Productive synthesis of cationic nitrophosphoamphiphilic lipids was developed basing on available tris(hydroxymethyl)nitromethane and cyclic reagents of trivalent phosphorus.In recent years a promising branch of medicine is successfully developed treating the disturbances of gene functions, genetic therapy [1-3]. One of the key problems of this therapy is delivery into the target cells of the therapeutic gene (transfection) with the use of cationic liposomes [4][5][6][7]. Among the cationic lipids included into these liposomes are widely studied ammonium phosphorus-free lipids [8][9][10][11][12]. At the same time the positively charged ammonium (cationic) phospholipids are far less understood [8,[13][14][15][16], although the pioneering study of cationic phospholipides preparation by an example of glycerophosphonate analogs has been performed more than 25 years ago [17].The present report concerns syntheses of new cationic lipid phosphonoamphiphiles proceeding from the acetone derivative of tris(hydroxymethyl)nitromethane (I). The choice of the trimethylolnitromethane core for the new lipid systems aimed at application in the genetic therapy was determined by the synthetic availability of the initial compound, its polarity, and also by the photosensitivity of its phospholipide derivatives. The latter quality may result in initiation of photochemical degradation reactions in the cell under light. These reactions may decrease the stability of the liposome membranes at fusion with endocytic vesicles and thus facilitate the transfection efficiency. A similar process was already studied in detail for a series of amphiphiles containing nitrobenzyl groups [18].The first line of this investigation consisted in application of O,O-ethylene-(II) and trimethylene-(III) cyclophosphites of the acetone derivative of the nitrooligool to the synthesis of methylphosphonate amphiphiles of ammonium type. To this end Arbuzov alkylation was performed on available alkenylphosphites II and III with bromomethane. P O (CH 2 ) n O RO CH 3 Br P RO O(CH 2 ) n Br CH 3 O IV, V II, III R = N C CH 2 O O _ + C CH 3 CH 2 O CH 3 ; n = 2 (II, IV), 3 (III, V). CH 2 OThe reaction was carried out at 100-120°C. Bromoalkenylphosphonates IV and V, pale yellow oily compounds, were obtained in 40-65% yields. Phosphonates IV and V are stable compounds that can be stored for a long time under inert atmosphere in the dark at room temperature. The alkylation was monitored by 31 P NMR spectroscopy. 31 P NMR spectra of methylphosphonates IV and V consist of singlets at δ 31.47 and 30.82 ppm respectively. In the 1 H NMR spectra of these compounds characteristic groups from all protons were observed. The protons of PCH 3 group appear at δ 1.48 ppm as doublet due to the coupling of methyl group protons with the phosphorus nucleus, methylene protons of CH 2 Βr group give rise to triplets in the region 3.45-3.47 ppm, and the signals from protons of the dioxane fragment are observed as doublets at 3.39 and 4.35 ppm The other signals in the spectra of methylphosphonates...