4,5-Seco-4,6-cyclosteroids. III. Observations on the course of reductive rearrangement of 6β-Bromo-4β,5-epoxy-5β-cholestan-3β-ol

1969 ◽  
Vol 22 (4) ◽  
pp. 807 ◽  
Author(s):  
DJ Collins ◽  
JJ Hobbs ◽  
RJ Rawson
Keyword(s):  
Hydrogen Bromide ◽  
High Yield ◽  
Lithium Aluminium Hydride ◽  
Experimental Conditions ◽  
Lithium Aluminium ◽  
Reaction Proceeds ◽  
Derivatives Of

It has been shown that reductive rearrangement of 6β-bromo-4β,5-epoxy- 5β-cholestan-3β-ol (I) to 4,5-seco-4,6-cycle-6β-cholestane-3β,5α-diol (IXa) with lithium aluminium hydride in tetrahydrofuran proceeds via 6β-bromo-5β-cholestane-3β,5-diol (IIa). Relevant reactions of the latter and the corresponding 3-ketone are discussed. ��� Similar conversion of the 3-epimer of (I) into 4,5-seco-4,6-cyclo- 6β-cholestane-3α,5α-diol (XIIIa) in high yield indicates that reductive rearrangement of the 6β-bromo-5β-hydroxy moiety proceeds without participation of the 3-aluminate complex. Some derivatives of (XIIIa) are described. ��� Experimental conditions required for the conversion of (I) into (IXa) are defined. ��� Combined evidence indicates that the reaction proceeds in a concerted manner by essentially base-catalysed, 1,3-elimination of hydrogen bromide from diol (IIa) with 4,5-bond migration to give the formal intermediate 3β-hydroxy-4,5-seco-4,6-cyclo-6β-cholestan-5-one (VI), further reduced to (IXa).

4,5-Seco-4,6-cyclosteroids. I. Structure and properties of the diol from reductive rearrangement of 6β-Bromo-4β,5-epoxy-5β-cholestan-3β-ol

1969 ◽  
Vol 22 (3) ◽  
pp. 607
Author(s):  
DJ Collins ◽  
JJ Hobbs ◽  
RJ Rawson
Keyword(s):  
Physical Properties ◽  
Transformation Products ◽  
High Yield ◽  
Lithium Aluminium Hydride ◽  
Structure And Properties ◽  
Lithium Aluminium

Treatment of 6β-bromo-4β,5-epoxy-5β-cholestan-3β-ol (IV) with lithium aluminium hydride in tetrahydrofuran at reflux for 16 hr gave a high yield of a new diol, C27H48O2, formulated as 4,5-seco-4,6-cyolo-6β- cholestane-3β,5α-diol (VIIa). This assignment follows from mechanistic considerations, and the chemical and physical properties of the dial and its transformation products. ��� Stepwise removal of the oxygen functions gave the new hydrocarbon 4,5-seco-4,6-cyclo-6β-cholestane (XIXg).

Flavan derivatives. XXIII. Preparation and synthetic applications of Flav-3-enes

1968 ◽  
Vol 21 (9) ◽  
pp. 2247 ◽  
Author(s):  
JW Clark-Lewis ◽  
RW Jemison
Keyword(s):  
Sodium Borohydride ◽  
Acidic Medium ◽  
Catalytic Reduction ◽  
Heterocyclic Ring ◽  
High Yield ◽  
Lithium Aluminium Hydride ◽  
Lower Field ◽  
Field Characteristic ◽  
Lithium Aluminium ◽  
New Synthesis

2'-Hydroxychalcones and α-alkoxy-2'-hydroxychalcones are converted by sodium borohydride in isopropanol into flav-3-enes and 3-alkoxyflav-3-enes in the convenient new synthesis which makes these flavenes readily available. Catalytic reduction of the flavenes gives the corresponding flavans or 3-alkoxyflavans in high yield, and the latter are obtained mainly in the 2,s-cis-form. The flavenes immediately give flavs lium cations in the cold when treated with acids in air, and oxidation of 5,7,3',4'-tetramethoxyflav-3-ene with benzoquinone in an acidic medium gave the flavylium salt, isolated as the ferrichloride. Reduction of 5,7,3',4'-tetramethoxy-flavylium chloride with lithium aluminium hydride gave 5,7,3',4'-tetramethoxy-flav-2-ene identical with the flavene obtained from (-)-epicatechin tetramethyl ether, and confirms an earlier investigation by Gramshaw, Johnson, and King. In its N.M.R. spectrum the heterocyclic-ring protons of this flav-2-ene give an ABX multiplet which is easily distinguished from the ABX multiplet at much lower field characteristic of flav-3-enes.

