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PubMed2002

Synthesis of allyl cyanamides and N-cyanoindoles via the palladium-catalyzed three-component coupling reaction.

The palladium-catalyzed three-component coupling reaction (TCCR) of aryl isocyanides, allyl methyl carbonate, and trimethylsilyl azide was conducted in the presence of Pd(2)(dba)(3).CHCl(3) (2.5 mol %) and dppe (1,2-bis(diphenylphosphino)ethane) (10 mol %). Allyl aryl cyanamides with a wide variety of functional groups were obtained in excellent yields. This palladium-catalyzed TCCR was further utilized for the synthesis of N-cyanoindoles. The reaction of 2-alkynylisocyanobenzenes, allyl methyl carbonate, and trimethylsilyl azide in the presence of Pd(2)(dba)(3).CHCl(3) (2.5 mol %) and tri(2-furyl)phosphine (10 mol %) at higher temperatures afforded N-cyanoindoles in good to allowable yields. (eta(3)-Allyl)(eta(3)-cyanamido)palladium complex, an analogue of the bis-pi-allylpalladium complex, is a key intermediate in the TCCR, and a pi-allylpalladium mimic of the Curtius rearrangement is involved to generate the (eta(3)-allyl)(eta(3)-cyanamido)palladium intermediate.

Crystallography, X-Ray↗
PubMed2000

The transduction of the signal for grape bud dormancy breaking induced by hydrogen cyanamide may involve the SNF-like protein kinase GDBRPK.

Alterations in gene expression during early stages of dormancy release in grapevine buds were analyzed to facilitate the identification of gene products that may mediate the signal transduction of a dormancy-release signal, or derepression of meristematic activity. In the present report we describe the identification of GDBRPK, a transcript for an SNF-like protein kinase that is up-regulated upon chemical induction of dormancy release by hydrogen cyanamide (HC). Since SNF and SNF-like protein kinases are known as sensors of stress signals, we hypothesize that GDBRPK may be involved in the perception of a stress signal induced by HC. We also describe a simultaneous and remarkable induction of both PDC and ADH transcripts that was observed shortly after HC application, and was of a transient nature. These data may imply that HC application leads to a transient respiratory stress, which likely results in a temporary increase in the AMP/ATP ratio. Since AMP is known as a stress signal that is sensed by SNF-like kinases, we suggest that the SNF-like GDBRPK could serve as the sensor of this signal.

Alcohol Dehydrogenase↗
PubMed1984

Structural hepatic changes associated with cyanamide treatment: cholangiolar proliferation, fibrosis and cirrhosis.

The authors present the clinical and histological findings in a series of 42 liver biopsies from 39 chronic alcoholics treated with cyanamide as aversion therapy. All biopsies displayed characteristic cytoplasmic inclusions in the liver-cells. Fibrosis and disruption of the parenchymal-connective tissue interface were observed in all cases. According to the severity and extension of fibrosis, three stages could be depicted: Stage I. Periportal activity cholangiolar type (ACT), which is defined by cholangiolar proliferation, fibroblastic activation and inflammatory infiltrate, which together cause a blurred appearance of the parenchymal-connective tissue junction. It is the elementary lesion and was observed alone in 26 biopsies. Stage II. Portal-to-portal linkage. It was observed in 10 biopsies, all of which also showed periportal ACT. Three of these came from patients with two biopsies in which transition from stage I (first biopsy) to stage II (second biopsy) was observed. Stage III. Nodular parenchymal regeneration, associated with changes observed in stage I and II. It was found in six patients. The histological picture resembles the biliary type of cirrhosis. There is a clear-cut correlation between the length of treatment and the stage of the hepatic lesion.

Adult↗
PubMed1983

Specificity of hepatic aldehyde dehydrogenase inhibition by calcium carbimide (calcium cyanamide) in the rat.

Acute, oral administration of 7.0 mg/kg calcium carbimide (calcium cyanamide) to rats, 2 h before sacrifice, produced complete inhibition of hepatic, low-Km (less than 1 microM acetaldehyde) mitochondrial and cytosolic aldehyde dehydrogenase enzymes and significantly inhibited high-Km (approximately 1 mM acetaldehyde) mitochondrial, cytosolic, and microsomal aldehyde dehydrogenase isozymes. Calcium carbimide had no effect on several other hepatic enzyme activities including mitochondrial glutamate dehydrogenase and monoamine oxidase, cytosolic alcohol dehydrogenase, microsomal NADPH-cytochrome c reductase, benzo[a]pyrene hydroxylase and aminopyrine N-demethylase activities, and microsomal cytochrome P-450 content. It is concluded that calcium carbimide is a more specific inhibitor of hepatic aldehyde dehydrogenase enzymes than disulfiram.

