Investigation of amino acid conjugates of (S)-1-[1-(4-aminobenzoyl)-2,3-dihydro-1H-indol-6-sulfonyl]-4-phenyl-imidazolidin-2-one (DW2282) as water soluble anticancer prodrugs.

The amino acid-conjugates (1a-k) with eleven amino acids attached to primary amine of (S)-1-[1-(4-aminobenzoyl)-2,3-dihydro-1H-indol-6-sulfonyl]-4-phenyl-imidazolidin-2-one (DW2282, 1) were prepared and studied for their prodrug characteristics and anti-cancer activity against SW620 cell line. All the amino acid derivatives showed not only improved water solubility but also displayed potent anti-cancer activity in vitro. Among these amino acid-conjugates the compounds, DW2282-L-Ala (1b), DW2282-L-Phe (1e), DW2282-L-Leu (1g) and DW2282-L-Met (1h) showed good reconversion within 8 h (104.

Design and synthesis of novel chromenone derivatives as interleukin-5 inhibitors.

A novel series of chromenone analogs were synthesized and evaluated for their inhibitory activity against interleukin-5. Among them 5-(cyclohexylmethoxy)-3-[3-hydroxy-3-(4-hydroxyphenyl)propyl]-4H-chromen-4-one (9b, 94% inhibition at 30 μM, IC(50) = 4.0 μM) and 5-(cyclohexylmethoxy)-3-[3-hydroxy-3-(4-methoxyphenyl)propyl]-4H-chromen-4-one (9c, 94% inhibition at 30 μM, IC(50) = 6.

Identification of novel chromenone derivatives as interleukin-5 inhibitors.

A series of (E)-5-alkoxy-3-(3-phenyl-3-oxoprop-1-enyl)-4H-chromen-4-ones (4) and (E)-5-alkoxy-3-(3-hydroxy-3-phenylprop-1-enyl)-4H-chromen-4-ones (5) were synthesized and evaluated for their IL-5 inhibitory activity. Propenone analogs 4 possess some of the structurally important characteristics of isoflavone 2 and chalcone 3 previously known as potent IL-5 inhibitor. However, the inhibitory activity of 4 was weak and therefore this structural hybridization appears to be ineffective for the design of IL-5 inhibitor.

Novel interleukin-5 inhibitors based on hydroxyethylaminomethyl-4H-chromen-4-one scaffold.

Hydroxyethylaminomethyl-4H-chromenones were previously discovered as fairly strong IL-5 inhibitor. For determination of detail structure activity relationship, N-substituted hydroxyethylaminomethylchromenones 4a-n were prepared and evaluated for their IL-5 inhibitory activity. Shifting the hydrophobic group to nitrogen from 1-position of hydroxyethylamino moiety of hydroxyethylaminomethyl-4H-chromenones enhances the activity.

Study on anti-proliferative effect of benzoxathiole derivatives through inactivation of NF-κB in human cancer cells.

To investigate the anti-proliferative effect of a newly discovered NF-kB inhibitor, 6,6-dimethyl-2-(phenylimino)-6,7-dihydrobenzo[d][1,3]oxathiol-4(5H)-one (1a), a series of its analogs (1b-n) were prepared and evaluated for their NF-κB inhibition and anti-proliferative activity against various human cancer cell lines. Slight variation of hydrophobicity by replacement of dimethyl group of 1a at 6-position with bulky isopropyl group and introduction of para-fluoro substitution on 2-phenyl group showed good NF-κB inhibitory activity and anti-proliferative activity. However, excessive increase in hydrophobicity with 2,4,6-trichloro substituents on phenyl group resulted in the loss of both the activities.

Chiral pharmacokinetics of zaltoprofen in rats by HPLC with solid-phase extraction.

We investigated the pharmacokinetic profile of (R)- and (S)-zaltoprofen (ZPF) in rats using rapid and selective liquid chromatography with solid-phase extraction (SPE). The ZPF enantiomers were extracted from a small volume of plasma (0.2 mL) by means of SPE using cartridges and were analyzed on a Chiralcel OJ-H (4.

