%) CCH was isolated after column chromatography and recrystallization from ethanol; mp 51-52 °C (lit.36 mp 53.5-54.5 °C).Product Balances. In the experiments performed to obtain the product balances, THF was added (if necessary) before the workup in order to restore the original volume. Then a 10-mL sample was hydrolyzed by 10 mL of 2 N HC1 and extracted with CHC13 (benzophenon case) or pentane and ether (cyclohexanone experiments). A 1-mL extract was mixed with 1 mL of an internal standard solution of dodecane by using calibrated micropipets and analyzed by gas chromatography. Concentrations of TPE were also measured by UV analysis starting from a 2-mL sample treated in the usual way and diluted to the desired dilution factor. Absorbances at "" = 309 nm (CHC13) were compared against absorbances of standard solutions of TPE. No interferences were observed.ESR Measurements. The reduction of TiCl3 with Mg at a 1:1.7 TiCl3/Mg ratio was followed by ESR. At regular intervals (about every 30 min) an aliquot of the reaction mixture was transferred with the help of a syringe into the ESR tube, which was flushed before with Ar and carefully closed immediately after being filled. Spectra were recorded at room temperature.Step 1 (eq 1) was also followed as a function of the TiCl3/Mg ratio ranging from 1:0.2 to 1:1.8. In each case [M] was prepared as (c6h5)2oh-<^>-ch3 (c6h5)2°ci~(^)-ooi3

Ring and nitrogen inversion account for the conformational equilibria of 3‐phenyl‐1, 2,3, 4‐tetrahydroiso‐quinolines. In order to quantitate the relative contribution of each conformer to the equilibrium, we undertook a molecular mechanics study on several substituted 3‐phenyl‐1, 2, 3, 4‐tetrahydroisoquinolines. Predictions from calculations were checked against cmr chemical shift data. No boat conformation contributed significantly to the equilibrium. A general result of our calculations is that in all cases the 3‐phenyl group in the equatorial position is strongly favored (by at least 2.50 kcal/mole). For 3‐phenyl‐1, 2, 3, 4‐tetrahydroisoquinolines without substitution at nitrogen, N‐H in equatorial position is preferred over the axial conformer, although the energy difference between both is always small (0.30–1.10 kcal/mole). For the cis‐1,3‐disubstituted compounds the le'3e conformers are the only species present (at least 99.8%). The calculated energy differences between the la′3a conformer and the le′3e conformer are always large (3.80–6.10 kcal/mole for the NHe conformers and 3.60–3.80 kcal/mole for the NHa conformers). The lack of a γ1a upfield shift at C3 also points to the preference for the pseudoequatorial‐equatorial conformer. For N‐methyl‐3‐phenyl‐1,2,3,4‐tetrahydroisoquinoline a preference for the NMe group in the equatorial position is predicted (0.60–2.00 kcal/mole). The small downfield shift at C4 (γNa = 0.5 ppm) is consistent with the equatorial NMe preference. For the cis‐1,2,3‐trisubstituted compounds no significant γ1a effect at C3 (γ1a = ‐0.2 and 1.0 ppm) or γNa effect at C4 (γNa = 0.1 and 0.4 ppm) is observed. For these compounds, deformations due to steric congestion are evidenced by the deviation from the values of the C4a‐C8a‐Cl‐N and C4a‐C4‐C3‐N torsional angles, as compared to less crowded 3‐phenyl‐1,2,3,4‐tetrahydroisoquinolines. Here the heterocyclic ring adopts a distorted half‐chair conformation.

956, (1 11 3) Capital Federal, ArgentinaThe electron impact mass spectral fragmentation of a series of 3-substituted-1,2,3,4-tetrahydroisoquinolinc~ are reported. The principal fragmentation modes of these compounds comply with the main generalizations reacbed earlier with simpler systems. Complete aromatizations to form the isoquinolinium ion are observed only for compounds 5 and 7 and no retro-Diels-Alder cleavage is observed when R' is a benzyl goup.

016ChemInform Abstract Four compounds of the title system (Tl4Sn5S12, Tl2Sn2S5, Tl2SnS3, Tl4SnS4) have been isolated. Results of Mössbauer spectroscopy indicate a 4, 5, and 6 fold coordination of the Sn atoms. The phases show a quasi-semiconductor behavior with n electronic gap of 1.17 to 1.51 eV (electrical conductivity and optical absorption measurements).

Indanes monosubstituted and 1,2-and 1,3-disubstituted in the pentagonal ring were synthesized, and configurations were assigned to the 1,2-disubstituted compounds by means of nuclear magnetic resonance spectroscopy.