Phase-Transfer Catalysed Alkylation of Enamines of some Cyclic β-Keto Carbothionic Acid Anilides with 1,2-Dibromoethane. Synthesis of Enamines of 1-Oxo-2-(3-phenyl tetrahydrothiazol-2-ylidene)-cycloalkanes

Abstract

<jats:p>The alkylation of morpholine enam ines of 2-oxo-cycloalkane-1-carbothionic acid anilides (1-3) with 1,2-dibromoethane under phase-transfer catalytic conditions yields enam ines of 1-oxo-2-(3-phenyl-tetrahydrothiazol-2-ylidene)-cycloalkanes (4-6). Compounds 4-6 were hydrolysed to appropriate keto derivatives 8-10. The structure of obtained com pounds was established on the basis of IR. NM R and MS spectral data.</jats:p>

Thioamides as Useful Synthons in the Synthesis of Heterocycles

“…N,S- Alkylation of thioamides with alkyl dihalides may be also realized in a two-phase system composed of a 50% aqueous solution of sodium hydroxide and benzene or dichloromethane as an organic phase, and benzyltriethylammonium chloride (TEBA) as a catalyst. , For example, thioanilides 4 react in such a system with 1,3-dibromopropane to give isomeric 3-aryl-1,3-thiazines 5 and 6 (Scheme ) 2 …”

“…Thioanilides derived from enamines or cyclic ketones reacted under analogous conditions with 1,2-dibromoethane, yielding thiazolidine derivatives 7 − 10 of Z configuration (Figure ). , The alkylation invariably occurred exclusively at the nitrogen and sulfur atoms, furnishing heterocyclic compounds in moderate to good yields.

3

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“…N,S-Alkylation of thioamides with alkyl dihalides may be also realized in a two-phase system composed of a 50% aqueous solution of sodium hydroxide and benzene or dichloromethane as an organic phase, and benzyltriethylammonium chloride (TEBA) as a cata- lyst. 16,17 For example, thioanilides 4 react in such a system with 1,3-dibromopropane to give isomeric 3-aryl-1,3-thiazines 5 and 6 (Scheme 2). 16 Thioanilides derived from enamines or cyclic ketones reacted under analogous conditions with 1,2dibromoethane, yielding thiazolidine derivatives 7-10 of Z configuration (Figure 3).…”

Regioselektive Cyclisierung von Thiocarbonsäureamiden mit Bisimidoyl- chloriden -Synthese von Thiazolidinen mit einer Ketenacetal-Substruktur / Regioselective Cyclization of Thiocarboxylic Amides with Bisimidoyl Chlorides - Synthesis of Thiadiazolidines Containing a Ketenacetal Substructure

“…A nh an d von sem iem pirischen B ere c h n u n gen w urde auch hier für 8 die P räferen z d e r Z-Form prognostiziert, vgl. [22,23] und durch N O E -D ifferenzspektroskopie im Fall von 8c bew iesen. N ach diesen B efunden zur A m bid o selek tiv ität der bielektro p h ilen C2-B austeine vom Typ 1 soll ten w eitere System e in diese B etrach tu n g en ein b e zogen w erden.…”