4-Isopropyltoluene

Novel Antitumor Invasive Actions of p-Cymene by Decreasing MMP-9/TIMP-1 Expression Ratio in Human Fibrosarcoma HT-1080 Cells.[Pubmed:27476935]

Biol Pharm Bull. 2016;39(8):1247-53.

p-Cymene (4-Isopropyltoluene) has been reported to have beneficial actions such as anti-inflammatory and antinociceptive activities. To evaluate whether p-cymene exhibits antitumor invasive actions, we examined the effects of p-cymene on the production of matrix metalloproteinase 9 (MMP-9)/gelatinase B and tissue inhibitor of metalloproteinases-1 (TIMP-1) in human fibrosarcoma HT-1080 cells. p-Cymene was found to dose-dependently inhibit the 12-O-tetradecanoylphorbol 13-acetate (TPA)-augmented production and gene expression of MMP-9 in HT-1080 cells. In contrast, p-cymene enhanced the TPA-augmented production and gene expression of TIMP-1 in HT-1080 cells. However, there was no change in the constitutive level of MMP-9 and TIMP-1 mRNAs and TIMP-1 protein in p-cymene-treated cells. In addition, we found that the in-vitro TPA-augmented invasiveness of HT-1080 cells was inhibited by p-cymene in a dose-dependent manner. Furthermore, p-cymene was found to suppress the constitutive and/or TPA-augmented phosphorylation of extracellular signal-regulated kinase (ERK)1/2 and p38 mitogen-activated protein kinase (MAPK) in HT-1080 cells. Thus, these results provide novel evidence that p-cymene is an effective candidate for the prevention of tumor invasion and metastasis through mechanisms that include the inhibition of MMP-9 expression and the augmentation of TIMP-1 production along with the suppression of ERK1/2 and p38 MAPK signal pathways in tumor cells.

Anaerobic Degradation of p-Alkylated Benzoates and Toluenes.[Pubmed:26960059]

J Mol Microbiol Biotechnol. 2016;26(1-3):63-75.

The anaerobic degradation of 4-alkylbenzoates and 4-alkyltoluenes is to date a rarely reported microbial capacity. The newly isolated Alphaproteobacterium Magnetospirillum sp. strain pMbN1 represents the first pure culture demonstrated to degrade 4-methylbenzoate completely to CO2 in a process coupled to denitrification. Differential proteogenomic studies in conjunction with targeted metabolite analyses and enzyme activity measurements elucidated a specific 4-methylbenzoyl-coenzyme A (CoA) pathway in this bacterium alongside the classical central benzoyl-CoA pathway. Whilst these two pathways are analogous, in the former the p-methyl group is retained and its 4-methylbenzoyl-CoA reductase (MbrCBAD) is phylogenetically distinct from the archetypical class I benzoyl-CoA reductase (BcrCBAD). Subsequent global regulatory studies on strain pMbN1 grown with binary or ternary substrate mixtures revealed benzoate to repress the anaerobic utilization of 4-methylbenzoate and succinate. The shared nutritional property of betaproteobacterial 'Aromatoleum aromaticum' pCyN1 and Thauera sp. strain pCyN2 is the anaerobic degradation of the plant-derived hydrocarbon p-cymene (4-Isopropyltoluene) coupled to denitrification. Notably, the two strains employ two different peripheral pathways for the conversion of p-cymene to 4-isopropylbenzoyl-CoA as the possible first common intermediate. In 'A. aromaticum' pCyN1 a putative p-cymene dehydrogenase (CmdABC) is proposed to hydroxylate the benzylic methyl group, which is subsequently further oxidized to the CoA-thioester. In contrast, Thauera sp. strain pCyN2 employs a reaction sequence analogous to the known anaerobic toluene pathway, involving a distinct branching (4-isopropylbenzyl)succinate synthase (IbsABCDEF).

Characterization of odor-active compounds of various Chrysanthemum essential oils by gas chromatography-olfactometry, gas chromatography-mass spectrometry and their correlation with sensory attributes.[Pubmed:26735711]

J Chromatogr B Analyt Technol Biomed Life Sci. 2016 Jan 15;1009-1010:152-62.

