RCAI-84, 91, and 105-108, ureido and thioureido analogs of KRN7000: their synthesis and bioactivity for mouse lymphocytes to produce Th1-biased cytokines

RCAI-84, 91, and 105-108 (1-6), the analogs of KRN7000 (A) with a ureido or a thioureido linkage instead of a carboxamido bond, were synthesized to examine their immunostimulatory activity against mouse lymphocytes. According to their bioassay, the ureido analog of KRN7000 [RCAI-105 (1)] and its 6'-O-methylated derivative [RCAI-106 (4)] induced a large amount of IFN-γ in mice in vivo. The hexadecyl ureido analog [RCAI-84 (2)] was comparable to KRN7000 in its bioactivity. The octylureido [RCAI-107 (3)], 5-phenylpentylureido [RCAI-108 (5)], and thioureido [RCAI-91 (6)] analogs were almost inactive.     

RCAI-61 and related 6′-modified analogs of KRN7000: Their synthesis and bioactivity for mouse lymphocytes to produce interferon-γ in vivo

We synthesized ten new analogs of 6′-modified KRN7000 (A): RCAI-58, 61, 64, 83, 85–87, 113, 119, and 125. They could be synthesized by α-selective galactosylation of ceramide 9 with the 6-modified d-galactopyranosyl fluorides (8a–8f) or l-arabinopyranosyl fluoride (17), or by etherification of the known alcohol 19. Bioassay of the ten analogs demonstrated that RCAI-61 (1, 6′-O-methylated analog of A) was the most potent immunostimulant among them, and could induce the production of a large amount of IFN-γ even at a low concentration in mice in vivo.     

Acyclic-sugar purine nucleosides derived from -glucose: stereochemical correlations in acyclic-sugar derivatives unequally substituted at c-1

Condensation of 2,3,4,5,6-penta-O-acetyl-l-bromo-1-s-methyl-l-thio- -glucito (1) with 6-chloro-9-(chloromercuri)purine gave 49% of crystalline, levorotatory (1s)-2,3,4,5,6-penta-O-acetyl-1-(6-chloropurin-9-yl)-1- -methyl-1-thio- -glucitol (3), together with a smaller proportion of the syrupy, dextrorotatory (1R) isomer. Thiourea converted 3 into its 6-mercaptopurine analog, whose O-deacetylated derivative could be s-methylated to the corresponding -(methylthio)purin-9-yl analog; all compounds in this sequence were crystalline and were the pure (1s) isomers, as were the corresponding 1′-s-ethyl derivatives prepared by a similar route. Crystal-structure analysis of the O-deacetylated derivative of the 1 s-ethyl analog of 3 established the relative stereochemistry of the ethylthio group, permitting assignment of the (1s) absolute stereochemistry to this compound and thus to all compounds in the sequence starting from 1, including the previously described, crystalline, levorotatory 1-(1,6-dihydro-6-thioxopurin-9-yl)-1-s-ethyl-1-thio- -glucitol, whose chirality at C-1 had not hitherto been established. The close similarity of the chiroptical properties of the crystalline 1′-s-methyl derivatives to those of their 1′-s-ethyl counterparts permitted firm attribution of (1s) chirality to the former series also. Conformational studies showed that all of the derivatives have the sugar chain in a non-extended (sickle) conformation.     

The synthesis of new deoxynitroinositols by cyclization of 6-deoxy-3-O-methyl-6-nitro-d-allose and -l-talose

