3-(2H-1,3-Benzodioxol-5-ylmeth-yl)-2-(2-meth-oxy-phen-yl)-1,3-thia-zolidin-4-one.

The title mol-ecule, C(18)H(17)NO(4)S, features a 1,3-thia-zolidine ring that is twisted about the S-C(methyl-ene) bond. With reference to this ring, the 1,3-benzodioxole and benzene rings lie to either side and form dihedral angles of 69.72 (16) and 83.60 (14)°, respectively, with the central ring. Significant twisting in the mol-ecule is confirmed by the dihedral angle of 79.91 (13)° formed between the outer rings. Linear supra-molecular chains along the a-axis direction mediated by C-H⋯O inter-actions feature in the crystal packing.

tert-Butyl N-[3-hy-droxy-1-phenyl-4-(pyrimidin-2-ylsulfan-yl)butan-2-yl]carbamate monohydrate.

In the title hydrate, C(19)H(25)N(3)O(3)S·H(2)O, the configuration at each chiral centre in the organic mol-ecule is S, with the hy-droxy and carbamate substituents being anti [O-C-C-N torsion angle = -179.3 (3)°]. The thio-pyrimidyl and carbamate residues lie to one side of the pseudo-mirror plane defined by the C(5)S backbone of the mol-ecule; this plane approximately bis-ects the benzene ring at the 1- and 4-C atoms. The dihedral angle formed between the terminal rings is 5.06 (18)°. In the crystal, supra-molecular tubes aligned along the b axis are found: these are sustained by a combination of O-H⋯O, O-H⋯N and N-H⋯O hydrogen bonds.

N-{(2S)-3-Hy-droxy-4-[(5-methyl-1,3,4-thia-diazol-2-yl)sulfan-yl]-1-phenyl-2-but-yl}-4-methyl-benzene-sulfonamide.

The thia-diazoyl and sulfonyl-benzene rings in the title compound, C(20)H(23)N(3)O(3)S(3), are aligned to the same side of the mol-ecule, forming a twisted 'U' shape [dihedral angle = 77.6 (5)°]. The benzyl-benzene ring is orientated in the opposite direction from the mol-ecule but projects approximately along the same axis as the other rings [dihedral angle between benzene rings = 28.2 (5)°] so that, overall, the mol-ecule has a flattened shape. The hy-droxy and amine groups are almost syn which enables the formation of inter-molecular hy-droxy-OH⋯N(thia-diazo-yl) and amine-H⋯O(sulfon-yl) hydrogen bonds leading to a supra-molecular chain aligned along the a axis.

(4-Benzyl-2-oxo-1,3-oxazolidin-5-yl)methyl methane-sulfonate.

The title compound, C(12)H(15)NO(5)S, features an approximately planar five-membered oxazolidin ring (r.m.s. deviation = 0.045 Å) with the peripheral benzyl and methyl methane-sulfonate residues lying to either side of the plane. In the crystal, N-H⋯O hydrogen bonds, involving one of the sulfur-bound oxo groups as acceptor, lead to the formation of supra-molecular chains along the b axis. These chains are reinforced by C-H⋯O contacts with the carbonyl O atom accepting three such inter-actions. The structure was refined as a racemic twin, with the major component being present 89% of the time.

A Review on Onychine and its Analogs: Synthesis and Biological Activity.

BACKGROUND: Onychine is a 4-azafluorenone alkaloid isolated from the Annonaceae family, in low concentrations. Onychine and its analogs exhibit a wide range of pharmacological activities such as antifungal, antibacterial, anticancer, and antimalarial. Because of the high bioactivity of some 4-azafluorenone derivatives, several synthetic methods have been developed for their procurement. OBJECTIVE: Considering the importance of these alkaloids, we aim to present the main synthetic approaches to onychines and its derivatives and the biological activity of some 4-azafluorenones. METHODS: The most prominent methodologies for the synthesis of onychines were reviewed. RESULTS: In this work, we cover many synthetic approaches for the synthesis of onychine and 4-azafluorenone derivatives including intramolecular cyclizations, multicomponent reactions, microwave-assisted multicomponent reactions, Diels-alder reactions, among others. Moreover, we also review the biological activity of 4-azafluorenones. CONCLUSION: 4-azafluorenones have risen as prominent structures in medicinal chemistry; however, most of the time, access to new derivatives involves toxic catalysts, harsh reaction conditions, and long-step procedures. Therefore, the development of new synthetic routes with more operational simplicity, simple purification procedure, good yields, and low environmental impact, is desirable.

Crystal structures and Hirshfeld surfaces of two 1,3-benzoxa-thiol-2-one derivatives.

