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Reagents ethoxycarbonyl chloride

Ethoxycarbonyl chloride is, by virtue of resonance involving the ester function, less reactive than acetyl chloride, and the reagent has found application for selective O-acylation in the steroid field.34 With this reagent, methyl 4,6-O-benzylidene-a-D-glucopyranoside yielded35 2- and 3-esters in the ratio 24 1, and the related benzyl-thiocarbonyl chloride gave the 2-ester in 58% yield.36... [Pg.20]

C-Acylation and -carboxylation also occur with pyrrole Grignard reagents (p. 106). Whilst lithium pyrrole and lithium 2,4-dimethylpyrrole react with ethoxycarbonyl chloride to give ethyl pyrrole-2- and 2,4-dimethylpyrrole-5-carboxylate, respectively the corresponding potassium salts give the N-substituted pyrroles (p. 81). [Pg.66]

Mercury(II) acetate tends to mercurate all the free nuclear positions in pyrrole, furan and thiophene to give derivatives of type (74). The acetoxymercuration of thiophene has been estimated to proceed ca. 10 times faster than that of benzene. Mercuration of rings with deactivating substituents such as ethoxycarbonyl and nitro is still possible with this reagent, as shown by the formation of compounds (75) and (76). Mercury(II) chloride is a milder mercurating agent, as illustrated by the chloromercuration of thiophene to give either the 2- or 2,5-disubstituted product (Scheme 25). [Pg.55]

The reagents and methods employed for coupling in solid-phase synthesis are the same as for synthesis in solution, but a few are excluded because they are unsuitable. The mixed-anhydride method (see Section 2.6) and l-ethoxycarbonyl-2-ethoxy-l,2-dihydroquinoline (see Section 2.15) are not used because there is no way to eliminate aminolysis at the wrong carbonyl of the anhydride. Acyl azides (see Section 2.13) are too laborious to make and too slow to react. The preparation of acyl chlorides (see Section 2.14) is too complicated for their routine use this may be rectified, however, by the availability of triphosgene (see Section 7.13). That leaves the following choices, bearing in mind that a two to three times molar excess of protected amino acid is always employed. [Pg.142]

In a one-pot synthesis of a-halo-a,p-unsaturatcd carboxylates from dialkyl l-(ethoxycarbo-nyl)methylphosphonate, the intermediate 1-chloro- and 1-bromo-l-(ethoxycarbonyl)methylphos-phonates were prepared by halogenation of sodium salt of dialkyl l-(ethoxycarbonyl)methylphos-phonates with NCS or NBS in THF at room temperature. Cupric chloride and cupric bromide have proved to be efficient reagents for the chlorination or bromination of sodium diethyl 1-(ethoxycarbonyl)ethylphosphonate in DMSO at room temperature in high yields (91%). ... [Pg.431]

Several compounds have been prepared by nucleophilic substitution of chlorine in 2-chloro-l,3-dithian with Grignard reagent (RMgBr), malonic esters, and phenols.A mechanism for the de-ethoxycarbonylation of the 2-(l,3-dithianyl)malonates by sodium chloride or sodium ethoxide has been studied. 2-Chlorotetrahydrofuran reacts with nucleophiles such as 2-lithio-2-phenyl-l,3-dithian (326) by three simultaneous mechanisms i.e. substitution, proton abstraction, and electron transfer) to give the products (327)—(330) (Scheme 12)/° When a dithian (331 R = H or COiMe) was treated with a sulphonyl chloride in pyridine, ring-expansion to the 5//-l,4-dithiepin (332) occurred instead of the expected formation of a sulphonate. ... [Pg.324]

Sample preparation 500 p-L Plasma + 100 p.L 200 p,g/mL tridecanoic acid in ethylene chloride + 200 xL 600 mM sulfuric acid + 3 mL isooctane isopropanol 95 5, extract. Remove the organic layer and evaporate it to dryness, reconstitute the residue in 1 mL 2.4 mg/mL 2-etho y-l-ethoxycarbonyl-l,2-dihydroquinoline (EEDQ) in ethylene chloride, add 5 mL reagent, reflux for 10 min, dilute with 10 mL ethylene chloride, wash with an equal volume of 200 mM NaOH, wash with an equal volume of 1 M HCl, wash with an equal volume of water. Remove the organic layer and diy it over sodium sulfate, evaporate to diyness, reconstitute the residue in mobile phase, ii ject an aliquot. (Prepare reagent by dissolving 5 mg p-nitrobenzylamine hydrochloride in 5 mL 200 mM NaOH, extract... [Pg.745]


See other pages where Reagents ethoxycarbonyl chloride is mentioned: [Pg.21]    [Pg.225]    [Pg.458]    [Pg.188]    [Pg.146]    [Pg.149]    [Pg.392]    [Pg.821]    [Pg.585]    [Pg.4]    [Pg.475]    [Pg.621]    [Pg.265]    [Pg.392]    [Pg.821]    [Pg.630]    [Pg.111]    [Pg.745]    [Pg.97]    [Pg.319]    [Pg.260]    [Pg.39]    [Pg.319]    [Pg.267]   
See also in sourсe #XX -- [ Pg.80 ]




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