Acyl mixed

For efficient acylation, mix 340 pi of stock solution B with 1 ml of stock solution A, and leave at room temperature in the dark for 2 h. 

Mao, R., Tang, J., and Swanson, B.G. 2000. Texture properties of high and low acyl mixed gellan gels. Carbohydr. Polym. 41, 331-338. 

Ketones can be prepared by trapping (transmetallation) the acyl palladium intermediate 402 with organometallic reagents. The allylic chloride 400 is car-bonylated to give the mixed diallylic ketone 403 in the presence of allyltri-butylstannane (401) in moderate yields[256]. Alkenyl- and arylstannanes are also used for ketone synthesis from allylic chlorides[257,258]. Total syntheses of dendrolasin (404)f258] and manoalide[259] have been carried out employing this reaction. Similarly, formation of the ketone 406 takes place with the alkylzinc reagent 405[260],... 

One type of o-aminobenzyl anion synthon is a mixed Cu/Zn reagent which can be prepared from o-toluidines by / i.s-trimethylsilylation on nitrogen, benzylic bromination and reaction with Zn and CuCN[l]. Reaction of these reagents with acyl halides gives 2-substituted indoles. 

The 7 glutamyl phosphate formed m this step is a mixed anhydride of glutamic acid and phosphoric acid It is activated toward nucleophilic acyl substitution and gives glutamine when attacked by ammonia... 

Fluorosulfuric acid [7789-21-17, HSO F, is a colodess-to-light yellow liquid that fumes strongly in moist air and has a sharp odor. It may be regarded as a mixed anhydride of sulfuric and hydrofluoric acids. Fluorosulfuric acid was first identified and characterized in 1892 (1). It is a strong acid and is employed as a catalyst and chemical reagent in a number of chemical processes, such as alkylation (qv), acylation, polymerization, sulfonation, isomerization, and production of organic fluorosulfates (see Friedel-CRAFTSreactions). 

Reactions with Acyl Garbanion Equivalents. Alkyl substituted carbanions CRXY with potential leaving groups X, Y, and acyl carbanion equivalents or CHRX (342) react with alkylboranes, providing products with mixed alkyl groups derived from both reagents. 

AijAT-dicyclohexylcarhodiimide (DCC) also leads to essentially quantitative conversion of amic acids to isoimides, rather than imides (30,31). Combinations of trifluoroacetic anhydride—triethjlarnine and ethyl chi oroform a te—triethyl amine also result in high yields of isoimides (30). A kinetic study on model compounds has revealed that isoimides and imides are formed via a mixed anhydride intermediate (12) that is formed by the acylation of the carboxylic group of amic acid (8). 

Mixed chloiide alkoxides aie prepared by reaction with acyl chlorides, metal chlorides, hydrogen chloride, or chlorine (64). 

Mixed aiihydiosulfides can be leaddy obtained by adding an acetone solution of the xanthate to an acetone solution of the acyl halide at —35 C (53) ... 

Mixed-Metal Systems. Mixed-metal systems, where a zirconium alkyl is formed and the alkyl group transferred to another metal, are a new apphcation of the hydrozirconation reaction. These systems offer the advantages of the easy formation of the Zr—alkyl as well as the versatiUty of alkyl—metal reagents. For example, Cp2ZrRCl (R = alkyl or alkenyl) reacts with AICI3 to give an Al—alkyl species which may then be acylated with... 

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). 

Broinonaphlhalene (9). in the same manner the acyl chloride 6 was reacted with hydroxamic denvative 7 to give the mixed ester 8, which heated In BrCCIa/PhCI In the presence of azolsobutyronitnle (AIBN) at 130°C afforded 9 in 85% yield. 

There are alternatives to the addition-elimination mechanism for nucleophilic substitution of acyl chlorides. Certain acyl chlorides are known to react with alcohols by a dissociative mechanism in which acylium ions are intermediates. This mechanism is observed with aroyl halides having electron-releasing substituents. Other acyl halides show reactivity indicative of mixed or borderline mechanisms. The existence of the SnI-like dissociative mechanism reflects the relative stability of acylium ions. 

Carboxylic acids react with trifluoroacetic anhydride to give mixed anhydrides that are especially useful for the acylation of hindered alcohols and phenols ... 

The active acylating agent may be the protonated mixed anhydride, or, alternatively, the anhydride m dissociate to the acylium and trifluoroacetate ions ... 

In a reaction related to the mixed Claisen condensation, nonenolizable esters are used as acylating agents for ketone enolates. Ketones (via their enolates) are converted to p-keto esters by reaction with diethyl carbonate. 

Mixed Claisen condensations (Section 21.3) Diethyl carbonate, diethyl oxalate, ethyl formate, and benzoate esters cannot form ester enolates but can act as acylating agents toward other ester enolates. 

Phase transitions have been characterized in a number of different pure and mixed lipid systems. Table 9.1 shows a comparison of the transition temperatures observed for several different phosphatidylcholines with different fatty acyl chain compositions. General characteristics of bilayer phase transitions include the following ... 

A solventless synthesis of pyrazoles, a green chemistry approach, has been described where an equimolar amount of the diketone and the hydrazine are mixed in a mortar with a drop of sulfuric acid and ground up. After an appropriate length of time ( 1 h) the product is purified to provide clean products. Even acyl pyrazoles 42 were obtained under the solvent-less reaction conditions in good yields. 

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