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.

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.

The Laser-Induced Nitrations of Several Hydrocarbons

1989 ◽  
Vol 43 (4) ◽  
pp. 674-681 ◽  
Author(s):  
A. E. Stanley ◽  
S. E. Godbey
Keyword(s):  
Reaction Mechanism ◽  
Nitrogen Dioxide ◽  
Chain Length ◽  
Continuous Wave ◽  
Infrared Laser ◽  
Major Product ◽  
Short Chain ◽  
Analogous Reaction ◽  
Thermal Reactions

The Army uses nitrated compounds as explosives and propellants. The ability to selectively nitrate materials is a much-needed process. Laser-induced chemistry possesses the potential to drive some reactions in an efficient and selective manner. Laser-induced chemistry may be useful in driving nitration reactions toward specific products. Reported herein are the results of several successful attempts to laser-induce the reaction of nitrogen dioxide with hydrocarbons of 3, 4, and 5 carbons. Specifically, the tunable continuous wave (cw) infrared laser was used to drive the reaction between nitrogen dioxide, NO2, and propane, n-butane, isobutane, and n-pentane. The major products of the reactions were secondary (tertiary in the isobutane reaction) nitrohydrocarbons, of the same chain length as the reacting hydrocarbon. Some short-chain nitrated compounds were also identified. The yield of 2-nitrobutane observed in the nitration of butane is ∼20% on the basis of the depletion of NO2. The propane reacted with NO2 to produce mostly 2-nitropropane with a smaller yield of 5–9%. The analogous reaction of pentane produced ∼9% of the major product, which is believed to be 2-nitropentane. The isobutane nitration resulted in approximately a 10% yield of 2-methyl-2-nitropropane. The results of these laser-induced reactions are contrasted to the corresponding thermal reactions. The reaction mechanism is also discussed for these two processes.

Synthesis of some bicyclo[2.2.2]oct-5-en-2-ones and bicyclo[2.2.2]octan-2-ones. Rearrangements accompanying oxidative decarboxylation with lead tetraacetate

1981 ◽  
Vol 59 (2) ◽  
pp. 344-355 ◽  
Author(s):  
Peter Yates ◽  
Gordon E. Langford
Keyword(s):  
Dicarboxylic Acid ◽  
Acyl Migration ◽  
Dicarboxylic Acids ◽  
Acid Group ◽  
Major Product ◽  
Lead Tetraacetate ◽  
Oxidative Decarboxylation ◽  
Similar Treatment ◽  
Carbonium Ion ◽  
A Minor

1-Methoxy-2-methyl-1,4-cyclohexadiene (3), 2-methoxy-1-methyl-1,3-cyclohexadiene (2), and 2-methoxy-1,5,5-trimethyl-1,3-cyclohexadiene (14) on heating with maleic anhydride give 1-methoxy-endo-7-methylbicyclo[2.2.2]oct-5-ene-syn-2,3-dicarboxylic acid anhydride (7) and its 6-methoxy-1-methyl (16a) and 6-methoxy-1,8,8-trimethyl (16b) analogues, respectively. On hydrolysis 16a and 16b give the corresponding keto dicarboxylic acids, 18a and 18b, via keto anhydrides 17a and 17b. Treatment of 18b with lead tetraacetate gives 1,8,8-trimethylbicyclo[2.2.2]oct-5-en-2-one (19) together with products in which rearrangement to a bicyclo[3.2.1]octane system has occurred. Treatment of 17b with bis(triphenylphosphino)nickel dicarbonyl gives only 19; similar treatment of 17a gives 1-methylbicyclo[2.2.2]oct-5-en-2-one (1). Reaction of bicyclo[2.2.2]octane-2,3-dione (27) with methyllithium gives 3-hydroxy-3-methylbicyclo[2.2.2]octan-2-one (28), its dimer 31, and a diol 30. Treatment of 5-exo-acetoxy-1, 5-endo-dimethyl-6-oxobicyclo[2.2.2]octane-anti-2,3-dicarboxylic acid (37) with lead tetraacetate gives 3-endo-acetoxy-1,3-exo-dimethyl-bicyclo[2.2.2]oct-5-en-2-one (33) as a minor product; the major product is derived by rearrangement to a bicyclo[3.2.1]octane system. It is proposed that this rearrangement, like that of 18b, involves oxidative decarboxylation of a single carboxylic acid group to give a carbonium ion that undergoes rearrangement via a 1,2-acyl migration.

