Aromatization of 1,6,7,7a-tetrahydro-2H-indol-2-ones by a novel process. Preparation of key-intermediate methyl 1-benzyl-5-methoxy-1H-indole-3-acetate and the syntheses of serotonin, melatonin, and bufotenin

Imine 7 of 1,4-cyclohexanedione mono-ethylene ketal 6 was reacted with maleic anhydride, affording the cyclized adduct 8. Methyl esterification of 8, accompanied by transacetalization, led to the dihydrooxindole derivative 10. Aromatization of 10 was then accomplished with POCl(3), leading directly to the key-intermediate title compound 11 in 74% yield from ketone 6. Serotonin, melatonin, and bufotenin were then obtained by standard reactions.     

Reaction of cyclohexanone benzylimines with ethylidenemalonate diesters. Diphenyl 2-ethylidenemalonate: a highly electrophilic synthetic equivalent of crotonic esters.

The diastereoselective Michael alkylation of alpha-substituted and alpha,alpha'-disubstituted cyclohexanone benzylimines with ethylidenemalonate diesters was carried out for mechanistic and synthetic purposes. In the first case, an inverse regioselectivity occurred in comparison with what is generally observed since the Michael adducts resulted from alkylation of the non substituted enamine tautomer. With alpha,alpha'-disubstituted imines, in all cases, the stereochemistry of the major diastereomer was the one anticipated from a mechanism including a chairlike complex approach with a preferred exo position for the beta-methyl group of the ethylidenemalonic acid diesters. Furthermore, diphenyl 2-ethylidenemalonate 4 was found to be a highly electrophilic synthetic equivalent of crotonic esters.     

A synthesis of (d.l) acoradiene III

A synthesis of (d.l) Acoradiene III (7 steps) starting from N-methyl N-phenyl amino acetylene is described.     

Acylation of ynamines by enol-lactones: A new method of stereoselective spiroannelation.

A new method of regio and stereoselective spiroannelation which leads to functionnalized spiro (4.5) decenes and (5.5) undecenes is described.     

SYNTHESIS OF SOME DITHIOCARBAMATE DERIVATIVES AND THEIR ANTIMICROBIAL ACTIVITY

Some new, 2-[(N-substituted aminothiocarbonylthio)acetyl]aminothiazole, N-substituted aminothiocarbonylthioacetylaminodiphenylmethane and 9-[(N-substituted aminothiocarbonylthio)acetyl]aminofluorene derivatives were synthesized by reacting 2-(chloroacetyl) aminothiazole, chloroacetylaminodiphenylmethane, and 9-(chloroacetyl)aminofluorene with secondary amine dithiocarbamate derivatives in acetone respectively. The structure elucidation of the compounds was performed by IR, ¹H-NMR, and FAB⁺-MS spectral data. The substances were tested for their antimicrobial activity.     

Enantioselective synthesis of (+)-α-vetivone through the Michael reaction of chiral imines

(+)-α-Vetivone has been synthesised in nine steps. The absolute stereochemistry of the two stereogenic centres is controlled in the same key step involving the stereoselective Michael addition of a chiral imine of 4-isopropylidene-2-methylcyclohexanone to phenyl crotonate.     

Crotonates as dienophiles in high pressure-induced diels-alder cycloadditions: compared intra and intermolecular situations

The cyclization reactions of trienes 1 and 2 related intermolecular systems (5+6) and (9+10) have been investigated.     

Enantioselective Michael reactions of chiral secondary enaminoesters with 2-substituted nitroethylenes. Syntheses of trans, trans-2,4-disubstituted pyrrolidine-3-carboxylates

The Michael reaction of chiral 3-substituted secondary enaminoesters with 2-substituted nitroethylenes leads to (Z)-adducts, with good to excellent diastereoselectivity. The nitro group of these adducts was catalytically reduced to give, after cyclization and chiral amine elimination, pyrrolines or pyrrolidines after further reduction. In particular, the syntheses of ethyl (2R,3S,4S)-2,4-dimethylpyrrolidine-3-carboxylate and ethyl (2R,3R,4S)-2-(4-methoxyphenyl)-4-(3,4-(methylenedioxy)phenyl)pyrrolidine-3-carboxylate are described.     

Stereoselective synthesis of (1R,3S)-cis-chrysanthemic acid through microbiological reduction of 2,2,5,5-tetramethyl 1,4-cyclohexanedione.

An efficient, highly stereoselective synthesis of (1$\text{R}$,3$\text{S}$)-$\text{cis}$-chrysanthemic acid 6 is described. The crucial step of this synthesis was the microbiological reduction of dione 1 into ($\text{S}$)-ketol 2.