A synthetic approach to (+)-aldosterone and its relatives (2)- a stereoselective synthesis of (+)-trans-4,5-(4-methoxybenzo)- 1β , 7aβ - ( 2α-methoxymethyl- 5 -oxofuro) hydrindane

A stereoselectivity in an intramolecular cycloaddition of the olefinic $\text{o}$-quinodimethanes 13 and 23 generated $\text{in}$$\text{situ}$ from the thermolysis of optically active 4β-[2-(4-methoxybenzocyclobutenyl)ethyl] -5α-methoxymethyl-3-phenyl-thio-methylenefuran-2-ones 12 and 22, respectively, is studied and a stereoselective synthesis of (+)-$\text{trans}$-4,5-( 4-methoxybenzo) -1β,7aβ-(2α-methoxymethyl-5-oxofuro)hydrindane 1 is also described.     

Sensitized photooxygenation of β-methoxystyrene and 1-(β-methoxyvinyl)naphthalene

Single oxygen can easily add to 1-(β-methoxyvinyl) naphthalene ($\text{1}$) with retention of sterochemistry to afford a stable 1,4-endoperoxide $\text{3}$. Sensitized photooxygenation of β-methoxystyrene ($\text{2}$) gives mainly Diels-Alder adducts of $\text{o}$-formylmethide quinone ($\text{12}$) which might be derived from initially formed 1,4-endoperoxide $\text{10}$.     

Heavenly blue anthocyanin II trans-4-0-(6-0-(trans-3-0-(β -d-glucopyranosyl)caffeyl)-β-d-glucopyranosyl)- caffeic acid,a novel component in heavenly blue anthocyanin

Structure of an alkaline hydrolysis product of heavenly blue anthocyanin was determined to be $\text{trans}$-4-0-(6-0-($\text{trans}$-3-0-(β-D-glucopyranosyl)caffeyl)-β-D- glucopyranosyl)caffeic acid ($\text{1}$).     

Synthesis of sterically hindered 1-arylpyrrolidines and 1-arylpiperidines by condensation of primary aromatic amines with cyclic ethers or diols

A variety of 1-($\text{o}$-alkylphenyl)- and 1-($\text{o}$-$\text{o}$'-dialkylphenyl)- pyrrolidines and -piperidines were prepared by the gas phase alumina mediated condensation of tetrahydrofuran (THF), tetrahydropyran (THP) or the corresponding diols with primary aromatic amines in fair to high yield. This methodology can also be used for the synthesis of 1-phenylhexahydroazepine from aniline. A mechanistic interpretation of the catalytic action of alumina is presented.     

Cycloaddition reactions of 1.3-benzothiazines v synthesis of new tetracyclic ring systems

New tetracyclic derivatives (3a,$\text{b}$, 5, 8) similar to protoberberines, but containing a lactam structural element and other hetero atoms besides the bridge-head nitrogen in rings B and C, were prepared by cycloaddition of 6,7-dimethoxy-2H-1,3-benzothiazine (1a) with $\text{o}$-substituted aromatic carboxylic acid derivatives (2a,$\text{b}$, 4) and from 4- methyl-6,7-dimethoxy-2$\text{H}$-1,3-benzothiazine (1b) with 3.5-dinitrobenzoyl chloride.     

Reactions of mesomeric fluorocarbanions with acid anhydrides. Transformation of trifluoromethyl groups into fluorocarbonyl and perfluoroacyl groups

It was found that the reaction of mesomeric fluorocarbanions of the CF₃$\text{C}\text{θ}$XCOY type with benzoic anhydride leads to the loss of benzoyl fluoride and the formation of mesomeric carbanions of the FCO$\text{C}\text{θ}$XCOY type. In a similar reaction with perfluorocarboxylic acid anhydrides, besides a CF₃→COF transformation, further change of COF into COR_F is observed, leading to the formation of salts containing mesomeric anions of the R_FCO$\text{C}\text{θ}$XCOY type, which, upon acidification, give 1,1- -bis(perfluoroacyl)-2,2,2-trifluoroethanes CF₃CH(COR_F)₂ , tris- (perfluoroacyl)methanes (R_FCO)₃CH and bis(trifluoroacetyl)- acetic ester (CF₃CO)₂CHCOOMe. It has been shown that perfluoroalkyl groups in β-diketones and β,β′-triketones may hinder enolization despite their electron-attracting effect.     

