Flavan derivatives. XII. Conversion of Flavan-3,4-cis-diols into trans-Diacetates, and a new route to 3,4-trans-Diacetoxy-2,3-cis-flavans

1965 ◽  
Vol 18 (1) ◽  
pp. 90
Author(s):  
JW Clark-Lewis ◽  
LR Williams
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Bromine Atom ◽  
Potassium Acetate ◽  
Reductive Dehalogenation ◽  
Lithium Aluminium Hydride ◽  
Lithium Aluminium ◽  
Convenient Route ◽  
In Cis

Reaction of trans-trans-3-bromoflavan-4-ols with ethanolic potassium acetate is shown to lead to 2,3-cis-3,4-trans-4-ethoxy- and -4-acetoxy-flavan-3-ols, as well as to 2,3-cis-flavan-3,4-trans-diols. Flavan-3,4-cis-diols are converted into 3,4-trans-diacetates by acetylation with a mixture of acetic acid, acetic anhydride, and potassium acetate. cis-cis-Flavan-3,4-diols are thus converted into 3,4-trans-diacetoxy-2,3-cis-flavans, and 2,3-trans-flavan-3,4-cis-diols give trans-trans-diacetates. Epimerization of cis-cis-glycols to cis-trans-diacetates provides the most convenient route to 3,4-trans-3',4'-dimethoxy-6-methyl-2,3-cis-flavan, and to the corresponding 4'-methoxy analogue, and reduction with lithium aluminium hydride then gives the 2,3-cis-flavan-3,4-trans-diols. 3',4'-Dimethoxy-6-methyl-2,3-cis-flavan-3,4-trans-diol prepared in this way was converted into the corresponding carbonate, which is the first example of a 2,3-cis-3,4-trans-carbonate and completes the set of the four possible racemates in this series. The bromine atom is unreactive in cis-cis-3-bromo-3',4'- dimethoxy-6-methylflavan, but reductive dehalogenation with lithium aluminium hydride gave the ,β-flavan-4-ol (2,4-cis).

Aminodideoxy sugars. Methyl 3-acetamido-2,3-dideoxy-α-D-arabino-hexopyranoside and methyl 2-acetamido-2,3-dideoxy-α-D-ribo-hexopyranoside

1969 ◽  
Vol 47 (15) ◽  
pp. 2747-2750 ◽  
Author(s):  
Alex Rosenthal ◽  
P. Catsoulacos
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Minor Amount ◽  
Yield Reduction ◽  
Aqueous Acetic Acid ◽  
Lithium Aluminium Hydride ◽  
Parallel Reaction ◽  
Lithium Aluminium ◽  
Methyl Sulfoxide ◽  
A Minor

Oxidation of methyl 4,6-O-benzylidene-3-deoxy-α-D-arabino-hexopyranoside (2) with methyl sulfoxide and acetic anhydride yielded methyl 4,6-O-benzylidene-3-deoxy-α-D-erythro-hexopyranosid-2-ulose (3) in an 80% yield. Reduction of the oximino derivative of 3 with lithium aluminium hydride in tetrahydrofuran or with diborane afforded, after acetylation, methyl 2-acetamido-4,6-O-benzylidene-2,3-dideoxy-α-D-ribo-hexopyranoside (6) in a 44% yield. The latter was also debenzylidenated with aqueous acetic acid. In a parallel reaction, methyl 4,6-O-benzylidene-2,3-dideoxy-3-oximino-α-D-erythro-hexopyranoside yielded mainly methyl 3-acetamido-4,6-O-benzylidene-2,3-dideoxy-α-D-arabino- (and a minor amount of the ribo-epimer)-hexopyranoside.

Flavan Derivatives. VII. The Stereochemical Course of the Synthesis of 2,3-cis-Flavan-3,4-trans-diol Diacetates, and the 2,4-cis-Stereochemistry of Flavan-4β-ols

1963 ◽  
Vol 16 (1) ◽  
pp. 107 ◽  
Author(s):  
JW Clark-Lewis ◽  
TM Spotswood ◽  
LR Williams
Keyword(s):  
Acetic Anhydride ◽  
Potassium Acetate ◽  
Lithium Aluminium Hydride ◽  
Lithium Aluminium

Lithium aluminium hydride reduces 2,3-trans-3-bromo-4'-methoxy-6-methyl-flavanone to 2,3-trans-3,4-trans-3-bromo-4'-methoxy-methylflvan-4-ol which is converted by acetic anhydride-potassium acetate into 3,4-trans-diacetoxy-4'-methoxy-6-methyl-2,3-cis-flavan. Similar reactions with the 3',4'-dimethoxy analogue give 3,4-trans-diacetoxy-3',4'-dimethoxy-6-methyl-2,3-cis-flavan. The corresponding cis-bromoflavanones are reduced to 2,3-cis-3,4-cis-3-bromoflavan-4-ols.

