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.

A New Synthesis of Occidol

1999 ◽  
Vol 64 (3) ◽  
pp. 533-538 ◽  
Author(s):  
Ramchandra Bhimrao Mane ◽  
Abhijit Jaysingrao Kadam
Keyword(s):  
Sodium Borohydride ◽  
Lithium Aluminium Hydride ◽  
Borohydride Reduction ◽  
Lithium Aluminium ◽  
New Synthesis ◽  
Naphthoic Acid ◽  
Sodium Borohydride Reduction ◽  
Jones Reagent

Sodium borohydride reduction of 5,8-dimethyl-3,4-dihydronaphthalen-1-(2H)-one (4) yielded 5,8-dimethyl-1,2,3,4-tetrahydro-1-naphthol (5). The tetralol 5 on Vilsmeier-Haack reaction with N,N-dimethylacetamide yielded 1-(5,8-dimethyl-3,4-dihydro-2-naphthyl)ethan-1-one (7) which on hydrogenation over Pd/C afforded 1-(5,8-dimethyl-1,2,3,4-tetrahydro-2-naphthyl)ethan-1-one (8). The tetralol 5 on Vilsmeier-Haack formylation gave 5,8-dimethyl-3,4-dihydro-2-naphthaldehyde (9) which on reduction with lithium aluminium hydride followed by oxidation with the Jones reagent furnished 5,8-dimethyl-1,2,3,4-tetrahydro-2-naphthoic acid (11). The acid 11 on treatment with excess of methyllithium yielded (±)-occidol (1); with two moles of methyllithium it yielded ketone 8, which on reaction with methyllithium furnished (±)-occidol (1).

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).

Reaction of 3,4a-disubstituted 4,4-dimethyl-5,6β-epoxy-A-homo-5β-cholestane derivatives with reducing agents

1985 ◽  
Vol 50 (11) ◽  
pp. 2457-2470 ◽  
Author(s):  
Helena Velgová ◽  
Jaroslav Zajíček
Keyword(s):  
Sodium Borohydride ◽  
Reducing Agents ◽  
Epoxide Ring ◽  
Lithium Aluminium Hydride ◽  
H Nmr ◽  
Lithium Aluminium ◽  
Nmr Data ◽  
Epoxy Alcohols

Reaction of all stereoisomeric 3-acetoxy-4,4-dimethyl-5,6β-epoxy-A-homo-5β-cholestan-4a-ols I-IV with lithium aluminium hydride and reduction of 3-acetoxy-4,4-dimethyl-5,6β-epoxy-A-homo-5β-cholestan-4a-ones XXII and XXIII with sodium borohydride were studied. It was found that reductive opening of the 5β,6β-epoxide ring occured only in the case of the derivatives III and IV due to 5(O)n participation of the 3α-oxygen-containing substituent under formation of the transannular 3α,5α-epoxides VIII and IX, resp. On reduction of the 4a-keto epoxides XXII and XXIII with sodium borohydride the trans-epoxy alcohols III and I were formed. On the basis of 1H NMR data the conformation of the A-ring in the epoxides I-IV, XXII, and XXIII is also discussed.

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).

Synthesis and stereochemistry of 1-Thiaflavan-4-ols

1966 ◽  
Vol 19 (7) ◽  
pp. 1251 ◽  
Author(s):  
GF Katekar
Keyword(s):  
Sodium Borohydride ◽  
Nitrous Acid ◽  
Lithium Aluminium Hydride ◽  
Lithium Aluminium

Lithium aluminium hydride or sodium borohydride reduced 1-thiaflavanone, 6-methyl-1-thiaflavanone, and 4'-chloro-1-thiaflavanone to the corresponding 2,4-cis-1-thiaflavan-4-ols. Deamination of 2,4-cis-4-amino-1-thiaflavans with nitrous acid gave rise to the 2,4-trans-1-thiaflavan-4-ols. N.m.r. measurements were used to determine the stereochemistry of these compounds.

Utilization of 1,6-anhydrohexoses for the preparation of some aliphatic adenosine analogs

1989 ◽  
Vol 54 (10) ◽  
pp. 2753-2766 ◽  
Author(s):  
Marcela Krečmerová ◽  
Miloslav Černý ◽  
Miloš Buděšínský ◽  
Antonín Holý
Keyword(s):  
Hydrochloric Acid ◽  
Sodium Borohydride ◽  
Sodium Salt ◽  
Dilute Hydrochloric Acid ◽  
Lithium Aluminium Hydride ◽  
Subsequent Reduction ◽  
Adenosine Analogs ◽  
Lithium Aluminium

Reaction of sodium salt of adenine with 1,6:3,4-dianhydro-2-O-p-toluenesulfonyl-β-D-galactopyranose (I) afforded 4-(adenin-9-yl)-1,6:2,3-dianhydro-4-deoxy-β-D-mannopyranose (II) and 2,4-bis(adenin-9-yl)-1,6-anhydro-2,4-dideoxy-β-D-glucopyranose (IV). Compound II was converted into 4-(adenin-9-yl)-1,6-anhydro-4-deoxy-β-D-glucopyranose (VI). Cleavage of the 1,6-anhydro bond in this compound with hot concentrated hydrochloric acid led to 4-(adenin-9-yl)-4-deoxy-D-glucose (VIII) which was reduced with sodium borohydride to give 4-(adenin-9-yl)-4-deoxy-D-glucitol (IX). Epoxide II was reduced with lithium aluminium hydride and the obtained 4-(adenin-9-yl)-1,6-anhydro-2,4-dideoxy-β-D-arabinohexopyranose (VII) on treatment with dilute hydrochloric acid and subsequent reduction with sodium borohydride gave 4-(adenin-9-yl)-2,4-dideoxy-D-arabino-hexitol (XI).

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.

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