engleski

New Thiazolidinone and Triazinethione Conjugates Derived from Amino-beta-lactams

Thioureas 3a-s, generated from amino-b-lactams 1a-c, were used to achieve two different cyclizations: (i) condensation with ethyl bromoacetate which resulted in the formation of a variety of iminothiazolidinones 4a/a'-n, and (ii) condensation with aqueous formaldehyde and methylamine which resulted in the formation of triazinethiones 5a-g. The condensation of thioureas 3b-f, 3h and 3m-s (R1 = cyclohexyl, exo-norbornyl, aryl, R2 = b-lactam) with ethyl bromoacetate proceeded with high regioselectivity leading exclusively to the formation of a single regioisomer A of iminothiazolidinones 4b-n. However, the cyclization of thiurea 3a (R1 = n-hexyl, R2 = b-lactam) with ethyl bromoacetate led to the formation of a mixture of two regioisomers A (minor) and B (major) of the iminothiazolidinones 4a/a' in the ratio 23:77. Furthermore, condensation of thioureas 3d, 3g, 3i-l and 3n with aqueous formaldehyde and methylamine furnished triazinethiones 5a-g.

b-Lactam ; Isothiocyanate ; Thiourea ; Iminothiazolidinone ; Triazinethione

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