Bromination of 5a-lanost-8-en-3-one and 5a-lanost-8-ene-3,7,ll-trione

1982 ◽  
Vol 35 (4) ◽  
pp. 857
Author(s):  
J Collins ◽  
PS Cooper ◽  
RE Gall ◽  
A Georges
Keyword(s):  
Acetic Acid ◽  
Sodium Borohydride ◽  
Major Product ◽  
Equilibrium Conditions

Monobromination of 5α-lanost-8-en-3-one (la) under kinetic conditions gave exclusively the 2β- bromo ketone (3a) whilst under equilibrium conditions the product contained 85% of the 2α-bromo ketone (2a). Monobromination of 5a-lanost-8-ene-3,7,11-trione (1b) under kinetic conditions gave the 2a-bromo ketone (2b); 33% of the 2β-bromo ketone (3b) was formed under equilibrium conditions. The configuration assigned to the bromo ketones (2b) and (3b) has been confirmed by reduction with sodium borohydride and treatment of the derived bromohydrins (4b) and (6b) with base to give the 2β,3β-epoxide (5b) and the 3-ketone (1b) respectively. Cleavage of the 2β,3β(-epoxide (5a) with acetic acid gave 2α-acetoxy-5α-lanost-8-en-3β-ol (7) as the major product and 3α-acetoxy-5α-lanost- 8-en-2β-ol (a), in a boat like conformation, as the minor product.

scholarly journals Eine neue Methode zur Herstellung und Reinigung von 5-Methyltetrahydrofolsäure / A New Method for Preparation and Purification of 5-M ethyltetrahydrofolic Acid

1973 ◽  
Vol 28 (11-12) ◽  
pp. 650-652
Author(s):  
Harold Rüdiger ◽  
Reinhard Siede
Keyword(s):  
Acetic Acid ◽  
Folic Acid ◽  
Ion Exchange ◽  
Sodium Borohydride ◽  
Sodium Salt ◽  
Barium Salt ◽  
Borohydride Reduction ◽  
Methyl Derivative ◽  
Crude Product ◽  
Sodium Borohydride Reduction

Abstract 5-Methyltetrahydrofolic acid is prepared from folic acid by sodium borohydride reduction, reac­ tion with formaldehyde and reduction to the methyl derivative by sodium borohydride. The crude product is precipitated as barium salt which after having been converted to the sodium salt by ion exchange is adsorbed to QAE-Sephadex and eluted by different acetic acid gradients in subsequent chromatographies. This method allows to process gram quantities on reasonably small columns

Bridged-ring steroids. II. The synthesis of bridged steroids with a bicyclo[2.2.1]heptane ring A system

1981 ◽  
Vol 59 (11) ◽  
pp. 1641-1650 ◽  
Author(s):  
Peter Yates ◽  
Françoise M. Winnik
Keyword(s):  
Sodium Borohydride ◽  
Major Product ◽  
Analogous Reaction ◽  
Ene Reactions ◽  
Similar Treatment

Bridged steroids with a bicyclo[2.2.1]heptane ring A system are formed on thermolysis of 5-vinyl 3-keto steroids. 5-Vinyl-5α-cholestan-3-one (26) on being heated at 350 °C in decalin gave 2α,5-(syn-methylmethano)-5α-cholestan-3-one (27). Similar treatment of 17β-hydroxy-5-vinyl-5β-estran-3-one (21) gave 17β-hydroxy-2β,5-(syn-methylmethano)-5β -estran-3-one (30), which was also obtained by reduction of 2β,5-(syn-methylmethano)-5β-estrane-3,17-dione (31) with sodium borohydride on alumina. Compound 31 was formed as the major product on thermolysis of 5-vinyl-5β-estrane-3,17-dione (24) at 350 °C, together with 5-(trans-propenyl)-A-nor-5β-estrane-3,17-dione (32). Compounds 27, 30, and 31 are considered to arise via intramolecular ene reactions of the Δ2-enols of compounds 26, 21, and 24, respectively. Compound 32 is postulated to be formed via an analogous reaction of the Δ3-enol of 24, followed by thermolysis of the resulting 3′-methyl-4β,5-dihydrocyclopropa[4,5]-5β-estrane-3,17-dione (36). Photolysis of 30 in methanol results in α-cleavage of the C2—C3 bond and the formation of a ketene-derived ester and two enal-derived oxetanes.