Aldehyde Dehydrogenase↗
PubMed1983

Inhibition of hepatic aldehyde dehydrogenases in the rat by calcium carbimide (calcium cyanamide).

Oral administration of 7.0 mg/kg calcium carbimide (calcium cyanamide, CC) to the rat produced differential inhibition of hepatic aldehyde dehydrogenase (ALDH) isozymes, as indicated by the time-course profiles of enzyme activity. The low-Km mitochondrial ALDH was most susceptible to inhibition following CC administration, with complete inhibition occurring at 0.5 h and return to control activity at 96 h. The low-Km cytosolic and high-Km mitochondrial, cytosolic, and microsomal ALDH isozymes were inhibited to a lesser degree and (or) for a shorter duration compared with the mitochondrial low-Km enzyme. The time course of carbimide, the hydrolytic product of CC, was determined in plasma following oral administration of 7.0 mg/kg CC to the rat. The maximum plasma carbimide concentration (102 ng/mL) occurred at 1 h and the apparent elimination half-life in plasma was 1.5 h. Carbimide was not measurable in the liver during the 6.5 h time interval when carbimide was present in the plasma. There were negative, linear correlations between plasma carbimide concentration and hepatic low-Km mitochondrial, low-Km cytosolic, and high-Km microsomal ALDH activities. In vitro studies demonstrated that carbimide, at concentrations obtained in plasma following oral CC administration, produced only 19% inhibition of low-Km mitochondrial ALDH and no inhibition of low-Km cytosolic and high-Km microsomal ALDH isozymes. These data demonstrate that carbimide, itself, is not primarily responsible for hepatic ALDH inhibition in vivo following oral CC administration. It would appear that carbimide must undergo metabolic conversion in vivo to inhibit hepatic ALDH enzymes, which is supported by the observation of no measurable carbimide in the liver when ALDH was maximally inhibited following oral CC administration.

Aldehyde Dehydrogenase↗
PubMed2004

Comparative effect of cyanamide and sodium nitroprusside on indolamine and lipid peroxidation levels in rat brain.

The aim of this study was to compare the effect of cyanamide (CNM) and sodium nitroprusside (SNP) on nitrite (NO2-) and nitrate (NO3-), stable metabolites of nitric oxide (NO), serotonin (5-HT), tryptophan (Trp), and lipid peroxidation (TBARS) levels in rat brain. Twenty-four male Wistar rats (350 g) were used, divided in 3 groups of 8 animals each. Control group I received 0.9 % NaCl, CNM (40 mg/kg) was administered to group II, and SNP (20 microg/kg) to group III; all animals received a single intraperitoneal dose. The animals were sacrificed by decapitation and the brain was homogenized to measure the NO2-, NO3-, 5-HT, and Trp levels by liquid chromatography, and TBARS levels by spectrophotometry. NO2- levels significantly increased (p< 0.01) in the CNM group, while 5-HT and TBARS significantly increased (p = 0.001) both in SNP and CNM groups in relation to the control group. Trp levels presented a slight increase in the CNM group with respect to the control group. The results suggest that free radicals (Nitroxyl and NO) generated by CNM and SNP, respectively, are responsible for oxidative stress induced in brain.

Animals↗
PubMed1993

A comparative study of ethanol absorption in the canine jejunum after pretreatment with cyanamide or pyrazole.

This report describes the retardation of ethanol absorption from the intestinal tract and reduction of portal blood flow by high acetaldehyde concentrations in dogs using a jejunal segment with the vascular supply intact. The cyanamide-pretreatment group (CY), in which an extremely high acetaldehyde concentration developed, in comparison with the control and pyrazole-pretreated (PY) groups, showed a gradual increase of portal blood ethanol, a 25% reduction in the amount of absorbed ethanol, and an 85% smaller absorption rate constant value (Ka). These facts indicate that the presence of a high acetaldehyde concentration in the blood results in a reduction of ethanol absorption and retardation of ethanol reaching the systemic circulation. The rapid reduction of portal blood flow and the lower ethanol level in the portal vein observed in the CY group, in comparison with the other two groups, also indicate that the reduction of ethanol permeability through the absorption site to the blood is an important retarding factor induced by acetaldehyde.

