Keywords: (1S,2S)-2-amino-1-(4-nitrophenyl)-1,3-propanediol, 2-oxazolidinone.In recent years there has been a marked upsurge of interest in the chemistry of 2-oxazolidinones. This can be explained, particular by their high biological activity. 2-Oxazolidinones have been patented as antibacterial preparations [1, 2] and as substances effective in the treatment of atherosclerosis, arthritis, and Alzheimer, Krebs [3], or Parkinson [4] deseases. In addition, 2-oxazolidinones are used in asymmetric synthesis [5] and as starting materials for subsequent reactions [6,7].In the majority of literature reports 2-oxazolidinones are prepared from the corresponding 3-amino-1,2diols [1-4]. 2-Amino-1,3-diols are used very rarely for this purpose.(1S,2S)-2-Amino-1-(4-nitrophenyl)-1,3-propanediol (1) [8] is a convenient and accessible reagent for the synthesis of 2-oxazolidinones. In this work we have prepared a series of 2-oxazolidinones by the following scheme: NH O RCOCl 5a-e + -4 4-6a-e K 2 CO 3 HOCHCHCH 2 OH -4 MeCH 2 OCOCl HOCHCHCH 2 OH -4 4 1 2 HOCH RCOCH 5, 6 a R = Me, b R = Et, c R = Pr, d R = Cl(CH 2 ) 3 , e R = PhCHCl __________________________________________________________________________________________

Keywords: (1R,2R)-and (1S,2S)-2-amino-1-(4-nitrophenyl)-1,3-propanediols, (4R,5R)-and (4S,5S)-4-hydroxymethyl-5-(4-nitrophenyl)oxazolidin-2-ones, (1'R,4R)-and (1'S,4S)-4-[hydroxy(4-nitrophenyl)-methyl]oxazolidin-2-ones.2-Oxazolidinones have attracted considerable attention in chemistry. These compounds display a variety of biological activity [1][2][3][4] and are used in asymmetric synthesis [5]. Formation of the 2-oxazolidinone ring is used when necessary to protect both the adjacent amino and hydroxy groups [6][7][8].In our previous work [9], we synthesized (1S,2S)-2-ethoxycarbonylamino-1-(4-nitrophenyl)-1,3-propanediol (2) from (1S,2S)-2-amino-1-(4-nitrophenyl)-1,3-propanediole (1) with subsequent conversion to isomeric 2-oxazolidinones: (1'S,4S)-4-[hydroxy(4-nitrophenyl)methyl)oxazolidin-2-one (4) and (4S,5S)-4-hydroxymethyl-5-(4-nitrophenyl)oxazolidin-2-one (3) according to Scheme 1.It is known that the closure of the oxazolidinone ring upon treatment of a suitable methylcarbamate proceeds rather rapidly even at room temperature and in a slightly basic medium (pH 9.5) in only 20 min [8]. But we maintained the reaction mixture under similar conditions for about 120 h, and only a slight amount of oxazolidinone 4 was obtained as a precipitate [9].In this conection the aim of the present work was the search of the conditions most favorable for formation of the one of the isomeric 2-oxazolidinones, permitting a reduction of the reaction time.Base is a catalyst in the formation of 2-oxazolidinones but it may lead to undesired racemization. Propanediol 2 is sensitive to the pH value and the solution at pH > 10 turns reddish; the product isolated is less pure. Thus, propanediol 2 is initially [9] treated with a 1:1 mixture of water and saturated methanolic potassium carbonate, which has pH ~9.5.In a search for optimal reaction conditions, the pH of the reaction solution was raised to 10 by addition solid potassium hydroxide. Furthermore, different amounts of propanediol 2 were treated with equal volumes of the indicated solution. In experiment 5, 20 ml water was added to 50 ml used solution to reduce the solubility of oxazolidinone 4 (Table 1).

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