Reduction of 3‐Acyl Derivatives of Oxindoles, Benzo[b]furan‐2‐ones, and Benzo[b]thiophen‐2‐ones to the Corresponding Alkyl Derivatives by Sodium Borohydride–Acetic Acid

2006 ◽  
Vol 36 (6) ◽  
pp. 765-769 ◽  
Author(s):  
Francis X. Smith ◽  
Brian D. Williams ◽  
Eric Gelsleichter ◽  
Judy A. Podcasy ◽  
John T. Sisko ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Sodium Borohydride ◽  
Alkyl Derivatives ◽  
Derivatives Of ◽  
Acyl Derivatives

Reactions of N-substituted 2-aminopyridines with chloroacetyl chloride; Formation of a new series of heterocyclic betaines: 1-Substituted 4-chloromethyl-2-oxopyrido[1,2-a]pyrimidin-5-ium-3-olates

1989 ◽  
Vol 54 (5) ◽  
pp. 1376-1387 ◽  
Author(s):  
Hana Hulinská ◽  
Miloš Buděšínský ◽  
Jiří Holubek ◽  
Oluše Matoušová ◽  
Hana Frycová ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Sodium Borohydride ◽  
Nmr Spectra ◽  
Aqueous Ethanol ◽  
Hydrogen Bromide ◽  
Chloroacetyl Chloride ◽  
Gastric Lesions ◽  
Substitution Reactions ◽  
Reaction Compound ◽  
C Nmr

N-(2-Pyridyl)-2-chloroacetamide reacted with 1-methylpiperazine and gave the expected compound III. Attempts at preparing the N-substituted N-(2-pyridyl)-2-chloroacetamides by reactions of N-substituted 2-aminopyridines with chloroacetyl chloride in benzene in the presence of N,N-dimethylacetamide were negative and took an unexpected course. 2-Anilinopyridine and 2-(cyclohexylamino)pyridine afforded compounds which were identified by 1H and 13C NMR spectra as the heterocyclic betaines IVa and IVb. 2-(1-Butylamino)pyridine, 2-(benzylamino)pyridine and 2-(2-phenylethylamino)pyridine gave similarly compounds IVc-IVe. The chloromethyl compounds IVa-IVe underwent normal substitution reactions with 1-methylpiperazine and gave the methylpiperazino compounds Va-Ve. Attempts to reduce the betaines with sodium borohydride in aqueous ethanol proceeded in one case as the hydrogenolytic displacement of the chlorine atom with hydrogen (product VIa), in another case as ethanolysis (product VIIb). Formation of VIb by treatment of IVb with hydrogen bromide in boiling acetic acid is probably the result of a disproportionation reaction. Compound III (dimaleate VÚFB-17 103) was practically equipotent with pirenzepine (I) as an anti-ulcer agent in the test of indomethacine-induced gastric lesions in rats but was much weaker in tests for antocholinergic and antisecretory activity.

THE PREPARATION OF 9-HYDROXYPYRAZOLO[3,4-b]QUINOLINES

1966 ◽  
Vol 44 (17) ◽  
pp. 2009-2014 ◽  
Author(s):  
R. T. Coutts ◽  
J. B. Edwards
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Hydrazine Hydrate ◽  
Sodium Borohydride ◽  
Sodium Acetate ◽  
The Other ◽  
Reduction Product ◽  
Type I

