Abstract  Highly stereoselective and rapid (<1 min) addition reactions to the imine double bond of 2-(methylimino)acetate complexes [L(4)Co(O(2)CCH=NCH(3))](2+) [L(4) = (en)(2) (7), (tren) (11)] were achieved in aqueous solution with nitromethane, ethyl 3-oxobutanoate or diethyl malonate. The molecular structures of two product complexes, rac-(Δ*-R(C)*-S(N)*)-[Co(en)(2)(O(2)CCH[CH(2)NO(2)]NHCH(3))]ZnCl(4) and rac-(Δ*-R(C)*-S(N)*)-[Co(en)(2)(O(2)CCH[CH(2)COCH(3)]NHCH(3))]ZnCl(4), were established by X-ray diffraction.

Abstract  1. Exogenous glycollate was rapidly metabolized in both the light and the dark by photoautotrophically grown Chlorella pyrenoidosa. 2. The incorporation of (14)C from [1-(14)C]glycollate by these cells was inhibited by the tricarboxylic acid-cycle inhibitors monofluoroacetate, diethylmalonate and arsenite, and also by alpha-hydroxypyrid-2-ylmethanesulphonate and isonicotinylhydrazine. 3. Short-term kinetic experiments showed over 80% of the total (14)C present in the soluble fraction from the cells to be in glycine and serine after 10s. This percentage decreased with time whereas the percentage radioactivity in glycerate increased for up to 30s then remained steady. The percentage of the total radioactivity present in citrate increased over the experimental period. Malate was the only other tricarboxylic acid-cycle intermediate to become labelled. 4. The kinetic and inhibitor experiments supported the following pathway of glycollate incorporation: glycollate --> glyoxylate --> glycine --> serine --> hydroxypyruvate --> glycerate --> 3-phosphoglycerate --> 2-phosphoglycerate --> phosphoenolpyruvate --> pyruvate --> acetyl-CoA. 5. The specific activities of the enzymes catalysing this metabolic sequence in cell-free extracts were great enough to account for the observed rate of glycollate metabolism of 0.25mumol/h per mg dry wt. of cells in the light.

Abstract  Regioselective nucleophilic addition of bisnucleophiles 1,2-benzenediamine, 2-amino-benzenethiol, and N-phenyl-1,2-benzenediamine to 1,3-diphenylbenzo[e][1,2,4]triazin-7(1H)-one (1) at C6 followed by intramolecular cyclocondensation at the C7 carbonyl afforded highly coloured tetracenes 1,3-diphenyl-1,6-dihydro-[1,2,4]triazino[5,6-b]phenazin-4-ium 4-methylbenzenesulfonate (12), 1,3-diphenyl-1H-[1,2,4]triazino[6,5-b]phenothiazine (14) and 1,3,11-triphenyl-1,6-dihydro-[1,2,4]triazino[5,6-b]phenazin-11-ium 4-methylbenzenesulfonate (15), respectively. Neutralization of the latter with alkali gave the free base 1,3,11-triphenyl-1H-[1,2,4]triazino[5,6-b]phenazin-11-ium-6-ide (16). Furthermore, the benzotriazinone 1 reacts with dimethyl malonate to give 6-(methoxycarbonyl)-7-oxo-1,3-diphenyl-7H-benzofuro[5,6-e][1,2,4]triazin-1-ium-4-ide (17) in 74% yield, while with S(4)N(4) [5,6-c]-thiadiazolo-7-oxo-1,3-diphenyl-1,2,4-benzotriazine (22) was formed in 15% yield. The free bases 16 and 17 display negative solvatochromism, which supports charge separated ground states similar to those of zwitterionic biscyanines, and DFT calculations at the UB3LYP/6-31G(d) level afford ΔE(ST) values of -13.6 and -18.7 kcal mol(-1), respectively that strongly favour the singlet ground state. All ring systems described are new and fully characterized.

