Metabolites of Alternaria solani part V. Biosynthesis of altersolanol A and incorporation of altersolanol A-13Cx into altersolanol B and macrosporin

The biosynthesis of the tetrahydroanthraquinone, altersolanol A ($\text{1}$), by $\text{Alternaria solani}$ has been established by the incorporation of [1,2-¹³C₂]-acetate. A blocked culture of $\text{A. solani}$ was utilized to reveal that $\text{1}$ is metabolized to altersolanol B and macrosporin.     

Synthesis of a key intermediate for the total synthesis of streptovaricin A

A key intermediate ($\text{3}$) for the total synthesis of streptovaricin A ($\text{1}$) is synthesized in its optically active form. Further elaboration of $\text{3}$ is also described.     

Rearrangement spinal en serie a/b cis : conversion du lithocholate de methyle en derives du d-homoandrostane

A new backbone rearrangement is observed in A/B $\text{cis}$ methyl lithocholate derivatives. It is initiated from the C-3 carbon either by dehalogenation of the chloroesters $\text{1}$ by AgSbFg₆ or by the action of the triflic anhydride on the si1y1ated ether $\text{2}$. This rearrangement leads to methyl diacholenate $\text{3}$ and new lactones in D-homoandrostane series $\text{5}$ and $\text{6}$. The differences of behaviour between A/B $\text{cis}$ and A/B $\text{trans}$ series and the mechanism of rearrangements are discussed.     

Synthesis of the parent compound of isobacteriochlorins - a diminution of the π-system of porphins

A four step synthesis of 1,4;6,9-bisdesethenophorphin $\text{3}$ proceeding via the intermediates $\text{4}$, $\text{5}$ and $\text{6}$ is presented. The spectral properties of $\text{3}$ indicate close similarities to porphyrins and isobacteriochlorins.     

Synthesis of 2-isopropylfuro(2,3-b)quinolines-a new synthesis of (±)-lunacrine, (±)-lunasine and (±)-demethoxylunacrine

A new and convenient synthesis of 2-isopropylfuro-(2,3-b)quinolines ($\text{4}$) from 3-(3-methylbut-1-enyl)-2-quinolones ($\text{2}$) is described. A neat synthesis of the alkaloids (±)-lunacrine ($\text{1a}$), (±)-lunasine ($\text{12a}$) and (±)-demethoxylunacrine ($\text{1b}$) is also reported.     

The conversion of methylenomycin A to natural botryodiplodin and their absolute configurations

Natural (?)-botryodiplodin($\text{1}$) has been synthesized from an antibiotic methylenomycin A ($\text{2}$). The absolute configurations of (?)-botryodiplodin($\text{1}$ and methylenomycin A ($\text{2}$) have also been established as shown in $\text{1}$ and $\text{2}$ respectively.     

Reaction of 2-heterosubstituted benzothiazoles with allylic grignard reagents

The title benzothiasoles $\text{1}$ react with allylic Grignard reagents affording 2-allylbenzothiazoles $\text{5}$, 2,2-diallyl- benzothiazolines $\text{6}$ and N-triallylmethyl-o-aminobenzenethiols as disulphides $\text{7}$ depending upon the experimental conditions. The reaction is considerably influenced by the solvent used and the nature of the allylic Grignard. A possible mechanism for the formation of compounds $\text{5}$, $\text{6}$ and $\text{7}$ is reported.     

Studies directed towards total synthesis of saframycin: I. A synthesis of hexahydro-1,5-imino-3-benzazocin-7,10-dione.

A short-step synthesis of $\text{2}$, the right-hand half of antibiotic saframycin ($\text{1}$), is described. The key steps of this synthesis are the acid catalyzed intramolecular double cyclization of $\text{4}$ and the oxidative demethylation of $\text{7}$ to the quinone ($\text{2}$).     

Amino acids derivatives that stabilize secondary structures of polypeptides-- : I. Synthesis of LL-3-amino-2-piperidone-6-carboxylic acid (LL-Acp), a novel beta-turn-forming amino acid

A six-step synthesis is reported of $\text{LL}$-3-amino-2-piperidone-6-carboxylic acid from $\text{L}$-homoserine lactone and the $\text{mono}$-$\text{t}$-butyl ester on $\text{N}$-benzyloxycarbonylaminomalonic acid. Evidence of chiral integrity is discussed.     

A convenient synthesis of flindersine,atanine and their analogues

A new synthesis of the pyranoquinolone alkaloids flindersine ($\text{8a}$), 8-methoxyflindersine ($\text{8c}$), N-methylflindersine ($\text{9a}$), zanthobunglanine ($\text{9c}$) oricine ($\text{9d}$) and veprisine ($\text{9e}$) and the prenylquinolone alkaloids atanine ($\text{13a}$), preskimmianine ($\text{13e}$) N-methylatanine ($\text{14a}$), O-methylglycosolone ($\text{14c}$) and N-methylpreskimmianine ($\text{14e}$) is described.     