A SAR study on a series of synthetic lipophilic chalcones as inhibitor of transcription factor NF-κB.

To define the structural features responsible for the activity of 2,4-dihydroxy-6-isopentyloxychalcone, a newly established inhibitor of LPS induced NF-κB activation (IC(50) = 10 μM), a series of its analogues was prepared and studied for their in vitro activities against LPS induced NF-κB inhibition in RAW 264.7 cells. Among the synthesized derivatives, (E)-1-(2-(decyloxy)-6-hydroxyphenyl)-3-(4-hydroxyphenyl)prop-2-en-1-one (IC(50) = 2.

Structure-activity relationship of naphthaldehydethiosemicarbazones in melanogenesis inhibition.

2-(Naphthalen-1-ylmethylene)hydrazinecarbothioamide (14, IC(50)=1.1μM) was discovered as a highly potent inhibitor of melanogenesis. To define the role of hydrogens (at N1 and N3) and sulfur in 14, a series of analogs 15a-p were synthesized and evaluated for anti-melanogenic activity using melanoma B16 cells under the stimulus of α-MSH.

Structure-activity relationship study of arylsulfonylimidazolidinones as anticancer agents.

In an effort to find novel N-arylsulfonylimidazolidinones as highly potent anticancer agent, the structure-activity relationship of ethyl 2-methyl-4-(2-oxo-4-phenylimidazolidin-1-ylsulfonyl)phenylcarbamate was explored through synthesis and evaluation of in vitro cytotoxicity of its analogs against HCT116, A549 and NCL-H460 cancer cell lines. Among the synthesized derivatives, the carbamate analogs (4a-f and 4k-p) exhibited superior cytotoxicity to doxorubicin for all cancer cell lines. The SAR studies of these derivatives confirm that the intact 4-phenyl-l-benzenesulfonylimidazolidinone has a pivotal role as a basic pharmacophore and hydrophobic substitutions only at 2-position of 1-aminobenzenesulfonyl moiety are beneficial for the enhancement of the activity.

Structural requirement of phenylthiourea analogs for their inhibitory activity of melanogenesis and tyrosinase.

Effect of a series of 1-phenylthioureas 1a-k and 1,3-disubstituted thioureas 2a-k were evaluated against melanin formation in melanoma B16 cell line and mushroom tyrosinase. Inhibitory activity of tyrosinase of 1-phenylthioureas 1a-k is parallel to their melanogenic inhibition. Thus, the melanogenic inhibition in melanoma B16 cells of 1-phenylthioureas could be the result of inhibition of tyrosinase.

Identification of indoline-2-thione analogs as novel potent inhibitors of α-melanocyte stimulating hormone induced melanogenesis.

Based on the hits, 3,4-dihydroquinazoline-2-thione (1) and benzimidazole-2-thione (2), a series of indole-2-thione (3) and indole-2-thiol inhibitors (4) of melanogenesis were designed, synthesized and evaluated in melanoma B16 cells under the stimulant of α-melanocyte stimulating hormone (α-MSH). The indole-2-thione compounds (3a-g) exhibited an effective inhibitory activity on melanin synthesis. The Structure-Activity Relationship (SAR) studies of 2 have revealed that in potent inhibitor 3a (>100% inhibition at 30 µM, IC50=1.

Ketonethiosemicarbazones: structure-activity relationships for their melanogenesis inhibition.

A series of 2-(1-phenylalkylidene)hydrazinecarbothioamides 2, 2-(1-phenylalkyl)hydrazinecarbothioamides 3, 2-(3,4-dihydronaphthalen-1(2H)-ylidene)hydrazinecarbothioamide (4), and 2-(1-(thiophen-2-yl)ethylidene)hydrazinecarbothioamide (5) were synthesized for their melanogenesis inhibition in melanoma B16 cells. The SAR of these ketonethiosemicarbazones revealed that the benzylidene hydrogen in aldehydethiosemicarbazones 1 can be replaced by hydrophobic moiety and substitutions with alkyl group for the terminal amino hydrogen of ketonethiosemicarbazones improved the activity appreciably. In addition, the double bond in thiosemicarbazones is an important factor for the increment of hydrophobicity.