Volatiles of five kinds of Chrysanthemum essential oils with different manufactures were characterized by descriptive sensory analysis, gas chromatography-olfactometry (GC-O), gas chromatography-mass spectrometry (GC-MS) and statistics analysis. Six sensory attributes (floral, woody, grassy, fruity, sour and minty) were selected to assess Chrysanthemum essential oils. A total of 38 volatile compounds were detected and quantified using standard substances by GC-O and GC-MS. Terpenes constituted the largest chemical group among the volatiles of the essential oils. Then partial least squares regression (PLSR) was used to elucidate the relationship between sensory attributes and aroma compounds. The result showed that alpha-pinene, beta-thujene, alpha-terpinolen, beta-cubebene, caryophyllene, (Z)beta-farnesene, (-)-spathulenol, linalool, camphor, camphene, 4-terpineol, Z-citral and 4-Isopropyltoluene were typical aroma compounds covaried with characteristic aroma of Chrysanthemum essential oils.

Catalytic transfer hydrogenation and anticancer activity of arene-ruthenium compounds incorporating bi-dentate precursors.[Pubmed:26287471]

Dalton Trans. 2015 Sep 28;44(36):16107-18.

Ruthenium based organometallic compounds are presently a subject of great attention as anticancer drugs and appear to work reasonably well on tumor cells. We develop a series of mononuclear arene-ruthenium compounds incorporating N,O and N,N bidentate ligands, and their activity as anticancer drugs against human hormone-refractory metastatic prostate cancer (HRMPCs) cell lines are investigated. The ruthenium compounds also act as effective catalysts in the transfer hydrogenation of the -C[double bond, length as m-dash]O- --> -CH(OH)- system. Three types of ligands, namely, sodium glutamate, C4H3NH(2-CH2NH(t)Bu), and C4H3NH(2-CH[double bond, length as m-dash]NR) are separately coupled with [(eta(6)-cymene)RuCl2]2 () (cymene = 4-Isopropyltoluene) to synthesize five Ru-derivatives: [(eta(6)-cymene)RuCl(kappa(2)-N,O-OOCCHNH2CH2CH2COOH)] (), {(eta(6)-cymene)RuCl[C4H3N(2-CH2NH(t)Bu)]} (), {(eta(6)-cymene)RuCl[C4H3N(2-CH[double bond, length as m-dash]NCH2Ph)]} (), {(eta(6)-cymene)RuCl{C4H3N[2-CH[double bond, length as m-dash]NCH2(C4H7O)]}} () and {(eta(6)-cymene)RuCl[C4H3N(2-CH(n)BuNHCH2(C4H7O))]} (). To the best of our knowledge, the aforementioned Ru compounds are not only characterized by (1)H and (13)C NMR spectroscopy, but for the first time their structures have been established by single crystal X-ray diffractometry. Compound influences a concentration-dependent apoptosis in PC-3 cells and initiates the conversion rate in transfer hydrogenation.

Anaerobic activation of p-cymene in denitrifying betaproteobacteria: methyl group hydroxylation versus addition to fumarate.[Pubmed:25261521]

Appl Environ Microbiol. 2014 Dec;80(24):7592-603.

The betaproteobacteria "Aromatoleum aromaticum" pCyN1 and "Thauera" sp. strain pCyN2 anaerobically degrade the plant-derived aromatic hydrocarbon p-cymene (4-Isopropyltoluene) under nitrate-reducing conditions. Metabolite analysis of p-cymene-adapted "A. aromaticum" pCyN1 cells demonstrated the specific formation of 4-isopropylbenzyl alcohol and 4-isopropylbenzaldehyde, whereas with "Thauera" sp. pCyN2, exclusively 4-isopropylbenzylsuccinate and tentatively identified (4-isopropylphenyl)itaconate were observed. 4-Isopropylbenzoate in contrast was detected with both strains. Proteogenomic investigation of p-cymene- versus succinate-adapted cells of the two strains revealed distinct protein profiles agreeing with the different metabolites formed from p-cymene. "A. aromaticum" pCyN1 specifically produced (i) a putative p-cymene dehydrogenase (CmdABC) expected to hydroxylate the benzylic methyl group of p-cymene, (ii) two dehydrogenases putatively oxidizing 4-isopropylbenzyl alcohol (Iod) and 4-isopropylbenzaldehyde (Iad), and (iii) the putative 4-isopropylbenzoate-coenzyme A (CoA) ligase (Ibl). The p-cymene-specific protein profile of "Thauera" sp. pCyN2, on the other hand, encompassed proteins homologous to subunits of toluene-activating benzylsuccinate synthase (termed [4-isopropylbenzyl]succinate synthase IbsABCDEF; identified subunits, IbsAE) and protein homologs of the benzylsuccinate beta-oxidation (Bbs) pathway (termed BisABCDEFGH; all identified except for BisEF). This study reveals that two related denitrifying bacteria employ fundamentally different peripheral degradation routes for one and the same substrate, p-cymene, with the two pathways apparently converging at the level of 4-isopropylbenzoyl-CoA.

