular reaction of the a, p-unsaturatedacylanthraquinone, 1 -hydroxy-2-(1 -oxopent-2-enyl)anthra-quinone illustrated with tert-butyl cyanoacetate followed by an intramolecular cyclisation of the product. The whole sequence was conducted at ambient temperature during 6 hours in dimethylformamide to give a substituted benzohydroxyanthraquinone in 75% yield (ref.84). 

The successive condensation of compound (318) with tert-butyl cyanoacetate, hydrogen cyanide, and acrylonitrile, and pyrolysis to eliminate the tert-butoxycarbonyl grouping, led to the trinitrile (321). Its intramolecular condensation by the Thorpe reaction gave the bicyclic product (320) which was... 

Cuprous -butylmercaptide, 42,22 Cuprous chloride as catalyst for 1,4 addition of Grignard reagents to ar,0-unsaturated esters, 41, 63 Cyanoacetic acid, tert-butyl ester, 41, 5... 

ZerZ-Butyl cyanoacetate [1116-98-9] M 141.2, b 40-42 /0.1mm, 54-56 /0.3mm, 90 /10mm, 107-108 /23mm, d 0.989, 0 1.4198. The IR spectrum of a film should have bands at 1742 (ester CO) and 2273 (C=N) but not OH band (ca 3500 broad) cm . If it does not have the last named band then fractionally dist, otherwise dissolve in Et2O, wash with satd aq NaHCO3, dry over K2CO3, evap Et2O, and dist residue under a vacuum (see tert-butyl ethyl malonate for precautions to avoid decomposition during distn). [JCS 423 7955 HCA 42 1214 7959]. 

The a-cyanoacetates 12 are optimal substrates for the approach outlined in Scheme 2.26 due to the low pKa of the a-proton. It has been reported that the quinidine-derived alkaloid /fisocupridine (/ -ICD) can catalyze the direct a-amination of a-cyanoacetates 12 (Eq. 4) and /fdicarbonyl compounds [10], probably by an enolate having a chiral /MCD-H+ counterion as the intermediate. The a-amination of a-cyanoacetates 12 with di-tert-butyl azodicarboxylate 2c is an efficient process that proceeds with only 0.5 mol% of /MCD. The expected products 13, having a stereogenic quaternary carbon center, were isolated in excellent yields and with excellent levels of enantioselectivity independently by the nature of the aryl-substituent in the a-cyanoacetates, while the / -dicarbonyl compounds give slightly lower enantioselectivty (83-90% ee). 

When malononitrile was used as a substrate, a high conversion of 98% was obtained after 12 h, whereas almost no activity was observed in the conversion of ethyl cyanoacetate and cyano-acetic acid tert-butyl ester, suggesting that the catalyst was size selective. The observation of reactant shape selectivity revealed that the catalytic turnovers take place in the MOF channels rather than at the outer surface of the MOF particles. Upon desolvation, for example, by the removal of water... 

Jorgensen et al. described a highly enantioselective amination of a-substituted a-cyanoacetates with di-tert-butyl-azodicarboxylate (DEAD) catalysed by the quinidine-derived constrained alkaloid, p-isocupreidine (p-ICPD). ° Products were isolated in excellent yield and enantioselectivity (up to >98%). The generality of the method was demonstrated by the reaction on both open-chain and cyclic p-ketoesters. Products were again obtained in up to 99% yield, but in somewhat lower ee (up to 90%). Deng... 

Trifluoroacetylglycine, benzylamine, isobutyraldehyde, and tert-huiyl iso-cyanoacetate in methanol allowed to stand 1 hr. at ca. 20° -> terf-butyl N- trifluoroacetylglycyl - N- benzylva-lylglycinate. Y 87%. 

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