Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Carbonic anhydrides

Ca.rboxyhc Acids. Esters are the main products in the reaction of chloroformates with carboxyHc acids. The intermediate mixed carboxyhc—carbonic anhydrides are very active acylating agents (25—27) but these agents may be isolated in cold temperatures for producing useful products (28). [Pg.39]

Chemical Designations - Synonyms Carbonic Acid Gas Carbonic Anhydride Chemical Formula CO2. [Pg.79]

Kohlensaure,/. carbonic acid carbon dioxide, -anhydrid, rt. carbonic anhydride (carbon dioxide), -ausscheidung,/. (Physiol.) c Tbon dioxide excretion, -bestimmer, m. apparatus for determining carbon dioxide, -brot, n, aerated bread, -chlorid, n. carbonyl chloride, -entwickelung,/. evolution of carbon dioxide, -ester, m. carbonic ester, -flasche, /. carbon dioxide cylinder, -gas, n, carbonic add gas (carbon dioxide), -gehalt, m. carbon dioxide content. [Pg.251]

The synthesis of key intermediate 12, in optically active form, commences with the resolution of racemic trans-2,3-epoxybutyric acid (27), a substance readily obtained by epoxidation of crotonic acid (26) (see Scheme 5). Treatment of racemic 27 with enantio-merically pure (S)-(-)-1 -a-napthylethylamine affords a 1 1 mixture of diastereomeric ammonium salts which can be resolved by recrystallization from absolute ethanol. Acidification of the resolved diastereomeric ammonium salts with methanesulfonic acid and extraction furnishes both epoxy acid enantiomers in eantiomerically pure form. Because the optical rotation and absolute configuration of one of the antipodes was known, the identity of enantiomerically pure epoxy acid, (+)-27, with the absolute configuration required for a synthesis of erythronolide B, could be confirmed. Sequential treatment of (+)-27 with ethyl chloroformate, excess sodium boro-hydride, and 2-methoxypropene with a trace of phosphorous oxychloride affords protected intermediate 28 in an overall yield of 76%. The action of ethyl chloroformate on carboxylic acid (+)-27 affords a mixed carbonic anhydride which is subsequently reduced by sodium borohydride to a primary alcohol. Protection of the primary hydroxyl group in the form of a mixed ketal is achieved easily with 2-methoxypropene and a catalytic amount of phosphorous oxychloride. [Pg.176]

The mixed carbonic anhydride procedure8-7 has been useful in the preparation of amide linkages and thiol esters. Mixed carbonic anhydrides have successfully acylated, under very mild conditions, the carb-anions derived from diethyl ethylmalonate and diethylcadmium.8 The latter gives as a product the corresponding ketone. Mixed anhydrides derived from acetic and acetylsalicylic acids give results similar to those described here.8... [Pg.12]

B. Mixed benzoic-carbonic anhydride (Note 7). In a 500-ml. threenecked flask, equipped with a low-temperature thermometer, an efficient sealed stirrer, and an adaptive joint carrying a drying tube and a dropping funnel, is placed a solution of 24.4 g. (0.2 mole) of benzoic acid (Note 8) and 20.2 g. (0.2 mole) of triethylamine (Note 9) in 200 ml. of dry toluene. The solution is cooled below 0° by means of an ice-salt mixture, and 21.7 g. (0.2 mole) of ethyl chlorocarbonate (Note 10) is added at such a rate that the temperature does not rise above 0° (approximate time for addition is 25-30 minutes). Triethylamine hydrochloride precipitates both during the addition and while the mixture is stirred for 15-25 minutes thereafter. [Pg.69]

Phenylcyclopentanecarboxylic acid, with ethyl chlorocar-bonate to give mixed carboxylic-carbonic anhydride, 51, 48... [Pg.63]

Sodium, with l-bromo-3-chloro-cyclobutane to give bicyclo [l.l.O]butane, 51, 55 Sodium amalgam, 50, 50, 51 Sodium amide, with 2,4-pentane-dione and diphenyliodonium chloride to give l-phenyl-2, 4-pentanedione, 51, 128 Sodium azide, 50, 107 with mixed carboxylic-carbonic anhydrides, 51, 49 Sodium borohydride, reduction of erythro-3-methanesulfony-loxy-2-butyl cyclobutanecar-boxylate, 51, 12 reduction of 2-(1-phenylcyclo-pentyl)-4,4,6-trimethyl-5,6-dihydro-1,3(4H)-oxazine to 2-(1-phenylcyclopentyl)-4,4, 6-trimethyltetrahydro-l,3-oxazine, 51, 25 Sodium cyanoborohydride, used... [Pg.135]

GW Anderson, JE Zimmerman, FM Callahan. A reinvestigation of the mixed carbonic anhydride method of peptide synthesis. J Am Chem Soc 89, 5012, 1967. [Pg.33]

J Meienhofer. The mixed carbonic anhydride method of peptide synthesis, in E Gross, J Meienhofer, eds. The Peptides Analysis, Synthesis, Biology, Academic, New York, 1979, Vol 1, pp 263-314. [Pg.34]

S Kim, JL Lee, YC Kim. A simple and mild esterification method for carboxylic acids using the mixed carboxylic-carbonic anhydrides. J Org Chem 50, 560, 1985. [Pg.86]

DS Tarbell, EJ Longosz. Thermal decomposition of mixed carboxylic-carbonic anhydrides. Factors affecting ester formation. J Org Chem 24, 774, 1959. [Pg.204]