Coordination chemistry of 2,6-dixylyl-4-phenylphosphabarrelene with selected transition metals.[Pubmed:19274295]

Dalton Trans. 2009 Mar 28;(12):2170-7.

The 2,6-dixylyl-4-phenylphosphabarrelene has been synthesised from the parent phosphinine and its properties as a ligand explored through the preparation and characterisation of the complexes W(CO)(5)(L), Re(CO)(4)(L)Cl, (eta(6)-cymene)RuCl(2)(L), [(eta(5)-Me(3)SiC(5)H(4))Fe(CO)(2)(L)]PF(6), Rh(1,5-COD)(L)Cl, Ir(1,5-COD)(L)Cl, and cis-Pt(L)(2)Cl(2), where L = 4-phenyl-2,10-bis-(2,4-dimethylphenyl)-4H-1,4-ethenophospholine ((x)PB), cymene = 4-Isopropyltoluene, eta(5)-Me(3)SiC(5)H(4) = trimethylsilylcyclopentadienyl and 1,5-COD = 1,5-cyclooctadiene. The new complexes were characterised by spectroscopic and analytical techniques and, for [(eta(5)-Me(3)SiC(5)H(4))Fe(CO)(2)(L)]PF(6) and Ru(eta(6)-cymene)(L)Cl(2), by single-crystal X-ray structure determination. The coordination properties of the phosphabarrelene have been established and compared with analogous complexes of triarylphosphines and triarylphosphites. Most spectroscopic and structural indicators suggest that the phosphabarrelene has coordination behaviour similar to that of simple triarylphosphines such as PPh(3).

Diffusion and NOE NMR studies on the interactions of neutral amino-acidate arene ruthenium(II) supramolecular aggregates with ions and ion pairs.[Pubmed:18853476]

Magn Reson Chem. 2008;46 Suppl 1:S72-9.

The interaction between [RuCl(AA)(cymene)]n supramolecular aggregates (1, AA = alpha-amino-acidate = alpha-aminoisobutyrate; 2, AA = N,N-dimethyl-Gly; 3, AA = Ala; 4, AA = Pro; cymene = 4-Isopropyltoluene) and ionic species derived from NBu4PF6 and KPF6 is investigated through diffusion NMR measurements and 19F,1H-hetero-nuclear Overhauser effect spectroscopy experiments in CDCl3 and CD2Cl2. Aggregates containing the -NH2 functionality (1 and 3) interact strongly with NBu4PF6 as demonstrated by the observation of intense nuclear Overhauser effects between the fluorine atoms of PF6(-) and the protons of [RuCl(AA)(cymene)]n. Unexpectedly, diffusion NMR measurements indicate that the average size of the aggregates increases when a small amount of NBu4PF6 is added (Csalt/CRu < 0.1) in CD2Cl2. At higher concentration levels of NBu4PF6 or in CDCl3, NBu4PF6 exerts a destructive effect that reduces the average size of the aggregates. [RuCl(AA)(cymene)]n aggregates with NR-H (4) and NR2 (2) functionalities are little affected by the addition of NBu4PF6. KPF6 also interacts with [RuCl(AA)(cymene)]n aggregates as demonstrated by the fact that it becomes noticeably soluble in CDCl3 and CD2Cl2. Diffusion1H-NMR experiments show that the addition of KPF6 does not markedly alter the average size of [RuCl(AA)(cymene)]n supramolecular aggregates. Interestingly, the average size of PF6(-)-containing supramolecular aggregates is, in some cases, slightly higher than that of the ones that do not contain PF6(-). This was deduced by independent measurements of the hydrodynamic volume of the anion and of the ruthenium complexes by diffusion 19F- and 1H-NMR experiments, respectively.

Molecule-bridged mixed-valent intermediates involving the Ru I oxidation state.[Pubmed:15535680]

J Am Chem Soc. 2004 Nov 17;126(45):14706-7.

