Palmitic aldehyde

Cetyl alcohol is oxidized with CBT in methylene chloride to form palmitic aldehyde in 10% yield, but after the addition of 25% pyridine the yield of aldehyde reached 80-90% (72MI1). Cyclobutanone was obtained in 72% yield by oxidation of cyclobutanol with CBT (72JCED108). 

A soln. of bis-(4-methylpiperazinyl)aluminum hydride prepared from AlHg and 4-methylpiperazine in anhydrous tetrahydrofuran added during 5 min. to an ice-cold soln. of palmitic acid in the same solvent, and refluxed 6 hrs. palmitic aldehyde. Y 77%. F. e. s. M. Muraki and T. Mukaiyama, Chem. Lett. 1974, 1447 aldehydes from carboxylic acid amides (cf. Synth. Meth. 16, 98), also with di-morpholinoaluminum hydride s. ibid. 1975, 875. 

Elsewhere, two methods for the preparation of 2-( -alkylamino)-1,3-diols from 2,3-epoxy-alcohols were described. The first involved sequential transformation of the epoxy-alcohol into an epoxy-urethane and thence to a 2-oxazolidinone, the second consisting of treating the epoxide derivative directly with benzyl isocyanate and sodium hydride in THE (Scheme 20). This methodology was utilised in the synthesis of (+)-erythro-dihydrosphlngoslne from palmitic aldehyde. 

The ( c,j8-unsaturated aliphatic carbon chain is probably derived from an alka-nal, e.g., palmitic aldehyde. 

Sphingosine often is accompanied by the saturated dihydrosphingosine, and in plants by phytosphingosine, with an additional hydroxy group (formally derived by addition of a molecule of water across the double bond of sphingosine). The biosynthesis begins with serine and a Cw compoimd, probably a fatty aldehyde palmitic aldehyde would produce dihydrosphingosine directly by a condensation with the a-C atom of serine and subsequent decarboxylation. 

Retinal (Vitamin A aldehyde). Retinoic acid (Vitamin A acid), Retinyl acetate, Retinyl palmitate see entries in Chapter 4. 

Solids. —It may Idc a hydrocM bon (c .g., paraffin wa, naphthalene) highei alcohol eg., cetyl alcohol) aldehyde e.g., z5-hydroxybenzaldehyde) ketone and qiiinonc e.g., benzo-phenone, camphor) acid (higher fatty, e.g., palmitic acid or aromatic acid) ester (of glycerol, phenols or aromatic alcohols) phenol e.g., thymol),... 

Tboros and Beekstroem Isolated n-hepiylic acid, palmitic acid, an unreoogn 1 sed unaaturated acid, eugenol, aud asarjlic aldehyde. There is also prusent a body ul the formula inultiiig at 128 , which... 

Vitamin A or a precursor must be provided in the diet. This vitamin occurs in various forms (vitamers) retinol (alcohol), retinal (aldehyde), retinoic acid and vitamin A palmitate (ester). Requirements for vitamin A are usually expressed in international units (IU) per kg of diet. The international standards for... 

Fatty acyls FA Fatty acids and conjugates Octadecanoids Eicosanoids Docosanoids Fatty alcohols Fatty aldehydes Fatty esters 0 Fatty acid palmitic acid... 

Silver oxide, easily prepared from silver nitrate and sodium hydroxide, is probably the best reagent for the preparation of pure acids from aldehydes. An additional advantage is that it does not attack other easily oxidizable groups in the molecule. Typical examples are 3-thiophene-carboxylic acid (97%), palmitic acid (98%), and anthracene-9 carboxyIic acid (72%). Its use in the preparation ol olefinic acids from olefinic aldehydes is illustrated by the preparation of 2-methyI-2-pentenoic acid (60%). Organic peracids have also been used in the oxidation of aldehydes to carboxylic acids. ... 

There is only one report in the literature concerning Astragalus essential oil. Miyazawa in 1987 [214] has studied the volatile flavour of "Astragali radix" (the root of A.membramceus, that has a good note and a dry green mild fruity odor), obtained by steam distillation under atmosferic pressure of the macerated roots twenty-two components have been identified by GC, GC-MS, IR and NMR analyses. They include 9 dimethylesters of dicarboxilic acids, 14 methylesters of fatty acids, 2 aldehydes, 1 ketone, 4 alcohols and 1 acid. Methyl palmitate is the main component (22.0 %), followed by dimethyl azelate (16.2 %), a compound with a fhiity-winey odor such as the dimethyl esters of dicarboxilic acids. 

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