The crystal structures of 6-meth-oxy-1,3-benzoxa-thiol-2-one, C9H8O3S, (I), and 2-oxo-1,3-benzoxa-thiol-6-yl acetate, C9H6O4S, (II), are described. Compound (I) is almost planar (r.m.s. deviation for the non-H atoms = 0.011 Å), whereas (II) shows a substantial twist between the fused-ring system and the acetate substituent [dihedral angle = 74.42 (3)°]. For both structures, the bond distances in the heterocyclic ring suggest that little if any conjugation occurs. In the crystal of (I), C-H⋯O hydrogen bonds link the mol-ecules into [1-11] chains incorporating alternating R22(8) and R22(12) inversion dimers. The extended structure of (II) features C(7) [201] chains linked by C-H⋯O hydrogen bonds, with further C-H⋯O bonds and weak π-π stacking inter-actions connecting the chains into a three-dimensional network. Hirshfeld fingerprint analyses for (I) and (II) are presented and discussed.

Evaluation of 1,3-benzoxathiol-2-one Derivatives as Potential Antifungal Agents.

BACKGROUND: Over the last few years, fungal infections have emerged as a worrisome global public health problem. Candidiasis is a disease caused by Candida species and has been a problem worldwide mainly for immunosuppressed patients. Lately, the resistant strains and side effects have been reported as important issues for treating Candidiasis, which have to be solved by identifying new drugs. OBJECTIVE: The goal of this work was to synthesize a series of 1,3-benzoxathiol-2-one derivatives, XYbenzo[ d][1,3]oxathiol-2-ones, and evaluate their antifungal activity against five Candida species. METHODS: In vitro antifungal screening test and minimum inhibitory concentration determination were performed according to CLSI protocols using ketoconazole as the reference drug. The cytotoxicity of the most active compounds was evaluated by hemolysis and MTT (Vero cells) assays. RESULTS: Compounds 2 (XY = 6-hydroxy-5-nitro, MIC = 4-32 µg/mL) and 7 (XY = 6-acetoxy-5-nitro, MIC =16-64 µg/mL) showed good results when compared with current antifungals in CLSI values (MIC = 0.04-250 µg/mL). These compounds exhibited a safer cytotoxicity as well as a lower hemolytic profile than ketoconazole. CONCLUSION: Overall, the in vitro results pointed to the potential of compounds 2 and 7 as new antifungal prototypes to be further explored.

Antibacterial activity of thioetherhydroxyethylsulfonamide derivatives.

Thioetherhydroxyethylsulfonamide derivatives were synthesized and evaluated for their in vitro antibacterial activity against Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853) and Staphylococcus aureus (ATCC 25923). Results have shown that compounds 8c and 9e display potent activity (MIC = 0.125 µg/mL) against E. coli when compared with the standard drug sulfamethoxazole (SMZ, MIC < 0.5 µg/mL) for this same strain. All the new compounds were fully identified and characterized by NMR ((1)H and (13)C) and X-ray crystallography (for compound 8c). This class of compounds can be considered as a good starting point for the development of new lead molecules in the fight against multi-drug bacterial resistance.

Syntheses and antimycobacterial activities of [(2S,3R)-2-(amino)-4-(arenesulfonamido)-3-hydroxy-1-phenylbutane derivatives.

The syntheses of hydroxyethylsulfonamides, (2S,3R)-tert-butyl N-[4-(N-benzyl-4-R-phenylsulfonamido)-3- hydroxy-1-phenylbutan-2-yl]carbamates and (5) (2S,3R)-2-amino-4-[N-benzyl-4-R-benzenesulfonamido]-3-hydroxy-1- phenylbutane hydrochlorides (6), derived from (2S,3S)-Boc-phenylalanine epoxide, are reported. None of the compounds, containing the Boc group, showed activity against M. tuberculosis ATTC 27294, while compounds 6 did, with the most active compounds having R = p-Cl, p-Br and p-Me. Results indicate that the presence of a free amino group at C2 and the sulphonamide moiety are important for biological activity. The antimycobacterial activity of compounds 6 correlated well with the calculated lipophilicities, but not with the electronic effects of the substituents, R. All compounds 6 were highly cytotoxic against the hepatoma cell lineage Hep G2 A16. The X-ray crystal structure of compound [(6: R = Me).H2O] is also reported. In the propeller-like conformation adopted by the cation, the amino and hydroxy groups have a cis arrangement, and thus are suitably placed to form 5- membered chelates.

Synthesis and in vivo antimalarial evaluation of novel hydroxyethylamine derivatives.

A series of hydroxyethylamines has been synthesized from the reaction of (2S,3S )Boc-phenylalanine epoxide with alkyl amines in good yields and evaluated for their in vivo antimalarial activity in mice. Compound 4g presented better activity then the reference artesunate in percentage of inhibition of parasitemia in treated P. berghei-infected mice and compare to the activity of artesunate in the survival of mice 14 days after infection. In addiction, no hemolytic activity was found, which supports that inhibition of parasitemia is due to antimalarial activity. The compound 4g inhibited the differentiation to schizonts suggesting that parasite metabolism is a possible target of 4g. These results indicate that this class of compound possesses promising perspectives for the development of new antimalarial drugs.