Abstract  The measurement of matrix metalloproteinase (MMP) activity in diseases like inflammation, oncogenesis, or atherosclerosis in vivo is highly desirable. Fine-tuned pyrimidine-2,4,6-triones (barbiturates) offer nonpeptidyl lead structures for developing imaging agents for specifically visualization of activated MMPs in vivo. The aim of this study was to modify a C-5-disubstituted barbiturate and thus design a highly affine, nonpeptidic, optical MMP inhibitor (MMPI)-ligand for imaging of activated MMPs in vivo. A convergent 10 step synthesis was developed, starting with a malonic ester and (4-bromophenoxy)benzene to generate 5-bromo-pyrimidine-2,4,6-trione as the key intermediate. To minimize the interactions between activated MMPs and the dye of the conjugate 6, a PEGylated piperazine derivative was used as a spacer and an azide as a protected amino function. After linking both building blocks, reducing the azide ( Staudinger reaction) and labeling with Cy 5.5, we obtained the nonhydroxamate MMP inhibitor 6 with high affinity (IC 50-value: 48 nM for MMP-2) measured in a fluorogenic assay using commercially available MMP-substrates and the purified enzyme. Zymography revealed an efficient blocking of enzyme activity of purified MMP-2 and MMP-9 and of MMP-containing cell supernatants (HT-1080), (A-673) using the PEGylated barbiturate 5. Fluorescence microscopy studies using a highly (A-673) and a moderate (HT-1080) MMP-2 secreting cell line showed efficient binding of the Cy 5.5 labeled tracer 6 to the MMP-2 positive cells while MMP-2 negative cells (MCF-7) did not bind. Therefore, this new barbiturate-based MMP-probe has a high affinity and specificity toward MMP-2 and -9 and is thus a promising candidate for sensitive MMP detection in vivo.

Abstract  The chemistry of chiral ligands for transition metal-catalyzed asymmetric reactions is an interesting research field in synthetic chemistry and has recently been the focus of much attention. Although a number of chiral ligands containing phosphorus (P) and arsenic (As) have been widely studied and are well documented, asymmetric reactions with optically active organoantimony compounds have not been reported so far. We are interested in the synthesis and utilization of optically active organoantimony compounds for asymmetric synthesis. We present here the synthesis and resolution of Sb-chiral and C2-symmetric compounds containing antimony as well as their physical and chemical properties. Resolution of (+/-)-1-phenyl-2-trimetylsilylstibindole (1), Sb (R/S)-(aryl) [2-(S)-(1-dimethylaminoethyl) phenyl] (p-tolyl) stibane (9), and (+/-)-2,2'-bis(diarylstibano)-1,1'-binaphthyl (13) can be achieved by the separation of a mixture of the diastereomeric antimony-palladium complexes. The optically pure Sb-chiral stibanes (1, 9) isolated here were optically stable, and no racemization on the chiral antimony center was observed even when they were heated under a neutral or a basic condition. Single-crystal X-ray analysis of Sb-chiral triarylstibane 9b-B revealed the presence of an intramolecular interaction between the antimony and nitrogen atoms. The optically active BINASb (13) can be used as powerful chiral ligand for the palladium-catalyzed asymmetric allylic alkylation of racemic 1,3-diphenyl-2-propen-1-yl acetate with dimethyl malonate. We also report the synthesis, molecular structure, and fluxional behavior of the (R)-(-)-7-p-tolyl-dinaphtho [2, 1-b; 1',2'-d] stibole (21c) which is the first isolated example of optically active C2-symmetric group 15 dinaphthoheteroles.

Abstract  The production and use pattern of Diethylmalonate (DEM) and Dimethylmalonate (DMM) are comparable. The two chemicals have very similar physico-chemical properties and both esters are hydrolyzed via a two step reaction to malonic acid and the corresponding alcohol, methanol or ethanol. It is likely that unspecific esterases in the body catalyze the hydrolysis. The alcohols and malonic acid are physiological substances that are metabolized via physiological pathways. Ethanol (CAS No. 64-17-5) and methanol (CAS No. 67-56-1) were assessed at SIAM 19. For ethanol it was concluded that the chemical is currently of low priority for further work, because the hazardous properties of ethanol are manifest only at doses associated with consumption of alcoholic beverages. As it is impossible to reach these exposure levels as a consequence of the manufacture and use of malonates, it can be expected that malonic acid will be the metabolite that determines the toxicity of DEM. For methanol, SIAM 19 decided that this chemical is a candidate for further work. Methanol exhibits potential hazardous properties for human health (neurological effects, CNS depression, ocular effects, reproductive and developmental effects, and other organ toxicity). The effects of methanol on the CNS and retina in humans only occur at doses at which formate accumulates due to a rate-limiting conversion to carbon dioxide. In primates, formate accumulation was observed at methanol doses greater than 500 mg/kg bw (which would require a DMM dose of more than 1000 mg/kg bw). As there were no indications of a methanol associated toxicity from a well performed repeated dose toxicity study with DMM in rodents (which are, however, known to be less sensitive to methanol toxicity than humans), and because methanol toxicity would not be expected up to doses as high as 1000 mg DMM/kg bw/day, it was concluded that methanol does not make a relevant contribution to the toxicity profile of DMM. A possible mode of action for systemic toxicity of DMM and DEM can only be deduced from the repeated dose study with DMM, indicating a reversible liver hypertrophy at the cellular level at high doses of 1000 mg/kg bw/day. This effect can be an indication of an induction of metabolism in the liver rather than a clear systemic toxicity.