STUDIES ON RDX AND RELATED COMPOUNDS: X. ANALYSIS FOR NITRIC ACID IN ACETIC ACID – ACETIC ANHYDRIDE MEDIA

1953 ◽  
Vol 31 (3) ◽  
pp. 214-215 ◽  
Author(s):  
R. A. Marcus ◽  
C. A. Winkler
Keyword(s):  
Acetic Acid ◽  
Nitric Acid ◽  
Acetic Anhydride ◽  
Analytical Method ◽  
Potassium Acetate ◽  
Standard Solution ◽  
Related Compounds

An analytical method has been developed for the estimation of nitric acid in acetic acid – acetic anhydride media, with a precision of 0.3%. The procedure involves the addition of a solution of potassium acetate in acetic acid to the sample. The excess is back-titrated conductometrically with a standard solution of nitric acid in acetic acid.

VIII.—Some 9-Fluorenyl and 9,9′-Bifluorenyl Derivatives.

1969 ◽  
Vol 68 (2) ◽  
pp. 120-126
Author(s):  
J. M. Birnie ◽  
Neil Campbell
Keyword(s):  
Acetic Acid ◽  
Thionyl Chloride ◽  
Potassium Cyanide ◽  
New Method ◽  
Lithium Aluminium Hydride ◽  
Characteristic Absorption ◽  
Lithium Aluminium ◽  
Aluminium Trichloride

Summary9-Carbamoylfluorene with lithium aluminium hydride, 9-cyanofluorene with this reagent and aluminium trichloride, or (on one occasion) treatment of the oximes of 9-formylfluorene with thionyl chloride yield 9,9′-dicyano-9,9′-bifluorenyl. 9-Bromofluorene and ethanolic potassium cyanide yield 9-cyano-9,9′-bifluorenyl, and 9-formylfluorene when kept in ether for a month gives 9,9′-diformyl-9,9′-bifluorenyl. The so-called α-oxime of 9-formylfluorene described in the literature contains about 33 per cent of the higher melting β-oxime. Reduction of the oximes with zinc and acetic acid yields di(9-fluorenylidenemethyl)amine, previously obtained by other methods. A new method for the preparation of 9-aminomethylenefluorene is described and its structure has been confirmed. Many 9-substituted and 9,9′-disubstituted fluorenes exhibit characteristic absorption at 1920–1880 and 1960–1940 cm.−1.

Fluorinated tricyclic neuroleptics: Synthesis and pharmacology of 2-chloro-8-fluoro-4-(4-methylpiperazino)-4,5-dihydrothieno[2,3-b]-1-benzothiepin

1981 ◽  
Vol 46 (9) ◽  
pp. 2222-2233 ◽  
Author(s):  
Zdeněk Polívka ◽  
Jiří Holubek ◽  
Emil Svátek ◽  
Jiřina Metyšová ◽  
Miroslav Protiva
Keyword(s):  
Acetic Acid ◽  
Title Compound ◽  
Substitution Reaction ◽  
Phosphorus Pentoxide ◽  
Lithium Aluminium Hydride ◽  
Lithium Aluminium ◽  
Chloro Derivative ◽  
Neuroleptic Agent ◽  
Long Acting ◽  
Animal Tests

Diazotization of 4-fluoroanthranilic acid (V) and the following reaction with sodium disulfide gave the dithio diacid VII which was reduced with lithium aluminium hydride to 4-fluoro-2-mercaprobenzyl alcohol (XI). Its reaction with 2-chloro-5-iodothiophene afforded the alcohol XIII which was transformed via the chloride XIV and the nitrile XV to [2-(5-chloro-2-thienylthio)-4-fluorophenyl]acetic acid (XVI). Cyclization with phosphorus pentoxide in toluene resulted in 2-chloro-8-fluorothieno[2,3-b]-1-benzothiepin-4(5H)-one (XVIII) which was converted via the alcohol XIX to the chloro derivative XX. The substitution reaction with 1-methylpiperazine led to the title compound IV which is a long-acting and very potent tranquillizer but did not reveal, in the animal tests performed, the properties of a neuroleptic agent.

