tert-Butyl N-[1-diazo­acetyl-3-(methyl­sulfan­yl)prop­yl]carbamate

In the enanti­omerically pure title compound, C11H19N3O3S, the chain C—N—C(O)—O—C—C (from the asymmetric carbon to a methyl of the tert-butyl group) displays an extended conformation. In the crystal, mol­ecules are linked into chains parallel to the c axis by classical N—H⋯Odiazo­carbon­yl hydrogen bonding and an unusual inter­molecular three-centre inter­action involving the amino acid (aa) carbonyl Oaa and the diazo­carbonyl grouping C(O)—CH—N N, with H⋯Oaa = 2.51 Å and N⋯Oaa = 2.8141 (14) Å

Carbonic anhydrase inhibitors. Inhibition of human tumor-associated isozymes IX and cytosolic isozymes I and II with some 1,3,4-oxadiazole-thiols.

A series of chiral 1,3,4-oxadiazole-5-thiols incorporating 2-substituted-benzenesulfonamide moieties has been prepared from amino acids, via the ester and carbohydrazide intermediate, followed by cyclization with carbon disulfide. Some of these compounds have been investigated for the inhibition of three physiologically relevant carbonic anhydrase (CA, EC 4.2.1.1) isoforms, the human cytosolic hCA I and II, and the human, transmembrane, tumor-associated isozyme hCA IX. All these compounds showed weak (millimolar) affinity for the three isozymes, except two carbohydrazides and two heterocyclic thiols which selectively inhibited the tumor-associated isozyme with inhibition constants around 10 microM. Such compounds constitute interesting lead molecules for the possible design of CA IX-selective inhibitors

Synthesis and antimalarial activity of novel chiral and achiral benzenesulfonamides bearing 1, 3, 4-oxadiazole moieties.

A series of new benzenesulfonamides, most of which are chiral, incorporating 1, 3, 4-oxadiazole and amino acid moieties have been synthesized. Some of these compounds were screened for antimalarial activity and also evaluated for their ability to inhibit hem polymerization. The electrophoretic analysis indicated that one compound was effective in inhibiting the degradation of hemoglobin. The synthesized compounds were tested in mice infected with Plasmodium berghei. These derivatives have the potential for the development of novel antimalarial lead compounds

Synthesis of trifunctional cyclo-β-tripeptide templates

The concept of template-assembled synthetic proteins (TASP) describes a central scaffold that predefines the three dimensional structure for diverse molecules linked to this platform. Cyclic β-tripeptides are interesting candidates for use as templates due to their conformationally defined structure, stability to enzymatic degradation, and ability to form intermolecular stacked tubular structures. To validate the applicability of cyclic β-tripeptides within the TASP concept, an efficient synthesis of the cyclopeptide with orthogonal functionalization of the side chains is desired. A solid-phase-supported route with on-resin cyclization is described, employing the aryl hydrazide linker cleavable by oxidation. An orthogonal protection-group strategy allows functionalization of the central cyclic β-tripeptide with up to three different peptide fragments or fluorescent labels

Cardiac SPECT radiomic features repeatability and reproducibility: A multi-scanner phantom study

Background: The aim of this work was to assess the robustness of cardiac SPECT radiomic features against changes in imaging settings, including acquisition, and reconstruction parameters. Methods: Four commercial SPECT and SPECT/CT cameras were used to acquire images of a static cardiac phantom mimicking typical myorcardial perfusion imaging using 185 MBq of 99mTc. The effects of different image acquisition and reconstruction parameters, including number of views, view matrix size, attenuation correction, as well as image reconstruction related parameters (algorithm, number of iterations, number of subsets, type of post-reconstruction filter, and its associated parameters, including filter order and cut-off frequency) were studied. In total, 5,063 transverse views were reconstructed by varying the aforementioned factors. Eighty-seven radiomic features including first-, second-, and high-order textures were extracted from these images. To assess reproducibility and repeatability, the coefficient of variation (COV), as a widely adopted metric, was measured for each of the radiomic features over the different imaging settings. Results: The Inverse Difference Moment Normalized (IDMN) and Inverse Difference Normalized (IDN) features from the Gray Level Co-occurrence Matrix (GLCM), Run Percentage (RP) from the Gray Level Co-occurrence Matrix (GLRLM), Zone Entropy (ZE) from the Gray Level Size Zone Matrix (GLSZM), and Dependence Entropy (DE) from the Gray Level Dependence Matrix (GLDM) feature sets were the only features that exhibited high reproducibility (COV � 5) against changes in all imaging settings. In addition, Large Area Low Gray Level Emphasis (LALGLE), Small Area Low Gray Level Emphasis (SALGLE) and Low Gray Level Zone Emphasis (LGLZE) from GLSZM, and Small Dependence Low Gray Level Emphasis (SDLGLE) from GLDM feature sets turned out to be less reproducible (COV > 20) against changes in imaging settings. The GLRLM (31.88) and GLDM feature set (54.2) had the highest (COV < 5) and lowest (COV > 20) number of the reproducible features, respectively. Matrix size had the largest impact on feature variability as most of the features were not repeatable when matrix size was modified with 82.8 of them having a COV > 20. Conclusion: The repeatability and reproducibility of SPECT/CT cardiac radiomic features under different imaging settings is feature-dependent. Different image acquisition and reconstruction protocols have variable effects on radiomic features. The radiomic features exhibiting low COV are potential candidates for future clinical studies. © 2020, American Society of Nuclear Cardiology