Thieno analogues synthesis

The last step in the synthesis of the sulfur- and selenium-containing psoralen analogues (174) (7/7-thieno[3,2- ][l]benzothiopyran-7-one, 7//-seleno[3,2-/][l]benzothiophen-7-one, 2//-selenolo [3,2- ][l]benzothiopyran-2-one, and 7//-selenolo[3,2-g][ 1 ]benzoselenopyran-7-one) was the poly-phosphoric acid silyl ether (PPSE)-mediated cyclization of benzol-thiophenes or selenophenes shown in Equation (76) <92H(34)lli9>. 

The palladium(O) catalysed tandem cyclisation of a bromoallene tethered with a sulfamide group 124 gives bicyclic azepines 125. The analogous reaction with Af-tethered bromoallene sulfamide 126 afforded bicyclic diazepine 127 <07CEJ1692>. Condensation of thiaisatoic anhydride with -amino acids proved to be a straightforward method for the synthesis of thieno[3,2-< ][l,4]diazcpin-2,5-dionc analogues 128 <07JOC2662>. 

Synthesis of another type of acyclo nucleosides start with thiophene-3-isocyanate and aminosugars to afford, with KOH/dioxan, thieno[3,2-pyrimidine nucleosides, while acryloylisocyanates react readily with aminoglucose or open chain analogues, resulting in open-chain (acyclo)ur-acil and an acyclo-acyclo species [92S(ip)J (Scheme 16, Scheme 17). 

Thiophen Analogues of Quinoline. - Pyrolysis of 3-(2-thienyl)propenal O-methyloxime at 650°C in a silica tube gave a 33% yield of thieno[3,2-h]-pyridine.New methods for the synthesis of 3-cyanopyridine-2-thiones... 

Diethyl 2,2 -dinitro-( )-stilbene-4,4 -dicarboxylate 132 proved to be a convenient starting compound in the synthesis of diethyl benzo[Z)]thieno[3,2- >]benzo[fe]thio-phene-2,7-dicarboxylate (133) and its selenium analogue 134 (93JOC5209). 

Thiophen Analogues of Quinoline and Related Compounds.—Convenient methods for the synthesis of the thiophen analogues of quinoline have been worked out. By the condensation of 2- and 3-thienylanunonium hexachlorostannates with malonic aldehyde tetraethyl acetal, thieno-[2,3-6]pyridine (538) and thieno[3,2-6]pyridine (539) were obtained in 44% and 77% yields. With other /5-dicarbonyl compotmds, substituted derivatives were obtained. Thus, acetoacetaldehyde dimethyl acetal gave... 

Thiophen Analogues of Isoquinoline and Related Compounds.— During the past three years, interest in the synthesis, reactions, and physical properties of these compounds has been noticeable, and four different research groups have made important contributions to this field. Both thieno[2,3-c]-pyridine (548) and thieno[3,2-c]pyridine (549) have been prepared in a... 

Reviews have appeared dealing with the synthesis of 6i/-pyrido[4,3- ]-carbazoles, thieno-pyridines, and imidazo-pyridines (and their benzo-analogues) having a bridgehead nitrogen atom. ... 

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