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Bromocrotonate

METHYL y-BROMOCROTONATE JV-Bromosuccinimide. Dissolve, with the aid of rapid mechanical stirring, 80 g. of pure succinimide (Section V,14) in a mixture of 150 g. of finely crushed ice and a solution of 32 g. of sodium hydroxide in 200 ml. of water contained in a litre beaker and cooled externally by ice. Immediately the imide has dissolved, continue the vigorous stirring and introduce 42 -5 ml. of bromine in one lot from a separatory funnel supported over the beaker it is essential that the bromine be instantly suspended in the solution. After stirring vigorously for 2 minutes, filter at the pump and... [Pg.926]

Methyl y-bromocrotonate. Mix 36 g. of iV-bromosuccinimide, 40 g. of methyl crotonate and 60 ml. of dry, redistilled carbon tetrachloride in a 500 ml. round bottomed flask. Reflux ou a water bath for 12 hours by this time all the sohd should have risen to the surface of the liquid. Filter off the succinimide at the pump and wash it with a little dry carbon tetrachloride. Remove the solvent on a water bath and distil the residue under reduced pressure, preferably from a Widmer flask (compare Figs. II, 24, 4-5). Collect the methyl y-bromocrotonate at 77-78°/8 mm. the yield is 31 g. [Pg.927]

The 3,4-dihydrodiol of BcP was synthesized from 4-oxo-l,2,3,4-tetrahydro-BcP (15) by Method I (66). The ketone L was itself prepared from 4-oxo-l,2,3,4-tetrahydrophenanthrene via a multistep sequence entailing Reformatsky reaction with methyl bromocrotonate, dehydration of the resulting alcohol, isomerization to the aryl-butyric acid, and cyclization of its acid chloride with SnCl - Full... [Pg.52]

Among early reported Pd-catalyzed reactions, the Mori-Ban indole synthesis has proven to be very useful for pyrrole annulation. In 1977, based on their success of nickel-catalyzed indole synthesis from 2-chloro-fV-allylaniline, the group led by Mori and Ban disclosed Pd-catalyzed intramolecular reactions of aryl halides with pendant olefins [122]. Compound 102, easily prepared from 2-bromo-lV-acetylaniline and methyl bromocrotonate, was adopted as the cyclization precursor. Treatment of 102 with Pd(OAc)2 (2 mol%), Ph3P (4 mol%) and NaHCQ3... [Pg.24]

Ethyl 2-bromocrotonate, CH3CH=C(Br)COOC2H5 (1). The reagent is prepared by bromination of ethyl crotonate followed by dehydrobromination with DBU. [Pg.161]

Methyl crotonate reacts with NBS and brominates is allylic position giving methyl 3-bromocrotonate, a valuable synthetic reagent used in Reformatsky reaction. [Pg.307]

The reaction of various thiophene carbonyl compounds with ethyl bromocrotonates was carried out smoothly in the presence of zinc in... [Pg.142]

The biochemical reduction of a, -unsaturated -haloaliphatic acids by means of Clostridium kluyveri yielded halogen-free satmated acids. The same products were obtained from saturated -halo acids. However, the same microorganism converted ix, -unsaturated a-halo acids to saturated a-halo acids with R configuration. Yields of reduction of a-fluoro-, a-chloro- and a-bromocrotonic acid ranged from 30% to 100% [330]. [Pg.142]

Cyclopropane ring formation has been brought about by Michael addition initiated ring closure (sometimes called MIRC). The reaction of methyl 4-bromocrotonate (3) with different nucleophiles either gives the SN2-displacement product 4 or the Michael addition intermediate 5 which finally forms the cyclopropane carboxylate 697 (the configuration of 6 has not been determined). This reaction has been studied with different nucleophiles in the solvent systems tetrahydrofuran-HMPA (20 1) and tetrahydrofuran the bromocrotonate 3 was reacted with 1 equivalent of a 1 M solution of the lithium enolates at —78 for 12 h at room temperature97. [Pg.748]

The sulfone-stabilized anions 7 reacted in much the same way with ethyl bromocrotonate but more cleanly, giving the cyclopropane carboxylates 8 exclusively in high yields98. The only observed products were the truws-substituted cyclopropanes. [Pg.748]

The dependence of the counterion and of the solvent99 was studied in the addition of sec-butyl and tert-butyl mercaptide to methyl 4-bromocrotonate (3). The highest yield of the Michael addition induced cyclopropane product 10 was observed with lithium as counterion in dichloromethane or pentane as solvent. [Pg.748]