Structure--activity relationship studies of novel arylsulfonylimidazolidinones for their anticancer activity.

To define the SAR, a series of novel N-arylsulfonylimidazolidinone derivatives were evaluated for their in vitro anticancer activity against five human tumor cell lines, including A549, COLO205, KATO III, K562, SK-OV-3 and murine leukemia (P288D1) cell line. Among them, N-(2-chloroacetyl)-6-(2-oxo-4-phenylimidazolidin-1-ylsulfonyl)-3,4-dihydroquinoline-1(2H)-carboxamide (4m) and N-cyclohexyl-6-(2-oxo-4-phenylimidazolidin-1-ylsulfonyl)-3,4-dihydroquinoline-1(2H)-carboxamide (4n) exhibited comparable in vitro anticancer activity to doxorubicin against A549, KATO III and K562 cell lines and gave superior xenographic results against NCI-H23 and SW620 cancer cell lines. Regarding the structure-activity relationship, two critical points were discovered; the steric congestion at 4-position of N-arylsulfonylimidazolidinone scaffold abolishes the activity and the bulkiness or hydrophobicity of acyl groups at 3,4-dihydroquinoline of 4, especially with carbamoyl moiety, enormously enhances the activity.

Structural requirements of (E)-6-benzylidene-4a-methyl-4,4a,5,6,7,8-hexahydronaphthalen-2(3H)-one derivatives as novel melanogenesis inhibitors.

Chalcone type compound 1a ((E)-6'-benzylidene-4a'-methyl-4',4a',7',8'-tetrahydro-3'H-spiro[[1,3]dithiolane-2,2'-naphthalen]-5'(6'H)-one) was discovered as an potent inhibitor in melanogenesis. To define its structure-activity relationship, a series of analogs 1b-n, dithiolane truncated 2a-b and ring A removed 3a-e were prepared and evaluated. The electron donating substitution on the phenyl ring (ring C) rather than an electron withdrawing group and dithiolane motif of 1 are needed for the activity enhancement.

Structural characteristics of thiosemicarbazones as inhibitors of melanogenesis.

A series of thiosemicarbazones 2(e-s) have been synthesized and studied their structure-activity relationship as melanogenesis inhibitor. Among them, (Z)-2-(naphthalen-1-ylmethylene)hydrazinecarbothioamide (2q, >100% inhibition at 10 μM, IC(50)=1.1 μM, ClogP=3.

Refinement of the pharmacophore of 3,4-dihydroquinazoline-2(1H)-thiones for their anti-melanogenesis activity.

In order to define the structural requirements of quinazoline-2(1H)-thiones 1 for their inhibitory activity on melanogenesis, a novel series of 3,4-dihydroquinazoline-2(1H)-thiones (3a-h) were prepared and screened for their melanogenesis inhibition on melanoma B16 cell line under the stimulant of alpha-MSH. The anti-melanogenesis activity of 3 is mainly mediated by the hydrogen bonding ability of thioamide unit in addition to complexation ability of thione and the hydrophobic binding power of side chain substitutions at 3-position. Thus, the pharmacophore of 3,4-dihydroquinazoline-2(1H)-thiones for their anti-melanogenesis activity could be refined as 3-hydrophobic substituted quinazolinethione.

Design and synthesis of novel hydroxyalkylaminomethylchromones for their IL-5 inhibitory activity.

A series of hydroxyalkylaminomethylchromone analogs 3 were prepared and evaluated as inhibitors of interleukin-5. The most active analog 3d inhibited interleukin-5 activity with an IC₅₀ of 17.5 μM.

Novel benzo[d]imidazole-2(3H)-thiones as potent inhibitors of the alpha-melanocyte stimulating hormone induced melanogenesis in melanoma B16 cells.

