PSEUDACONITINE, AND THE STEREOCHEMICAL RELATIONSHIP OF THE HIGHLY OXYGENATED ACONITE ALKALOIDS

1963 ◽  
Vol 41 (6) ◽  
pp. 1485-1489 ◽  
Author(s):  
Y. Tsuda ◽  
Léo Marion

An alkaloid isolated from Aconitum spicatum Stapf has been found to be identical not only with the originally described pseudaconitine but also with 'α-pseudaconitine'. The product of the partial hydrolysis of the base, i.e., veratroylpseudaconine, is dextrorotatory, and not laevorotatory as recorded in the old literature. On heating, pseudaconitine undergoes pyrolysis, loses the elements of acetic acid, and gives rise to pyropseudaconitine. This substance, on treatment with lithium aluminum hydride, is converted to demethoxyisopyropseudaconine which is identical with the Wolff–Kishner reduction product of pyraconine. This correlation establishes that pseudaconitine and aconitine possess the same absolute configuration, which, in the light of previous knowledge, is extended also to indaconitine, delphinine, mesaconitine, and jesaconitine.

1997 ◽  
Vol 75 (6) ◽  
pp. 616-620 ◽  
Author(s):  
Chi-Ming Yang ◽  
Dennis D. Tanner

The hydrolysis of a pyridine solution of lithium tetrakis(N-dihydropyridyl)aluminate (LDPA), which was prepared at 0 °C, yields a mixture of 1,4-, 1,2-, and 2,5-dihydropyridines (DHPs) in a ratio of 26:37:38. The subsequent reversible base-catalyzed condensation of a 1:1 mixture of 1,2- and 2,5-DHPs carried out in the presence of oxygen affords an 89% yield of (±)-anatabine. When the reaction mixture is allowed to stand in the presence of oxygen, anabasine is slowly formed from anatabine by the reaction of the residual DHPs. Anatabine can also be converted into (±)-anabasine by catalytic hydrogenation. Keywords: lithium aluminum hydride, pyridine, anatabine, anabasine.


1973 ◽  
Vol 51 (7) ◽  
pp. 969-972 ◽  
Author(s):  
Clifford Raymond Haylock ◽  
Keith Norman Slessor

Synthesis of the only unknown deoxyfructose, 4-deoxy-D-threohexulose, is reported. Its preparation involved reductive lithium aluminum hydride ring opening of 3,4-anhydro-1,2:5,6-di-O-isopropylidene- D-talitol, followed by hydrolysis of the resulting epimeric deoxy diisopropylidene hexitols and selective Acetobacter suboxydans oxidation of 3-deoxy-D-arabinohexitol. Kinetic studies using 4-deoxy-D-threohexulose as substrate for yeast hexokinase support the premise that the C-4 hydroxyl is a binding group in formation of the enzyme–substrate complex. Enzymatic synthesis of 4-deoxy-D-threohexulose 6-phosphate and 4-deoxy-D-threohexulose 1,6-diphosphate has been achieved in low yield from 4-deoxy-D-threohexulose.


1953 ◽  
Vol 31 (9) ◽  
pp. 775-784 ◽  
Author(s):  
Edward Leete ◽  
Léo Marion

Indole-3-aldehyde, indole-3-carboxylic acid and its ethyl ester were reduced by excess lithium aluminum hydride to skatole. The expected reduction product, 3-hydroxymethylindole, was obtained by the action of sodium hydroxide on gramine methiodide. It and its alkyl ethers were readily reduced to skatole. 3-Hydroxymethylindole underwent self-condensation to 3,3′-di-indolylmethane in neutral and alkaline media, and with acidic reagents was converted to an oxygen-free polymeric substance. The mechanism of these reactions and of the hydrogenolysis is discussed


1960 ◽  
Vol 38 (7) ◽  
pp. 1035-1042 ◽  
Author(s):  
J. C. Seaton ◽  
M. D. Nair ◽  
O. E. Edwards ◽  
Léo Marion

Isorhyncophylline, the isomer into which rhyncophylline is convertible, has been found to occur in nature. Both bases are interconvertible. Isorhyncophylline on hydrolysis with dilute hydrochloric acid is converted to an aldehyde reducible to isorhyncophyllol. When the aldehyde is reduced in the Wolff–Kishner reaction, it is also isomerized and the product is isorhyncophyllane. This reduction product is oxidized by mercuric acetate to a neutral dilactam which still contains the oxindole carbonyl and further contains a new lactam carbonyl present in a six-membered ring. Reduction of the dilactam with lithium aluminum hydride gave a product having the spectroscopic properties of an indole. This confirms the assumption previously made that in rhyncophylline, ring C is five-membered. The isomerization of rhyncophylline, mitraphylline, and formosanine is described. Formosanine has been shown to be identical with uncarine-B and thus uncarine-A is the iso base derivable from formosanine.


