5 research outputs found
(7R,8R,8aS)-8-HydrÂoxy-7-phenylÂperÂhydroÂindolizin-3-one
The absolute configuration of the title compound, C14H17NO2, was assigned from the synthesis. There are two molÂecules in the asymmetric unit. Their geometries are very similar and corresponding bond lengths are almost identical [mean deviation for all non-H atoms = 0.015 (2) Å]. The six-membered ring of the indolizine system adopts a chair conformation. In the crystal structure, molÂecules form chains parallel to the a axis via interÂmolecular O—Hâ‹ŻO hydrogen bonds, which help to stabilize the crystal structure
Synthetic approaches to dexmedetomidine (review)
Abstract: The review is an attempt at critical evaluation of known synthetic procedures used for laboratory and industrial preparation of a synthetic antihypertensive -Dexmedetomidine as to their complexity, published yield and atom economy
Synthesis and reductive desulfurization of chiral non-racemic benzothienoindolizines. An efficient approach to a novel bioactive tylophorine alkaloid analogue and 6-phenylindolizidine
International audienc
Highly diastereoselective approach to novel tetrahydrofuran-fused indolizidinols: a one-step formation of three contiguous stereocenters
International audienc
The oxidative rearrangement of furan-2-carboximidamides: preparation and properties of 2-acylaminofurans
Oxidation of furan-2-carboximidamides 8 by (dicarboxyiodo)benzenes gives N-1-acyl-N-1-(2-furyl)ureas 9 via rearrangement to a carbodiimide. Thermolysis of eleven ureas 9 gave the corresponding 2-acylaminofurans 10, which cannot be made from the free amines owing to their high instability. When oxidation of the corresponding benzo[b]furan derivatives 12 was investigated a new type of product was isolated, in addition to the expected ureas 14, and these were shown to be benzo[4,5]furo[2,3-d]pyrimidine derivatives 15. The mechanism of formation of these products must involve reaction of the carbodiimide intermediate with the amidine precursor and cyclisation of the resulting guanidine derivatives 19. The corresponding tetraphenylguanidine 21 was prepared and underwent thermal cyclisation but the quinazoline derivative formed 23 was shown to occur via an alternative cyclisation mechanism. The structures of cyclisation products 15 and 23 were confirmed by X-ray crystallography. N-(2-Furyl)acetamide 10a readily undergoes cycloaddition reactions with electron-deficient alkynes to give phenols after spontaneous ring opening. Observed regioselectivity is in agreement with the results of AM1 molecular orbital calculations. Reaction of the amide 10a with Lawesson's reagent gave the thioamide 26