6-Deoxy-3-O-methyl-6-nitro-d-allose (5) and -l-talose (6) were synthesized from 1,2-O-isopropylidene-3O-methyl-α-d-allofuranose (1) by the nitromethane method via their furanoid, 1,2-O-isopropylidene derivatives (2 and 3). The barium hydroxide-catalyzed cyclization of the free nitrohexoses (5 and 6) was investigated. Under conditions favoring kinetic control (pH ～8, 0°), 5 gave mainly 1d-5-deoxy-2-O-methyl-5-nitro-allo-inositol (7), with the 1l-epi-1 (8) and epi-6 (9) stereoisomers as minor products. Compound 6 afforded a high yield of the myo-5-isomer (11); the 1l-allo-5 (13) and 1d-epi-1 (14) isomers were formed in small proportions but not isolated. The thermodynamically controlled, mutual interconversion of the stereoisomeric products was studied, as was the formation of nitronate salts and the regeneration of free nitroinositols. Upon immediate acidification, the nitronate obtained from 11 gave 11 and the neo-2 epimer (12) in a ratio of 2:3. The nitronate produced by 7 underwent rapid β-epimerization. The five isolated deoxynitroinositol monomethyl ethers were further characterized as tetra-acetates (7a, 9a, 11a, and 12a) and isopropylidene derivatives (7b, 8b, and 9b).     

The cyclization of 3-O-benzyl-6-deoxy-6-nitro-D-glucose and -L-idose to O-benzyldeoxynitroinositols,and epimerizations related thereto

3-O-Benzyl-1,2-O-isopropylidene-α-D-xylo-pentodialdo-1,4-furanose (1) was found to give, with nitromethane under catalysis by sodium methoxide, 3-O-benzyl-6-deoxy-1,2-O-isopropylidene-6-nitro- α-D-glucofuranose (2) as the kinetically favored product. Subsequent, spontaneous epimerization led to a 2:1 mixture of 2 and its β-L-ido isomer (3), from which crystalline 3 was isolated. The free nitro hexoses (4 and 5) obtained by deacetonation of 2 and 3 were subjected to barium hydroxide-catalyzed cyclization (internal Henry reaction) to give mixtures of O-benzyldeoxynitroinositols. Under conditions of kinetic control, the α-D-gluco derivative 4 furnished 6-O-benzyl-3-deoxy-3-nitro-muco-inositol (6) and optically active 4-O-benzyl-1-deoxy-1-nitro-L-myo-inositol (L-7) in a ratio of 3:1. The β-L-ido derivative 5 gave the enantiomer (D-7) of the myo compound and 4-O-benzyl-1-deoxy-1-nitro-scyllo-inositol (8) in a similar ratio. Slow, thermodynamically controlled epimerization led from each individual nitro inositol to mixtures of the same composition, with 17–18% of 6, 68–69% of DL-7, and 11–12% of 8. All of the nitroinositol benzyl ethers were isolated crystalline and characterized further as crystalline tetraacetates (6a–8a). The muco isomer 6 gave a di-O-isopropylidene derivative (6b).     

Acyclic-sugar purine nucleosides derived from d-glucose: stereochemical correlations in acyclic-sugar derivatives unequally substituted at c-1

Condensation of 2,3,4,5,6-penta-O-acetyl-l-bromo-1-s-methyl-l-thio-d-glucito (1) with 6-chloro-9-(chloromercuri)purine gave 49% of crystalline, levorotatory (1s)-2,3,4,5,6-penta-O-acetyl-1-(6-chloropurin-9-yl)-1-s-methyl-1-thio-d-glucitol (3), together with a smaller proportion of the syrupy, dextrorotatory (1R) isomer. Thiourea converted 3 into its 6-mercaptopurine analog, whose O-deacetylated derivative could be s-methylated to the corresponding 6-(methylthio)purin-9-yl analog; all compounds in this sequence were crystalline and were the pure (1s) isomers, as were the corresponding 1′-s-ethyl derivatives prepared by a similar route. Crystal-structure analysis of the O-deacetylated derivative of the 1$\text{-}\text{?}$s-ethyl analog of 3 established the relative stereochemistry of the ethylthio group, permitting assignment of the (1s) absolute stereochemistry to this compound and thus to all compounds in the sequence starting from 1, including the previously described, crystalline, levorotatory 1-(1,6-dihydro-6-thioxopurin-9-yl)-1-s-ethyl-1-thio-d-glucitol, whose chirality at C-1 had not hitherto been established. The close similarity of the chiroptical properties of the crystalline 1′-s-methyl derivatives to those of their 1′-s-ethyl counterparts permitted firm attribution of (1s) chirality to the former series also. Conformational studies showed that all of the derivatives have the sugar chain in a non-extended (sickle) conformation.     