The diruthenium(II) complexes {(mu-L)[RuCl(Cym)]2}(PF6)n, Cym = p-cymene = 4-Isopropyltoluene, L = 2,2'-azobispyridine = abpy and n = 1, or L = 2,5-bis(1-phenyliminoethyl)pyrazine = bpip and n = 2, were synthesized and characterized by NMR (n = 2) or EPR spectroscopy (n = 1). Whereas the (n = 1) species are ligand radical-bridged RuIIRuII complexes, the three-electron reduction under loss of both chloride ions produces the ions {(mu-L)[Ru(Cym)]2}+, which could be identified as RuI(4d7)-containing mixed-valent species (Ru0RuI or RuIRuII) through UV-vis-NIR spectroelectrochemistry (intervalence charge-transfer bands around 1500 nm) and EPR (rhombic g tensor anisotropy). The weak metal-metal interaction of the dsigma electrons from the eg set is responsible for the small electrochemical coupling with comproportionation constants Kc approximately 102.

Metal-induced B-H activation: addition of acetylene, propyne, or 3-methoxypropyne to Rh(Cp*), Ir(Cp*), Ru(p-cymene), and Os(p-cymene) half-sandwich complexes containing a chelating 1,2-dicarba-closo-dodecaborane-1,2-dichalcogenolato ligand.[Pubmed:11843151]

Chemistry. 2002 Jan 18;8(2):388-95.

The addition reactions of the 16e half-sandwich complexes [M(eta5-Cp*)[E2C2(B10H10)]] (Cp*=pentamethylcyclopentadienyl: 1S: E=S, M=Rh; 2S: E=S; M=Ir; 2Se: E=Se, M=Ir) and [M(eta6-p-cymene)[S2C2(B10H10)]] (p-cymene=4-Isopropyltoluene; 3S: M=Ru; 4S: M=Os), with acetylene, propyne, and 3-methoxypropyne lead to the 18e complexes 5-19 with a metal-boron bond in each case. The reactions start with an insertion of the alkyne into one of the metal-chalcogen bonds, followed by B-H activation, transfer of one hydrogen atom from the carborane via the metal to the terminal carbon of the alkyne, and concomitant ortho-metalation of the carborane. The E-eta2-CC and the C(1)B units are arranged either cisoid or transoid at the metal. X-ray structural analyses are reported for one of the starting 16e complexes (4S), the cisoid complex 12S (from 2S and HC[triple bond]C-CH3), and the transoid complexes 9S and 14S (from 1S and HC[triple bond]C-CH2OMe, and from 3S and HC[triple bond]CH, respectively). All new complexes 5-19 were characterized by NMR spectroscopy (1H, 11B, 13C, and 77Se and 103Rh NMR spectroscopy when appropriate).

Occurrence of organic pollutants in recovered soil fines from construction and demolition waste.[Pubmed:11699628]

Waste Manag. 2001;21(8):703-15.

The objective of this study was to characterize recovered soil fines from construction and demolition (C&D) waste recycling facilities for trace organic pollutants. Over a period of 18 months, five sampling trips were made to 14 C&D waste recycling facilities in Florida. Screened soil fines were collected from older stockpiles and newly generated piles at the sites. The samples were analyzed for the total concentration (mg/kg) of a series of volatile organic compound (VOCs) and semi-volatile organic compounds (semi-VOCs). The synthetic precipitation leaching procedure (SPLP) test was also performed to evaluate the leachability of the trace organic chemicals. During the total analysis only a few volatile organic compounds were commonly found in the samples (trichlorofluoromethane, toluene, 4-Isopropyltoluene, trimethylbenzene, xylenes, and methylene chloride). A total of nine VOCs were detected in the leaching test. Toluene showed the highest leachability among the compounds (61.3-92.0%), while trichlorofluoromethane, the most commonly detected compound from both the total and leaching tests, resulted in the lowest leachability (1.4-39.9%). For the semi-VOC analysis, three base-neutral semi-VOC compounds (bis(2-ethylhexyl)phthalate, butyl benzyl phthalate, and di-n-butyl phthalate) and several PAHs (acenaphthene, pyrene, fluoranthene, and phenanthrene) were commonly detected in C&D fines samples. These compounds also leached during the SPLP leaching test (0.1-25%). No acid extractable compounds, pesticides, or PCBs were detected. The results of this study were further investigated to assess risk from land applied recovered soil fines by comparing total and leaching concentrations of recovered soil fines samples to risk-based standards. The results of this indicate that the organic chemicals in recovered soil fines from C&D debris recycling facilities were not of a major concern in terms of human risk and leaching risk to groundwater under reuse and contact scenarios.

