STEROIDS AND RELATED PRODUCTS: VII. THE SYNTHESIS OF 17α-METHYLCORTICOSTERONE

1957 ◽  
Vol 35 (2) ◽  
pp. 131-140 ◽  
Author(s):  
Ch. R. Engel
Keyword(s):  
Ethylene Glycol ◽  
Biologically Active ◽  
The Other ◽  
Keto Group ◽  
Methyl Group ◽  
Other Hand ◽  
Hydrolysis Of

The synthesis of 17α-methylcorticosterone, a new biologically active homologue of corticosterone and analogue of cortisol, is described. In the course of the work it was observed that the 17-methyl group greatly impeded both the formation and the hydrolysis of a 20-ketal. On the other hand, evidence was obtained that the 11-keto group is not completely unreactive towards ethylene glycol, in the presence of p-toluenesulphonic acid.

Selective cyclization modes of methyl 3′-heteroarylamino-2′-(2,5-dichlorothiophene-3-carbonyl)acrylates. Synthesis of model (thienyl)pyrazolo- and triazolo[1,5-α]pyrimidines

2020 ◽  
Vol 75 (12) ◽  
pp. 1037-1042
Author(s):  
Nuha I. Sweidan ◽  
Mustafa M. El-Abadelah ◽  
Musa Z. Nazer ◽  
Wolfgang Voelter
Keyword(s):  
Spectral Data ◽  
The Other ◽  
Keto Group ◽  
Other Hand ◽  
Selective Displacement ◽  
New Compounds

AbstractInteraction of methyl 3-ethoxy-2-(2,5-dichloro-3-thenoyl)acrylate (I) with 3-aminopyrazole and 3-amino-1,2,4-triazole generated the respective pyrazolo[1,5-α]pyrimidine (4) and triazolo[1,5-α]pyrimidine (7). The formation of 4 entails selective and consecutive displacement of the 3-ethoxy and methoxy (ester) anions in I by 3-NH2 and 1-NH of 3-aminopyrazole. On the other hand, the formation of 7 implies selective displacement of 3-ethoxy in I by the ring-NH followed by cyclocondensation involving the keto group in I and 3-NH2 of aminotriazole. This latter selective displacement sequence is also followed by 3-amino-5-hydroxypyrazole in its reaction with I. The structures of the new compounds are supported by microanalytical and spectral data.

Full Cleavage of C≡C Bond in Electron-Deficient Alkynes via Reaction with Ethylenediamine

2017 ◽  
Vol 70 (4) ◽  
pp. 421 ◽  
Author(s):  
Sergei F. Vasilevsky ◽  
Maria P. Davydova ◽  
Victor I. Mamatyuk ◽  
Nikolay Tsvetkov ◽  
Audrey Hughes ◽  
...  
Keyword(s):  
Aryl Halides ◽  
The Other ◽  
Keto Group ◽  
Sonogashira Coupling ◽  
Methyl Group ◽  
Concomitant Reduction

Reaction of 1,2-diaminioethane (ethylenediamine) with electron-deficient alkynes leads to full scission of the C≡C bond even in the absence of a keto group directly attached to the alkyne. This process involves oxidation of one of the alkyne carbons into C2 of a 2-R-4,5-dihydroimidazole with the concomitant reduction of the other carbon to a methyl group. The sequence of Sonogashira coupling with the ethylenediamine-mediated fragmentation described in this work can be used for selective formal substitution of halogen in aryl halides by a methyl group or a 4,5-dihydroimidazol-2-yl moiety.

scholarly journals Diaqua(nitrato-κ2O,O′)bis(L-valine-κO)lead(II) nitrate at 296 K

IUCrData ◽  
2016 ◽  
Vol 1 (4) ◽  
Author(s):  
Sylvain Bernès ◽  
Laura Gasque
Keyword(s):  
Low Temperature ◽  
Bond Length ◽  
Coordination Number ◽  
Coordination Sphere ◽  
Title Complex ◽  
The Other ◽  
Methyl Group ◽  
Space Group ◽  
Polymeric Nature ◽  
Other Hand

The structure of the title complex, [Pb(NO3)(C5H11NO2)2(H2O)2]NO3, had been determined previously at 173 and 193 K, and is now reported at 296 K, in the same space group. The main difference with the low-temperature structures is that a methyl group of one valine ligand is clearly disordered over two positions, for which the occupancies converged to 0.56 (3) and 0.44 (3). Bond-length variations within the coordination sphere of PbIIas a function ofTare difficult to assess because uncertainties on these parameters are high. On the other hand, Pb...O distances above 2.9 Å cannot be assigned unambiguously to formal Pb—O bonds. As a consequence, the polymeric nature of the complex previously described at 173 K is uncertain, as well as the actual coordination number of PbII, and it is thus not possible to determine if the metal environment is holo- or hemidirected.

scholarly journals ATP-dependent structural changes of the outer dynein arm in Tetrahymena cilia: a freeze-etch replica study.