DL-Threonic acid (10) seemed to be a promising source of DL-threose. Therefore, other routes to 10 were elaborated. By a procedure consisting of five steps" 2-propenal (acrolein) — vinylglycoloni-trile — ethyl vinylglycolate — ethyl 4-bromocrotonate — 3-hydroxy-crotonic acid — 10, DL-threonic acid was obtained in an overall yield of 4.1%. Another synthesis of 10 was achieved17 in six steps starting... [Pg.5]

The influence of a Lewis acid in favouring the ring closure was confirmed by the use of a catalytic amount of CpiTiCL in imino-Reformatsky reactions with a-bromoesters, -bromocrotonates and a-bromomethylacrylates the corresponding cis /9-lactams were obtained in excellent yields in THF at rt129. [Pg.825]

TABLE 5. Reformatsky reaction of 4-bromocrotonate 191b with benzalacetone... [Pg.853]

Lastly, a formal synthesis of almotriptan (5) has been published by the Bosch group in Spain using an intramolecular Heck approach (Scheme 23). lodination of aniline 58 with bis(pyridine)iodonium(I) tetrafluoroborate followed by reaction with trifluoroacetic anhydride (TFAA) gave the o-iodotrifluoroacetanilide 66. Alkylation of 66 with methyl 4-bromocrotonate afforded 67, which underwent palladium catalyzed... [Pg.179]

A common goal of library synthesis is to maximize diversity around a core, so the synthetic route described above was extended to accommodate a variety of substituted aryl groups. The modified route is shown in Scheme 11. The solid-phase starting material was Rink amide resin,36 which had been loaded with y-bromocrotonic acid (attempts to load with other suitable fragments, such as fumaraldehydic acid, or the pentafluorophenol-activated ester, failed). Substituted ort o-iodoanilines could then be used to alkylate... [Pg.35]

Methyl n-amyl carbinol. 247, 254 Methyl n-amyl ketone, 482 Methylaniline (mono), pure, from commercial methylaniline, 562, 570 P-Methylanthraquinone, 728, 740 Methyl benzoate, 780, 781 p-Methyl benzyl alcohol, 811,812 Methyl benzyl ketone, 727, 735 Methyl y-bromocrotonate, 926, 927 2-Methyl-2-butene, 239 Methyl n-butyl carbinol, 247,255 Methyl n-butyl ether, 314 Methyl n-butyl ketone, 475, 481 4-Methylcarbostyril, 855 p-Methylcinnamic acid, 719 4-Methylcoumarin, 853, 854 Methyl crotonate, 926, 927 Methylethylacetic acid, 354, 358 Methylethylethynyl carbinol, 468 Methyl ethyl ketone, 335, 336 purification of, 172 Methyl n-hexyl ether, 314 Methyl n-hexyl ketone, 335, 336 Methyl n-hexyl ketoxime, 348 Methyl hydrogen adipate, 938 Methyl hydrogen sebacate, 938,939 4-Methyl-7-hydroxycoumarin, 834 Methyl iodide, 287 Methyl isopropyl carbinol, 247,255 Methyl 4-keto-octanoate, 936... [Pg.1179]

Reformatsky reaction.5 The Reformatsky reaction of y-bromocrotonic acid with aldehydes or ketones in THF gives rise to a mixture of branched and linear unsaturated hydroxy acids. The former are the kinetic products and, on equilibration, rearrange to the latter products. [Pg.346]

Various 3-substituted l-cyano-2-methylthioindolizines (68) have been prepared by treating a-[bis(methylthio)methylene]-2-pyridine acetonitrile with a-haloketones and ethyl-y-bromocrotonate nitromethane gave the 3-nitroso compound.80... [Pg.124]


See other pages where Bromocrotonate is mentioned: [Pg.177]    [Pg.178]    [Pg.381]    [Pg.319]    [Pg.99]    [Pg.318]    [Pg.300]    [Pg.318]    [Pg.255]    [Pg.256]    [Pg.307]    [Pg.173]    [Pg.50]    [Pg.748]    [Pg.106]    [Pg.478]    [Pg.106]    [Pg.215]    [Pg.299]    [Pg.1426]   
See also in sourсe #XX -- [ Pg.129 , Pg.471 ]




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4-bromocrotonic acid

Benzyl 4-bromocrotonate

Bromocrotonates, Reformatsky reactions

Ethyl 2-bromocrotonate

Methyl bromocrotonate

Methyl y-bromocrotonate

Y-Bromocrotonate

Y-Bromocrotonic acid

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