Herve Quiniou

Lactamisation par le bop : acethyl-3 methyl-7 phtalimido-7 cepheme

Resume A 1,3-thiazine with a prelactamic chain is obtained via a (4+2) cycloaddition reaction. The regioselective hydrogenation at 2,3 and subsequent lactamisation using BOP is described.

Thermolysis of Substituted-4H-1,3-Thiazines

Abstract Thermolysis of 4-dimethylamino-2-phenyl-4-substituted 4H-1,3-thiazines leads to thioamide vinylogs or N-methyl 2H-3,4-dihydrothiazine by thermal rearrangement depending on the nature of the substituents.

The preparation and rearrangements of 5-acyl-2-phenyl-4-substituted 6H-1,3-thiazines. X-Ray molecular structure of 3-acetyl-2-ethoxycarbonyl-4-(3-oxobutylthio)-5-phenylpyrrole

5-Acyl-2-phenyl-4-substituted 6H-1,3-thiazines are prepared by the reaction of N′,N′-substituted N2-thiobenzoylformamidines with methyl vinyl ketone or acrylaldehyde. Rearrangement catalysed by base and subsequent condensation with the acrylic reagent gives substituted pyrrolyl sulphides or substituted 2,6-dihydrothiopyrano[2,3-c]pyrrole.

ENCHAINEMENTS HETEROATOMIQUES ET LEURS PRODUITS DE CYCLISATION–VIII1 METHYLENE-2 DIHYDRO-3,6 2H-THIAZINES-1,3 FONCTIONNALISEES EN POSITION 4 PAR SUBSTITUTION NUCLEOPHILE D'UN GROUPEMENT BROMOMETHYLE ET PAR CONVERSION D'UN GROUPEMENT DIBROMOMETHYLE EN ALDEHYDE, NITRILE ET ESTER

Abstract Treatment with NBS of 2-methylene-3,6-dihydro-2H-1,3-thiazines carrying an ester function on 5 and a methyl on 4 gives the corresponding 4-bromomethyl and 4,4-dibromomethyl derivatives in a perfectly selective manner. The monobromo compounds give access to 4-aminomethyl, 4-alkoxymethyl, 4-alkylthiomethyl, 4-acetoxymethyl and 4-formyl thiazines. These aldehydes, also prepared from the dibromo derivatives, are converted into 4-cyano and 4-alkoxycarbonyl thiazines. In certain cases, interactions with the neighbouring ester group, leading to lactones are observed.

Total synthesis of N-protected 7-amino-7-methoxy cephems

N-Protected7-amino-7-methoxy cephems are synthesised from methylN-(O-methoxycarbonylbenzoyl)methoxy(thiocarbamoyl)glycinate in two major steps: construction of the thiazine ring and subsequent closure of the β-lactam ring.

Simple and efficient methoxylation of 1,3-dihydrothiazine derivatives

The methoxylation of dihydrothazine derivatives has been carried out using t-butyl hypochlorite and lithium methoxide; a possible mechanism involving an acylimine intermediate is proposed.

Addition of sulphenes to thioamide vinylogues: substituted 5,6-dihydro-1,2-dithiin 1,1-dioxides and 1,2-dithiin 1,1-dioxides

Syntheses of substituted 1,2-dithiin 1,1-dioxides via the addition of sulphenes to thioamide vinylogues are described.

ORGANOSCHWEFELVERBINDUNGEN 10. MITT. 2,5-DIARYL-1,6,6A-S(IV)-TRITHIAPENTALEN-3-CARBALDEHYDE

Die aus den Estern (I) und Aceton (II) in Dimethoxyathan in Gegenwart von NaH erhaltenen Triketone (III) (60, 65 bzw. 25% Ausbeute) cyclisieren sich beim Erhitzen mit P4810 in Benzol zu den Trithiapentalenen (IV) (54, 20 bzw. 24%).

RK. VINYLOGER THIOAMIDE MIT OX.‐MITTELN UND BENZONITRIL‐OXID

Bei der Oxidation vinyloger Thioamide, z.B. (Ia) bzw. (Ib), mit Hg-acetat werde die entsprechenden Propenamine (II) erhalten.