Catalyst-free synthesis of novel 1,5-benzodiazepines and 3,4-dihydroquinoxalines using isocyanide-based one-pot, three- and four-component reactions.

Reaction of benzimidazolone derivatives, or their thio- or aza-counterparts, with an isocyanide in the presence of acetone unexpectedly gave rise to novel tricyclic benzodiazepine derivatives in good yield by means of a four-component reaction incorporating two moles of acetone. Benzimidazole starting substrates bearing an electron-withdrawing group gave rise instead to dihydroquinoxaline derivatives by means of a three-component reaction. Use of deuterated acetone instead of acetone in the reactions significantly affected yield and reactivity in the four-component reaction but not in the three-component reaction.

Chains or rings? Polymorphism of an isoniazid derivative derivatized with diacetone alcohol.

Isoniazid was derivated with diacetone alcohol in a Schiff-base reaction in order to yield '-[(2)-4-hydroxy-4-methylpentan-2-ylidene]pyridine-4-carbohydrazide. The resulting product was determined to be polymorphic, exhibiting two crystal forms: form I and form II. From the crystal structure determination using SC-XRD it was determined that form I crystalizes in the 2/ space group while form II crystalizes in the 2/ space group.

Spatially resolved birefringence measurements with a digital micro-mirror device.

We demonstrate a novel technique to measure spatially resolved birefringence structures in an all-digital fashion with a digital micro-mirror device (DMD). The technique exploits the polarization independence of DMDs to apply holographic phase control to orthogonal polarization components and requires only a static linear polarizer as an analyzer for the resulting phase shift polarization measurements. We show the efficacy of this approach by spatially resolving complex polarization structures, including nano-structured metasurfaces, customized liquid crystal devices, as well as chiral L-Alanine and N-Acetyl-L-cystein crystals.

Synthesis of 6-Membered-Ring Fused Thiazine-Dicarboxylates and Thiazole-Pyrimidines via One-Pot Three-Component Reactions.

A facile and efficient one-pot three-component reaction method for the synthesis of thiazine-dicarboxylates is reported. Reaction of an isocyanide and dialkyl acetylenedicarboxylate with 2-amino-4-1,3-thiazin-4-one derivatives containing both an acidic proton and an internal nucleophile gave the products in good yields of 76-85%. The reactivity of dialkyl acetylenedicarboxylates was further tested in the synthesis of thiazole-pyrimidines where a two-component reaction of 2-aminothiazole with dialkyl acetylenedicarboxylates was successfully converted to a more efficient three-component reaction of a thiourea, α-haloketone and dialkyl acetylenedicarboxylate (DMAD/DEtAD) to give thiazole-pyrimidines in good yields of 70-91%.

Total synthesis of -pavettamine.

Pavettamine, a plant toxin first isolated from in 1995, was previously identified as a polyamine with symmetry and a 1,3--diol moiety on a C carbon backbone - one of very few substituted polyamines to be isolated from nature. Its absolute configuration was later established by our first reported total synthesis in 2010. Herein we report the first total synthesis of the enantiomer of pavettamine, -pavettamine.

A Cytotoxic Bis(1,2,3-triazol-5-ylidene)carbazolide Gold(III) Complex Targets DNA by Partial Intercalation.

The syntheses of bis(triazolium)carbazole precursors and their corresponding coinage metal (Au, Ag) complexes are reported. For alkylated triazolium salts, di- or tetranuclear complexes with bridging ligands were isolated, while the bis(aryl) analogue afforded a bis(carbene) Au -CNC pincer complex suitable for oxidation to the redox-stable [Au (CNC)Cl] cation. Although the ligand salt and the [Au (CNC)Cl] complex were both notably cytotoxic toward the breast cancer cell line MDA-MB-231, the Au complex was somewhat more selective.

Targeting the SARS-CoV-2 main protease using FDA-approved Isavuconazonium, a P2-P3 α-ketoamide derivative and Pentagastrin: An in-silico drug discovery approach.

