Palmitoyl chloride

Nitrobenzoylimidazole, however, forms with HC1 a sparingly soluble salt that reacts at room temperature only slowly. At higher temperature / -nitrobenzoyl chloride can be readily obtained (refluxing 1,2-dichloroethane). Analogous preparations are those of Af-palmitoyl chloride and caproyl chloride (chloroform, 55-60 °C). 

Scheme 5 Palmitoylation under acidic conditions using 20-fold excess of palmitoyl chloride.

Afterward, the peptide chain was elongated following the standard Fmoc-based protocol. Before cleavage of the peptide the incorporated Mmt-protected cysteine was deprotected using 1% TFA. Under these very mild conditions the farnesyl moiety was not harmed. Palmitoylation could he achieved using an excess of palmitoyl chloride. Cleavage with copper acetate and methanol as a nucleophile gave the farnesylated and palmitoylated N-Ras sequence with the C-terminal methyl ester 78. ... 

To prevent the S—>N acyl shift, S-palmitoylation with palmitoyl chloride is performed in anhydrous solvents on N -aminoacylated cysteines, e.g. dipeptide building blocks, whereby the residual functionalities of the peptide have to be protected taking into account the base-lability of the thioester bond. 

An early synthesis of A5-palmitoy]-.S -[2,3-bis(palmitoyloxy)propyl]cysteine employed cysteine methyl ester, however, this leads to difficulties in the saponification step of the tri-palmitoylated residue. 96 The optimized procedure, in which the cystine di-fert-butyl ester is used, 90 is outlined in Scheme 6 after N-acylation with palmitoyl chloride, the ester is reduced to the cysteine derivative for S-alkylation with l-bromopropane-2,3-diol to yield chirally defined isomers if optically pure bromo derivatives are used. Esterification of the hydroxy groups is best carried out with a 1.25-fold excess of palmitic acid, DCC, and DMAP. The use of a larger excess of palmitoyl chloride is not recommended due to purification problems. The diastereomeric mixture can be separated by silica gel chromatography using CH2Cl2/EtOAc (20 1) as eluent and the configuration was assigned by comparison with an optically pure sample obtained with 2R)- -bromopropane-2,3-diol. 

Dissolve 2.5 g palmitoyl chloride in 25 ml toluene and then add dropwise to TEA/PEG solution (from step 2). 

A partial synthesis of cerebroside sulfate [ sulfatide, the glycoside of ceramide with galactose 3-sulfate, (90)] was achieved [90] by acylating the sphingosine galactosyl 3-sulfate (89) (obtained by basic hydrolysis of natural sulfatide) with palmitoyl chloride or D-2-acetoxypalmitoyl chloride (and subsequent basic hydrolysis of the... 

Sodium bicarbonate Hydrochloric acid Palmitoyl chloride... 

A solution of palmitoyl chloride in dioxane was added dropwise to a cooled dispersion of sodium borohydride.The mixture was heated on the steam bath for a short time and then, after cooling, water was added. On distillation a yield of hexadecanol 87%, M.P. 49°C, B.P. 344°C. 

In this context, the chiral hyperbranched polyglycerols (-)-PG [Mn = 3000, with bis(2,3-dihydroxypropyl)undecenylamine as the initiator] and (+)-PG [Mn = 5500, with trimethylolpropane (TMP) as the initiator] were used. Esterification of the hydroxyl groups of these hyperbranched polyglycerols with hydrophobic alkyl chains as palmitoyl chloride, yielded amphiphilic molecular nanocapsules with reverse micelle-type architecture, in which approximately 50% of the hydroxyl groups were functionalized with palmitoyl chains [96-98]. These materials exhibit low polydispersity (Mw/Mn < 2), and the amphiphilic molecular nanocapsules are soluble in nonpolar solvents and irreversibly encapsulate various polar, water-soluble dye molecules in their hydrophilic interior by liquid-liquid extraction [96,98]. 

Hydrogenation of the mixture followed by hydrolysis gave solamine (159) and a mixture of palmitic acid (80%) and stearic acid (20%). The alkaloid containing stearic acid was not investigated further. The structure of sola-mine was confirmed by direct comparison with the synthetic 4,4 -bis(di-methylamino)dibutylamine. Treatment of solamine (159) with palmitoyl chloride and ( )-hexadec-2-enoyl chloride produced solapalmitine (160) and solapalmitenine (161), respectively (118,119). 

Pentadecyl phenyl thloether (5),2 From palmitoyl chloride and the hydroxamic sodium salt 2 there was obtained the ester 3 which by heating m neat PhSSPh (30 equivalents) afforded 5 in 74% yield. 

N-hydroxysuccinimidyl palmitate was prepared by dropwise addition of palmitoyl chloride to a rigorously stirred suspension comprising one equivalent each of N-hydroxysuccinimide and triethylamine in dry tetrahydrofuran at room temperature. After removal of solids by filtration, the solvent was evaporated and the product (yield -70%) was used without further treatment. 

Starch palmitate is prepared by treating 1 part of starch in a mixture of 4 parts of benzene and 1.8 parts of pyridine with 6 parts of palmitoyl chloride and 4 parts of benzene for thirty minutes at 60° and precipitating the product with ethanol. Quinoline may be substituted for the benzene and pyridine. Because of the high boiling point of quinoline, an elevated esterification temperature can be used and triesters produced in about three hours. 

Palmitic acid, 36, 83 37, 69 Palmitonitrile, 32, 67 Palmitoyl chloride, 37, 69 Parabanic acid, 37, 71 Paraffin-oil test for water in ethanol, 32,69... 

Immediately add 1 mL palmitoyl chloride solution to the 1 mL of mannan solution. Mix to dissolve. 

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