Synthesis of substituted 2,4-dimethylthieno[3,2-c]quinolines

Abstract

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Recent Advances in the Synthesis of Thienoquinolines (Quinoline‐fused heterocycle)

“…In 2007, Sargsyan and co-workers reported a new class of 2,4dimethylthieno [3,2-c]quinolines 64 from substituted dihydroquinoline-4-thiones. [45] (Scheme 21) The reaction of 4-chloro-3-(2-chloropropyl) and 4-chloro-3-(2-oxopropyl)-2-methylquinoline upon heating with thiourea, and anhydrous acetone resulted in S-quinolylthiuroniu m chloride-salt intermediate, further base hydrolysis led to the formation of dihydroquinoline-4-thiones 62 and 63, which were treated with 96% H 2 SO 4 at room temperature to access corresponding 2,4dimethyl-thieno[3,2-c]quinolines, 64 via intramolecular cyclization. The current procedure is enclosed with advantages, including mild reaction conditions and greater yields.…”

“…In 2007, Sargsyan and co-workers reported a new class of 2,4dimethylthieno[3,2-c]quinolines 64 from substituted dihydroquinoline-4-thiones. [45] In 2008, Mekheimer and co-workers developed fused quinoline heterocycles, alike 3-amino-thieno[3,2-c]quinolines 67 from 2,4-dichloroquinoline-3-carbonitrile 65. [46] (Scheme 22) The reaction of compound 65 with ethyl mercapto-acetate in the presence of DMF and triethylamine resulted in 3-amino-4-chlorothieno[3,2-c]quinoline-2-carboxylate 66, [47] which further treated with various secondary amines using DMF under reflux to obtain the corresponding 3-amino substituted thieno[3,2-c] quinolines 67 in excellent yields.…”

Synthesis of 4-phenylthieno[2,3-c]quinolines via Suzuki–Miyaura cross-couplings

“…7 Two general strategies have been investigated to prepare thieno [3,2-c]quinolines. Specifically, a number of methods have accessed these heterocycles via quinoline substrates, [8][9][10][11][12] while other approaches have employed thiophene precursors. [13][14][15][16][17][18][19] In this work, we deployed robust cross-coupling methodology [20][21][22] to establish a short, modular synthetic route enabling the efficient construction of a small library of functionalized 4-phenylthieno [3,2-c]quinolines from a simple thiophene starting material.…”

Novel Polycarbo-Substituted Alkyl (Thieno[3,2-c]quinoline)-2-Carboxylates: Synthesis and Cytotoxicity Studies

“…Some thieno[3,2- c ]quinoline derivatives have also been found to inhibit protein kinases in cancer cells [4,5]. A series of substituted 2,4-dimethyl-thieno[3,2- c ]quinolones was previously prepared via intramolecular cyclization and subsequent aromatization of 3-(2-chloroprop-2-en-1-yl)- and 3-(2-oxopropyl)-2-methylquinolin-4-thiols [6]. The reaction of 4-chloroquinolin-2(1 H )-ones with thioglycolic acid and/or 2-sulfanylpropionic acid in the presence of a base as catalyst and subsequent polyphosphoric acid-promoted cyclodehydration, on the other hand, yielded the 3-hydroxythieno[3,2- c ]quinolin-4(1 H )-ones [7].…”