Convenient synthesis of 3-amino-3-deoxy-D-ribose

1968 ◽  
Vol 46 (9) ◽  
pp. 1586-1589 ◽  
Author(s):  
Walter Sowa
Keyword(s):  
Acetic Anhydride ◽  
Dimethyl Sulfoxide ◽  
Sodium Borohydride ◽  
Lithium Aluminium Hydride ◽  
Lithium Aluminium ◽  
Convenient Synthesis ◽  
Sugar Derivative

3-Amino-3-deoxy-D-ribose and D-ribose were prepared from a derivative of D-xylose. 1,2-O-Isopropylidene-5-O-triphenylmethyl-α-D-xylofuranose (2) was oxidized by dimethyl sulfoxide – acetic anhydride to 1,2-O-isopropylidene-5-O-triphenylmethyl-α-D-erythro-pentofuranos-3-ulose (3). The oxime (4) of this 3-keto sugar derivative was reduced with lithium aluminium hydride to 3-amino-3-deoxy-1,2-O-isopropylidene-5-O-triphenylmethyl-α-D-ribofuranose (5), isolated as the acetamido derivative (6). Hydrolysis yielded 3-amino-3-deoxy-D-ribose hydrochloride. 3 was reduced by sodium borohydride to 1,2-O-isopropylidene-5-O-triphenylmethyl-α-D-ribofuranose (7), which yielded D-ribose on hydrolysis.

REACTIONS OF 2-ACETOXY-4,6-DI-O-ACETYL-3-O-(2,6-DICHLOROBENZOYL)-D-GLUCAL, TRI-O-ACETYL-3-DEOXY-α-D-erythro-HEX-2-ENOPYRANOSYL CHLORIDE, AND RELATED COMPOUNDS

1966 ◽  
Vol 44 (15) ◽  
pp. 1855-1862 ◽  
Author(s):  
R. U. Lemieux ◽  
R. J. Bose
Keyword(s):  
Acetic Acid ◽  
Sulfuric Acid ◽  
Acetic Anhydride ◽  
Potassium Acetate ◽  
Equimolar Mixture ◽  
Related Compounds ◽  
Reaction Compound

Attempts to dehydrobrominate tri-O-acetyl-3-O-tosyl-α-D-glucopyranosyl bromide with diethylamine led directly to products resulting from the replacement of the tosyloxy group by the diethylamine. It was readily possible to prepare 2-acetoxy-di-O-acetyl-3-(2,6-dichlorobenzoyl)-D-glucal (V). Acetolysis of this compound gave an equimolar mixture of the α- and β-anomers (II and VI, respectively) of 2-acetoxy-di-O-acetyl-pseudo-D-glucal as the first products of the reaction. Compound V reacted only reluctantly with methanol in pyridine to give a mixture of the anomeric methyl di-O-acetyl-3-deoxy-D-erythro-hex-2-enopyranosides. These glycosides were readily prepared by reaction of tri-O-acetyl-3-deoxy-α-D-erythro-hex-2-eno-pyranosyl chloride with methanol in the presence of pyridine. 2-Acetoxy-di-O-acetyl-3-O-mesitoyl-D-glucal was prepared from 3-O-mesitoyl-β-D-glucose. The anomerizations of compounds II and VI were examined with both sulfuric acid in 1:1 acetic acid – acetic anhydride and potassium acetate in acetic acid. The conformations of II and VI are discussed, as are a number of the mechanistic features of the reactions studied.

Reactivity of 2,2-difluoro-3-methyl-3-butenal toward some O-, N- and C-nucleophiles

1985 ◽  
Vol 50 (12) ◽  
pp. 2730-2742 ◽  
Author(s):  
Ivan Veselý ◽  
Václav Dědek
Keyword(s):  
Double Bond ◽  
Acetic Anhydride ◽  
Acetyl Chloride ◽  
Dimethyl Acetal ◽  
Sodium Cyanide ◽  
Acetate Anion ◽  
Cyclic Acetal ◽  
Lithium Aluminium Hydride ◽  
Spontaneous Polymerization ◽  
Lithium Aluminium

Addition of nucleophiles to 2,2-difluoro-3-methyl-3-butenal (I) is complicated by its spontaneous polymerization. Compound I afforded neither hydrate nor dimethyl acetal but reacted with ethylene glycol to give the cyclic acetal II. Reaction with acetyl chloride and acetic anhydride led to the respective acetate III and diacetate IV. Satisfactory reaction with N-nucleophiles was observed only in the case of hydroxylamine and dinitrophenylhydrazine. Diethylamine reacted with I only at 150 °C to give the reduction product VI and the ethylaldimine VII. The compound I added nitromethane and sodium cyanide (giving X and XI, respectively); the adducts or products of their reduction with lithium aluminium hydride were hydroxylated at the double bond to give analogues of alcoholic sugars with difluoromethylene group in position 3. Hydroxylation of the butenal I or the acetate III afforded 3,3-difluoro-2,4-dihydroxy-4-methyloxolane (XIX) which was prepared also by cleavage of the acetal XVIII obtained from II by hydroxylation. Addition of bromine to the double bond in III and IV gave the dibromo derivatives XV and XVI; the attempted replacement of bromine in XV and XVI by acetate anion failed. Bromination of I in aqueous medium afforded 3-bromo-2,2-difluoro-3-methyl-4-butanolide (XIV).

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