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. 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).

Selective O-Methyloxime Formation From 6-Methoxy-2-[(1'-methyl-2',5'-dioxocyclopentyl)-methyl]-3,4-dihydronaphthalen-1(2H)-one

1994 ◽  
Vol 47 (4) ◽  
pp. 649 ◽  
Author(s):  
DJ Collins ◽  
GD Fallon ◽  
CE Skene
Keyword(s):  
Lithium Aluminium Hydride ◽  
X Ray ◽  
X Ray Crystallography ◽  
Lithium Aluminium ◽  
Major Isomer ◽  
Toluenesulfonic Acid ◽  
Ester Formation ◽  
Diastereomeric Mixture ◽  
A Minor

Reaction of 6-methoxy-2-[(1′-methyl-2′,5′-dioxocyclopentyl)methyl]-3,4-dihydronaphthalen-1(2H)-one (4a) with 1 or 2 moles of O- methylhydroxylamine hydrochloride in pyridine gave (1′SR,2RS)-6-methoxy-2-[(1′-methyl-2′,5′-dioxocyclopentyl)methyl]-3,4-dihydronaphthalen-1(2H)-one (E)-2′-O-methyloxime (5a), or the corresponding 2′,5′-bis(O-methyloxime ) (6), respectively. A minor product from the formation of the bis (O- methyloxime ) (6) was the (Z) isomer (5b) of the mono(O- methyloxime ) (5a); the structure and stereochemistry of (5a) and (5b) were established by X-ray crystallography. Reduction of the keto bis (O-methyloxime ) (6) with 0.25 mole of lithium aluminium hydride gave a diastereomeric mixture of the corresponding alcohols (7a), of which the major isomer was characterized by ester formation. The bis (O-methyloxime ) (6) could be hydrolysed to the parent triketone (4a), but it resisted deprotection with cetyltrimethylammonium permanganate. Reaction of the triketone (4a) with 1 mole of 4-anisidine in the presence of 4-toluenesulfonic acid resulted in retro Michael cleavage with formation of 3-(4′-methoxyphenyl)amino-2-methylcyclopent-2-en-1-one (1).

Synthesis of 5,6-Diaryl-1,2,4-triazines

1978 ◽  
Vol 33 (12) ◽  
pp. 1503-1507 ◽  
Author(s):  
Farid S. G. Soliman ◽  
Ibrahim M. Labouta ◽  
A. Ibrahim El Sebai ◽  
S. A. Shams El Dine
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Sodium Carbonate ◽  
Sodium Carbonate Solution ◽  
Carbonate Solution ◽  
Aqueous Acetic Acid ◽  
Semicarbazide Hydrochloride

AbstractThe synthesis of 6-(4-methoxyphenyl)-5-phenyl-3-oxo-2,3-dihydro-1,2,4-triazine (5a) from 4-methoxybenzoin, 4-methoxybenzil, or 4-methoxybenzoin semicarbazone and semi-carbazide hydrochloride is reported. The condensation of 4-methoxybenzil with thiosemi-carbazide yielded 6-(4-methoxyphenyl)-5-phenyl-3-thioxo-2,3-dihydro-I,2,4-triazine (5b) which was converted to its 3-oxo analogue 5 a with acetic anhydride. Reduction of 5 a and 5 b with zinc and aqueous acetic acid led to the corresponding 2,3,4,5-tetrahydro-1,2,4-triazines 6 a and 6b, respectively. Oxidation of 5 b with iodine in sodium carbonate solution afforded bis [6-(4-methoxyphenyl)-5-phenyl-1,2,4-triazin-3-yl]disulphide (7). Analogous triazines were prepared by condensing 3,3'-diiodobenzil with semicarbazide hydrochloride or thiosemicarbazide.

3'-O-Formyl-(N-acyl)-2'-deoxyribonucleosides as building units in the synthesis of oligodeoxyribonucleotides

1982 ◽  
Vol 47 (8) ◽  
pp. 2157-2169 ◽  
Author(s):  
Jiří Smrt
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Silica Gel ◽  
Subsequent Treatment ◽  
Aqueous Acetic Acid ◽  
Formyl Group ◽  
Layer Chromatography ◽  
Methanolic Ammonia

5'-O-Dimethoxytrityl-(N-acyl)-2'-deoxyribonucleosides afford 3'-O-formyl-(N-acyl)-2'-deoxyribonucleosides Ia-Id by the action of formic acetic anhydride followed by the action of 80% aqueous acetic acid. The formyl group is removed from Ia-Id by treatment with 1 mol l-1 triethylamine 3'-O-Formyl-2'-deoxythymidine (Ia) gives 3'-O-dimethoxytrityl-2'-deoxythymidine (V) by subsequent treatment with acetic anhydride, triethylamine, dimethoxytrityl chloride and methanolic ammonia. The use of compounds I for the synthesis of d-GGAGG (XIX) and d-T16 (XXXII) is described. Systems for thin-layer chromatography of 5'-O-dimethyltrityl-oligodeoxyribonucleotides on silica gel are described.

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.

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.

scholarly journals SYNTHESIS OF p-METHOXY-CYNNAMIL- p-METOXYCINAMATE FROM ETHYL p-METHOXYCINAMAT WAS ISOLATED FROM DRIED RHIZOME Kaempferia Galanga L AS SUNSCREEN COMPOUND

2010 ◽  
Vol 5 (3) ◽  
pp. 193-197 ◽  
Author(s):  
Titik Taufikkurohmah
Keyword(s):  
1H Nmr ◽  
Yield Reduction ◽  
Lithium Aluminium Hydride ◽  
Lithium Aluminium ◽  
Kaempferia Galanga ◽  
Methoxycinnamic Acid ◽  
Hydrolysis Of

Synthesis of p-methoxy-cynnamil-p-methoxy-cinnamate, (PMS)2O from ethyl-p-methoxy-cinnamate (EPMS) from dry rhizome of kaempferia galanga L as sunscreen compound have been done. Isolation of EPMS was done by percholation using ethanol 96 % and recrystallitation using methanol to have 2.2 % yield. Hydrolysis of EPMS using alcoholic KOH resulted methoxycinnamic acid (APMS) of 90.26 % yield. Reduction EPMS using lithium aluminium hydride in dry ether would give p-methoxycinnamoyl alcohol (PMS-OH) of 41.98 % yield. Then reaction of p-methoxycinnamoyl chloride (PMS-Cl) and PMS-OH in chloroform would produce p-methoxycinnamoyl p-methoxycinnamate ((PMS)2O) of 1.77 % yield. All compound were identified by TLC and several spectrometry methodes i.e. U.V Vis, IR, 1H-NMR and GC-MS   Keywords: esther cinnamate, sunscreen, Kaempferia galanga.

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.

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