Hetero-Cope-Umlagerungen. 4. Mitteilung. Regiokontrollierte Indolsynthesen

Hetero-Cope-Rearrangements, Regio-Controlled Synthesis of Indoles The reaction of O-deprotonated N-phenylhydroxylamines 1 with various electron-deficient allenes 2 , 14 , 16 gives, via Michael addition and Cope-rearrangement, substituted anilines 5 , which are easily convertible into indoles 6 . In this manner, sulfoxides 17 , serve as equivalents of 2-vinylindoles. Diels-Alder reaction with this 2-vinylindole equivalent followed by indolisation affords isoquinuclidine derivative 21 which may be a useful precursor for the preparation of Iboga alkaloids.     

Oxazolochlorins. 14.

The structure of 8‐oxo‐5,10,15,20‐tetraphenyl‐7‐oxaporphyrin N²⁴‐oxide, C₄₃H₂₈N₄O₃, (4B), shows that N‐oxidation of the pyrrole opposite the oxazolidone group cants the pyrrole out of the mean plane of the chromophore. This also affects the oxazolidone group, which is also slightly canted out. This conformation is qualitatively similar to that of the parent meso‐tetraphenylporphyrin N‐oxide, but dissimilar to that of the porpholactone N‐oxide isomer 8‐oxo‐5,10,15,20‐tetraphenyl‐7‐oxaporphyrin N²²‐oxide, (4A), carrying the N‐oxide at the oxazolidone group. While the degree of canting of the N‐oxidized groups in both cases is comparable (and more pronounced than in the porphyrin N‐oxide case), in (4A) the pyrrolic groups adjacent to the N‐oxidized group are more affected than the opposing group. These differences in the conformational modes may contribute to rationalizing the distinctly different electronic properties of (4A) and (4B).     

E.S.R. and D.S.C. investigations of phase transitions in polymorphic 4-n-alkoxybenzylidene-4′-n-alkylanilines

Abstract

It is shown that the McMillan parameter M = T _SAN/T _N1 (where T _SAN and T _NI are respectively the temperatures of the smectic A to nematic (SAN) and the nematic to isotropic (NI) phase transitions) is useful in analysing the crossover between second and first order behaviour of the S_NN transition in the nO.m homologous liquid crystal series (the 4-n-alkoxybenzylidene-4′-n-alkylanilines). Using a phase diagram of orientational ordering versus M for this series, as obtained in this work (from E.S.R. and D.S.C), a symmetric tricritical point with mean field exponent β₂ = 1 is demonstrated. In a preliminary study of E.S.R. linewidth parameters B and C of nitroxide spin probes dissolved in members of the nO.m series exhibiting a first order S_AN transition, critical-type divergences are observed near this transition. In the case where M is closer to 0.959 (the value at the tricritical point), these divergences appear similar to those previously observed in related nO.m members with a second order S_AN transition; however, they are considerably enhanced for an M value closer to unity (i.e. more removed from the tricritical point). This indicates the importance of coupling between orientational and positional order parameters in the observed critical-type divergences.     

Acetylenchemie. 9. Mitt. Anellierte imidazole aus N-propinylamid-vorstufen

The Compound 2-(N-Formyl-N-prop-2′-inyl)aminopyridine was cyclised in boiling formic acid to 3-methylimidazo[1,2-a]pyridine, with 3-methylene-2H-imidazo[1,2-a]pyridine as the intermediate. Under similar conditions the 1,3-diprop-2-inylpyrimido[4,5-b]quinoline-2,4-dione resulted from 1-methylimidazo[1,2-a]quinoline-4-carbonic acid-N-2-prop-2′-inylamide and from the 1-prop-2′-inylbenzo[b][1,8]naphthyridin-2-one the 1-methylbenzo[b]imidazo[1,2,3-ij]naphthyridine-4,7-dione as a new ring system, was obtained.     

Polysulfonylamines. CXXXII.

The crystal structure of the title compound, C₅H₇N₂⁺·C₁₂H₁₀NO₄S₂⁻, consists of two independent cation–anion pairs, A and B. Within each pair, the H—N—C—N*—H grouping (N*—H is the pyridinium function) and one N—S—O moiety of the anion are linked by N*—H⃛N and N—H⃛O hydrogen bonds to form an antidromic ring motif of type R²₂(8). The remaining amino donors give rise to N—H⃛O hydrogen bonds, connecting the ion pairs into A–B–A–B– chains. The structure testifies to the persistence of the R²₂(8) motif in question, which was previously detected as a highly robust supramolecular synthon in a series of onium di(methane­sulfonyl)­amidates. The structure is pseudosymmetric; the anion positions correspond to space group P2₁/n, but those of the cations do not.     