The SARS-CoV-2 main protease (M) is an attractive target towards discovery of drugs to treat COVID-19 because of its key role in virus replication. The atomic structure of M in complex with an α-ketoamide inhibitor (Lig13b) is available (PDB ID:6Y2G). Using 6Y2G and the prior knowledge that protease inhibitors could eradicate COVID-19, we designed a computational study aimed at identifying FDA-approved drugs that could interact with M.

Fischer Carbene Complexes of Iridium(I) for Application in Catalytic Transfer Hydrogenation.

New examples of the very rare class of iridium(I) Fischer carbene complexes (FCCs) are reported from the facile transmetalation from group 6 FCCs. Postcomplexation modification of either the carbene ligand or the ancillary coligands results in a tunable Ir metal center, for unprecedented application as a (pre)catalyst in a benchmark transfer hydrogenation reaction. The introduction of an aminocarbene ligand with a pendant N-donor moiety capable of hemilabile coordination yielded the best catalytic results with turnover frequencies reaching 445 h and requiring 0.

Synthesis and Photophysical Properties of T-Shaped Coinage-Metal Complexes.

The photophysical properties of a series of T-shaped coinage d metal complexes, supported by a bis(mesoionic carbene)carbazolide (CNC) pincer ligand, are explored. The series includes a rare new example of a tridentate T-shaped Ag complex. Post-complexation modification of the Au complex provides access to a linear cationic Au complex following ligand alkylation, or the first example of a cationic square planar Au -F complex from electrophilic attack on the metal centre.

Efficient one-pot synthesis of functionalised imidazo[1,2-]pyridines and unexpected synthesis of novel tetracyclic derivatives by nucleophilic aromatic substitution.

Novel tetracyclic imidazo[1,2-]pyridine derivatives have been prepared by intramolecular nucleophilic aromatic substitution of 5-fluoroimidazo[1,2-]pyridines under basic conditions. Use of the non-nucleophilic alcoholic solvent -butanol, rather than methanol, increased the yield of the tetracycles by reducing the competing intermolecular reaction observed for methanol. In addition, a modified protocol for the dehydration of formamides to isocyanides has been found to be tolerant of an unprotected hydroxyl functional group and one-pot conversion to imidazo[1,2-]pyridyl-aminocyclohexanol analogues is reported.

V2-Directed Vaccine-like Antibodies from HIV-1 Infection Identify an Additional K169-Binding Light Chain Motif with Broad ADCC Activity.

Antibodies that bind residue K169 in the V2 region of the HIV-1 envelope correlated with reduced risk of infection in the RV144 vaccine trial but were restricted to two ED-motif-encoding light chain genes. Here, we identify an HIV-infected donor with high-titer V2 peptide-binding antibodies and isolate two antibody lineages (CAP228-16H/19F and CAP228-3D) that mediate potent antibody-dependent cell-mediated cytotoxicity (ADCC). Both lineages use the IGHV5-51 heavy chain germline gene, similar to the RV144 antibody CH58, but one lineage (CAP228-16H/19F) uses a light chain without the ED motif.

Synthesis of heterobimetallic gold(i) ferrocenyl-substituted 1,2,3-triazol-5-ylidene complexes as potential anticancer agents.

1,2,3-Triazol-5-ylidene (trz) complexes of gold(i) containing a ferrocenyl substituent on the C4-position of the trz ring were synthesized to yield the neutral heterobimetallic gold(i) trz chlorido (2), gold(i) trz phenyl (3), and the cationic gold(i) trz triphenylphospine (5) complexes. In order to compare the effect of silver(i) as central metal vs. gold(i), [Ag(trz)2]+ (4) was also prepared, while variation of the C4-1,2,3-triazol-5-ylidene substituent from a ferrocenyl to a phenyl group was done to prepare the monometallic analogue of 5, namely the cationic Au(i) trz triphenylphosphine complex 6.