In order to determine the optimum size of heterocycle of lead compound 1 (6-methyl-3-phenethyl-3,4-dihydro-1H-quinoline-2-thione; IC(50)=0.8 microM) for inhibition of melanogenesis, we have synthesized and evaluated some benzimdazole-2(3H)-thiones 5a-e. The preliminary bioassay has shown that the benzimdazole-2(3H)-thione motif of 5 is essential structural unit for their inhibitory activity.

Structural requirement(s) of N-phenylthioureas and benzaldehyde thiosemicarbazones as inhibitors of melanogenesis in melanoma B 16 cells.

In order to define the structural requirements of phenylthiourea (PTU), a series of thiourea and thiosemicarbazone analogs were prepared and evaluated as inhibitors of melanogenesis in melanoma B16 cells. The most potent analog was 2-(4-tert-butylbenzylidene)hydrazinecarbothioamide (1u) with an IC(50) value of 2.7 microM in inhibition of melanogenesis.

Synthesis and evaluation of novel chromone analogs for their inhibitory activity against interleukin-5.

A novel series of chromone analogs were synthesized and evaluated for their inhibitory activity against interleukin-5. Among them compounds 5-Cyclohexylmethoxy-3-(4-hydroxybenzyl)-4H-chromen-4-one (6a, 98% inhibition at 30 microM, IC50<3.0 microM) and 5-Cyclohyxylmethoxy-3-(hydroxymethyl)-4H-chromen-4-one (8a, 84% inhibition at 30 microM, IC50=7.

Evaluation of 3,4-dihydroquinazoline-2(1H)-thiones as inhibitors of alpha-MSH-induced melanin production in melanoma B16 cells.

Novel 3,4-dihydroquinazoline-2(1H)-thiones (QNTs) 1 were found to be potent inhibitors of alpha-MSH-induced melanin production. The effect of QNTs to inhibit melanin formation in B16 melanoma cells was screened in the presence of alpha-MSH. In defining the mechanism of activity, the effects on tyrosinase activity, on tyrosinase synthesis and on the depigmentation of melanin were evaluated.

Inhibitory effect of novel tetrahydropyrimidine-2(1H)-thiones on melanogenesis.

The series of imidazoldine-2-thiones 2 and tetrahydropyrimidine-2-thiones 3 were discovered as inhibitor of alpha-MSH-induced melanin production in melanoma B16 cells. The primary bioassay showed that 1-(4-ethylbenzyl)-tetrahydropyrimidine-2(1H)-thione 3e (>100% inhibition at 10 microM, IC(50)=1.2 microM) and 1-(4-tert-butylbenzyl)-tetrahydropyrimidine-2(1H)-thione 3f (>100% inhibition at 10 microM, IC(50)=0.

A convenient preparation of a disaccharide motif and its role in the cytotoxicity of the triterpenoid saponin, alpha-hederin.

The sugar structures of triterpenoid saponins, such as alpha-hederin, are intimately associated with their antitumor activities and other biological activities. The alpha-L: -rhamnopyranosyl-(1-->2)-alpha-L: -arabinopyranoside group of alpha-hederin alters the cytotoxicity of its aglycon, hederagenin. This study explored the role of this saccharide unit in the cytotoxic effect of alpha-hederin and the possibility of its use as a carrier moiety in prodrugs of anticancer agents.

Evaluation of anticancer activity of 4-vinyl-1-arylsulfonylimidazolidinones.

To continue exploration of structure activity relationship of novel 1-(indoline-5-sulfonyl)-4-phenylimidazolidinones (1) reported as anticancer agent with broad spectrum, three 1-(arylsulfonyl)-4-vinylimidazolidinones (2) were synthesized from methyl serinate (3) in 8 steps. Reaction of intermediate 2-phenoxycarbonylaminobut-3-enyl p-toluenesulfonate (10) with arylsulfonamide in the presence of potassium carbonate produced corresponding 2 and N-(4-vinyloxazolidin-2-yl)arylsulfonamide 11 in approximately equal ratio. This reaction is believed to undergo through urea intermediate 16 as shown in scheme 3.