Diethyl 1-(<i>N</i>-acetylamino)-1-(diphenylphosphinoyl)-1-phenylmethylphosphonate

Diethyl 1-(N-acetylamino)-1-(diphenylphosphinoyl)-1-phenylmethylphosphonate was synthesized at room temperature, starting from 1-ethoxy derivative of diethyl 1-(N-acetylamino)-1-phenylmethylphosphonate via the corresponding phosphonium salt as a reactive intermediate in the Michaelis–Arbuzov-like reaction with methyl diphenylphosphinite. The structure of the compound obtained was confirmed by spectroscopic techniques (1H, 13C, 31P NMR, IR, and MS)

Amide-Type Substrates in the Synthesis of N-Protected 1-Aminomethylphosphonium Salts

Herein we describe the development and optimization of a two-step procedure for the synthesis of N-protected 1-aminomethylphosphonium salts from imides, amides, carbamates, or lactams. Our “step-by-step” methodology involves the transformation of amide-type substrates to the corresponding hydroxymethyl derivatives, followed by the substitution of the hydroxyl group with a phosphonium moiety. The first step of the described synthesis was conducted based on well-known protocols for hydroxymethylation with formaldehyde or paraformaldehyde. In turn, the second (substitution) stage required optimization studies. In general, reactions of amide, carbamate, and lactam derivatives occurred at a temperature of 70 °C in a relatively short time (1 h). On the other hand, N-hydroxymethylimides reacted with triarylphosphonium salts at a much higher temperature (135 °C) and over longer reaction times (as much as 30 h). However, the proposed strategy is very efficient, especially when NaBr is used as a catalyst. Moreover, a simple work-up procedure involving only crystallization afforded good to excellent yields (up to 99%)

Wielka moc w małej cząsteczce : właściwości i zastosowania bisfosfonianów

Great power in a small molecule : properties and applications of bisphosphonate

One-Pot and Catalyst-Free Transformation of N-Protected 1-Amino-1-Ethoxyalkylphosphonates into Bisphosphonic Analogs of Protein and Non-Protein &alpha;-Amino Acids

Herein, we describe the development of one-pot transformation of &alpha;-ethoxy derivatives of phosphorus analogs of protein and non-protein &alpha;-amino acids into biologically important N-protected 1-aminobisphosphonates. The proposed strategy, based on the three-component reaction of 1-(N-acylamino)-1-ethoxyphosphonates with triphenylphosphonium tetrafluoroborate and triethyl phosphite, facilitates good to excellent yields under mild reaction conditions. The course of the reaction was monitored by 31P NMR spectroscopy, allowing the identification of probable intermediate species, thus making it possible to propose a reaction mechanism. In most cases, there is no need to use a catalyst to provide transformation efficiency, which increases its attractiveness both in economic and ecological terms. Furthermore, we demonstrate that the one-pot procedure can be successfully applied for the synthesis of structurally diverse N-protected bisphosphonic analogs of &alpha;-amino acids. As shown, the indirect formation of the corresponding phosphonium salt as a reactive intermediate during the conversion of 1-(N-acylamino)-1-ethoxyphosphonate into a 1-aminobisphosphonate derivative is a crucial component of the developed methodology

Archeological reconnaissance surveys on site 16 in Powidz, Powidz commune from 2017

Since at least the 13th century Powidz has functioned as an important though small urban centre. The fact that it was located at the intersection of the trade routes and at a water reservoir, were important factors which influenced the development of the town. Archaeological and environmental surveys conducted in 2017 throw light on the modern stage of the development of the discussed centre. The turbulent changes through which the historical centre of Powidz and Castle Hill underwent in the last 200 years are clearly marked in the layerings recognised in both trenches. What is more, some of them were not documented, and the interviews with the inhabitants of the town are mostly the source of knowledge about them. Hence, determining the chronology of some of the layerings is signifi cantly hindered. For instance, the presence of single and partially preserved human bones suggests the presence of burials in the layers leveled from the immediate surroundings to T 2/17, though the soil in which they were registered could have been brought from a larger distance away as well. It seems that in T 2/17 the layering arrangements were registered, which provide evidence of a moat. It probably bordered the residence of the Powidz starost in the past. Information about the presence of such an assumption on the so-called Castle Hill can be found in numerous written sources [cf. e.g. Ganińska 1993]. The presence of a moat on the other hand is confirmed not only by the documented systems of layerings, but also the results of the analyses of plant macro-remains suggest it. Th e presence of a moat is confi rmed among others by the fact that it was filled with the ground brought in the 20th century. Simultaneously, the layerings registered in both excavations seem to confirm numerous levellings of the surrounding terrain and the Castle Hill itself. More diversified materials were gathered from T 2/17 than from T 1/17, though most of them come from backfill layers. Nevertheless, the presumption that the backfill is made of materials from the adjacent elevation seems justified. Both the qualitative and quantitative analysis of the artifacts (window glass, glass vessels, richly ornamented plate tiles, ceramic vessels), animal bones or plant remains, seem to confirm the initial assumption that there was a residence of a representative of a wealthier bourgeoisie, probably the Powidz starost, on the so called Castle Hill. The presence of post-consumer remains or broken pottery suggest significant activity in the modern period if it is assumed that they come from the layers levelled at the cone. Unfortunately, in the light of the present data, backfilling and lowering of a terrain (moat) with the ground from another part of Powidz cannot be excluded. Nevertheless, the presence of a window glass, richly ornamented plate tiles or, finally, written sources are in accord with the earlier hypothesis. The conducted natural analyses enrich our knowledge about the past of Powidz, but they also significantly influence the perception and proper reading of a history of the formation of the particular layers, and hence, a better analysis of cultural processes, even if they occurred recently. Despite the not numerous collections and rather small area which was examined, environmental studies can be the source of interesting conclusions