Nucleosides, 45.-Assignment of glycosylation sites in o-hexopyranosyl-ribonucleosides by 13C-NMR

Evidence is presented that glycosylation of a ribose-OH group in nucleosides results in a significant downfield shift for the appended ¹³C nucleus and smaller upfield displacements for the adjacent carbons, providing an efficient tool for differentiating between 2′-$\text{o}$-, 3′-$\text{o}$- and 5′-$\text{o}$-glycosyl-ribonucleosides. Therewith, the products formed on enzymatic galactosylation of uridine, inosine, and adenosine are unequivocally assigned β(1→3)-glycosidic linkages ($\text{3a}$ – $\text{3c}$).     

Ring cleavage and ring expansion of indoles by superoxide ion

The reaction of indoles ($\text{1}$) with superoxide ion resulted in ring cleavage to give $\text{o}$-formyl and $\text{o}$-acylaminoketones ($\text{6}$) or N-acylanthranilic acid ($\text{8}$) and ring expansion yielding 2-quinolones ($\text{7}$). All reactions are chemiluminescent except that of 2-methylindole ($\text{lh}$), which gave a coupled product ($\text{9}$).     

Some reactions of phenolic maleamic acids relevant to carboxypeptidase catalysis

In neutral aqueous acetonitrile, N-$\text{o}$-hydroxybenzyl-2,3-dimethylmaleamic acid is rapidly converted to N-$\text{o}$-hydroxybenzyl-2,3-dimethylmaleimide, while N-propyl-N-$\text{o}$-hydroxybenzyl-2,3-dimethylmaleamic acid is converted to dimethylmaleic anhydride; both reactions are catalyzed by the phenolic groups.     

A novel synthesis of 3-cyanoindoles and a new route to indole-3-carboxylic acid derivatives

2-Alkyl-3-cyanoindoles are obtained when 1-alkylmethyl-2-chloro-(or 2-phenylsulfonyl)-3-phenylsulfonylindoles are reacted with excess azide ion (90°/DMF). The reaction is considered to occur by a fragmentation recombination process in which the Schiff's base $\text{12}$ is of central importance. This proposal is supported by the formation of 2-substituted indole-3-carboxylates $\text{17}$ from aldehydes and the α-phenylsulfonyl-$\text{o}$-aminophenylacetic acid ester derivative $\text{16}$.     

Research on african medicinal plants - X: Glucosides of Hypoxis nyasica bak. the structure of nyasoside,a new glucoside biologically related to hypoxoside

From rhizome of $\text{Hypoxis nyasica}$ two diglucosides were isolated: hypoxoside, (1), and a new one, the 0,0-β,β-di-D-glu- copyranoside of 1-(4$\text{-}\text{?}$hydroxyphenyl)-3-(4$\text{-}\text{?}$hydroxyphenyl)-1,4-pen- tadiene, (2), named nyasoside.     

A new optical resolution method of tertiary acetylenic alcohol utilizing complexation with brucine

Some tertiary acetylenic alcohols were resolved efficiently utilizing complexation with brucine. The crystal structure of 1:1 brucine complex of 1-(o-bromophenyl)-1-phenyl-2-propynol ($\text{1}$$\text{d}$) was reported.     

