Ethoxycarbonylmethylene

Ethyl (triphenylphosphoranylidene)acetate is available from FIuka AG and Trldom Chemical Inc. under the name (ethoxycarbonylmethylene)triphenyl-phosphorane and from Aldrich Chemical Company, Inc. under the name (carbethoxymethylene)triphenylphosphorane. The reagent may be prepared from triphenyl phosphine and ethyl bromoacetate by the following procedure. ... 

Carbethoxymethylene)triphenylphosphorane, (Ethoxycarbonylmethylene)tri-phenylphosphorane Acetic acid, (triphenylphosphoranylidene)-, ethyl ester (8,9) (1099-45-2)... 

Ethoxycarbonylmethylene)triphenylphosphorane [ethyl (triphenylphosphoranylidene)-acetate] [1099-45-2] M 348.4, m 116-117°, 128-130°. Cryst by dissolving in AcOH and adding pet ether (b 40-50°) to give colorless plates. UV Xmax (A ) 222nm (865) and 268nm (116) [Isler et al. Helv Chim Acta 40 1242 1957]. 

Heating 9-ethoxycarbonylmethylene-4-oxo-6,7,8,9-tetrahydro-4//-pyrido-[l,2-n]pyrimidine-3-carboxylate (157) at 250°C yielded 6,7-dihydro derivative 158 (99T10221). Under similar conditions 9-benzylidene-6,7,8,9-tetrahydro derivatives 159 did not gave the respective 9-benzyl-6,7-dihydro isomer. 

Alkyl-Alkylidene Tautomerism. Some 2- or 3-(substituted alkyl)quinoxalines, like 3-ethoxycarbonylmethyl-2(177)-quinoxalinone (133), have long been known to exist in equilibrium with their (substituted methylene) tautomers, for example 3-ethoxycarbonylmethylene-3,4-dihydro-2( 1 /7)-quinoxalinone (133a).The effects of solvent change, protonation, and the like on such tautomeric systems have been examined as well as the kinetics thereof. In... 

Buchanan and coworkers113c investigated the reaction of 2,3,5-tri-O-benzyl-D-ribofuranose with (ethoxycarbonylmethylene)triphenyl-phosphine in anhydrous 1,2-dimethoxyethane in the presence of a catalytic amount of benzoic acid. The alkenic products were isolated in high yield, and each was converted into an anomeric mix-... 

A vinylogous indole derivative like 264 reacts with DMAD to give a phenanthridone derivative (267) (Scheme 42). An interesting case of the reaction of an enamine system is observed in the case of the 2H-pyrrolizine (268), which gives a mixture of the azepino[2,l,7-crflpyrrolizine derivative (271) and the 1 1 adduct (275) (Scheme 43) 164,165 reaction of 3-ethoxycarbonylmethylene-3 -pyrrolizine, on the other hand, yields a pyrrolo[2,l,5-croom temperature, the primary adduct (278) is isolated and undergoes thermal cyclization to 281 (Scheme 44). ... 

Micheel and Flitsch116,118 used 3,5-dioxopyrrolizidine (59) and 3-(ethoxycarbonylmethylene)pyrrolizid-5-one (166) as starting compounds in the synthesis of various pyrrolizidine derivatives. The series... 

Ethoxycarbonylmethylene-3//-pyrrolizine (32), prepared from pyr-rolizin-3-one with ethoxycarbonylmethylenetriphenylphosphorane,34-36 reacted slowly with dimethyl acetylenedicarboxylate to give a mixture of products from which the [3,2,2]azine ly was isolated in 12%lyield.37... 

Selective epoxidation of the isolated double bond (Equation 35) in the ester 79, prepared from citronellal and triphenyl(ethoxycarbonylmethylene)phosphorane, followed by treatment with Na2PdCl4 and v/-butyl hydroperoxide gives the bis-ether 80 <1994CC903>. 

Application of the Hammett pa equation to the related reaction of ethoxycarbonylmethylene with substituted benzenes indicates that here too the carbene behaves as an electrophile of low selectivity (Baldwin and Smith, 1967). 

Amongst the monocyclic sesquiterpenes, the plant growth hormone (+)-abscisic acid 446 and a-humulene 451 are found which both can be synthesized by Wittig reactions. To synthesize (+)-abscisinic acid 446 D. L. Roberts et al. 239) converted a-ionone 444 into the allylic alcohol 445 by /-butyl chromate oxidation. 445 is reacted with ethoxycarbonylmethylene-triphenylphosphorane 238 and subsequently... 

Azine approach. Cyclization of /3-oxo oximes yields isoxazoles. In an adaptation of this method to the preparation of fused isoxazoles, 3-ethoxycarbonylmethylene-2(lH)-quin-oxalinone is nitrosated and the resulting oxime (43) cyclized to the fused isoxazole (44) (72JOC2498). 

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