Microbial transformation of isosteviol oxime and the inhibitory effects on NF-κB and AP-1 activation in LPS-stimulated macrophages

Microbial transformation of isosteviol oxime (ent-16-E-hydroxyiminobeyeran-19-oic acid) (2) with Aspergillus niger BCRC 32720 and Absidia pseudocylindrospora ATCC 24169 yielded several compounds. In addition to bioconverting the d-ring to lactone and lactam moieties, 4α-carboxy-13α-hydroxy-13,16-seco-ent-19-norbeyeran-16-oic acid 13,16-lactone (7) and 4α-carboxy-13α-amino-13,16-seco-ent-19-norbeyeran-16-oic acid 13,16-lactam (10), one known compound, ent-1β,7α-dihydroxy-16-oxo-beyeran-19-oic acid (6), and five new compounds, ent-7α-hydroxy-16-E-hydroxyiminobeyeran-19-oic acid (3), ent-1β,7α-dihydroxy-16-E-hydroxyiminobeyeran-19-oic acid (4), ent-1β-hydroxy-16-E-hydroxyiminobeyeran-19-oic acid (5), ent-8β-cyanomethyl-13-methyl-12-podocarpen-19-oic acid (8), and ent-8β-cyanomethyl-13-methyl-13-podocarpen-19-oic acid (9), were isolated from the microbial transformation of 2. Elucidation of the structures of these isolated compounds was primarily based on 1D and 2D NMR, and HRESIMS data, and 3–5 were further confirmed by X-ray crystallographic analyses. Additionally, the inhibitory effects of all of these compounds were evaluated on NF-κB and AP-1 activation in LPS-stimulated RAW 264.7 macrophages. Among the compounds tested, 5 and 10 significantly inhibited NF-κB activation, with 5 showing equal potency to dexamethasone; 3 and 6–9 significantly inhibited AP-1 activation, particularly 8, which showed more inhibitory activity than dexamethasone.     

Synthesis,structures and urease inhibitory activity of cobalt(III) complexes with Schiff bases

A series of new cobalt(III) complexes were prepared. They are [CoL¹(py)₃]·NO₃ (1), [CoL²(bipy)(N₃)]·CH₃OH (2), [CoL³(HL³)(N₃)]·NO₃ (3), and [CoL⁴(MeOH)(N₃)] (4), where L¹, L², L³ and L⁴ are the deprotonated form of N′-(2-hydroxy-5-methoxybenzylidene)-3-methylbenzohydrazide, N′-(2-hydroxybenzylidene)-3-hydroxylbenzohydrazide, 2-[(2-dimethylaminoethylimino)methyl]-4-methylphenol, and N,N′-bis(5-methylsalicylidene)-o-phenylenediamine, respectively, py is pyridine, and bipy is 2,2′-bipyridine. The complexes were characterized by infrared and UV–Vis spectra, and single crystal X-ray diffraction. The Co atoms in the complexes are in octahedral coordination. Complexes 1 and 4 show effective urease inhibitory activities, with IC₅₀ values of 4.27 and 0.35 μmol L⁻¹, respectively. Complex 2 has medium activity against urease, with IC₅₀ value of 68.7 μmol L⁻¹. While complex 3 has no activity against urease. Molecular docking study of the complexes with Helicobacter pylori urease was performed.     

Cyclitols from Croton celtidifolius

Croton celtidifolius has been found to contain 1l-1-O-methyl-myo-inositol, neo-inositol and sitosterol. Structure of 1l-1-O-methyl-myo-inositol pentaacetate, elaborated by NMR decoupling technique, is described.     