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.

Campnosperma Exudates. The Optically Active Long Chain 5-Hydroxycyclohex-2-Enones and Long-Chain Bicyclo[3.3.1]Nonane-3,7-Diones

1987 ◽  
Vol 40 (1) ◽  
pp. 79 ◽  
Author(s):  
SR Johns ◽  
JA Lamberton ◽  
TC Morton ◽  
H Suares ◽  
RI Willing
Keyword(s):  
Sodium Borohydride ◽  
Chair Conformation ◽  
Major Product ◽  
Optically Active ◽  
High Yield ◽  
Enol Ethers ◽  
Phenolic Components ◽  
Long Chain ◽  
Equatorial Substituent

Re-examination of the optically active long-chain 5-hydroxycyclohex-2-enones of Campnosperma species has confirmed the former structural assignments, except that in Tigaso oil both the 5- hydroxycyclohex-2-enones and the phenolic components contain a significant (35-40%) proportion of compounds with di-unsaturation in the C19-chain. Further study has been made of the conversion of (-)-endo-4-hexadecyl-l-hydroxybicyclo[3.3.l]nonane-3,7-dione (10) into a mixture of an optically inactive and optically active β- diketones. The major product from this reaction is (�)-5-(1-acetylheptadecy1)cyclohexane-1,3-dione (1l), which on methylation with diazomethane gives a mixture of two diastereoisomeric Omethyl ethers. These undergo cyclization to give a mixture of two epimeric 4-hexadecyl-l-methoxybicyclo[3.3.l]nonane-3,7-diones, (16) and (17), but reduction of the enol ethers followed by cyclization leads to an epimeric mixture of 4 hexadecylbicyclo [3.3.l]nonane-3,7-dion, (21) and (22). A detailed n.m.r. study of the bicyclo[3.3.l]nonane-3,7-diones, (10), (16), (17), (21), (22), (27) and (28), indicates that all have a chair-chair conformation, and also shows which of these compounds have an equatorial substituent, (10), (16), (21) and (27), and which an axial, (17), (22) and (28), at C4. Reduction of the bicyclo[3.3.1]nonane-3,7-diones with sodium borohydride gives oxaadamantane derivatives, and reduction of one diastereoisomeric β- diketone Omethyl ether gives a high yield of (�)-endo-4-hexadecyl-exo-3-methyl-2-oxabicyclo[3.3.l]nonane-7-one (25), the structure of which has been fully derived from n.m.r. study.

REACTIONS OF OZONIDES: III. OZONOLYSIS OF ETHYL 10-UNDECENOATE IN ETHANOL

1965 ◽  
Vol 43 (2) ◽  
pp. 319-327 ◽  
Author(s):  
D. G. M. Diaper ◽  
D. L. Mitchell
Keyword(s):  
Sebacic Acid ◽  
Major Product ◽  
Alkyl Ester ◽  
Similar Treatment ◽  
Oxidative Esterification ◽  
Temperature Range ◽  
Ester Formation ◽  
Minor Degree ◽  
A Minor ◽  
Undecenoic Acid

Diethyl sebacate was the major product obtained by ethanolysis of the ozonization products of ethyl 10-undecenoate in the temperature range 28 to 170 °C. Mixed esters of sebacic acid were similarly obtained, in poor to moderate yields, by alcoholysis of the ozonization product from an alkyl ester of 10-undecenoic acid in the appropriate alcohol. Sebacic acid half esters are prepared by a similar treatment of the ozonization products from 10-undecenoic acid itself. Ester formation has been shown to proceed mainly by rearrangement of an alkoxyhydroperoxide, with oxidative esterification of an aldehyde intermediate contributing to a minor degree.

scholarly journals Zur Reaktion von (CO)4FeP(R)Cl2 mit Na2Cr2(CO)10 / Reactions of (CO)4FeP(R)Cl2 with Na2Cr2(CO)10

1986 ◽  
Vol 41 (5) ◽  
pp. 532-540 ◽  
Author(s):  
Jutta Borm ◽  
Konrad Knoll ◽  
Laszlo Zsolnai ◽  
Gottfried Huttner
Keyword(s):  
Spectroscopic Data ◽  
Minor Component ◽  
Major Product ◽  
High Yield ◽  
Analogous Reaction ◽  
X Ray ◽  
A Minor