Studies on the stereochemical course of intramolecular cycloaddition reactions of olefinic o-quinodimethanes-stereoselective synthesis of 8α, 9α, 14β-estranes

The stereoselective synthesis of 3-O-methyl-7α-$\text{p}$-toluenesulphonyl-8α, 9α, 14β-estradiol ($\text{25}$) and its 11-oxo derivative ($\text{26}$) $\text{via}$ thermolysis of 1β-$\text{tert}$-butoxy-2α-[2-(4-methoxybenzocyclobutenyl)ethyl]-2β-methy1-3α-[2-($\text{p}$-toluenesulphonyl)ethenyl] cyclopentane ($\text{22}$) and its oxo derivative ($\text{24}$), which were derived from condensation product ($\text{9}$) of optically active aldehyde ($\text{8}$) and 1-cyano-4-methoxybenzocyclobutene through $\text{10}$ and $\text{11}$ to selenides $\text{16}$ and $\text{21}$, is described.     

The effect of alkene configuration on the partitioning between the carbenic reactions and the 1,7-electrocyclisation of α-)o-alkenylaryl)diazoalkanes

The 1,7-electroclyclisation of α-($\text{o}$-alkenylaryl)diazoalkenes to 1$\text{H}$-2,3-benzodiazepines is blocked by the $\text{cis}$ substituent in $\text{Z}$ alkenyl groups and the diazo-compounds then react via alternative routes including a new intramolecular carbene reaction to give naphtho[a]cycloheptenes.     

A novel synthesis of 9-hydroxyaporphine

(±)-N-Methyllaurotetanine (3) was readily prepared $\text{via}$ the $\text{o}$-quinol acetate (2), which was obtained from the 1-(3′-hydroxybenzyl)-tetrahydroisoquinoline (1) by lead tetraacetate oxidation.     

The anhydride structure of several previously reported stable areneselenenic acids1

The compounds previously reported² to be the stable areneselenenic acids, $\text{o}$-nitro-($\text{la}$ and $\text{+o}$-benzoylbenzeneselenenic acid ($\text{lb}$), are shown actually to be the corresponding selenenic anhydrides (ArSeOSeAr). Solutions of the selenenic acids (ArSeOH), however, can be easily generated from the anhydrides byacid-catalyzed hydrolysis.     

Synthese et cyclisation electrophile de la bromhydrine de l'acide homogeranique

A new synthesis of 5-bromohexahydro-4,4,7a-trimethyl-2($\text{3H}$)-Benzofuranone (3aα,5β,7aβ)($\text{1}$) was achieved by electrophilic cyclization of the bromohydrin issued from pure homogeranic acid.     

Direct incorporation of A 6α(7α)-formamido group into penicillins and cephalosporins

6β(7β)-($\text{N}$-2,2,2-Trichloroethoxycarbonyl-$\text{N}$-trifluoromethanesulphonylamino) penicillins and cephalosporins have been converted into the corresponding 6α(7α)-formamido-6β(7β)-2,2,2-trichloroethoxycarbonylamino derivatives, by treatment with $\text{N}$,$\text{N}$-bis(trimethylsilyl) formamide and triethylamine.     

A novel and efficient synthesis of the naturally occurring nucleoside doridosine

1-Methylisoguanosine was synthesized by a one-pot reaction involving a condensation of 5-amino-1-(β-$\text{D}$-ribofuranosyl)imidazole-4-carboxamide (1) with methyl isothiocyanate, treatment of the resulting thiourea derivative with DCC furnished 5-(3-methyl-1-ureido)-1-(β-$\text{D}$-ribofuranosyl)imidazole-4-carbonitrile (4) which was then annulated with ethanolic ammonia to furnish doridosine in a 68% yield from 1.     

Use of the E-vinyloxyborane derived from S-phenyl propanethioate for stereospecific aldol-type condensation. A simplified synthesis of the prelog-djerassi lactonic acid

The $\text{E}$-vinyloxyborane ($\text{5}$), prepared from S-phenyl propanethioate, 9-BBN triflate, and diisopropylethylamine, reacts stereoselectively with aldehydes to provide $\text{erythro}$-β-hydroxy-α-methylcarboxylic acid thiol esters. This reaction has been applied to a synthesis of Prelog-Djerassi lactonic acid ($\text{6}$).