Thiophenes,polyacetylenes and terpenes from the aerial parts of Eclipata prostrata

One new bithiophenes, 5-(but-3-yne-1,2-diol)-5′-hydroxy-methyl-2,2′-bithiophene (2), two new polyacetylenic glucosides, 3-O-β-d-glucopyranosyloxy-1-hydroxy-4E,6E-tetradecene-8,10,12-triyne (8), (5E)-trideca-1,5-dien-7,9,11-triyne-3,4-diol-4-O-β-d-glucopyranoside (9), six new terpenoid glycosides, rel-(1S,2S,3S,4R,6R)-1,6-epoxy-menthane-2,3-diol-3-O-β-d-glucopyranoside (10), rel-(1S,2S,3S,4R,6R)-3-O-(6-O-caffeoyl-β-d-glucopyranosyl)-1,6-epoxy menthane-2,3-diol (11), (2E,6E)-2,6,10-trimethyl-2,6,11-dodecatriene-1,10-diol-1-O-β-d-glucopyranoside (12), 3β,16β,29-trihydroxy oleanane-12-ene-3-O-β-d-glucopyranoside (13), 3,28-di-O-β-d-glucopyranosyl-3β,16β-dihydroxy oleanane-12-ene-28-oleanlic acid (14), 3-O-β-d-glucopyranosyl-(1→2)-β-d-glucopyranosyl oleanlic-18-ene acid-28-O-β-d-glucopyranoside (15), along with fifteen known compounds (1, 3–7, and 16–24), were isolated from the aerial parts of Eclipta prostrata. Their structures were established by analysis of the spectroscopic data. The isolated compounds 1–9 were tested for activities against dipeptidyl peptidase IV (DPP-IV), compound 7 showed significant antihyperglycemic activities by inhibitory effects on DPP-IV in human plasma in vitro, with IC₅₀ value of 0.51 μM. Compounds 10–24 were tested in vitro against NF-κB-luc 293 cell line induced by LPS. Compounds 12, 15, 16, 19, 21, and 23 exhibited moderate anti-inflammatory activities.     

Synthesis of myo- and muco-inositol esters,and some nitrogen derivatives thereof

Starting from myo-inositol, 1,2-O-isopropylidene-3,4,5,6-tetra-O-(methylsulfonyl)-, 1,4,5,6-tetra-O-(methylsulfonyl)-, and 2,3-di-O-acetyl-1,4,5,6-tetra-O-(methylsulfonyl)-myo-inositol (3) were synthesized. Compound 3 was treated with sodium azide to give 3-azido-3-deoxy-1,5,6-tri-O-(methylsulfonyl)-muco-inositol, reduction of whose diacetate led to a mixture of 3-amino-3-deoxy- and 3-acetamido-2-O-acetyl-3-deoxy-1,5,6-tri-O-(methylsulfonyl)-muco-inositol. The configurations and conformations of these compounds were ascertained by n.m.r. spectroscopy. 3-Acetamido-3-deoxy-1,5,6-tri-O-(methylsulfonyl)-muco-inositol and its 2,4-diacetate are also described.     

neo-Clerodane diterpenes from Ajuga ciliata and their inhibitory activities on LPS-induced NO production

Two new neo-clerodane diterpenes, (12S)-6α-acetoxy-4α,18-epoxy-12-hydroxy-19-tigloyloxy-neo-clerod-13-en-15,16-olide (1) and 6α,18-diacetoxy-4α-hydroxy-19-tigloyloxy-neo-clerod-13-en-15,16-olide (2), along with three known analogs (3–5) have been isolated from the whole plants of Ajuga ciliata Bunge. Their structures were elucidated on the basis of spectroscopic data analyses (IR, ESI-MS, HR-ESI-MS, HMQC, HMBC, COSY, and NOESY). The inhibitory activities on LPS-induced NO production of these diterpenes were evaluated and compounds 1 and 5 showed inhibitory effects.     

