3- aminated tetrahydrofurane products

Scheme 4.9 Aminoalkoxylation reactions to form 3-aminated tetrahydrofurane products.

Instmmental methods of analysis provide information about the specific composition and purity of the amines. QuaUtative information about the identity of the product (functional groups present) and quantitative analysis (amount of various components such as nitrile, amide, acid, and deterruination of unsaturation) can be obtained by infrared analysis. Gas chromatography (gc), with a Hquid phase of either Apiezon grease or Carbowax, and high performance Hquid chromatography (hplc), using siHca columns and solvent systems such as isooctane, methyl tert-huty ether, tetrahydrofuran, and methanol, are used for quantitative analysis of fatty amine mixtures. Nuclear magnetic resonance spectroscopy (nmr), both proton ( H) and carbon-13 ( C), which can be used for quaHtative and quantitative analysis, is an important method used to analyze fatty amines (8,81). 

The substrate-controlled diastereoselective addition of lithiated alkoxyallenes to chiral nitrones such as 123, 125 and 126 (Scheme 8.32) furnish allenylhydroxyl-amines as unstable products, which immediately cydize to give enantiopure mono-orbicyclic 1,2-oxazines (Eqs 8.25 and 8.26) [72, 76]. Starting with (R)-glyceraldehyde-derived nitrone 123, cydization products 124 were formed with excellent syn selectivity in tetrahydrofuran as solvent, whereas precomplexation of nitrone 123 with... 

Di-/m-butyl-4-methylphenyl cyclopropanecarboxylatc (8) can be quantitatively lithiated by treatment with 1 equivalent of le/7-butyllithium at — 78 °C in tetrahydrofuran 64 to give an amine-free, slightly yellow solution of the lithium species 9, which is then attacked by an electrophile to furnish the alkylated product 10 in good yield. Diastereomers were obtained when R1 = CH3 or C6H5. 

Therapeutics. Compounds containing the furan or tetrahydrofuran ring are biologically active and are present in a number of pharmaceutical products. Furfuryl amine [617-89-0] is an intermediate in the diuretic, furosemide. Tetrahydrofurfurylamine [4795-29-3] may also have pharmaceutical applications. 5-(Dimethylaminomethyl)furfuryl alcohol [15433-79-1] is an intermediate in the preparation of ranitidine, which is used for treating ulcers. 

Increasing the solvent polarity results in a red shift in the -t -amine exciplex fluorescence and a decrease in its lifetime and intensity (113), no fluorescence being detected in solvents more polar than tetrahydrofuran (e = 7.6). The decrease in fluorescence intensity is accompanied by ionic dissociation to yield the t-17 and the R3N" free radical ions (116) and proton transfer leading to product formation (see Section IV-B). The formation and decay of t-17 have been investigated by means of time resolved resonance Raman (TR ) spectroscopy (116). Both the TR spectrum and its excitation spectrum are similar to those obtained under steady state conditions. The initial yield of t-1 is dependent upon the amine structure due to competition between ionic dissociation and other radical ion pair processes (proton transfer, intersystem crossing, and quenching by ground state amine), which are dependent upon amine structure. However, the second order decay of t-1" is independent of amine structure... 

The base (B) used was dicyclohexylethylamine. At the higher temperatures the isomeric products that one would expect from an isomerization of the acylcobalt carbonyls were formed (see Section II, A). Amines were also used in place of alcohols to give amides. Thus benzyl chloride reacted with carbon monoxide and aniline in tetrahydrofuran solution at 35° C in the presence of sodium cobalt carbonylate catalyst to give a 47% yield of phenylacetanilide. 

Various procedures for the purification of specific amine-boranes have been reported.12 Ethylenediamine-bisborane can be purified conveniently by aqueous extraction to remove water-soluble impurities. The crude product obtained from the tetrahydrofuran solution is ground to a fine powder in a mortar and added in small portions, with stirring, to about 75 ml. of water which has been cooled in an ice-water bath. Foaming may occur during this treatment. The white crystalline solid which does not dissolve is collected by filtration through a coarse-fritted-glass funnel and washed several times with small portions of cold water (about 5°C.). The final wash filtrate should be neutral toward pH paper. The product is dried by... 

These fluoroscent products emitted a greater fluorescence than the diacetylmonoxime fluorophors and were found to be easy to analyze and quite stable compounds. Fluram in tetrahydrofuran is nonfluoroescent and the reaction with primary amines is stated to be proportional to the actual amine content. This procedure was further evaluated by placing known quantities of... 

Gross44 chlorinated tetrahydrofuran at —30 to -40° in UV light. Dehydrohalogenation of the product with tertiary amines yielded furan. 

---