Chemistry of the Podocarpaceae. XXII. Aspects of the chemistry of Totara-8,11,13-trien-13-ol

1969 ◽  
Vol 22 (9) ◽  
pp. 1975 ◽  
Author(s):  
RC Cambie ◽  
DR Crump ◽  
RN Duve
Keyword(s):  
Sulphuric Acid ◽  
Methyl Ether ◽  
Major Product ◽  
High Yield ◽  
Lithium Aluminium Hydride ◽  
Birch Reduction ◽  
Transannular Cyclization ◽  
Lithium Aluminium ◽  
Fragmentation Reactions

Attempts have been made to effect fragmentation reactions with bromo- tetralone systems related to 6α-bromo-13-hydroxytotara-8,11,13-trien-7- one (VII), a compound which affords a secoditerpenoid (IX) when treated with DMSO-NaHCO3. On treatment with sulphuric acid in acetone, the mono- epoxide derivative (XXVIII) of the methyl ether of the secoditerpenoid undergoes a novel aromatization to a naphthalenic aldehyde (XXXI) by successive transannular cyclization and fragmentation reactions. ��� A 7β-hydroxy configuration has been confirmed for the major product from reduction of 13-acetoxytotara-8,11,13-trien-7-one (VIII) with lithium aluminium hydride. 13-Methoxytotara-8,11,13-triene (II) has been deisopropylated and then subjected to Birch reduction in an attempt to effect a high yield conversion into (+)-podocarp-8(14)-en- 13-one (XXXVII), a potentially useful intermediate for synthesis.

scholarly journals Synthesis of olivomycose (2,6-dideoxy-3-C-methyl-L-arabino-hexose)

1969 ◽  
Vol 47 (23) ◽  
pp. 4467-4471 ◽  
Author(s):  
E. H. Williams ◽  
W. A. Szarek ◽  
J. K. N. Jones
Keyword(s):  
Wittig Reaction ◽  
High Yield ◽  
Lithium Aluminium Hydride ◽  
Ruthenium Tetroxide ◽  
Lithium Aluminium ◽  
Acid Catalyzed ◽  
Hydrolysis Of

Oxidation of methyl 4,6–O-benzylidene-2-deoxy-α-L-arabino-hexopyranoside (1) with ruthenium tetroxide gave the 3-ketone 2 in high yield. A Wittig reaction between methylenetriphenylphosphorane and compound 2 gave methyl 4,6-O-benzylidene-2,3-dideoxy-3-C-methylene-α-L-erythro-hexopyranoside (3), which was hydrated by the oxymercuration–demercuration procedure to afford methyl 4,6-O-benzylidene-2-deoxy-3-C-methyl-α-L-arabino-hexopyranoside (4). The reaction of compound 4 with N-bromosuccinimide gave methyl 4-O-benzoyl-6-bromo-2,6-dideoxy-3-C-methyl-α-L-arabino-hexopyranoside (5) in high yield. Treatment of compound 5 with lithium aluminium hydride followed by acid-catalyzed hydrolysis of the resultant product, gave L-olivomycose (6).

Preparation of 12,20-disubstituted lupane derivatives

1979 ◽  
Vol 44 (1) ◽  
pp. 194-210 ◽  
Author(s):  
Vladimír Pouzar ◽  
Alois Vystrčil
Keyword(s):  
Hydroxy Group ◽  
Sodium Borohydride ◽  
Nmr Spectra ◽  
Unsaturated Ketone ◽  
Lithium Aluminium Hydride ◽  
H Nmr ◽  
Unsaturated Alcohols ◽  
Lithium Aluminium ◽  
Primary Hydroxy Group ◽  
Derivatives Of

Ketoester I was reduced to diol VI. The higher reactivity of its primary hydroxy group was made use of for the preparation of 12α-hydroxy derivatives VII, VIII and X the oxidation of which led to oxo derivatives XII, XIII and XIV. The reduction of the 12-oxo group in compounds XII and XIV with lithium aluminium hydride takes place stereospecifically under formation of 12α-hydroxy derivatives VII and X, while on reduction with sodium in 1-propanol corresponding 12β-hydroxy derivatives XV and XVI are also formed. Reduction of the unsaturated ketone XVII with sodium borohydride gave unsaturated alcohols XVIII and XX. As acetoxy ketone XXIV was obtained from olefin XIX in a 12% yield only, its alternative preparation was carried out from acetoxy ketone XXXIV via the intermediates XXXII, XXXV, XXVIII and XXXI in an overall yield of 27%. The structures of the derivatives of 12-lupene (III, V, XVII, XIX and XXI), 12-lupanol (II, VII, X, XV, XXXI and XXVII) and 12-lupanone (I, XII, XIII, XIV, XXIII, XXIV, XXXIII and XXXIV) were confirmed by the analysis of their 1H NMR spectra.