Acetaldehyde↗
PubMed1999

Application of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry to the structure determination of medium and large macrocycles formed by palladium(0)-catalyzed allylation of arenesulfonamides, sulfamide, and cyanamide.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry allowed the direct determination of the extent of macrocyclic and linear oligomer formation in the palladium(0)-catalyzed allylation of highly acidic and non-nucleophilic arenesulfonamides, sulfamide, and cyanamide. Palladium-containing 15-membered-ring macrocyclic compounds gave unusual [M - H](+) ions besides [M + Na](+) and [M + K](+) adducts. Copyright 1999 John Wiley & Sons, Ltd.

Journal Article↗
PubMed2002

The reactivity of [PhP(Se)(mu-Se)]2 and (PhP)3Se2 towards acetylenes and cyanamides: X-ray crystal structures of some P-Se-C and P-Se-C-N heterocycles.

Several unusual P-Se-C and P-Se-C-N heterocycles are formed by the reaction of [PhP(Se)(mu-Se)]2 or (PhP)3Se2 with alkynes or cyanamides, generated by the fragmentation of the organophosphorus-selenium compound and addition across the C identical to C or C identical to N triple bond of the organic substrate. X-ray crystallographic analysis reveals an unexpected diversity of structural motifs within these heterocyclic systems, including P2SeCN, P2C2Se and PC2Se2 rings.

Journal Article↗
PubMed1998

Assignment and Power Series Analysis of the FIR Fourier Transform Spectrum of Cyanamide Using a Multimolecule Ritz Program.

The "Ritz" program, originally written for the analysis of the Fourier transform spectra of the methanol isotopomers and presented in previous papers, has been extended in order to analyze the spectra of other molecules. This program evaluates the term values involved in the assigned transitions by the Rydberg-Ritz combination principle, and can tackle such perturbations as Fermi-type resonances or Coriolis interactions. As a first application of the extended version, we present an investigation of the Fourier transform spectrum of cyanamide between 25 and 980 cm-1. More than 16 000 lines have been assigned. Our Ritz database now comprises a list of more than 19 000 assigned lines (including of the microwave and FIR lines available in the JPL database) and more than 3900 term values. All of the lines presented in this paper correspond to transitions within the ground and first excited inversion levels of the ground vibrational state of the small-amplitude modes. Copyright 1998 Academic Press.

Journal Article↗
PubMed1977

Cyanamide mediated syntheses under plausible primitive earth conditions. I. The synthesis of P1, P2 dideoxythymidine 5'-pyrophosphate.

When an aqueous solution (pH 7.0) of deoxythymidine 5'-phosphate, 4-amino-5-imidazolecarboxamide and cyanamide was dried and heated for 18 h at 60 degrees C, P1, P2-dideoxythymidine 5'-pyrophosphate (I) was formed in a 58% yield. Oligonucleotides were not detected in the reaction product. Under conditions employed in the above reaction, (I) was shown to be stable. In prebiotic polymerization reactions employing deoxythymidine 5'-triphosphate as the polymerizing species, (I) could therefore function as a primer and minimize the formation of cyclic nucleotides.

Amines↗
PubMed1977

Cyanamide mediated syntheses under plausible primitive earth conditions. II. The polymerization of deoxythymidine 5'-triphosphate.

When an aqueous solution (pH 7.0) of 3H deoxythymidine 5'-triphosphate, deoxythymidine 5'-phosphate, 4-amino-5-imidazolecarboxamide, cyanamide and ammonium chloride was dried and heated at 60 degrees C for 18 h, oligomers were obtained in a yield of approximately 80%. After the chemical degradation of any pyrophosphate bonds present in these oligomers, linear polynucleotides of up to 7-8 units in length were isolated by DEAE cellulose column chromatography and identified by enzymatic digestion procedures. The di- and trinucleotide fractions were degraded 87% and 100% by snake venom phosphodiesterase and 39% and 9% by spleen phosphodiesterase. This synthesis of deoxythymidine oligonucleotides was conducted under potentially prebiotic conditions and may offer a possible method for the synthesis of deoxyoligonucleotides on the primitive Earth.