Abstract  Nine alpha-dibutylaminomethylbenzo[h]quinoline-4-methanols were synthesized from the corresponding 1-amino-naphthalenes by the following sequence: 1-aminonaphthalene leads to 1H-benz[g]indole-2,3-dione leads to benzo[h]quinoline-4-carboxylic acid leads to acid chloride leads to bromomethyl ketone leads to epoxide leads to benzo[h]quinoline-4-methanol. Several acid chlorides substituted in the 3 position reacted incompletely with ethereal diazomethane but were efficiently converted, without isolation of the intermediates, to the bromomethyl ketones by reaction with ethoxymagnesium diethylmalonate, bromination, hydrolysis, and decarboxylation. Several compounds prepared, especially alpha-dibutylaminomethyl-2-(2',4'-dimethylphenyl)-3-methyl-6-chlorobenzo[h]quinoline-4-methanol, showed significant antimalarial activity against Plasmodium berghei in infected mice but were moderately phototoxic.

Abstract  Fullerenes could potentially play a valuable role in radioimmunotherapy by more stably encapsulating radionuclides, especially where conventional chelation chemistry is inadequate due to the physical and/or chemical properties of the radionuclide. One of the therapeutically useful radionuclides that requires improved containment in vivo is Pb-212 (tau(1/2) = 10.6 h), the beta-emitting parent to alpha-emitting Bi-212 (tau(1/2) = 60.6 min). Myelotoxicity resulting from the accumulation of Pb-212 in the bone marrow has limited the use of this radionuclide despite its favorable decay characteristics. In this work, Pb-212@C-60 and its malonic ester derivatives were prepared for the first time by allowing the Pb-212 to recoil into C-60 following alpha-decay from its parent, 0.15-s Po-216, generated in situ from the decay of Ra-224 (tau(1/2) = 15 days). Repeated washing of the organic phase containing the Pb-212@C-60 malonic esters with challenge solutions containing cold Pb2+ ions demonstrated that some of the Pb-212 could not be exchanged and was apparently inside of the fullerenes. Malonic esters of endohedral alpha-emitting Bi-213 (tau(1/2) = 45 min) fullerenes were prepared by an analogous procedure. Following acidification of the esters, a preliminary biodistribution study in mice was performed with the untargeted water-soluble radiofullerenes. It was found that Pb-212 did not accumulate in bone after being administered as an endohedral fullerene, in contrast to results with polyhydroxylated radiofullerenes and conventional polyaminocarboxylate chelators for Pb-212. The results indicate that Pb-212 is held more tightly in the fullerene than in other methods and suggest that fullerenes may have an important role in the targeted delivery of Pb-212.

Abstract  We describe a brass light pipe (LP) mounted in a cylindrical optical accessory for attenuated total reflection (ATR) that can be used to readily obtain the infrared spectra of liquids and monolayers. As examples, we show the LP spectra of isooctane, decane, dimethyl malonate, dodecanol, dodecanethiol, and acetic acid and compare them to those obtained by transmission as well as by ATR. In addition, we utilize a dodecanethiol monolayer spectrum to illustrate the sensitivity of the LP scheme.

Abstract    Ethyl 4-bromo (and chloro)-3-oxobutanoate (1 and 2) reacts with diethyl malonate in the presence of sodium hydride to give diethyl 5-ethoxycarbonyl-3-oxohexanedioate (3) and diethyl 5-carboxy-3-oxohexanedioate (4). Similarly, reaction of the haloester (1, 2) with methyl cyanoacetate gives 1-ethyl methyl 5-cyano-3-oxohexanedioate (6) and 1-ethyl hydrogen 5-cyano-3-oxohexanedioate (7). On the other hand, 1 reacts with malononitrile in the presence of triethylamine to give ethyl 5-amino-4-cyanofuran-2-acetate (8) and ethyl 3-amino-2, 4, 4-tricyano-2-cyclopenten-1-ylideneacetate (9).

