The Synthesis of New Dibenzothiophen Amino Acid and Cyclophane Derivatives

Abstract

Some novel dibenzothiophen amino acid and cyclophane derivatives have been produced as a result of synthetic studies on the development of dibenzothiophen-based antibacterial compounds. Allylation through a Stille reaction has produced 2-allyl-8-bromodibenzothiophen (3a) and 2,8-diallyldibenzothiophen (3b). Under different conditions, the Stille reaction also produced 2-bromo-8-(prop-1-enyl)dibenzothiophen (4a) and 2,8-di(prop-1- enyl)dibenzothiophen (4b) via double bond isomerization. Olefin metathesis with (3b) and methyl N-acetylallylglycinate (5) produced two homodimers, the novel [4](5,11)[4](18,24)dibenzothiophenophane-2,15-diene (6), as a mixture of geometrical isomers, and dimethyl (E)- and (Z)-(R,S)-2,7-diacetamidooct-4-enedioate 8), and the two cross-metathesis products methyl (E)- and (Z)-(R,S)-2-acetamido-6-(8-allyldibenzothien-2-yl)hex-4-enoate (7a) and dimethyl (E)- and (Z)-(R,S)-6,6¢-(dibenzothiophen-2,8-diyl)bis(2-acetamidohex-4-enoate) (7b). Palladium-catalysed hydrogenation of the homodimer (6) and the cross-metathesis products (7a,b) yielded the corresponding reduced compounds (9) and (10a,b), respectively.