(CO)4FeP(R)Cl2 reacts with Na2Cr2(CO)10 to give the μ3 RP capped trigonal heterom etallic closed cluster Fe(CO)3Cr(CO)4Cr(CO)5(μ3-PR)(1) as a major product. ACr(CO)5-derivative of a metal substituted phosphane [(μ2(tBuPCl)Fe2(CO)7)(tBuPH)]Cr(CO)5 (2) is obtained as a minor component.The analogous reaction with (CO)4FeP(Ph)Cl2 only gives the known cluster Fe3(CO)9(μ3-PR)2 (3), while (CO)4FeP(c-hexyl)Cl2 results in 4, a pentacarbonylchromiumderivative of the diiron species Fe2(CO)6μ-(PR)3. Species o f this type, containing an Fe2(CO)6 entity doubly bridged by μ2-PR entities, which are them selves linked by another PR-group, are obtained in a systematic high yield process by reacting Fe2(CO)6(μ2-RPH)2 with n-BuLi/TMEDA , RPCl2. For com pound identification, analytical and spectroscopic data as well as four X-ray analyses are presented.

Polysulfide-borohydride modification of southern pine alkaline pulping integrated with hydrothermal pre-extraction of hemicelluloses

TAPPI Journal ◽  
2011 ◽  
Vol 10 (7) ◽  
pp. 9-16
Author(s):  
SUNG-HOON YOON ◽  
HARRY CULLINAN ◽  
GOPAL A. KRISHNAGOPALAN
Keyword(s):  
Loblolly Pine ◽  
Sodium Borohydride ◽  
Kraft Pulping ◽  
Hot Water ◽  
Pulp Yield ◽  
Paper Strength ◽  
Southern Pine ◽  
Two Stage ◽  
Simultaneous Treatment ◽  
Process Modification

We studied three process modifications to investigate their effects on the property and yield recovery capabilities of kraft pulping integrated with hemicellulose pre-extraction of southern pine. Loblolly pine chips were pre-extracted with hot water until the sugar extraction yield reached the targeted value of 10% and then subjected to conventional and modified kraft pulping. Modification included polysulfide pretreatment; polysulfide-sodium borohydride dual pretreatment, and polysulfide followed by polysulfide-sodium borohydride dual pretreatment two-stage pretreatments prior to kraft pulping. In the first modification, about 5% of the lost pulp yield (total 7%) caused by hemicellulose pre-extraction could be recovered with 15%-20% polysulfide pretreatment. Complete recovery (7%) was achieved with simultaneous pretreatment using 15% polysulfide and 0.5% sodium borohydride with 0.1% anthraquinone in polysulfide-sodium borohydride dual pretreatment. Two-stage pretreatment using recycled 15% polysulfide followed by simultaneous treatment of 6% polysulfide and 0.4%–0.5% sodium borohydride with 0.1% anthraquinone also achieved 100% yield recovery. Continuous recycling of 15% polysulfide employed in the two-stage process modification maintained its yield protection efficiency in a repeated recycling cycle. No significant changes in paper strength were found in handsheets prepared from the three process modifications, except for a minor reduction in tear strength.

METABOLISM OF 17α-HYDROXYPROGESTERONE-4-14C-17α-CAPROATE BY HOMOGENATES OF RAT LIVER AND HUMAN PLACENTA

1961 ◽  
Vol 36 (4) ◽  
pp. 511-519 ◽  
Author(s):  
Margaret Wiener ◽  
Charles I. Lupa ◽  
E. Jürgen Plotz
Keyword(s):  
Rat Liver ◽  
Human Placenta ◽  
Steric Hindrance ◽  
Placental Tissue ◽  
Caproic Acid ◽  
Major Product ◽  
Side Chain ◽  
Anaerobic Conditions ◽  
Prolonged Action ◽  
Long Acting

ABSTRACT 17α-hydroxyprogesterone-4-14C-17α-caproate (HPC), a long-acting progestational agent, was incubated with homogenates of rat liver and human placenta. The rat liver was found to reduce Ring A of HPC under anaerobic conditions to form allopregnane-3β,17α-diol-20-one-17α-caproate and pregnane-3β,17α-diol-20-one-17α-caproate, the allopregnane isomer being the major product. The caproic acid ester was neither removed nor altered during the incubation. Placental tissue did not attack HPC under conditions where the 20-ketone of progesterone was reduced. It is postulated that this absence of attack on the side chain is due to steric hindrance from the caproate ester, and that this may account for the prolonged action of HPC.

Sign in / Sign up

Export Citation Format

Share Document