Marie-Louise Roumestant

2-Hydroxy-3-pinamone as chiral auxiliary in the asymmetric synthesis of α-amino acids

Abstract The reactivity of lithiated chiral Schiff bases 2 with carbonyl compounds is studied. They do not react with ketones but with aldehydes good chemical yields are obtained in the presence of cosolvents. On the other hand, the reaction with unsaturated carbonyl compounds (ethylenic, acetylenic, allenic) is very rapid and affords a variety of amino esters with good chemical and optical yields. With the lactone 7 , prepared by cyclisation of the ester of glycine with 2-hydroxy 3-pinanone, the first results obtained with alkyl halides, aldehydes and epoxide show excellent stereoselectivity and good chemical yields.

SYNTHESIS OF ENANTIOMERICALLY PURE AMINOPHOSPHONIC ACIDS

Abstract An efficient general asymmetric synthesis of α-aminophosphonic acid derivatives has been achieved by alkylation of the Schiff bases 2, prepared from (1R,2R, 5R)(+) or (1S,2S, 5S)(-) 2-hydroxy 3-pinanone 1 and α-aminomethyl phosphonic acid diethylester. Diastereoisomeric alkylated Schiff bases separated on column chromatography afforded after hydrolytic cleavage enantiomerically pure compounds.

Reactions of Schiff base anions with electrophiles: role of the initial stereochemistry

Abstract It is shown that the reactivity towards electrophites of diastereomeric Schiff bases of *R and *S valine, leucine, phenylalanine and norvaline methyl esters with (1S,2S,5S) or (lR,2R,5R) 2-hydroxy 3-pinanone, is highly dependent on the stereochemistry of the starting product.

Synthèse et réactivité des dérivés de la 2,3-dihydro-3-hydroxy-2-phényl-1,5-benzothiazépin-4(5H)-one

Abstract New 1,5-benzothiazepinone derivatives have been synthesized. The cycloaddition of benzylazide with 5-propargyl-1,5-benzothiazepinone 7 gave compounds 9 and 10 . The 1,5-benzothiazepinone 8 reacts with hydrazine to give 1,5-benzothiazepinone 11, which gave in hot acetic acid compound 12 . The reaction of 3-chloro-1,5-benzothiazepinones 13 , 14 or 15 with nucleophiles in DMF afforded the 2-benzylidenebenzothiazin-3-ones 16 and 17 . The tosylate 18 gave the 1,5-benzothiazepinone 19 by reaction with N 3 TMS in the presence of CsF in DMF.

Synthièse de nouveaux systèmes hétérocycliques renfermant le benzothiazole, le 1,3,4-thiadiazole et le furane

Resume Le 2-(4-methylphenyl)acyl-l,3-benzothiazole 3b reagit avec le N -bromosuccinimide pour donner le produit de dimerisation 4 . Ce dernier, porte au refux du triethylphosphite, se transforme en furane 5. Le 2-phenacyl-1,3-benzothiazole 3a , apres sulfuration et reaction avec les nitrilimines 7 et 8 conduit aux 1,3,4-thiadiazoles 9 et 10 .