Synthesis of 5,6-dideoxy-3-O-methyl-5-C-(phenylphosphinyl)-d-glucopyranose and its 1,2,4-triacetate

Methyl phenylphosphonite or dimethyl phosphite underwent acid-catalyzed addition reactions with some hexofuranos-5-ulose 5-(p-tolylsulfonylhydrazones) (7, 9, and 16), to give the corresponding adducts, 17, 18, 19, and 21. The isomer ratios of the adducts were affected by a 3-substituent in the hydrazones. Treatment of adduct 21 with sodium borohydride and sodium dihydrobis(2-methoxyethoxy)-aluminate (SDMA), followed by acid hydrolysis, gave 5,6-dideoxy-3-O-methyl-5-C-(phenylphosphinyl)-d-glucopyranose (26), which was acetylated to give the 1,2,4-tri-O-acetyl derivatives 27a and 27b. Conformational analysis of compound 27a by X-ray crystallography revealed that the compound was 1,2,4-tri-O-acetyl-5,6-dideoxy-3-O-methyl-5-C-[(S)-phenylphosphinyl]-β-d-glucopyranose in the ⁴C₁(d) form having all substituents equatorial.     

First microwave-assisted synthesis of an electron-rich phosphane and its coordination chemistry with platinum(II) and palladium(II)

The P-O ligand 3-(di(2-methoxyphenyl)phosphanyl)propionic acid (HL) was synthesized by a microwave-assisted reaction of a secondary phosphane. The coordination of HL to Pt^II yielded the neutral mononuclear complex trans-[PtCl(κ²-P,O-L)(κ-P-HL)] (1), while the reaction of PdClMe(η⁴-COD) (COD = 1,4-cyclooctadiene) with HL in the presence of NEt₃ gave the anionic Pd^II compound of the formula (HNEt₃)[PdClMe(κ²-P,O-L)] (2). Upon crystallization of the latter compound the neutral chloride-bridged dimetallic compound cis-[Pd(μ-Cl)Me(HL)]₂ (3) was obtained. HL, 1 and 3·CH₂Cl₂ have been characterized by single crystal X-ray structure analyses.     

The stereochemistry of palladium- and platinum-catalyzed hydrogenations of nitro sugar epoxides

The catalytic hydrogenation of carbohydrate α-nitroepoxides with palladium and platinum was investigated with regard to regiospecificity and stereochemistry of ring opening, and the fate of the nitro group. 5,6-Anhydro-1,2-O-isopropylidene- 6-C-nitro-α-D-glucofuranose gave 6-amino-6-deoxy-1,2-O-isopropylidene-α-D-gluco-furanose under platinum catalysis. The methyl 2,3-anhydro-4,6-O-benzylidene-3-C- nitrohexopyranosides having the β-D-gulo (4), ?-D-allo (9), α-D-manno (13), and β-D-manno (18) configurations underwent facile, hydrogenolytic ring-opening in the presence of palladium, to give, regardless of the orientation of the oxirane ring, methyl 4,6-O-benzylidene-3-deoxy-3-C-nitro-D-hexopyranosides having an equatorial nitro group (5, 10, 14, and 19, respectively). In addition, 3-deoxy-3-oximino derivatives arose in various proportions, and two of these (from 9, and from 18) were isolated crystalline. It was shown that the oximes did not result from over-hydrogenation of the 3-deoxy-3-C-nitro glycosides produced, and it is suggested that they originated from intermediary nitronic acids. By catalysis with platinum, the oxirane rings in 4, 9, 13, and 18 were opened in the same regiospecific sense as with palladium, but notable differences were observed otherwise. Compound 4 gave the amino analog of 5, whereas 9 retained the nitro group and gave the 4,6-O-(cyclohexylmethylene) analog of 10. The α-D-manno epoxide 13 reacted with concomitant debenzylidenation, to yield methyl 3-amino-3-deoxy-α-D-altropyranoside hydrochloride, whereas the β-D-manno epoxide 18 gave the corresponding, debenzylidenated amino β-D-altroside together with the 4,6-O-(cyclohexylmethylene)-3-nitro- and -3-amino-β-D-mannosides. The results are compared with literature reports on the stereochemistry of hydrogenolysis of oxiranes, and mechanisms that may operate for the nitro derivatives are discussed.     