4-(2-Nitrobenzylidene)-2-pyrazolin-5-ones (I) were best prepared by heating o-nitrobenzaldehyde and 2-pyrazolin-5-ones in acetic anhydride containing fused sodium acetate (cf. Erlenmeyer azlactone synthesis). Pyrazolones of type I were reductively cyclized with cyclohexene and palladium–charcoal, and gave 3a,4,9,9a-tetrahydro-9-hydroxy-1H-pyrazolo-[3,4-b]quinolines (II) which, as expected, were amphoteric compounds. Of the three other methods of reduction used in this study, two (zinc and acetic acid; sodium borohydride and palladium–charcoal) were capable of producing pyrazoloquinolines, but were less reliable. The other method employed (hydrazine hydrate and palladium–charcoal) caused degradation of the pyrazolone molecule in the two cases examined, and in both, bis(2-aminobenzylidene) hydrazine (V) was the reduction product isolated.

Aril Azines. II. Hydrogenation of p-Tolil Monoazine

1975 ◽  
Vol 53 (5) ◽  
pp. 748-752 ◽  
Author(s):  
Peter Yates ◽  
E. M. Levi
Keyword(s):  
Hydrogen Atom ◽  
Carbon Atom ◽  
Sodium Borohydride ◽  
Sodium Methoxide ◽  
Major Product ◽  
Lead Tetraacetate ◽  
Ring Closure ◽  
Carbonyl Carbon Atom ◽  
Carbonyl Carbon ◽  
Independent Synthesis

Hydrogenation of p-tolil monoazine (1b) over palladium-on-charcoal gives as the major product 4,5-dihydro-5-(p-toluyl)-3,4,5-tri-(p-tolyl)-1H-pyrazol-4-ol (2b), which has previously been obtained by treatment of 1b with sodium methoxide. Several minor products are formed, which include p-tolualdehyde, p-toluic acid, and p-toluamide, p-tolunitrile, p-tolualazine, and 3,4,5-tri-(p-tolyl)-4H-pyrazo-4-ol (9). The structure of the last compound, which is also formed on reduction of 1b with sodium borohydride, was established by its independent synthesis from 1,2,3-tri-(p-tolyl)-1,3-propanedione by oxidation with lead tetraacetate followed by treatment with hydrazine. It is suggested that 2b arises via reduction of a C=N bond of 1b and aldol ring closure. The minor hydrogenation products are of interest in that their formation involves C—C hydrogenolysis; it is suggested that this is initiated by addition of a hydrogen atom to a carbonyl carbon atom of 1b.

Synthesis of l,2-dihydro-3H-pyrrolo[1,2-a]pyrrole-1-carboxylic acids and homologous pyridine and azepine analogues thereof

1982 ◽  
Vol 60 (18) ◽  
pp. 2295-2312 ◽  
Author(s):  
Humberto Carpio ◽  
Edvige Galeazzi ◽  
Robert Greenhouse ◽  
Angel Guzmán ◽  
Esperanza Velarde ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Carboxylic Acid ◽  
Acid Derivative ◽  
Sodium Borohydride ◽  
Acid Ester ◽  
Keto Acid ◽  
Acid Salt ◽  
Keto Ester ◽  
Acetic Acid Esters ◽  
Acid Esters

Several syntheses of the previously unknown 1,2-dihydro-3H-pyrrolo[1,2-a]pyrrole-1-carboxylic acid and various 5- and 6-substituted derivatives thereof have been devised. Some of these processes have been extended to the heretofore unreported 5,6,7,8-tetrahydropyrrolo[1,2-a]pyridine-8-carboxylic acid and 5,6,7,8-tetrahydro-9H-pyrrolo[1,2-a]azepine-9-carboxylic acid derivatives.Two new processes were developed for the conversion of pyrroles into the corresponding pyrrol-2-acetic acid esters. Both processes were based on the use of the readily available ethoxalylpyrrole derivatives as the starting material. One sequence involved saponification of the α-keto ester, followed by Wolff–Kishner reduction of the crude α-keto acid salt and subsequent esterification of the acetic acid derivative thus produced. The second synthesis commenced with reduction of the 2-ethoxalpyrrole with sodium borohydride to the α-hydroxy ester, which was further reduced to the acetic acid ester with an equimolar mixture of triphenylphosphine and triphenylphosphine diiodide.

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