Abstract  The biosynthesis of 5-hydroxy-4-oxo-L-norvaline (HON) in Streptomyces akiyoshiensis has been investigated using super(13)C-labelled substrates. Incorporations of super(13)C label from sodium [1- super(13)C]-, [2- super(13)C]-, and [1,2- super(13)C sub(2)]acetate indicated that HON was formed from a four-carbon compound derived from the citric acid cycle and the methyl carbon of acetate. Feeding experiments using DL-[4- super(13)C]- and DL-[2- super(13)C, super(15)N]aspartate demonstrated that aspartate served as the four-carbon precursor to HON. Both enantiomers of aspartate were metabolized by S. akiyoshiensis, but the D isomer was consumed at a slower rate. The distribution of super(13)C label in the intracellular L-glutamic acid isolated in these feeding experiments is consistent with the operation of the citric acid cycle in S. akiyoshiensis. A biosynthetic hypothesis that involves a condensation reaction between acetyl or malonyl CoA and the beta -carboxyl group of aspartate, and subsequent oxidative decarboxylation, is proposed to account for the incorporation results. An analogous condensation step has been proposed for the biosynthesis of other natural products, including the carbapenem antibiotics. DL-[2- super(13)C, super(15)N]Aspartate was synthesized from [2- super(13)C]diethylmalonate and potassium [ super(15)N]phthalimide via diethyl [2- super(13)C, super(15)N]phthalimidomalonate.

Abstract    Veratraldehyde was condensed with methyl 2-chloropropanoate to give a glycidic ester. This was hydrolyzed with aqueous sodium hydroxide and the resulting sodium salt was treated with lead(IV) tetraacetate to give 1-acetoxy-1-(3, 4-dimethoxyphenyl)propan-2-one (13). Condensation of 13 with dimethyl malonate, followed by acidic hydrolysis and sodium borohydride reduction afforded (2R*, 3S*, 4R*)-4-(3, 4-dimethoxyphenyl)-2-methoxycarbonyl-3-methyl-4-butanolide (7a). The γ-lactone 7a was then converted into 5'-demethoxyporosin (10) by means of a series of reactions : Michael reaction with methyl vinyl ketone, elimination of the methoxycarbonyl group, acetalization, allylation, deacetalization, and intramolecular aldol reaction. Introduction of a hydroxyl group at the C-5' position in 10, followed by methylation with diazomethane afforded racemic porosin. The synthetic porosin was further converted into 5-demethoxymegaphone acetate.

Abstract  We have carried out a detailed examination of L-glutamine metabolism in rat islets in order to elucidate the paradoxical failure of L-glutamine to stimulate insulin secretion. L-Glutamine was converted by isolated islets into GABA (gamma-aminobutyric acid), L-aspartate and L-glutamate. Saturation of the intracellular concentrations of all of these amino acids occurred at approx. 10 mmol/l L-glutamine, and their half-maximal values were attained at progressively increasing concentrations of L-glutamine (0.3 mmol/l for GABA; 0.5 and 1.0 mmol/l for Asp and Glu respectively). GABA accumulation accounted for most of the 14CO2 produced at various L-[U-14C]glutamine concentrations. Potentiation by L-glutamine of L-leucine-induced insulin secretion in perifused islets was suppressed by malonic acid dimethyl ester, was accompanied by a significant decrease in islet GABA accumulation, and was not modified in the presence of GABA receptor antagonists [50 micromol/l saclofen or 10 micromol/l (+)-bicuculline]. L-Leucine activated islet glutamate dehydrogenase activity, but had no effect on either glutamate decarboxylase or GABA transaminase activity, in islet homogenates. We conclude that (i) L-glutamine is metabolized preferentially to GABA and L-aspartate, which accumulate in islets, thus preventing its complete oxidation in the Krebs cycle, which accounts for its failure to stimulate insulin secretion; (ii) potentiation by L-glutamine of L-leucine-induced insulin secretion involves increased metabolism of L-glutamate and GABA via the Krebs cycle (glutamate dehydrogenase activation) and the GABA shunt (2-oxoglutarate availability for GABA transaminase) respectively, and (iii) islet release of GABA does not seem to play an important role in the modulation of the islet secretory response to the combination of L-leucine and L-glutamine.