Die sterischen Bedingungen der Fragmentierungsreaktion. II. Teil. Stereoisomere 3-Aminocyclohexyl-p-toluolsulfonate. Fragmentierungsreaktionen, 15. Mitteilung

The solvolytic fragmentation of cis- and of trans-3-amino-cyclohexyl p-toluenesulfonates 8a and 9a and the corresponding N, N-dimethyl derivatives 8b and 9b has been studied. In 80% ethanol the cis-amino-tosylates 8a and 8b react faster than the homomorphous cis-3-alkyl-cyclohexyl tosylates 11a and 11b to yield fragmentation product exclusively or predominantly. The synchronous mechanism predictable on stereoelectronic grounds is therefore indicated.     

Furanverbindungen, 15. Mitt.

Zusammenfassung In mehrstufiger Synthese werden 1-Methyl-benzo[a]furo[3,2-h]xanthon (II) und 8-Acetyl-10-methyl-benzo[a]furo[2,3-i]-xanthon (III) aus 8-Acetyl-9-hydroxy-benzo[a]xanthon dargestellt.

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Starting with 8-acetyl-9-hydroxy-benzo[a]xanthone, 1-methyl-benzo[a]furo[3,2-h]xanthone and 8-acetyl-10-methyl-benzo[a]-furo[2,3-i]xanthone have been synthesized and the results recorded.

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Diese Veröffentlichung ist ein Teil der Arbeiten für die Dissertation zur Erlangung des Ph. D. an der Karnatak University vonA. Nagana Goud.     

P.M.R. analysis of several phosphorylated aziridines

Several new phosphorylated aziridines of related structure were prepared. P.m.r. analysis via decoupling experiments provided cis H-H, trans H-H, gem H-H and PNCH coupling values. Similar to simple aziridines, the cis H-H coupling is larger than trans H-H coupling (on vicinal ring carbons) which in turn is larger than gem H-H coupling. In one example operating at 100 MHz and 0° it was possible to detect the presence of two invertomers.     

13C n.m.r. spectra of some polychloroalkenes

¹³C n.m.r. spectra have been measured for thirty-two polychloroalkenes including (i) monosubstituted compounds CH₂?CHCCl_nH_2?nX, where ? X stands for ? H, ? Cl, alkyl, and trisubstituted alkenes CCl₂?CHAlk, none of which form geometric isomers; (ii) disubstituted compounds RCH?CHR′; (iii) and (iv) trisubstituted compounds of the types RCCl?CHR′ and CHCl?CClR, respectively. Compounds (ii) to (iv) represent either individual isomers or mixtures of the Z and E forms. In the case of compounds (ii) and (iii), the ordering of chemical shifts is δ_E > δ_Z for the sp²-carbon atoms and δ_E < δ_z for the adjacent tetrahedral ones. On the contrary, the signals of the sp²-carbon atoms of compounds (iv) obey the rule δ_E < δ_z. The effect of vinyl and allyl groups as substituents on the ¹³C chemical shifts of chlorine-containing groups is discussed. The dependence of the sp²-carbon spin–spin coupling constants J(¹³C? ¹H) on the number of chlorinated substituents in the molecule is also considered.     

Thermodynamic Studies of Bi-Univalent Electrolytes. VI. Thermodynamics of Cadmium Acetate from E. M. F. and Calorimetric Measurements

E. M. F. of the Cell, Cd-Hg (2-phase)/CdAc₂(m), Hg₂Ac₂(s)/Hg was measured at 20°, 25°, 30° and 40°C. The standard e. m. f. of the cell, Cd/CdAc₃(m), Hg₂Ac₂(c)/Hg was evaluated as E°=1.1500?11.09×10^?4T+1.06×10^?8T² The thermodynamic data of the reaction, Cd(c) + Hg₂Ac₂(c)=2Hg(l)+Cd⁺⁺(aq)+2Ac^?(aq) at 25°C were estimated as ΔF°=?42,139, ΔH°=?48,698 cal mole^?1 and ΔS°=?22.0 cal deg^?1 mole^?1 at 25°C. The thermodynamic data for the formation of Hg₂Ac₂(s) were evaluated as ΔF_f°=?202.3, ΔH_f°=?154.5 Kcal mole^?1 and S°=72.9 cal deg^?1 mole^?1. From measurements of the heats of solution of CdAc₂·2H₂O in aqueous solution, the relative partial molal enthalpies of cadmium acetate in aqueous solution were estimated.     