Stereoselective synthesis and Diels-Alder reactions of bis-Ether 1,3 Dienes. A further test for cooperativity during cycloaddition reactions.

A stereoselective synthesis of dienes $\text{1a}$ and $\text{1b}$, using butadiene-iron tricarbonyl complexes, is described. Higher diastereoselectivity is observed during Diels-Alder reaction of $\text{1a}$ as compared with $\text{1c}$, affording good evidence for cooperativity in these cycloadditions.     

Inter vs intramolecular amidoalkylations of aromatics - a new synthesis of oxindoles,isoquinolones and benzazepinones

A new synthesis of oxindoles ($\text{8}$) isoquinolones ($\text{5}$) and benzazepinones ($\text{10}$) by the intramolecular amidoalkylation of aromatic amides of bismethoxycarbonylaminoacetic acid ($\text{4}$, $\text{7}$, $\text{9}$) is described.     

Chemistry of singlet Oxygen. XXVII. Directing effect of methoxy group in additions to methoxystyrenes

A methoxy group on a styrene double bond directs O₂ attack $\text{cis}$, giving 1,4 addition if the phenyl is $\text{cis}$, or ene reaction if a CH₃ is $\text{cis}$. If no substituent is $\text{cis}$, 1,4 attack on the $\text{trans}$ phenyl occurs at a slower rate.     

Synthesis of O-6-alkylated deoxyguanosine nucleosides

A general route for synthesis of 6-$\text{O}$-alkyl-2∝deoxyguanosine nucleosides is described. The key step is conversion of the 6-$\text{O}$-TPS derivative $\text{2}$ to the 6-trimethylamino compound $\text{3}$. The trimethylamino group is readily displaced by alcohols in the presence of DBU. Using this route the 6-$\text{O}$-methyl, ethyl and n-butyl 2∝-deoxyguanosine derivatives $\text{5a-c}$ have been prepared in excellent overall yields.     

Ring opening of benzoxazoles with allylic grignard reagents: synthesis of n-diallylalkyl-o-aminophenols.

The title benzoxales $\text{1a-d}$ react cleanly with allylic Grignard reagents $\text{2a-c}$ undergoing ring opening to give good yields of N-diallyl- alkyl-$\text{o}$-aminophenols $\text{3a-m}$. A plausible mechanism is discussed.     

Action de CF3 of sur des aziridines N-non substitutees

Aziridines $\text{I}$ react with trifluoromethyl hypofluorite at ? 40°C to produce mixtures of 1-(aziridine)carbonyl fluoride $\text{II}$ and 1-fluoroaziridine $\text{III}$, the proportions of which depend on steric effects. Several compounds $\text{II}$ react with starting materials to give 1, 1′-(carbonyl)bisaziridines $\text{IV}$. Most compounds $\text{II}$ and all compounds $\text{IV}$ are isolated. Chemical properties and ir and nmr data of $\text{II}$, $\text{III}$, $\text{IV}$ are described; the formation of an isocyanate and a substituted urea from a compound $\text{II}$ is observed. A mechanism for this reaction is suggested.     

Remote inductive effects on secondary and tertiary 2-norbornyl solvolysis rates

A 5-cyano substituent decelerates the solvolysis rate of exo-2-norbornyl brosylate $\text{(1-H)}$ by a factor of 1790. A much smaller deceleration (24–90 fold) is observed for the secondary $\text{endo}$ and for both $\text{exo}$ and $\text{endo}$ tertiary 2-norbornyl derivatives. These results support the occurrence of σ-participation in the solvolysis of $\text{1-H}$.     

Dimeric sesquiterpene lactone. Structure of isoabsinthin acid isomerization of absinthin derivatives

Isoabsinthin $\text{2}$ is a new diguaianolide constituent of $\text{A.absinthium}$$\text{1}$. The acid isomerizations of several derivatives of absinthin have been studied.     

Complexes of carbonyl compounds with RnAlX3-n compounds: III. The stoichiometry of complexes of ketones with aluminium trichloride

Acetophenone and p-methylacetophenone complex with aluminium trichloride; $\text{1}\text{1}$ and $\text{1}\text{2}$ complexes are formed in equilibrium in benzene solution. A 6-membered ring structure is proposed for the $\text{1}\text{2}$ complex.     

Eine einfache photochemische synthese von cyclopent[d][1,3]oxazinen aus 2,4-cyclohexadienimin-derivaten

A synthesis of cyclopent[d][1,3]oxazines $\text{8}$ is reported involving the photochemically induced transformation of 2,4-cyclohexadienimines $\text{4}$ via dienylketenimine intermediates $\text{6}$ and the dihydroderivatives $\text{7}$.