Functionally substituted 1,3-diethenyl [1,2- c ][1,3]pyrrolothiazoles from pyrrole-2-carbodithioates

C-Vinylpyrroles as Pyrrole Building Blocks

“…36 Using a mixture of osmium tetraoxide and HIO 4 as a oxidizing agent, the yield of 97 was increased to 86%. 37 The same procedure was employed for the preparation of 1-(N-fluorenyl-methoxycarbonylamino)butyl-2-formyl-5-hydroxymethylpyrrole (98), an intermediate in the synthesis of magnolamide alkaloid 99 (Scheme 38). 38 The key stage in the synthesis of distamycin antibiotic nitro analogue 100 is represented by the oxidation of dipyrrolylethene 101 to dipyrrolyldiketone 102 by potassium permanganate in acetic anhydride (Scheme 39).…”

“…95 Reaction of vinylthiolates 281, which are formed in situ from pyrrole-2-carbodithioates 264 and methylenoactive nitriles, with 2-benzoyl-1-bromo-and 2-chloro-1-ethylthioacetylenes 282a,b in the KOH-DMSO system affords functionalized pyrrolothiazoles 283a,b (Scheme 103). [97][98][99][100] Vinylthiolates 281 and bromobenzoylacetylene 282a stereoselectively form Z-isomers of pyrrolothiazoles 283a. The observed stereospecificity is likely caused by steric hindrances which do not allow formation of the E-isomer.…”

“…All steps of the synthesis of pyrrolothiazoles 283a,b are performed in a single reactor without isolation of intermediate products. [97][98][99][100] 2-and 3-Vinylpyrroles 285a react with NH-and N-methylglycinate to afford dipyrroles 286 with the 2,5-substituted pyrrole ring (Scheme 104). 101 When the chlorine atom in salt 285a is replaced by a dimethylamino group (the salt 285b), dipyrroles with a 2,3-disubstituted ring 287 are formed (Scheme 105).…”

Base‐Promoted Formation of an Annelated Pyrrolo‐1,4‐oxazine Ensemble from 1H‐pyrrol‐2‐ylmethanol and Propargyl Chloride: A Theoretical and Experimental Study

“…Such methods have successfully been used previously for the efficient and straightforward preparation of hardly accessible pyrrole systems. [35][36][37][38][39][40][41][42][43][44] In addition, an approach to the synthesis of N-allenylpyrroles via the efficient and straightforward reaction of pyrroles with propargyl chloride in the superbasic KOH/DMSO suspension has been elaborated. [45] The target compounds are formed in highto-quantitative yields.…”

“…The high synthetic potential of this reaction permits to employ it as a starting point for the synthesis of diverse annelated heterocyclic ensembles from the pyrroles. Such methods have successfully been used previously for the efficient and straightforward preparation of hardly accessible pyrrole systems . In addition, an approach to the synthesis of N ‐allenylpyrroles via the efficient and straightforward reaction of pyrroles with propargyl chloride in the superbasic KOH/DMSO suspension has been elaborated .…”