Alginate microbead-encapsulated silver complexes for selective delivery of broad-spectrum silver-based microbicides.

In sub-Saharan Africa, human immunodeficiency virus (HIV) infections are predominantly acquired via heterosexual contact, and women are at greatest risk of being infected. This region also has the highest rates of sexually transmitted infections (STIs) per capita worldwide; STIs are strongly associated with increased HIV transmission. Therefore, there is an urgent requirement for microbicides that are active against HIV and STIs.

Crystal structures of 2,2'-bipyridin-1-ium 1,1,3,3-tetracyano-2-ethoxyprop-2-en-1-ide and bis(2,2'-bipyridin-1-ium) 1,1,3,3-tetracyano-2-(dicyanomethylene)propane-1,3-diide.

In 2,2'-bipyridin-1-ium 1,1,3,3-tetra-cyano-2-eth-oxy-prop-2-en-1-ide, C10H9N2 (+)·C9H5N4O(-), (I), the ethyl group in the anion is disordered over two sets of atomic sites with occupancies 0.634 (9) and 0.366 (9), and the dihedral angle between the ring planes in the cation is 2.

Di-chlorido-dimethyl-bis-(thio-urea-κS)tin(IV).

The title compound, [Sn(CH3)2Cl2(CH4N2S)2], crystallizes with two half-mol-ecules in the asymmetric unit. Both mol-ecules are completed by inversion symmetry with the two Sn(IV) atoms located on inversion centers. The metal atoms have distorted octa-hedral coordination environments defined by two Cl atoms, two C atoms of methyl groups and two thio-urea S atoms.

The synthesis of a corrole analogue of aquacobalamin (vitamin B12a) and its ligand substitution reactions.

The synthesis of a Co(III) corrole, [10-(2-[[4-(1H-imidazol-1-ylmethyl)benzoyl]amino]phenyl)-5,15-diphenylcorrolato]cobalt(III), DPTC-Co, bearing a tail motif terminating in an imidazole ligand that coordinates Co(III), is described. The corrole therefore places Co(III) in a similar environment to that in aquacobalamin (vitamin B12a, H2OCbl(+)) but with a different equatorial ligand. In coordinating solvents, DPTC-Co is a mixture of five- and six-coordinate species, with a solvent molecule occupying the axial coordination site trans to the proximal imidazole ligand.

Formation of isostructural solid solutions in 2,6-disubstituted N-phenylformamides and N-phenylthioamides.

In order to investigate possible isostructural solid solutions of disubstituted N-phenylformamides and thioamides, we have studied the re-crystallization of pairs of compounds selected from 2,6-difluoro-N-phenylformamide (I), 2,6-dichloro-N-phenylformamide (II), 2,6-dimethyl-N-phenylformamide (III), 2,6-dichloro-N-phenylthioamide (IV), 2,6-dimethyl-N-phenylthioamide (V), 2,6-diisopropyl-N-phenylformamide (VI) and 2,6-diisopropyl-N-phenylthioamide (VII). For single-component 2,6-disubstituted-N-phenylformamides only the trans form occurs in the pure crystal, while for thioamides the cis form occurs, with only one exception. By forming solid solutions of pairs of these molecules the resulting structures all adopt similar N-H.

Outer-sphere anion recognition by a cyclen-based octadentate europium(III) complex: pH dependent recognition of ortho-phthalic acid.

An octadentate cyclen-based europium complex with amidic and hydroxyalkyl pendent moieties exhibits pH dependent ligand denticity associated with anion recognition. Unusually high hydration numbers are determined for ortho-phthalate ternary outer-sphere complexes for which modulation of lanthanide-based luminescence is observed.

Phenylvinylcobalamin: an alkenylcobalamin featuring a ligand with a large trans influence.