1983 ◽  
Vol 96 (5) ◽  
pp. 1480-1485 ◽  
Author(s):  
S Tsukita ◽  
S Tsukita ◽  
J Usukura ◽  
H Ishikawa
Keyword(s):  
Structural Changes ◽  
Lateral View ◽  
The Other ◽  
Replica Technique ◽  
Other Hand ◽  
Dynein Arms ◽  
Hydrolysis Of

With the rapid-freeze, deep-etch replica technique, the structural conformations of outer dynein arms in demembranated cilia from Tetrahymena were analyzed under two different conditions, i.e., in the absence of ATP and in the presence of ATP and vanadate. In the absence of ATP, the lateral view of axonemes was characterized by the egg-shaped outer dynein arms, which showed a slightly baseward tilt with a mean inclination of 11.1 degrees +/- 3.4 degrees SD from the perpendicular to the doublet microtubules. On the other hand, in the presence of 1 mM ATP and 100 microM vanadate, the outer arms were extended and slender and showed an increased baseward tilt with a mean inclination of 31.6 degrees +/- 4.9 degrees SD. In ATP-activated axonemes, these two types of arms coexisted, each type occurring in groups along one row of outer arms. These findings strongly suggest that the interdoublet sliding is caused by dynamic structural changes of dynein arms that follow the hydrolysis of ATP.

scholarly journals First result of tartaric stabilization by adding mannoproteins (Mannostab™)

OENO One ◽  
1997 ◽  
Vol 31 (1) ◽  
pp. 23 ◽  
Author(s):  
Virginie Moine-Ledoux ◽  
A. Perrin ◽  
I. Paladin ◽  
Denis Dubourdieu
Keyword(s):  
Cell Wall ◽  
Enzymatic Hydrolysis ◽  
New Product ◽  
Model Solution ◽  
The Other ◽  
Inhibitor Activity ◽  
Commercial Preparation ◽  
Other Hand ◽  
Crystallization Inhibitor ◽  
Hydrolysis Of

<p style="text-align: justify;">Some mannoproteins which are extracted by enzymatic hydrolysis of yeast's cell wall with the aid of commercial preparation composed with beta-glucanases (Glucanex™) inhihits the tartaric acid's salt breakdown in model solution as well as in wines for an addition between 10 and 25 g/hl. On the other hand, heat extracted mannoproteins arc inactive on the tartaric precipitation stabilization. Furthermore, the crystallization inhibitor activity of the enzymatic extracted mannoproteins is due to the presence of sharply glycosylated mannoproteins of mediummolecular weight (30 to 50 kda) which are not heat extracted. That is why the heat extracted mannoproteins are inactive. The enzymatic extracted mannoproteins are produced at a pilot plan. This preparation (Mannostab™), soluble in wines, colourless and without any flavour, stabilize with the same efficiency than a freeze treatment and this effective live is superior to the metatartric acid. Moreover, the necessary steps were been taked to permit experimentally this new product : Mannostab™</p>

Synthesen von Heterocyclen, CC Reaktionen mit cyclischen Oxalylverbindungen, XVIII Zur Reaktion von 4-Benzoyl-5-phenyl-2,3-dihydrofuran-2,3-dion mit Η-aktiven Nucleophilen. / Syntheses of Heterocycles, CC Reactions of Cyclic Oxalyl Compounds, XVIII The Reaction of 4-Benzoyl-5-phenyl-2,3-dihydrofuran-2,3-dione with Η-active Nucleophiles

1976 ◽  
Vol 31 (11) ◽  
pp. 1511-1514 ◽  
Author(s):  
Gert Kollenz ◽  
Erich Ziegler ◽  
Walter Ott ◽  
Herwig Igel
Keyword(s):  
Acetic Acid ◽  
Acrylic Acid ◽  
Oxalic Acid ◽  
Ethyl Ester ◽  
Acid Ethyl Ester ◽  
The Other ◽  
Other Hand ◽  
Hydrolysis Of ◽  
Acid Anilides