DS Tarbell. The carboxylic carbonic anhydrides and related compounds. Acc Chem Res 2, 296, 1969. [Pg.204]

Polycarbonates are polyesters resulting from the polycondensation of carbonic anhydride (furnished by phosgene) and a bisphenol. [Pg.437]

Amine oxides, anhydrous, SO, 55, 58 Amines, protecting group for, 50,12 AMINES FROM MIXED CARBOXYLIC-CARBONIC ANHYDRIDES 1-PHENYLCYCLOPENTYL-AMINE,51,4S... [Pg.72]

Bis alkanoyl amino-2,4,6-triiodobenzyl esters Nanoparticulate diagnostic diatrizoxy ester Nanoparticulate diagnostic mixed carbonic anhydrides... [Pg.117]

AMINES FROM MIXED CARBOXYLIC-CARBONIC ANHYDRIDES ... [Pg.25]

Alenylacetylenes, 50,101 Aluminum chloride, with ethylene and p-methoxyphenylacetyl chloride to give 6-methoxy-/3-tetralone, 51,109 with propylene and acetyl chloride to give 4-chloropentan-2-one, 51,116 Amine oxides, anhydrous, 50, 55, 58 Amines, protecting group for, 50,12 AMINES FROM MIXED CARBOXYLIC-CARBONIC ANHYDRIDES 1-PHENYLCYCLOPENTYLAMINE,... [Pg.76]

Curtius reaction, modification using mixed carboxylic-carbonic anhydrides, 51,51... [Pg.77]

Phenylcyclopentylamine has also been prepared from 1-phenylcyclopentanecarboxylic acid by means of the Hofmann degradation of the intermediate amide4 6 and from the intermediate carboxylic acid chloride by the Curtius reaction.6 In the method described, using the mixed carboxylic-carbonic anhydride,7 improved yields of the amine are obtained. [Pg.110]

The usual procedure of preparing acid azides, which involves treating an acid chloride with sodium azide,8,9 suffers from the disadvantage that it is often difficult to obtain pure acid chlorides in good yields from acids which either decompose or undergo isomerization in the presence of mineral acids.7 Synthesis of the azide by way of the ester and hydrazide10 has been used to circumvent this difficulty but is much less convenient. The present procedure permits ready formation of acid azides in excellent yields from mixed carboxylic-carbonic anhydrides and sodium azide under very mild conditions. [Pg.110]

Synonyms ammonium aminoformate ammonium carbonate anhydride... [Pg.29]

One atom of carbon and two atoms of oxygen form carbonic anhydride. [Pg.18]

Oxygen is evolved in nature in a remarkable manner by the decomposition of carbonic anhydride, C0 by the green leaves of plants, the vegetable assimilating the carbon, whilst the oxygen escapes into the atmosphere —... [Pg.50]


See other pages where Carbonic anhydrides is mentioned: [Pg.413]    [Pg.251]    [Pg.12]    [Pg.45]    [Pg.45]    [Pg.57]    [Pg.59]    [Pg.87]    [Pg.376]    [Pg.432]    [Pg.110]    [Pg.21]    [Pg.667]    [Pg.34]    [Pg.36]   
See also in sourсe #XX -- [ Pg.79 ]

See also in sourсe #XX -- [ Pg.116 ]

See also in sourсe #XX -- [ Pg.79 ]

See also in sourсe #XX -- [ Pg.82 ]




SEARCH



1-Phenylcyclopentanecarboxylic acid mixed carboxylic-carbonic anhydride

AMINES FROM MIXED CARBOXYLIC-CARBONIC ANHYDRIDES

Alkyl carbonic acid mixed anhydrides

Ammonium carbonate anhydride

Anhydrid, acetic carbonic

Anhydrides and diaryl carbonates

Anhydrides, mixed carbonic

Benzoic-carbonic anhydride

Carbon anhydride

Carbon monoxide anhydrides

Carbonic acid anhydrides

Carbonic acid anhydrides 7-lactones

Carbonic acid anhydrides active

Carbonic acid anhydrides alcohols

Carbonic acid anhydrides carbonates

Carbonic acid anhydrides chloride

Carbonic acid anhydrides cyclic

Carbonic acid anhydrides dichlorides

Carbonic acid anhydrides diols

Carbonic acid anhydrides diphenyl carbonate

Carbonic acid anhydrides enol carbonates

Carbonic acid anhydrides esters

Carbonic acid anhydrides ethers

Carbonic acid anhydrides ethylene derivatives

Carbonic acid anhydrides l,3-dioxolan-2-ones

Carbonic acid anhydrides phenols

Carbonic acid anhydrides selective

Carbonic acid anhydrides urethans

Carbonic acid anhydrides vinylene carbonate

Carbonic acid, mixed anhydrides

Carbonic-carboxylic anhydrides

Carboxylic acids, functional derivatives Acid anhydrides, Amides, carbonic

Curtius reaction, modification using mixed carboxylic-carbonic anhydrides

INDEX carbonic anhydrides

Mixed carbonic-carboxylic anhydrides

Sodium azide with mixed carboxylic-carbonic anhydrides

Sodium borohydride anhydrides, carboxylic-carbonic

Sulfur analogues, carbonic anhydride

Tert carbonic anhydride

Transition state carbonic anhydrides

With mixed carboxylic-carbonic anhydrides

© 2024 chempedia.info