The Smallest Vicinal Tricarbonyl Compound as a Monohydrate and Tetracarbonyl Compound as a Thiane Derivative – First Effective Synthesis, Characterization and Chemistry

Abstract

An effective synthesis of 2‐oxo‐1,3‐propanedial monohydrate or mesoxaldehyde (6a) and the first synthesis of 2,3‐dioxo‐1,4‐butanedial (18) as a thiane derivative are reported. These first members of the smallest vicinal tri‐ and tetracarbonyl compounds are stabilized by conversion to thiane derivatives 8, 9, 10, 11, 12, 15 and 19, which can be isolated as long‐lived compounds at room temperature. The structures of these novel thianes 8, 10, 12 and 15 were confirmed by their X‐ray crystal structures. The synthesis of a series of protected as well as free heterocyclic aldehydes (pterins and quinoxalines) by the use of the appropriate tricarbonyl compounds is also reported. Additionally, a one‐step synthetic strategy to prepare a series of different biheterocycles with the smallest vicinal tetracarbonyl compound is demonstrated.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Efficient Preparation of α-Ketoacetals

“…R f = 0.63 n- hexane-EtOAc (4:1). 1 H-NMR (300 MHz; CDCl 3 ): δ 4.49 (s, 1H) H-1, 3.40 (s, 6H) (OCH 3 ) 2 , 2.58 (q, 2H, J = 7.5 Hz) H-3, 1.05 (t, 3H, J = 7.5 Hz) H-4 [ 11 , 30 , 31 , 32 , 33 ].…”

Aldo‐X Bifunctional Building Blocks for the Synthesis of Heterocycles

“…Because a metal‐free method is used to synthesize phenylglyoxal, considering also that 1) I 2 and DMSO are readily available, and 2) the reaction is very fast and can be performed in a homogeneous solution, I 2 /DMSO has been widely used to establish one‐pot tandem reactions, in which the generated phenylglyoxal component was trapped in situ by the other reactant to form the final product. Methylglyoxal is another easily available aldo‐ketone bifunctional building block (Figure ), which can also be prepared on the laboratory scale by oxidation with SeO 2 or tert ‐butyl hydroperoxide by using acetone as a substrate . An aqueous solution of methylglyoxal is commercially available, which is prepared in industry from either 1,2‐propanediol or dihydroxyacetone .…”

2-(Pyrene-1-yl)-1,3-dithiane

“…Thioacetal protection of carbonyl groups is of paramount importance in synthetic organic chemistry and hence the development of novel thionation reactions remains of great interest (Goswami & Maity, 2008;Fun et al, 2009;Goswami et al, 2009). In addition, thioacetals are also utilized as masked acyl anions or masked methylene functions in carboncarbon bond forming reactions.…”