1977 ◽  
Vol 55 (15) ◽  
pp. 2856-2866 ◽  
Author(s):  
Ronald T. Coutts ◽  
Abdel-Monaem El-Hawari

1′,2′-Dihydro-3-methyl-1-phenylspiro[[2]pyrazoline-4,3′(4′H)-quinoline]-5-one (8q), the structurally related 1,3-diphenylspiro[pyrazolone-quinoline] 8r and numerous 2′-substituted derivatives of 8q and 8r are readily accessible from catalytic reduction of 3-methyl-1-phenyl- or 1,3-diphenyl-4-(2-nitrobenzyl)-2-pyrazolin-5-one (1a, 1b, respectively) in alcohols (with the incorporation of the alkylidene moiety) or by interaction of the corresponding 2-aminobenzyl precursors (3a, 3b) with appropriate aldehydes and ketones. All spiro compounds were characterized by mass, ir, and 1Hmr spectra. The products obtained by reducing the spiro compounds with sodium borohydride and with lithium aluminum hydride are described. Reduction of 1a and 1b with zinc and acetic acid gave 3-methyl-1-phenyl- and 1,3-diphenyl-1H-pyrazolo[3,4-b]quinoline (2a, 2b, respectively).


1991 ◽  
Vol 69 (5) ◽  
pp. 772-778 ◽  
Author(s):  
Youla S. Tsantrizos ◽  
Kelvin K. Ogilvie

The antifungal antibiotic pisolithin B (p-hydroxymandelic acid, 2-(4′-hydroxyphenyl)-2-hydroxyethanoic acid, 1a) was shown to have the absolute (R) configuration. The stereochemistry was established via comparison of its optical rotation to that of its synthetic (R) and (S) enantiomers. The synthetic samples were prepared by the stereospecific reduction of the prochiral α-keto acid, p-hydroxybenzoylformic acid (2-(4′-hydroxyphenyl)-2-oxoethanoic acid, 2a), with (R) or (S)-2,2′-dihydroxy-1,1′-binaphthyl lithium aluminum hydride (BINAL-H). The absolute configuration and enantiomeric purity of both products were determined using the 1H NMR of their isobutyl esters in the presence of the chiral solvating agent (R)-(−)-2,2,2-trifluoro-1-(9-anthryl)ethanol. Key words: pisolithin B, p-hydroxymandelic acid, antifungal, absolute configuration.


1969 ◽  
Vol 52 (6) ◽  
pp. 1240-1248
Author(s):  
A S Y Chal

Abstract Chemical conversions followed by GLC analysis are described for the confirmation of residues of α- and β-endosulfan in agricultural crops. Both isomers were reduced to the same diol by lithium aluminum hydride in tetrahydrofuran. Subsequent silylation to the disilyl ether can be used for the routine confirmation of both isomers down to a level of 0.02 p pm in a 10 g sample extract. Alternatively, the insecticide or its reduction product can be acetylated. By this procedure, 0.03 ppm or more of the parent insecticide can be identified in a 10 g sample extract.


1949 ◽  
Vol 27b (12) ◽  
pp. 902-906 ◽  
Author(s):  
G. Papineau-Couture ◽  
Gordon A. Grant ◽  
E. M. Richardson

Lithium aluminum hydride has been used successfully in the partial reduction of phthalic anhydride to phthalide, in the selective reduction of the carbonyl group of dehydroisoandrosterone-3-acetate, and in the reduction of oestrone acetate to α-oestradiol without simultaneous production of the β-isomer. A new reduction product of Δ5-3(β)hydroxyetiobilienic acid, Δ9,14-2,13-dimethyl-7(β)hydroxy-2-hydroxymethyl-1-hydroxyethyl dodecahydrophenanthrene, is also described.


1971 ◽  
Vol 49 (20) ◽  
pp. 3342-3347 ◽  
Author(s):  
U. P. Singh ◽  
R. K. Brown

The reaction of butyllithium in ether with 1,6:2,3-dianhydro-4-deoxy-β-DL-ribo-hexopyranose (1), a substance obtained in five steps from acrolein dimer, gave 1,6-anhydro-3,4-dideoxy-β-DL-erythro-hex-3-enopyranose (2). The compound 1,6:3,4-dianhydro-β-DL-allo-hexopyranose (3), obtained from 2, was converted by reaction with aqueous barium hydroxide followed by hydrolysis of the product, to DL-glucose 5. Treatment of 3 with sodium methoxide in methanol followed by acid hydrolysis of the 1,6-anhydro intermediate 6, gave 3-O-methyl-DL-glucose (7). The same intermediate, 6, along with the methyl glycoside 8, could be obtained by the acid-catalyzed reaction of 3 with methanol. Lithium aluminum hydride reacted with 3 to form 1,6-anhydro-3-deoxy-β-DL-ribo-hexopyranose (9), which was hydrolyzed readily to 3-deoxy-DL-ribo-hexopyranose (10).Yields were excellent throughout. All products obtained from the oxirane 3 were those resulting only from trans diaxial opening of the oxirane ring.


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