Hydrolysis of 4-Benzoyl-5-phenyl-2,3-dihydrofuran-2,3-dione (1) in water (ethanol) gives dibenzoylmethane and oxalic acid (ethyl ester). 1 reacts with aniline or p-toluidine yielding the 2-pyrrolones (2), which on the other hand are synthesized by addition of the corresponding anilines to the pyrrol-2,3-diones (8). 3 a adds methanol to give the 2-pyrrolone (4), which with aniline can be converted into 2 a. 2 a, b show fragmentation to oxalic acid anilides by heating (2 b) or treating with diazomethane (2 a). The reaction of 1 with p-nitroaniline leads via the furanone-derivative 6 to oxalic acid-di-p-nitroanilide. 1 and N-methylaniline combine to acrylic acid-N-methylanilide (7), which by heating gives the dibenzoyl acetic acid-N-methylanilide

Studies in Solvolysis. Part IV. Substituent and Solvent Isotope Effects in the Solvolysis of a Series of Benzyl Trifluoroacetates

1972 ◽  
Vol 50 (12) ◽  
pp. 1886-1890 ◽  
Author(s):  
June G. Winter ◽  
J. M. W. Scott
Keyword(s):  
Isotope Effect ◽  
Deuterium Oxide ◽  
Isotope Effects ◽  
The Other ◽  
Solvent Isotope Effect ◽  
Other Hand ◽  
Solvent Isotope ◽  
Hydrolysis Of ◽  
Solvent Isotope Effects

The rates of neutral hydrolysis of a series of 4-substituted benzyl trifluoroacetates 4-X-C6H4CH2OCOCF3, X = NO2, Cl, H, CH3, and OCH3 have been studied in water and deuterium oxide, both solvents containing 0.012 mol fraction of acetone. The alteration of the rates with the nature of the 4-substituent and the kinetic solvent isotope effect (k(H2O)/k(D2O)) are consistent with the proposal that the esters with X = NO2, Cl, H, and CH3 all react by an acyl–oxygen BAc2 mechanism. On the other hand, the same mechanistic criteria indicate that the 4-methoxybenzyl ester reacts by both the BAc2 and the SN1 alkyl–oxygen fission paths in equal amounts.

Stereochemistry of bimolecular nucleophilic opening of a dioxolenium ring fused to an anchored cyclohexane system

1969 ◽  
Vol 47 (9) ◽  
pp. 1445-1459 ◽  
Author(s):  
J. F. King ◽  
A. D. Allbutt
Keyword(s):  
Transition States ◽  
Heterocyclic Ring ◽  
The Other ◽  
Cyclohexane Ring ◽  
Methyl Group ◽  
Other Hand ◽  
Opening Ratio ◽  
Nucleophilic Reagents

This paper describes the characterization of certain dioxolenium salts in which the heterocyclic ring is fused (via positions-4 and -5) to an anchored cyclohexane ring, and the steric course of their bimolecular cleavage with nucleophilic reagents. It was found that diaxial opening is normally favored strongly over diequatorial; this is accounted for in terms of differences in angle strain in the transition states. The presence of an axial (angular) methyl group gave a preference for diequatorial opening; on the other hand an analogous investigation of the diaxial: diequatorial opening ratio with epoxides showed the stereochemistry of the reaction to be virtually insensitive to an angular methyl group. These observations are interpreted in terms of the different non-bonded interactions arising from the different geometrical arrangements of epoxides and dioxolenium ions. The variation in the diaxial: diequatorial opening ratio is shown to be of significance in the interpretation of rates of diaxial → diequatorial rearrangement.

Total synthesis of the stemodane-type diterpenoids (±)-stemodin and (±)-maritimol. Formal total synthesis of (±)-stemodinone and (±)-2-desoxystemodinone

1985 ◽  
Vol 63 (12) ◽  
pp. 3418-3432 ◽  
Author(s):  
Edward Piers ◽  
Brian F. Abeysekera ◽  
David J. Herbert ◽  
Ian D. Suckling
Keyword(s):  
Total Synthesis ◽  
Room Temperature ◽  
The Other ◽  
Subsequent Reaction ◽  
Total Syntheses ◽  
Keto Esters ◽  
Other Hand ◽  
Synthetic Intermediates ◽  
Separation Of Mixtures ◽  
Hydrolysis Of