Design,synthesis and pharmacological characterization of coumarin-based fluorescent analogs of excitatory amino acid transporter subtype 1 selective inhibitors,UCPH-101 and UCPH-102

The excitatory amino acid transporters (EAATs) play a pivotal role in regulating the synaptic concentration of glutamate in the mammalian central nervous system. To date, five different subtypes have been identified, named EAAT15 in humans (and GLAST, GLT-1, EAAC1, EAAT4, and EAAT5, respectively, in rodents). Recently, we have published and presented a structure–activity relationship (SAR) study of a novel class of selective inhibitors of EAAT1 (and GLAST), with the analogs UCPH-101 (IC₅₀ = 0.66 μM) and UCPH-102 (IC₅₀ = 0.43 μM) being the most potent inhibitors in the series. In this paper, we present the design, synthesis and pharmacological evaluation of six coumarin-based fluorescent analogs of UCPH-101/102 as subtype-selective inhibitors at EAAT1. Analogs 1114 failed to inhibit EAAT1 function (IC₅₀ values >300 μM), whereas analogs 15 and UCPH-102F inhibited EAAT1 with IC₅₀ values in the medium micromolar range (17 μM and 14 μM, respectively). Under physiological pH no fluorescence was observed for analog 15, while a bright blue fluorescence emission was observed for analog UCPH-102F. Regrettably, under confocal laser scanning microscopy selective visualization of expression of EAAT1 over EAAT3 was not possible due to nonspecific binding of UCPH-102F.     

Caffeic acid derivatives and further compounds from Espeletia barclayana Cuatrec. (Asteraceae,Espeletiinae)

This work describes the isolation of seven (1–7) secondary metabolites from Espeletia barclayana (Asteraceae, Espeletiinae) and their identification by spectroscopic (NMR) and spectrometric (MS) techniques. Ten (8–17) additional compounds were identified based on their retention times, high-resolution mass spectrometry data, and comparison with reference substances or data from literature. The systematic significance of some of the identified substances – the sesquiterpene lactone longipilin acetate, four caffeoylquinic acids and two tri-caffeoylaltraric acids – is discussed with the aim of providing insights into the complex relationships among Espeletiinae taxa and its closest relatives. Five of the isolated metabolites [5-O-(E)-caffeoylquinic acid (1), 1,3-di-O-(E)-caffeoylquinic acid (2), 1,5-di-O-(E)-caffeoylquinic acid (3), 3,4-di-O-(E)-caffeoylquinic acid (4) and 3-O-methylquercetin 7-O-β-glucopyranoside (7)] constitute new reports for the genus Espeletia and for the subtribe Espeletiinae. Chemical data suggest that Espeletiinae might have a closer relationship with Smallanthus than with Ichthyothere, i.e., the two genera suggested to be the sister groups of Espeletiinae based on molecular markers.     

Investigation of the acetolysis products of the sulphated polysaccharide of Aeodes ulvoidea

Investigation of the acetolysis products of the sulphated polysaccharide of the seaweed Aeodes ulvoidea led to the isolation and characterization of the following oligosaccharides: 3-O-α- -galactopyranosyl- -galactose (1), 3-O-(2-O-methyl-α- -galactopyranosyl)- -galactose (2), 4-O-β- -galactopyranosyl-2-O-methyl- -galactose (3), 4-O-β- -galactopyranosyl-2-O-methyl- -galactose (4), O-β- -galactopyranosyl-(1→4)-O-α- -galactopyranosyl-(1→3)- -galactose (5), O-α- -galactopyranosyl-(1→3)-O-β- -galactopyranosyl-(1→4)- -galactose (6), O-α- -galactopyranosyl-(1→3)-O-β- -galactopyranosyl-(1→4)-2-O-methyl- -galactose (7), O-(2-O-methyl-α- -galactopyranosyl)-(1→3)-O-β- -galactopyranosyl-(1→4)-2-O-methyl- -galactose (10), and O-α- -galactopyranosyl-(1→3)-O-β- -galactopyranosyl-(1→4)-O-α- -galactopyranosyl-(1→3)- -galactose. In addition, the isolation of a tetrasaccharide possessing alternating - and -galactose residues demonstrates the hitherto unexpected presence of -galactose in the polysaccharide. The structure of the polysaccharide is discussed.     