Abstract  This paper describes the synthesis of 5-fluoro-D/L-dopa and the corresponding [F-18]5-fluoro-L-dopa starting from 5-nitrovanillin via malonic ester synthesis, the Balz-Schiemann reaction and the separation of the racemic mixture [F-18]5-fluoro-D/L-dopa with a chiral HPLC system. The inactive 5-fluoro-D/L-dopa was obtained in an eight-step synthesis with an overall yield of 10%. For a reliable synthesis, the nitro group was reduced with hydrazine hydrate and ruthenium on charcoal.

Abstract  The synthesis of C-14-2-amino-9-(3-hydroxymethyl-4-isopropoxycarbonyloxy-but-1-yl)purine from [1-C-14] diethyl malonate is described. The overall radiochemical yield of the product in a nine-step sequence was 16.1%, and the compound's radiochemical purity was 98.5%.

Abstract  Furan ring opening with benzohydroxamic acid of methyl 9,12-epoxy-9,11-octadecadienoate gave a mixture of positional isomers of conjugated methyl 3-phenyl-1,4,2-dioxazolyl C18-enone esters 6a,6b. Michael addition of diethyl malonate anion to the conjugated enone system of 6a,6b furnished the corresponding malonyl intermediates 7a,7b, which upon removal of the dioxazole ring by hydrolysis gave methyl 10- and 11-dicarbethoxymethyl-9,12-dioxooctadecanoate 8a,8b. Cyclization of the latter gave the trisubstituted C18 furanoid fatty esters 9a,9b, containing the malonate ester function at the 3-/4-position of the furan ring. Base hydrolysis of compounds 9a,9b gave the corresponding tricarboxylic acid derivatives 10a,10b, which were esterified to the trimethyl esters 11a,11b in BF3/MeOH. When a mixture of 9a,9b was refluxed with Na2CO3/MeOH, hydrolysis of the malonate ester function was followed by decarboxylation to yield a -CH2COOH substituent at the 3-/4-position of the furan ring (12a,12b). Esterification of the latter with BF3/MeOH gave the corresponding methyl diester derivatives 13a,13b. When a mixture of tricarboxylic acids 10a,l0b was heated at 160-180-degrees-C for 6 hr, exhaustive decarboxylation of malonic acid function furnished a methyl group at the 3-/4-position of the furan nucleus. Esterification of the decarboxylated product gave a mixture of trisubstituted furanoid compounds 14a,14b (overall yield 28%). The procedure constitutes a novel method for the introduction of a methyl group via a malonic acid group to the 3-/4-position of the furan ring of a 2,5-disubstituted C18 furanoid fatty ester.

Abstract  A series of new steroid pyrimidines (7-9) were synthesized by reacting steroidal thiosemicarbazones (46) with diethyl malonate. The new compounds were characterized by IR, H-1 NMR, C-13 NMR, MS and analytical data. The interaction studies of compounds (7-9) with DNA were carried out by employing gel electrophoresis, UV-vis and fluorescence spectroscopy. The acting force between the compounds (7-9) and DNA was mainly hydrophobic while the other interactions like van der Waals, hydrogen bonding cannot be ruled out. The gel electrophoresis pattern also demonstrated that the compound 7 alone or in presence of Cu (II) causes the nicking of supercoiled pBR322 and it seems to follow the mechanistic pathway involving generation of hydroxyl radicals that are responsible for initiating DNA strand scission. The docking study of compounds (7-9) suggested that the intercalation of compounds in between the nucleotide base pairs might be due to the presence of pyrimidine moiety in steroid molecule. MTT assay was carried out to check the toxicity of new compounds (7-9) against the different human cancer as well as non-cancer cell lines A545, MCF-7, HeLa, HL-60, SW480, HepG2, HT-29, A549, 184B5, MCF10A, NL-20, HPC and HPLF. Apoptotic degradation of DNA in presence of steroidal pyrimidines (7-9) was analyzed by agarose gel electrophoresis and visualized by ethidium bromide staining (comet assay). (C) 2013 Elsevier B.V. All rights reserved.