Cob(I)alamin reacts with phenylacetylene to produce two diastereomers in which the organic ligand is coordinated to the upper (β) and lower (α) face of the corrin ring, respectively. The isomers were separated chromatographically and characterised by ESI-MS and, in the case of the β isomer, by (1)H and (13)C NMR. Only the β isomer crystallised and its molecular structure, determined by X-ray diffraction, shows that the organic ligand coordinates Co(III) through the β carbon of the phenylvinyl ligand.

3-Methyl-1-tosyl-1H-indole-2-carbaldehyde.

The title indole derivative, C(17)H(15)NO(3)S, crystallizes with two independent mol-ecules in the asymmetric unit. The benzene ring of the tosyl group is almost perpedicular to the indole ring in both mol-ecules, with inter-planar angles of 82.60 (5)° and 81.

Tungsten-183 NMR study of cis-[W(CO)4(PPh3)(4-RC5H4N)]; effect of varying the σ donor strength of the pyridine.

Tungsten-183 NMR data are reported for the complexes cis-[W(CO)4(PPh3)(4-RC5H4N)] (R = H, Me, Ph, COMe, COPh, OMe, NMe2, Cl, NO2). The (183)W chemical shift (obtained by indirect detection using (31)P) is found to correlate with the Hammett σ function for the group R, with (183)W shielding increasing approximately linearly with the donor strength of the pyridine over a range of 93 ppm. The X-ray structures of cis-[W(CO)4(PPh3)(4-MeOC5H4N)] and cis-[W(CO)4(PPh3)(4-PhCOC5H4N)] are also reported.

Oxovanadium(IV)-catalysed oxidation of dibenzothiophene and 4,6-dimethyldibenzothiophene.

The reaction between [V(IV)OSO(4)] and the tetradentate N(2)O(2)-donor Schiff base ligand, N,N-bis(o-hydroxybenzaldehyde)phenylenediamine (sal-HBPD), obtained by the condensation of salicylaldehyde and o-phenylenediamine in a molar ratio of 2 : 1 respectively, resulted in the formation of [V(IV)O(sal-HBPD)]. The molecular structure of [V(IV)O(sal-HBPD)] was determined by single crystal X-ray diffraction, and confirmed the distorted square pyramidal geometry of the complex with the N(2)O(2) binding mode of the tetradentate ligand. The formation of the polymer-supported p[V(IV)O(sal-AHBPD)] proceeded via the nitrosation of sal-HBPD, followed by the reduction with hydrogen to form an amine group that was then linked to Merrifield beads followed by the reaction with [V(IV)OSO(4)].

Helical self-assembly of 2-(1,4,7,10-tetraazacyclododecan-1-yl)cyclohexan-1-ol (cycyclen).

The title macrocyclic amino alcohol compound, C(14)H(30)N(4)O, is investigated as a solid-state synthon for the design of a self-assembled tubular structure. It crystallizes in a helical column constructed by stereospecific O-H···N and N-H···N interactions. The hydrogen-bonding interactions, dependent upon macrocyclic ring helicity and molecular conformation, link R,R and S,S enantiomers in a head-to-tail fashion, forming a continuous hydrophilic inner core.

Hexa-kis-(propyl-ammonium) benzene-1,2,4,5-tetra-carboxyl-ate 2,5-dicarb-oxy-benzene-1,4-carboxyl-ate tetra-hydrate.

The title organic salt, 6C(3)H(10)N(+)·C(10)H(2)O(8) (4-)·C(10)H(4)O(8) (2-)·4H(2)O, contains seven independent entities in the asymmetric unit which comprises three propyl-ammonium cations, two water mol-ecules, half a 2,5-dicarb-oxy-benzene-1,4-carboxyl-ate dianion (H(2)btc(2-)) and half a benzene-1,2,4,5-tetra-carboxyl-ate tetra-anion (btc(4-)), the latter two anions being located about centres of inversion. One of the water mol-ecules is disordered over two positions in a 0.55 (2):0.