An approach to branched-chain amino sugars, particularly derivatives of -vancosamine (3-amino-2,3,6-trideoxy-3-C-methyl- -lyxo-hexose) and its enantiomer, via the cyanohydrin route

Methyl 4,6-O-benzylidene-2-deoxy-α- -erythro-hexopyranosid-3-ulose reacted with potassium cyanide under equilibrating conditions to give, initially, methyl 4,6-O-benzylidene-3-C-cyano-2-deoxy-α- -ribo-hexopyranoside (7), which, because it reverted slowly to the thermodynamically stable -arabino isomer, could be crystallised directly from the reaction mixture. The mesylate derived from the kinetic product 7 could be converted by published procedures into methyl 3-acetamido-2,3,6-trideoxy-3-C-methyl-α- -arabino-hexopyranoside, which was transformed into methyl N-acetyl-α- -vancosaminide on inversion of the configuration at C-4. A related approach employing methyl 2,6-dideoxy-4-O-methoxymethyl-α- -erythro-hexopyranosid-3-ulose gave the kinetic cyanohydrin and thence, via the spiro-aziridine 27, methyl 3-acetamido-2,3,6-trideoxy-3-C-methyl-α- -arabino-hexopyranoside, a known precursor of methyl N-acetyl-α- -vancosaminide.     

(Pyrazolylmethyl)pyridine platinum(II) and gold(III) complexes: Synthesis, structures and evaluation as anticancer agents

Reactions of 2-(3,5-dimethylpyrazol-1-ylmethyl)pyridine (L1), 2-(3,5-diphenylpyrazol-1-ylmethyl)pyridine (L2), 2-(3,5-di-tert-butylpyrazol-1-ylmethyl)pyridine (L3) and 2-(3-p-tolylpyrazol-1-ylmethyl)pyridine (L4) with K₂[PtCl₄] in a mixture of ethanol and water formed the dichloro platinum complexes [PtCl₂(L1)] (1), [PtCl₂(L2)] (2), [PtCl₂(L3)] (3) and [PtCl₂(L4)] (4). Complex 1, [PtCl₂(L1)], could also be prepared in a mixture of acetone and water. Performing the reactions of L2 and L3 in a mixture of acetone and water, however, led to C-H activation of acetone under mild conditions to form the neutral acetonyl complexes [Pt(CH₂COCH₃)Cl(L2)] (2a) and [Pt(CH₂COCH₃)Cl(L3)] (3a). The same ligands reacted with HAuCl₄ · 4H₂O in a mixture of ethanol and water to form the gold salts [AuCl₂(L1)][AuCl₄] (5) [AuCl₂(L2)][Cl] (6) [AuCl₂(L3)][Cl] (7) and [AuCl₂(L4)][AuCl₄] (8); however, with the pyrazolyl unit in the para position of the pyridinyl ring in 4-(3,5-dimethylpyrazol-1-ylmethyl)pyridine (L5), 4-(3,5-diphenylpyrazol-1-ylmethyl)pyridine (L6) neutral gold complexes [AuCl₃(L5)] (9) and [AuCl₂(L6)] (10) were formed; signifying the role the position of the pyrazolyl group plays in product formation in the gold reactions. X-ray crystallographic structural determination of L6, 2, 33a, 8 and 10 were very important in confirming the structures of these compounds; particularly for 3a and 8 where the presence of the acetonyl group confirmed C-H activation and for 8 where the counter ion is . Cytotoxicity studies of L2, L4 and complexes 1-10 against HeLa cells showed the Au complexes were much less active than the Pt complexes.