Thieno acridines

The chemistry of thienoquinolines has been explored to a limited degree. Two types (378,379) will be described in this subsection. The pharmacological interest in thieno[2,3-Z>]quinoline (378) and derivatives thereof stems from their isosteric and isoelectronic resemblance to acridine furthermore, (378) constitutes the sulfur analog of furoquinoline (Section 3.17.2.1.5), which is the parent system of a number of alkaloids. Thieno[3,4-6]quinoline (379) is an o-quinonoidal heterocycle which is of interest both for theoretical reasons compared with its isoconjugate analogues and as a synthon in Diels-Alder reactions for the preparation of other condensed heterocycles. 

The Fetvadjian-Ullmann reaction between 4-hydroxy-7-(p-tolyl)ben-zothiophene 314, aniline, and paraformaldehyde provides another pathway for the construction of thieno[2,3-c]acridines, such as 315 (Scheme 61) (81JHC1519). 

Suresh et al. (93SUL7) have described a novel route for the preparation of thieno[2,3-c]acridines 316 that involves photocyclization (Scheme 62). 

Buu-Hoi and Royer (46CR806) obtained a series of thieno[3,2-c]acridines 320 by using the Pfitzinger reaction between 4,5-dihydrobenzothiophene-7(6//)-one 318 and isatins 319, followed by decarboxylation at high temperature (Scheme 63). One of the decarboxylated products 320 (R = Me, R = H) was dehydrogenated with PbO at 310°C to give the fully aromatic system 321. 

We have used the strategy developed for the synthesis of pyrido[2,3-c]acridines to prepare thieno[2,3-c]acridines, such as 317 (96TH1). 

Several reports of pyrimidine-based anticancer agents were published in 2013. George and his collaborators reported the synthesis of novel tetra-hydrobenzo[4,5]thieno[2,3-d] pyridimidine derivatives and explored their antitumor and antibacterial activities (Figure 3) (13EJM195). Compounds 101 and 102 were found to be very active against the bacterial species Staphylococcus aureus (G" "), Pseudomonas aeruginosa (G ), Bacillus subtilis (G ), and Escherichia coli (G ). Furthermore, 9-methyl-A/-substi-tuted acridine-3,6-diamino derivative 103 was shown to be active solely... 

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