Abstract  The synthesis and transannular Diels-Alder reactions of trans-trans-trans (TTT) macrocyclic trienes 16 and 26 containing a dimethyl malonate and a monomethyl ester are reported. Compound 16 yields a mixture of two trans-anti-cis (TAC), (27, 73% and 28, 19%) and one cis-anti-trans (CAT) tricycle (29, 8%). Macrocycle 26 gives one TAC (31, 17%) and two CAT tricycles (33, 78% and 34, 5%). These results are explained by considering steric effects in competing chair-boat-chair and chair-boat-boat transition states.

Abstract  The synthesis of two new N- and C-functionalized tetraazamacrocyclic ligands intended to be covalently linked to biomolecules like monoclonal antibodies and to bind the gamma-emitting isotope indium-111 in a thermodynamically and/or kinetically inert way is described. 12-(p-Nitrobenzyl)-l,4,7,10-tetraazacyclotridecane-1,4,7,10-tetraacetic acid (L1) was synthesized by means of bimolecular cyclization with the appropriate malonic acid diethyl ester and triethylenetetraamine, followed by reduction with diborane and alkylation of the cyclic tetraamine with bromoacetic acid. The corresponding triscarboxymethylated ligand L2 was made by statistical alkylation of the tetraamine. Both ligands fulfill the criteria for antibody labeling using the bifunctional chelate approach, namely fast chelate formation, high radiochemical yield, and high stability under physiological conditions. Surprisingly the hepta-dentate ligand L2 confers higher stability to In(3+) and exhibits faster complex formation than octadentate L1. (13)C NMR spectra in solution indicate that the difference in stability is not due to incomplete coordination of all four carboxylate groups in In-L1.

Abstract  Reaction of diethyl phosphorocyanidate (DEPC) with dimethyl malonate (1a) and ethyl cyanoacetate (1b) in the presence of zinc chloride and triethylamine resulted in selective addition of 1a,b to the cyano group of DEPC to give alpha,beta-unsaturated alpha-aminophosphonates (2a,b). In contrast, similar treatment of enolizable methyl acetoacetate (1c) and acetylacetone (1d) with DEPC gave the corresponding enolphosphates (4c,d) as a result of nucleophilic displacement on the phosphorus atom of DEPC. Conversion of the resulting alpha-aminophosphonate (2a) to uracil-6-phosphonates (6a,b) was achieved by treatment with phenyl isocyanate (5a) and isothiocyanate (5b), respectively.

Abstract  Various side-chain modifications of 6- and 7-substituted 1,3-dimethyl-lumazines are described. Wittig reactions with 1,3-dimethyllumazin-6- (13) and 1,3-dimethyllumazin-7-yl-methyltriphenylphosphonium bromide (10) lead to styryl derivates (8, 9, 14) as well as a variety of structural analoges 15 - 27. Compound 10 could be converted by DBU in the stable 1,3-dimethyllumazin-7-yl-triphenylphosphoniumylide (11). 1,3.6-Trimethyl- (1) and 6-benzyl- 1,3-dimethyllumazine (29) have been subject for Claisen-condensations with ethyl oxalate to give 28 and 30. 1,3-Dimethyllumazine-6-carbonylchloride (33) reacted well with the ethoxy-magnesium salt of ethyl malonate, ethyl cyanoacetate, ethyl acetacetate and malononitrile to form elongated side-chains (34 - 37).

Abstract  Study of the regioselectivity of addition of Grignard reagents onto imide ester 7 led to the expected phenyl derivative 12. By contrast, the methyl derivative 15 necessitated the use of a Mannich reaction onto the ketone 4. Finally, reaction of diethyl malonate with ketone 4 exhibited a dehydrogenation leading to a conjugate diester 19 and the expected diester 18.

Abstract  The article presents pioneering research of textile chemiresistors on Evolon and Polyester substrates equipped with graphite electrodes and in-situ polymerized poly(tetrabutylphosphonium 3-sulfopropylacrylate) or poly(tributylhexylphosphonium 3-sulfopropylacrylate) sensitive layers. The DC- and AC-responses to 10 ppm of methanol, nitrogen dioxide, 4-bromoacetophenone, diethylmalonate and yperite were then investigated at laboratory temperature - the reference was "pure" synthetic air. Under these circumstances the DC-responses (S-DC) varied from 0.48 to 1.36 and maximum AC-responses (S-pa) from 8 to 26 deg. It was shown that sensor dynamics depends mainly on molecular weight of the analytes. Moreover, the magnitude of AC-responses correlated both qualitatively and quantitatively with the dipole moments of the analyzed molecules. (C) 2018 Elsevier B.V. All rights reserved.