ChemInform Abstract: REDUCTION OF METHYL-2,3-DIDESOXY-DL-PENT-2-ENOPYRANOSID-4-ULOSE WITH SODIUM BOROHYDRIDE AND WITH LITHIUM ALUMINIUM HYDRIDE

1973 ◽  
Vol 4 (41) ◽  
pp. no-no
Author(s):  
OSMAN JUN. ACHMATOWICZ ◽  
PAWEL BUKOWSKI
Keyword(s):  
Sodium Borohydride ◽  
Lithium Aluminium Hydride ◽  
Lithium Aluminium

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.

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.

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).

Regulators of cell division in plant tissues. VII. The synthesis of zeatin and related 6-substituted purines

1969 ◽  
Vol 22 (1) ◽  
pp. 205 ◽  
Author(s):  
DS Letham ◽  
RE Mitchell ◽  
T Cebalo ◽  
DW Stanton
Keyword(s):  
Zea Mays ◽  
Cell Division ◽  
Acid Hydrolysis ◽  
Sodium Borohydride ◽  
Aluminium Chloride ◽  
Plant Tissues ◽  
Lithium Aluminium Hydride ◽  
Lithium Aluminium

6-(4-Hydroxy-3-methylbut-trans-2-enylamino)purine (zeatin), a cytokinin isolated from Zea mays, has been synthesized by a new route. β- Methylcrotononitrile was brominated with N-bromosuccinimide yielding γ- bromo-β-methylcrotononitrile, from which trans-γ-acetoxy-β- methylcrotononitrile was prepared. The alcohol derived from this acetate was converted into trans-β-methyl-γ-(tetrahydropyran-2- yloxy)crotononitrile. Reduction and acid hydrolysis gave 4-amino-2- methylbut-trans-2-en-1-ol which was made to react with 6-chloropurine to yield zeatin. ��� Several γ-alkoxy-β-methylcrotononitriles were prepared and reduced by aluminium chloride-lithium aluminium hydride to the corresponding unsaturated amines. Saturated nitrile formation also occurred in these reductions. The amines prepared were condensed with 6-chloropurine to yield a series of O-alkylzeatins. A number of other zeatin analogues were also synthesized. Two 6-methoxyalkylamino-purines were cleaved by sodium borohydride in the presence of iodine to 6-hydroxy- alkylaminopurines.

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.

Synthesis of racemic and optically active erythro- and threo-9-(2,3,4-trihydroxybutyl)adenines and related compounds

1979 ◽  
Vol 44 (2) ◽  
pp. 593-612 ◽  
Author(s):  
Antonín Holý
Keyword(s):  
Sodium Borohydride ◽  
Sodium Salt ◽  
Sodium Periodate ◽  
Optically Active ◽  
Protecting Groups ◽  
Lithium Aluminium Hydride ◽  
Acidic Hydrolysis ◽  
Lithium Aluminium ◽  
Hydrolysis Of ◽  
Related Compounds

Reduction of diethyl 2,3-O-isopropylidene-DL-tartrate (II) with lithium aluminium hydride afforded 2,2-dimethyl-1,3-dioxolane-threo-4,5-dimethanol (III) which was transformed to the monotosyl derivative VI. Reaction of this compound with sodium salt of adenine, followed by acidic deblocking, gave 9-(DL)-threo-(2,3,4-trihydroxybutyl)adenine (IX). Analogously, 9-(DL)-erythro-(2,3,4-trihydroxybutyl)adenine (XVII) was prepared from diethyl meso-tartrate (XI) via the diol XIII and the tosyl derivative XV. 1,3-O-Benzylidene-D-threitol (D-XVIII) was converted successively into the 4-O-tosyl derivative XIX and the 2-O-benzoyl-4-O-tosyl derivative XX. Reaction of the compound XX with sodium salt of adenine, followed by removal of the protecting groups in the intermediate XXI, afforded 9-(D)-threo-(2,3,4-trihydroxybutyl)adenine (D-XXII); analogously, 1,3-O-benzylidene-L-threitol (L-XVIII) was transformed into the 9-(L)-threo-derivative L-XXII. The D-threo-derivative D-XXII was prepared also from 5-O-tosyl-3-O-benzoyl-1,2-O-isopropylidene-α-D-xylofuranoside (XXIII) or from 3-O-benzyl derivative XXIX by condensation with sodium salt of adenine, followed by acidic hydrolysis, degradation of the 1,2-diol grouping by sodium periodate and sodium borohydride, and methanolysis or hydrogenolysis. An analogous procedure was used for preparation of 1-(D)-threo-(2,3,4-trihydroxybutyl)uracil (D-XXVII). Methyl 2,3-O-isopropylidene-5-benzoyl-6-tosyl-D-mannofuranoside (XXXVI) was transformed to the 5-(adenin-9-yl) derivative XXXVII which after hydrolysis of the dioxolane ring, followed by cleavage of the cis-diol with sodium periodate, reduction with sodium borohydride and methanolysis, afforded 9-(D)-erythro-(2,3,4-trihydroxybutyl)adenine (D-XL). The L-enantiomer (L-XL) was obtained from 5-O-(adenin-9-yl)-3-O-benzoyl-1,2-O-isopropylidene-β-L-arabinofuranoside (XXXIIIb) by acidic cleavage, degradation of the intermediate XXXIV with periodate and methanolysis.

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