No abstract

Abstract. We use various geophysical datasets (multibeam and singlebeam echosounder data, sub-bottom profiling Chirp and sonar data and very high-resolution boomer seismic data) along with published sedimentological data and depth data from nautical charts in order to create models of the depth of the seafloor and the base of Holocene marine sediment in the Gulf of Trieste. The two models are later used in order to calculate the thickness of marine Holocene sediment which has been depositing on the Late Pleistocene alluvial plain since the Holocene transgression in the Italian and Slovenian parts of the gulf. Thicker Holocene marine sedimentary sequences averaging at around 5 m are characteristic for the southeastern part of the gulf. In other parts of the gulf the Holocene marine sedimentary cover is very thin or even absent, except in close proximity to the shoreline and fluvial sediment sources, in the area of the Trezza Grande paleodelta and above topographic depressions of the Late Pleistocene base. The presented datasets available from the OGS SNAP data repository (http://doi.org/cpz2) represent a valuable reference for a wide variety of research disciplines dealing with the dynamic Earth system in the Gulf of Trieste and could be used as a valuable tool for designing sampling and geophysical campaigns in the studied area.

No abstract

Two variations of enaminone-based parallel solution-phase synthesis of 1-substituted 4-(2-aminoethyl)-1 H-pyrazol-5-ols 8 and their NH-tautomers 8' were developed. The synthetic strategy comprises a two step preparation of the N-protected alpha-enamino lactams 3a and 3b from 2-pyrrolidinone (1), "ring switching" transformation of 3a, b with monosubstituted hydrazines 4a-u, and acidolytic removal of the N-protecting group. In order to ensure a clean and fast conversion, reactions of Cbz-enaminone 3a with hydrazines 4a-k were carried out under microwave irradiation to afford the "ring-switched" intermediates 7a-k. Deprotection of 7a-k with HBr-AcOH at 50 degrees C gave a library of 11 analytically pure 4-(2-aminoethyl)-1 H-pyrazol-5-ols (di)hydrobromides 8/ 8'a-k in 16-75% yields over two steps. The other reagent, Boc-enaminone 3b, was more reactive and ring switching transformations with hydrazines 4b, d, k proceeded smoothly and cleanly under conventional heating. Finally, a parallel one-pot transformation of the Boc-enaminone 3b with hydrazines 4a-u followed by subsequent deprotection of the intermediates 9a-u with HCl-EtOAc furnished a library of 21 analytically pure 4-(2-aminoethyl)-1 H-pyrazol-5-ols (di)hydrochlorides 8/ 8'a-u in 40-100% yields.

on the occasion of his 70th birthday.Abstract: A series of tetrahydropyrazolo[1,5-c]pyrimidine-2,7(1H,3H)-diones 3a-h as the first representatives of the so far unexplored saturated heterocyclic system have been synthesized, formally in 12 steps from methyl acrylate (4). The synthesis comprises a four-step preparation of methyl N-Cbz-5-alkylamino-3-oxopentanoates 9a-c, their three-step transformation into 5-{2-[(alkyl)(benzyloxycarbonyl)amino]ethyl}pyrazolidin-3-ones 12a-c, three-step selective alkylation of the amidic N-2 to give 2-alkyl-5-{2-[(alkyl)(benzyloxycarbonyl)amino]ethyl}pyrazolidin-3-ones 16b-h, followed by hydrogenolytic Cbz-deprotection and subsequent cyclization of the intermediate 1,4-diamine with CDI to furnish the title compounds 3. Most of the synthetic steps were performed as a one-pot transformation.

No abstract

Catalytic hydrogenation of (4R*,5R*)-4-benzyloxycarbonylamino-5-phenylpyrazolidin-3-one 2 in the presence of Pd-C furnished an unexpected 'ring switching' transformation product, 3-amino-5-benzylimidazolidine-2,4-dione 4. Furthermore, heating of azomethine imines 3a,b (derived from 2 and aromatic aldehydes) afforded the corresponding (Z)-5-benzylidene-3-[(E)-benzylideneamino]imidazolidine-2,4-diones 8a,b as ring transformation products. Both reactions are explainable by cleavage of the C(5)-N(1) single bond in substrates 2 and 3 followed by cyclocondensation of the amide nitrogen to the carbamate carbonyl group. The structure of hydantoin 8a was confirmed by X-ray diffraction.

Estimating sound velocity in seabed sediment of shallow near-shore areas submerged after the Last Glacial Maximum is often difficult due to the heterogeneous sedimentary composition resulting from sea-level changes affecting the sedimentary environments. The complex sedimentary architecture and heterogeneity greatly impact lateral and horizontal velocity variations. Existing sound velocity studies are mainly focused on the surficial parts of the seabed sediments, whereas the deeper and often more heterogeneous sections are usually neglected. We present an example of a submerged alluvial plain in the northern Adriatic where we were able to investigate the entire Quaternary sedimentary succession from the seafloor down to the sediment base on the bedrock. We used an extensive dataset of vintage borehole litho-sedimentological descriptions covering the entire thickness of the Quaternary sedimentary succession. We correlated the dataset with sub-bottom sonar profiles in order to determine the average sound velocities through various sediment types. The sound velocities of clay-dominated successions average around 1530 m/s, while the values of silt-dominated successions extend between 1550 and 1590 m/s. The maximum sound velocity of approximately 1730 m/s was determined at a location containing sandy sediment, while the minimum sound velocity of approximately 1250 m/s was calculated for gas-charged sediments. We show that, in shallow areas with thin Quaternary successions, the main factor influencing average sound velocity is the predominant sediment type (i.e. grain size), whereas the overburden influence is negligible. Where present in the sedimentary column, gas substantially reduces sound velocity. Our work provides a reference for sound velocities in submerged, thin (less than 20 m thick), terrestrial-marine Quaternary successions located in shallow (a few tens of meters deep) near-shore settings, which represent a large part of the present-day coastal environments.