Total syntheses of the stemodane-type diterpenoids (±)-stemodin (2) and (±)-maritimol (4), as well as formal total syntheses of (±)-stemodinone (3) and (±)-2-desoxystemodinone (5), are described. The known ketol 12 was converted into the tricyclic enone 7. Photoaddition of aliène to 7 gave (96%) a mixture of the photoadducts 20–23 (40:51:6:3, respectively). Ozonolysis of 20, followed by treatment of the resultant dione 24 with MeONa–MeOH (room temperature, 2.5 h), provided the keto ester 26 (94%). Subjection of 21 to an identical sequence of reactions gave (86%) the same product 26. On the other hand, when the dione 25 was treated with MeONa–MeOH under much milder conditions (0 °C, 5 min), the isomeric keto esters 27 (39%) and 28 (33%) were produced. Both 27 and 28, upon reaction with MeONa–MeOH at room temperature, were converted efficiently into 26. Reduction (NaBH4 or Lisec-Bu3BH) of 26 provided separable mixtures of the ester alcohol 32 and the lactone 33, which could be transformed readily into the dimesylates 35 and 39, respectively. Reaction of 35 and 39 with NaCN in warm hexamethylphosphoramide afforded the dinitriles 37 and 40, both of which, upon treatment with t-BuOK in refluxing t-BuOH, produced the sameenaminonitrile 41. Acid hydrolysis of 41 provided the dione 42. Preparatively, compound 26 could be transformed conveniently into the dione 42 (52% overall yield) without separation of mixtures of isomeric synthetic intermediates. Treatment (CH2Cl2, −95 °C) of 42 with Mc3Sil–Et3N, followed by oxidation of the resultant products 46 and 47 with Pd(OAc)2 in acetonitrile, gave the bis enones 48 (67%) and 49 (19%). Compound 48 was converted into the dione 52 which, upon reaction with (i-PrO)3 TiMe in ether, provided an 86:14 mixture of the keto alcohols 53 and 54 (63% from 48). Reduction (NaBH4) of 53 afforded (±)-maritimol (4). On the other hand, conversion of the 86:14 mixture of 53 and 54 into the p-toluenesulfonylhydrazones 55 and subsequent reaction of 55 with NaH in refluxing toluene gave the alkene alcohols 56 (58%) and 57 (12%). Hydroboration–oxidation (9-BBN, refluxing tetrahydrofuran; NaOH, H2O2) of 56 afforded (88%) (±)-stemodin (2).

STEROIDS AND RELATED PRODUCTS: XIX. THE SYNTHESIS OF 3,9,12,20-TETRAOXYGENATED 9,12-seco STEROIDS. PART III. 11-AZA STEROIDS. PART I

1962 ◽  
Vol 40 (11) ◽  
pp. 2153-2162 ◽  
Author(s):  
Ch. R. Engel ◽  
S. Rakhit
Keyword(s):  
Methyl Ester ◽  
Ethylene Glycol ◽  
Ethyl Acetate ◽  
Good Yield ◽  
Boron Trifluoride ◽  
Osmium Tetroxide ◽  
Periodic Acid ◽  
Boron Trifluoride Etherate ◽  
The Other ◽  
Other Hand

The smooth conversion of 3β-acetoxy-5α-pregnane-12,20-dione (IV), readily available from hecogenin (I), to Δ9(11)-3β,20β-diacetoxy-5α-pregnan-12-one (VIII) is reported. Ozonolysis of this product in ethyl acetate gave, in almost 90% yield, 3β-hydroxy-20β-acetoxy-9-oxo-9,12-seco-11-nor-5α-pregnan-12-oic acid (XI), further characterized by its ester derivatives XIa and XIb. The conversion of the seco acid XI to Δ8(9)-3β-hydroxy-20β-acetoxy-9-amino-9,12-seco-11-nor-5α-pregnen-12-oic acid lactam (12 → 9) (XII) and thence to Δ8(9)-N-acetyl-3β,20β-diacetoxy-11-aza-5α-pregnene (XIVa), the first 11-aza steroids to be known, is described. On the other hand, Δ9(11)-3β,20β-diacetoxy-5α-pregnen-12-one (VIII) is readily transformed to the 9α,11α-glycol VII with osmium tetroxide and thence, with periodic acid, to 3β,9α-dihydroxy-20β-acetoxy-11-oxo-11,12-seco-5α-pregnan-12-oic acid (X), characterized as the methyl ester Xa and diacetoxy methyl ester Xb, and easily converted to the acetoxy hydroxy keto dicarboxylic seco acid XIII. In the course of this work it is shown that, whereas ketalization of the saturated 12,20-diketone IV with ethylene glycol and boron trifluoride etherate gives a good yield of the 12-monoketal (in accordance with the reports of the literature), treatment of the analogous 16-unsaturated 12,20-diketone with the same reagents under the same conditions leads not to ketal formation but to addition of ethylene glycol in position 16.

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