Cyclohexyl acetate, preparation from

Piperazine-2,3,5-trione has been prepared from aminoacetamide and diethyl oxalate in methanolic sodium methoxide (365b). Oxanilic acid (PhNHCOCOOH) refluxed with thionyl chloride gave 1,4-diphenylpiperazinetetraone (identical with authentic material obtained by chromic acid oxidation of 1,4-diphenylpiperazine-2,5-dione) (1640). Hydrolysis of 3,3,5,5,6,6-hexachloro-4-cyclohexyl-I-phenyl-piperazin-2-one by heating at 100° with aqueous acetic acid gave l-cyclohexyl-4-phenylpiperazinetetraone (probably) (853). 

C-Silylated cyclohexyl diazo esters can be prepared from the appropriate diazo acetates by treatment with TMSOTf and ethyl diisopropylamine in ether at -78 °C (eq A9) ... 

Ethereal methyllithium added at -70 to -60° to propargyl chloride in tetrahydro-furan, treated immediately at -70 to -60° with a soln. of tricyclohexylborane prepared from borane and cyclohexene in tetrahydrofuran, allowed to warm to room temp., ether and tetrahydrofuran removed under reduced pressure, the residue treated with acetic acid, and stirred 1 hr. at 25-30° 1-cyclohexyl-1,2-propadiene. Y 77%. F. e. s. T. Leung and G. Zweifel, Am. Soc. 96, 5620 (1974). 

However, more-rigorous treatment (5% acetic acid, 100°C, 17 hours) opened the imidazole ring and produced /V -cyclohexyl-a-formylaminoacetamidine (57), characterized as the crystalline picrate. Amidine 57 produced no dye in the Bratton-Marshall assay. The same behavior can be expected from AIR (46), although the product of hydrolytic ring-opening was not actually isolated. On the other hand, it was observed that a solution of AIRs (0.2 mM in 0.01-M ammonium hydroxide) prepared by biosynthesis, when stored at 4°C, did not change appreciably within a day. A decrease in the concentration of AIRs of about 30% occurred within a month. 

Apart from the reaction of cyclohexanecarboxylic acid with methyllithium, cyclohexyl methyl ketone has been prepared by the reaction of cyclohexylmagnesium halides with acetyl chloride or acetic anhydride and by the reaction of methylmagnesium iodide with cyclohexanecarboxylic acid chloride. Other preparative methods include the aluminum chloride-catalyzed acetylation of cyclohexene in the presence of cyclohexane, the oxidation of cyclohexylmethylcarbinol, " the decarboxylation and rearrangement of the glycidic ester derived from cyclohexanone and M)utyl a-chloroj)ropionate, and the catalytic hydrogenation of 1-acetylcycIohexene. "... 

The situation is similar with cyclic boronates, which are prepared by the following procedure. Steroid (10 pmol) and the respective substituted boric acid (10 jumol) are dissolved in ethyl acetate (1 ml) and the mixture is allowed to stand for 5 min at room temperature. Under these conditions, 17,20-diols, 20,21-diols and 17,20,21-triols are converted completely into boronates. Cyclic boronate was mainly produced from 17,21-dihydroxy-20-ketone, but side-products also appeared, the formation of which could be suppressed by adding a 10% excess of the reagent [387—389]. Different substituents on the boron atom, such as methyl, n-butyl, tert.-butyl, cyclohexyl and phenyl, are interesting from the viewpoint of GC—MS application. They are further suitable for converting isolated hydroxyl groups into TMS or acetyl derivatives. 

The vicinal diol 216, prepared in 10 steps from quinic acid, was elaborated into V-alkylated 2-epi-valienamines 217 in variable (16-98%) yield by reaction with Viehe s salt followed by Pd(0)-catalysed coupling with a range of primary e.g. R = H = Et, Bu, Hept, Oct, cyclohexyl, Bn) and secondary amines e.g. R = R = Bu, cyclohexyl, Pr). Carbocyclic influenza neuraminidase inhibitors 219 (n = 3-8) with a cyclic amine side-chain have also been prepared via Pd(0)-catalysed coupling of acetate 218 with the corresponding cyclic amines. The use of pentafunctional quinic acid as a polyoxygenated scaffold for combinatorial synthesis has also been described. ... 

High yields of p-D-ribofuranosides and P-D-glucopyranosides have been obtained by treating l-0-acetyl-2,3,5-tri-0-benzoyl-P-D-ribofuranose and p-o-glu-copyranose penta-acetate, respectively, in dichloromethane with equimolar quantities of an alcohol and tin(iv) chloride at or below room temperature. Several alkyl and cyclohexyl p-D-ribofuranosides were prepared by this method, which was extended to the synthesis of the protected disaccharide 6-0-(2,3,5-tri-0-benzoyl-P-D-ribofuranosyl)-l,2 3,4-di-0-isopropylidene-a-D-galactopyranose. Tin(iv) chloride also catalysed the formation of aryl p-D-ribofuranosides from P-D-ribofuranosyl tetra-acetate. An acetylated precursor has also been used in... 

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