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Fused quinoline heterocycles VI: Synthesis of 5 H ‐1‐thia‐3,5,6‐triazaaceanthrylenes and 5 H ‐1‐thia‐3,4,5,6‐tetraazaaceanthrylenes
Author(s) -
Mekheimer Ramadan Ahmed,
Sadek Kamal Usef,
ElNabi Hisham Ahmed Abd,
Mohamed Afaf Abd ElHameid,
Ebraheem Ehab Anwer,
Smith Michael B.
Publication year - 2005
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570420415
Subject(s) - chemistry , quinoline , ethyl chloroformate , synthon , yield (engineering) , triethyl orthoformate , alkyl , organic chemistry , medicinal chemistry , catalysis , materials science , metallurgy
Ethyl 3‐amino‐4‐chlorothieno[3,2‐c]quinoline‐2‐carboxylate ( 4 ) is a versatile synthon, prepared by reacting an equimolar amount of 2,4‐dichloroquinoline‐3‐carbonitrile ( 1 ) with ethyl mercaptoacetate ( 2 ). Ethyl 5‐alkyl‐5 H ‐1‐thia‐3,5,6‐triazaaceanfhrylene‐2‐carboxylates 9a‐c , novel perianellated tetracyclic heteroaro‐matics, were prepared by refluxing 4 with excess of primary amines 7a‐c to yield the corresponding amino‐thieno[3,2‐c]quinolines 8a‐c . Subsequent reaction with an excess of triethyl orthoformate (TEO) furnished 9a‐c . Reaction of 4 with TEO in Ac 2 O at reflux, gave the simple acetylated compounds, thieno[3,2‐ c ]‐quinolines 12 and 13 . Refluxing 4 with benzylamine ( 7d ) gave 10 , and subsequent treatment with TEO gave the tetracyclic compound 11 . Refluxing 13 with an excess of alkylamines 7a‐d gave the fhieno[3,2‐ c ]quino‐lines 15 . Refluxing the aminothienoquinolines 8b with an excess of triethyl orthoacetate gave thieno[3,2‐ c ]quinoline 17 , while heating with Ac 2 O gave 18 and 19 , with small amounts of 16 . Reaction of 8a,b with ethyl chloroformate and phenylisothiocyanate generated the new 1‐thia‐3,5,6‐triazaaceanthrylenes 20a,b and 21a,b , respectively. Diazotization of 8a‐c afforded the novel tetracyclic ethyl 5‐alkyl‐5 H ‐1‐fhia‐3,4,5,6‐tetraazaaceanthrylene‐2‐carboxylates 22a‐c in good yields.