Poly(trifluoromethanesulfonatosilyl)methanes - Precursors to Polysilylmethanes

1994 ◽  
Vol 49 (3) ◽  
pp. 337-339 ◽  
Author(s):  
Sebastian Bommers ◽  
Hubert Schmidbaur
Keyword(s):  
High Selectivity ◽  
Hydrogen Bromide ◽  
Reaction Times ◽  
Trifluoromethanesulfonic Acid ◽  
Lithium Aluminium Hydride ◽  
Synthetic Route ◽  
Triflic Acid ◽  
Lithium Aluminium ◽  
Simple Alternative

AbstractA new and efficient synthetic route to di- and tri(silyl)methane is presented. Starting from bis- and tris(phenylsilyl)methane, bis- and tris(trifluoromethanesulfonatosilyl)methane can be obtained by Si-Ph cleavage with equivalent quantities of trifluoromethanesulfonic acid (triflic acid). Their reduction with lithium aluminium hydride yields di- and tri(silyl)methane. Substitution of the previously employed liquid anhydrous hydrogen bromide by triflic acid thus offers an experimentally more simple alternative with shorter reaction times and high selectivity.

N-(Aminoacyl) and N-(aminoalkyl) derivatives of 4-cyclopentylaniline and N-ethyl-4-cyclopentylaniline; Synthesis and pharmacological screening

1983 ◽  
Vol 48 (1) ◽  
pp. 156-162 ◽  
Author(s):  
Zdeněk Vejdělek ◽  
Marie Bartošová ◽  
Miroslav Protiva
Keyword(s):  
Lithium Aluminium Hydride ◽  
Substitution Reactions ◽  
Rotarod Test ◽  
Lithium Aluminium ◽  
Local Anaesthetic Effect ◽  
Anorectic Effect ◽  
Pharmacological Screening ◽  
Derivatives Of ◽  
Higher Doses ◽  
Anaesthetic Effect

Acylation of 4-cyclopentylaniline (I) with chloracetyl chloride, 3-chloropropionyl chloride, 4-chlorobutyryl chloride and 2-bromo-4-methylvaleryl bromide gave the halogenoacyl derivatives IV - VII out of which the first two were subjected to substitution reactions with diethylamine and piperidine. The N-(aminoacyl) derivatives VIII - XI obtained were reduced with lithium aluminium hydride to the N-(aminoalkyl) derivatives XII and XV. N-Ethyl-4-cyclopentylaniline (XVI), prepared by reduction of N-(4-cyclopentylphenyl)acetamide (II), was similarly transformed via the chloroacetyl derivative XVII to the amide XVIII and the diamine XIX. Salts of the compounds prepared (amino amides and diamines) bring about in higher doses central excitation which is apparently in close connection with the found discoordinating effect of a part of products (VIII - XI, XIII) in the rotarod test, further with the antireserpine effects in the tests of antagonization of reserpine ptosis and hypothermia (VIII, X, XII, XIII) and finally with the anorectic effect of compound X. All substances showed a mild spasmolytic effect of the anticholinergic type. On the other hand, the expected local anaesthetic effect was found only with compounds VIII, XVIII, XIX.

Synthesis of 1,6-Anhydro-2,3,4-trideoxy-2,3-epimino- and 1,6-Anhydro-2,3,4-trideoxy-3,4-epimino-β-D-hexopyranoses and Their NMR and Infrared Spectra

2004 ◽  
Vol 69 (10) ◽  
pp. 1939-1954 ◽  
Author(s):  
Jindřich Karban ◽  
Miloš Buděšínský ◽  
Jiří Kroutil
Keyword(s):  
Infrared Spectra ◽  
Lithium Aluminium Hydride ◽  
Aziridine Ring ◽  
Hydride Reduction ◽  
Lithium Aluminium ◽  
Complete Series ◽  
Derivatives Of ◽  
Unusual Formation

A complete series of 2,3,4-trideoxy-2,3-epimino and 2,3,4-trideoxy-3,4-epimino derivatives of 1,6-anhydro-β-D-hexopyranoses were prepared by lithium aluminium hydride reduction of vicinal trans azido tosylates. Unusual formation of the aziridine ring from precursors with the trans-diequatorial arrangement of the reacting groups was observed. NMR and infrared spectra of the aziridines are discussed.

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