Synthesis of Heterobimetallic Fe-M (M = Ni, Pd, Pt) Complexes Containing the 1,1'-Ferrocenedithiolato Ligand and Their Conversion to Trinuclear Complexes.[Pubmed:11670762]

Inorg Chem. 1998 Dec 14;37(25):6428-6434.

The reaction of [NiCl(2)(PMe(2)Ph)(2)] with fc(SH)(2) (fcS(2) = 1,1'-ferrocenedithiolato) afforded the Ni-Fe heterobimetallic complex containing an Fe-->Ni dative bond [Ni(S(2)fc)(PMe(2)Ph)] (1) with concurrent liberation of one of the PMe(2)Ph ligands. In contrast, similar treatment of [MCl(2)(dppe)] (M = Ni, Pd, Pt; dppe = Ph(2)PCH(2)CH(2)PPh(2)) gave a series of group 10 metal-ferrocenedithiolato complexes [M(S(2)fc)(dppe)] (2) which do not contain such a dative bond. Furthermore, oxidation of complexes 2 with 1 equiv of [(eta(5)-C(5)H(5))(2)Fe][PF(6)] resulted in the formation of 1,1'-ferrocenedithiolato-bridged complexes [{M(dppe)}(2)(&mgr;-S(2)fc)][PF(6)](2) (3) along with poly(1,1'-ferrocenylene disulfide). Complexes 2 were also converted into the Fe-Ru-M heterotrimetallic complexes [(p-cymene)RuCl(&mgr;-S(2)fc)M(dppe)][PF(6)] (4; p-cymene = 4-Isopropyltoluene) by the reaction of 2 with [(p-cymene)RuCl(2)](2) and NH(4)PF(6) in acetonitrile. The detailed structures of 1, [Ni(S(2)fc)(dppe)] (2a), [Pd(S(2)fc)(dppe)] (2b), [{Ni(dppe)}(2)(&mgr;-S(2)fc)][PF(6)](2) (3a), and [(p-cymene)RuCl(&mgr;-S(2)fc)Ni(dppe)][PF(6)] (4a) have been determined by X-ray crystallography.

Metal-induced B-H activation: addition of methyl acetylene carboxylates to Cp*Rh-, Cp*Ir-, (p-cymene)Ru-, and (p-cymene)Os half-sandwich complexes containing the chelating 1,2-dicarba-closo-dodecaborane-1,2-dithiolate ligand[Pubmed:10993263]

Chemistry. 2000 Aug 18;6(16):3026-32.

The reactions of the 16e half-sandwich complexes [Cp*M[S2C2(B10)H10)]] (1: M=Rh; 2: M = Ir) and [eta6-(4-Isopropyltoluene)M[S2C2(B10H10)] (3: M=Ru; 4: M=Os) with both methyl acetylene monocarboxylate and dimethyl acetylene dicarboxylate were studied in order to obtain more evidence for B-H activation, ortho-metalation, and B(3,6)-substitution of the carborane cluster. In the case of rhodium, the reaction of 1 with methyl acetylene monocarboxylate led to new complexes after twofold insertion into one of the Rh-S bonds (7), and twofold insertion together with B-substitution at the carborane cage (8). In the case of iridium, the reactions of 2 with methyl acetylene monocarboxylate gave two geometrical isomers 10 and 11, in which the alkyne is inserted into one of the Ir-S bonds, followed by hydrogen transfer from the carborane via the metal to the former alkyne and formation of an Ir-B bond. Only one type each (12 and 13) of these isomers was obtained from the reactions of the ruthenium and osmium half-sandwich complexes 3 and 4. The 16e starting materials 1-4 reacted with dimethyl acetylene dicarboxylate at room temperature to give the complexes 14-17, respectively, which are formed by addition of the C=C bond to the metal center and insertion into one of the metal-sulfur bonds. The proposed structures in solution were deduced from NMR data (1H, 11B, 13C, 103Rh NMR), and X-ray structural analyses were carried out for the rhodium complexes 7 and 8.