Structural characterisation of a water-soluble polysaccharide from tissue-cultured Dendrobium huoshanense C.Z. Tang et S.J. Cheng

A water-soluble polysaccharide TC-DHPA4 with a molecular weight of 8.0 × 10⁵ Da was isolated from tissue-cultured Dendrobium huoshanense by anion exchange and gel permeation chromatography. Monosaccharide analysis revealed that the homogeneous polysaccharide was made up of rhamnose, arabinose, mannose, glucose, galactose and glucuronic acid with a molar ratio of 1.28:1:1.67:4.71:10.43:1.42. The sugar residue sequence analysis based on the GC-MS files and NMR spectra indicated that the backbone of TC-DHPA4 consisted of the repeated units:→6)-β-Galp-(1→6)-β-Galp-(1→4)-β-GlcpA-(1→6)-β-Glcp-(1→6)-β-Glcp-(→. The sugar residue sequences β-Glcp-(1→)-α-Rhap-(1→3)-β-Galp-(1→, β-Glcp-(1→4)-α-Rhap-(1→3)-β-Galp-(1→, β-Galp-(1→6)-β-Manp-(1→3)-β-Galp-(1→, and α-l-Araf-(1→2)-β-Manp-(1→3)-β-Galp-(1→ were identified as the branches attached to the C-3 position of (1→6)-linked galactose in the backbone.     

Carbon-13 n.m.r. studies of methylquinolines and methylisoquinolines

Spectra are reported for all seven methylquinolines, nine dimethylquinolines, six methylisoquinolines and one dimethylisoquinoline. Substituent effects for the α, ortho, meta, para, vinylogous para and peri positions are reported for the monomethylcompounds. Additivity of these substituent effects is demonstrated for the dimethyl compounds which also exhibit a vicinal dimethyl steric effect.     

Azole. 45.

The three title compounds, namely (Z)‐1‐(4,5‐di­nitro­imidazol‐1‐yl)‐3‐morpholinopropan‐2‐one 2,4‐di­nitro­phenyl­hydrazone, C₁₆H₁₇N₉O₉, (IV), (Z)‐3‐morpholino‐1‐(4‐morpholino‐5‐nitro­imidazol‐1‐yl)propan‐2‐one 2,4‐di­nitro­phenyl­hydrazone, C₂₀H₂₅N₉O₈, (Va), and (E)‐3‐morpholino‐1‐(4‐morpholino‐5‐nitro­imidazol‐1‐yl)propan‐2‐one 2,4‐di­nitro­phenylhydra­zone tetra­hydro­furan solvate, C₂₀H₂₅N₉O₈·C₄H₈O, (Vb), have been prepared and their structures determined. In (IV), the C‐4 nitro group is nearly perpendicular to the imidazole ring and the C‐4—NO₂ bond length is comparable to the value for a normal single Csp²—NO₂ bond. In (IV), (Va) and (Vb), the C‐­5 nitro group deviates insignificantly from the imidazole plane and the C‐5—NO₂ bond length is far shorter in all three compounds than C‐4—NO₂ in (IV). In consequence, the C‐4 nitro group in (IV) is easily replaced by morpholine, while the C‐5 nitro group in (IV), (Va) and (Vb) shows an extraordinary stability on treatment with the amine. The E configuration in (Vb) is stabilized by a three‐centre hydrogen bond.     

Prins-Reaktionen mit Arylaldehyden, 3. Mitt.

By reaction of excess benzaldehyde with cyclohexene in presence of sulfuric acid besider-2,c-4-diphenyl-(t-4aH,c-8aH)-hexahydro-4H-1,3-benzodioxin (2) andr-4-phenyl-(t-4aH,c-8aH)-hexahydro-4H-1,3,2-benzodioxathiin-2,2-dioxide (3),trans-2-benzyloxycyclohexyl phenyl ketone (5) and (E)-3-benzylidene-1-cyclohexenyl phenyl ketone (6) are obtained. The formation of5 and6 is shown to proceed via an acid catalyzedCannizzaro reaction of benzaldehyde.

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2. Mitt.:H. Griengl undK. P. Geppert, Mh. Chem.107, 675 (1976).     

Synthese von Haschisch-Inhaltsstoffen. 4. Mitteilung

(?)-Cannabidiol has been synthesized from (+)-cis- and (+)-trans-p-menthadien-(2, 8)-ol-(1) and olivetol, using N, N-dimethylformamide dineopentyl acetal or weak acids, such as oxalic, picric, or maleic acid, as catalysts. Since the chirality of (+)-trans-p-menthadien-(2, 8)-ol-(1) is known, the above synthesis constitutes an unambiguous prove for the absolute configuration of (?)-cannabidiol and the two isomeric (?)-6a, 10a-trans-tetrahydrocannabinols. If stronger acids, such as p-toluenesulfonic, trifluoroacetic, or hydrochloric acid, are used as mediators for the reaction, (?)-Δ⁸-6a, 10a-trans-tetrahydrocannabinol is obtained as the main product. Transformation of the thermodynamically more stable Δ⁸-tetrahydrocannabinol into the less stable Δ⁹-isomer was achieved in a practically quantitative yield by addition of hydrochloric acid and elimination of the elements of hydrochloric acid by means of potassium t-amylate. If resorcinols I were used instead of olivetol in the condensation reaction with strong acids, the corresponding homologues of Δ⁸-tetrahydrocannabinol were obtained in varying yields.     