Efficient sonochemical synthesis of thiazolidinones from piperonilamine.

An efficient multicomponent reaction of arenealdehydes, mercaptoacetic acid and piperonilamine under ultrasound irradiation to afford 2-aryl-3-(piperonylmethyl)-1,3-thiazolidin-4-ones is reported. Applying this methodology, eleven heterocycles were synthesized and isolated in good yields after short reaction times.

Synthesis and anti-mycobacterial activity of novel amino alcohol derivatives.

Thirteen new hydroxyethylamines have been synthesized from reactions of (2S,3S)Boc-phenylalanine epoxide, piperonylamine and arenesulfonyl chlorides in good yields. These compounds were evaluated as antibacterial agents against Mycobacterium tuberculosis H37Rv using the Alamar Blue susceptibility test and their activity expressed as the minimum inhibitory concentration (MIC) in µM. Two amino alcohols displayed significant activity when compared with first line drug ethambutol (EMB). Therefore this class of compounds could be a good starting point to develop new lead compounds in the treatment of tuberculosis.

Synthesis and antimycobacterial activity of novel amino alcohols containing central core of the anti-HIV drugs lopinavir and ritonavir.

Eleven new amino alcohol derivatives have been synthesized from reactions of lopinavir intermediate and heteroaromatic aldehyde in good yields. These compounds, the antiretrovirals (lopinavir and ritonavir) and lopinavir key intermediate were evaluated as antibacterial agents against Mycobacterium tuberculosis H37Rv using the Alamar Blue susceptibility test and their activity expressed as the minimum inhibitory concentration (MIC) in µM. Ten amino alcohols evaluated displayed significant activity (MIC between 6.15 and 108.4 µM) when compared to first-line drug ethambutol (MIC = 15.9 µM). Three of them showed more activity than ethambutol (MIC = 6.15; 6.21 and 13.4 µM). The appreciable activity of these compounds can be considered an important finding for the rational design of new leads for anti-TB compounds.

Synthesis and antimalarial activity of thioetherhydroxyethylsulfonamides, potential aspartyl protease inhibitors, Part 3.

A series of novel thioetherhydroxyethylsulfonamide derivatives has been synthesized from the coupling of intermediates 3-amino-4-phenyl-1-thioetherazine-butan-2-oles 6,7 with arenesulfonyl chlorides in good yields. Characterizations of products were achieved by NMR techniques and specifically for compound 8e by X-ray crystallography. Preliminary results of antimalarial activity in vitro against the Plasmodium falciparum W2 clone (chloroquine resistant and mefloquine sensitive) showed moderate activity for hydroxyethylsulfonamide 8f. In addition, none of the compounds tested showed cytotoxicity at high concentration tested against HepG2 and BGM cell lines.

Synthesis and antimalarial activity of hydroxyethylpiperazine derivatives.

The antimalarial activity of hydroxyethylpiperazine derivatives, synthesized from the reaction of (2S,3S)Boc-phenylalanine epoxide with benzylpiperazines in good yields (76-96%), has been evaluated in vitro against the Plasmodium falciparum W2 clone (chloroquine resistant). The results show that some compounds have moderate activity against this parasite and none of the active compounds showed cytotoxicity at high concentration (100 microg/ml).

Synthesis, antimalarial evaluation and molecular modeling studies of hydroxyethylpiperazines, potential aspartyl protease inhibitors, part 2.

The antimalarial acitivity of hydroxyethylamines, synthesized from the reaction of intermediated hydroxyethypiperazines with benzenesulfonyl chlorides or benzoyl chlorides, has been evaluated in vitro against a W2 Plasmodium falciparum clone. Some of the nineteen tested derivatives showed a significant activity in vitro, thus turning into a promising new class of antimalarials. In addition, a molecular modeling study of the most active derivative (5l) was performed and its most probable binding modes within plasmepsin II enzyme were identified.

Racemic 2-isopropyl-3-(2-nitrobenzyl)-1,3-thiazolidin-4-one crystallizes in the space group P2(1)2(1)2(1) with Z' = 2: two different interpenetrating three-dimensional frameworks formed by C-H...O hydrogen bonds.

rac-2-Isopropyl-3-(2-nitrobenzyl)-1,3-thiadiazolin-4-one, C(13)H(16)N(2)O(3)S, is a rare example of a racemate crystallizing in the space group P2(1)2(1)2(1), with one molecule each of S and R configurations, whose conformations are almost mirror images, within the asymmetric unit. The molecules of S configuration are linked by two C-H...O hydrogen bonds into a three-dimensional framework, and the molecules of R configuration are linked by two further C-H...O hydrogen bonds into a different type of three-dimensional framework; the two frameworks are linked by a fifth C-H...O hydrogen bond.