Aminoimidazole Carboxamide↗
PubMed1977

Cyanamide mediated syntheses under plausible primitive earth conditions. III. Synthesis of peptides.

Peptides were formed in yields of 5%, 17% and 66%, respectively, when aqueous solutions of glycine, isoleucine or phenylalanine were dried and heated for 24 h at 90 degrees C with adenosine 5'-triphosphate, 4-amino-5-imidazolecarboxamide and cyanamide. Glycine and L-phenylalanine produced mixtures of di-, tri- and tetrapeptides, while L-isoleucine gave only the dipeptide in detectable quantities. The dipeptides of L-isoleucine and L-phenylalanine were identified by mass spectrometry and enzymatic and enzymatic degradation.

Adenosine Triphosphate↗
PubMed2006

Crystal structures of extended europium cyanamide-carbodiimide compounds derived from different reaction conditions: temperature-controlled syntheses of In(0.08)Eu4(NCN)3I3, Eu8I9(CN)(NCN)3, and In(0.28)Eu12(NCN)5I(14.91).

A different thermal treatment of identical reactants (EuI2, NaCN, NaN3, and InI) leads to the formation of the three title compounds. In(0.08)Eu4(NCN)3I3 is isotypic with the reported LiEu4(NCN)3I3, Eu8I9(CN)(NCN)3 represents the first mixed cyanide-cyanamide rare-earth compound, and In(0.28)Eu12(NCN)5I(14.91) is characterized by a sandwich-like stacking motif involving Eu4-NCN double layers stuffed by a layer of vertex-sharing InI6 octahedra. The redox behavior of In is the main factor that leads to alternative product formation as a function of the temperature.

Journal Article↗
PubMed1999

Diethylcarbamoylating/nitroxylating agents as dual action inhibitors of aldehyde dehydrogenase: a disulfiram-cyanamide merger.

Benzenesulfohydroxamic acid (Piloty's acid) was functionalized on the hydroxyl group with the N,N-diethylcarbamoyl group, and the hydroxylamine nitrogen was substituted with acetyl (1a), pivaloyl (1b), benzoyl (1c), and ethoxycarbonyl (1d) groups. Only compound 1d inhibited yeast aldehyde dehydrogenase (AlDH) in vitro (IC(50) 169 microM). When administered to rats, 1d significantly raised blood acetaldehyde levels following ethanol challenge, thus serving as a diethylcarbamoylating/nitroxylating, dual action inhibitor of AlDH in vivo. A more potent dual action agent was N-(N, N-diethylcarbamoyl)-O-methylbenzenesulfohydroxamic acid (5c), which was postulated to release diethylcarbamoylnitroxyl (9), a highly potent diethylcarbamoylating/nitroxylating agent, following metabolic O-demethylation in vivo. The dual action inhibition of AlDH exhibited by 1d, and especially 9, constitutes a merger of the mechanism of action of the alcohol deterrent agents, disulfiram and cyanamide.

Acetaldehyde↗
PubMed1999

Kinetics of the Reaction of beta-Methoxy-alpha-nitrostilbene with Cyanamide in 50 DMSO-50 Water. Failure to Detect the S(N)V Intermediate.

A kinetic study of the reaction of beta-methoxy-alpha-nitrostilbene (1-OMe) with cyanamide (CNA) over a pH range from 8.5 to 12.4 shows that it is the anion (CNA(-), pK(a) = 11.38) rather than the neutral amine that is the reactive species. Attempts at monitoring the reaction with the neutral CNA at low pH were unsuccessful because of competing hydrolysis. It is shown that the nucleophilic reactivity of CNA is abnormally low, probably because of a resonance effect, and that the reactivity of CNA(-) is high, higher than that of strongly basic oxyanion because of relatively weak solvation. The high reactivity of both 1-OMe and CNA(-) appeared to constitute favorable conditions conducive to the detection of the S(N)V intermediate, as has been the case in the reactions of 1-OMe with thiolate ions, alkoxide ions, and some amines. However, no intermediate was observed. Reasons for this failure are discussed.

Journal Article↗