Flavonoid glycosides fromThalictrum squarrosum St. ex Willd. andThalictrum minus L.

Two flavonoid allose diglycosides were found in the terrestrial part ofThalictrum squarrosum St. ex Willd. andT. minus L. (Ranunculaceae). 7,4′-Di-O-β-allopyranosylapigenin was isolated fromT. minus. InT. squarrosum, its monoacetate was also found and characterized as 7-O-(6-O-acetyl-β-allopyranosyl)-4′-O-(β-allopyranosyl)apigenin. The sites of attachment of the carbohydrate residues were determined by HMBC; the location of the acetate group was identified by ROESY. Both substances were isolated from these plants for the first time. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 392–394, February, 1999.     

Triterpene glycosides from Astragalus and their genins. LXXVIII. Chemical transformation of cycloartanes. VI. Partial synthesis of cycloadsurgenina

Cycloadsurgenin, 20R,24 S-epoxycycloartan-6α,25-diol-3,16-dione, was partially synthesized in four steps from cyclosieversigenin. Side products with the structures 17E,24S-cycloart-17-en-6α,24,25-triol-3,16-dione and 17Z,24 S-cycloart-17-en-6α,24,25-triol-3,16-dione were obtained in addition to the desired product. Presented at the 1st International Symposim on Edible Plant Resources and the Bioactive Ingredients, Xinjiang, China, July 25–27, 2008. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 591–595, November–December, 2008.     

Carbon-13 n.m.r. spectra of saturated heterocycles. Part VII—Thianium Salts

The ¹³C n.m.r. spectra of 53 thianium, S-methylthianium, S-alkylthianium and S-methyl-1-thiadecalinium salts, most of them substituted with methyl groups in the ring, have been recorded. The chemical shifts of the ring carbons in these thianium and S-methylthianium salts and the S-methyls in the S-methylthianium salts have been analyzed in terms of additive parameters of the methyl substituents which are compared to those previously determined for the parent thianes. Comparison is also made with other charged species.     

13C n.m.r. spectra of some thiobenzamides. Correlation between 13C and 1H n.m.r. spectra and signal assignments of syn and anti CH2 groups

¹³C n.m.r. spectra of a series of N,N-disubstituted thioamides have been recorded and signal assignments were performed. Separate signals are observed for methylene groups fixed on the nitrogen atom. Since the carbon atom syn to the thiocarbonyl sulfur resonates at higher field than the anti carbon, the syn-anti assignment in ¹H n.m.r. is easily obtained by selective double irradiation. This method, which is rapid and reliable, affords a rather general solution to the interesting problem of resonance assignments in tertiary amides and thioamides (and in analogous molecules such as oximes and nitrosamines).     

Cover Picture: Angew. Chem. Int. Ed. 7/2002

The cover picture shows Cu₂(μ‐O)₂ and Fe₂(μ‐O)₂ complexes with the M₂(μ‐O)₂ diamond core motif (the core is shown bottom right, M=green and oxygen=red spheres) and a representative example of a non‐heme multimetal enzyme (hydroxylase component of methane monooxygenase, in the background). Although quite a familiar feature in high‐valent manganese chemistry, the M₂(μ‐O)₂ diamond core motif has only recently been found in synthetic complexes for M=Cu or Fe. Despite differences in electronic structures that have been revealed through experimental and theoretical studies, Cu₂(μ‐O)₂ and Fe₂(μ‐O)₂ cores exhibit analogously covalent metal–oxo bonding, and similar tendencies to abstract hydrogen atoms from substrates. Our understanding of biocatalysis has been enhanced significantly through the isolation and comprehensive characterization of the Cu₂(μ‐O)₂ and Fe₂(μ‐O)₂ complexes. In particular, it has led to the development of new mechanistic notions about how non‐heme multimetal enzymes, such as, methane monooxygenase, fatty acid desaturase, and tyrosinase, may function in the activation of dioxygen to catalyze a diverse array of organic transformations. To find out more see the review by L. Que, Jr. and W. B. Tolman on p.1114 ff.