were removed from the mixture, quenched with methanol, and analyzed by vpc to determine the extent of reaction. The reaction material was then cooled and decomposed with 3 ml of methanol. Analysis was made on this material by vpc or on the hydrogenated products obtained over a 10% palladium/charcoal catalyst.Reaction Products.-The liquid, cyclized reaction products that were isolated from the general reactions described above were separated from one another by means of preparative vpc. When separation of product from starting material was impossible because of identical relative retention times, e.g., 3 and 9 or 4 and 11 (Table II), the reaction mixture was first hydrogenated and separations were then performed. All products were shown to be of greater than 95% purity by vpc. The products were identified by means of nmr and ir spectral analyses. It is possible to assign the direction of cyclization in the case of the tricyclic products 5-8 by examination of the pyridine ring protons. Compounds 5 and 7 show three different protons at 8.20-8.26, 7.26-7.39, and 6.90-6.96 ppm corresponding to the a, , and ß protons, thus indicating that cyclization occurred in the a position. Similarly, with compounds 6 and 8, the presence of two a protons a 8.20-8.26 ppm and one ß proton at 6.93-7.00 ppm denotes that cyclization occurred in the position. For compounds 5-8 no methyl groups were present, only methylene and methine protons were present as indicated by a broad band at 1.00-2.34 ppm that correctly integrated for the proposed number of protons. Com-pounds 9-12 all had spectra similar to one another. The stereochemistry was determined from nmr by examining the chemical shift fo the methyl group and by coupling constants. Integration again was consistent with the proposed structures. No unsaturation was found by nmr or ir in any of the compounds 5-12.Refractive indices also indicate cyclic compounds (see Table II).Analyses.17-The nmr spectra of the pure samples in carbon tetrachloride were taken with a Varían T-60 spectrophotometer using tetramethylsilane as an internal standard. The microanalysis was done by M-H-W Laboratories, Garden City, Mich.Vapor phase chromatographic analyses and separations were performed on an F & M Model 720 dual-column instrument equipped with a thermal conductivity detector and using helium as a carrier gas. The separation of products for identification was accomplished with a 6 ft X 3/s in. column packed with Versamid 900 on Gas-Pack WAB.
A large variety of alkylaromatic compounds were found to undergo nucleophilic addition to conjugated olefins at room temperature when the reaction was performed in a dipolar aprotic solvent using potassium ierf-butoxide as a catalyst. The effectiveness of each of the solvents was determined from pseudo-first-order rate constants for the addition of 4-isopropylpyridine to isoprene in a variety of solvents and it was found to be DMSO > HMPA > NM2P > DMF > TMSO » TMU (NM2P = A-methyl-2-pyrrolidone, TMSO = tetramethylene sulfoxide, TMU = tetramethylurea). The rates of reaction were also measured when the conjugated olefin used was styrene, -methylstyrene, and ^-methylstyrene. The mechanism of nucleophilic addition is discussed with regard to the effect of solvent and olefins used. Some selected reactions were run at different temperatures and their activation parameters were calculated.
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