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The reaction of 4-aminocoumarin (2) with benzaldehyde gave the bisenamino derivatives 4. Thus, transamination of 2 with o-phenylenediamine furnished enamino skeleton 3, which can be obtained from 1. Reaction of 1 with 5-aminoisoxazole afforded 5. While reaction of 2 with benzalaniline, isatinanil and phenyl isothio cyanate afforded the corresponding 7, 8 and 9, respectively. Heterocyclic annulations of 2-phenylthiazolidine-4-one 10 2-phenylthiazolidin-4-one 10 and 2-phenyl-thiazinan-4-one 11 systems were achieved via reaction of 2 with benzaldehyde and rather either 2-mercaptoacetic acid or 3-mercaptopropanoic acid respectively. The behavior of 2 towards monochloro acetic acid and 4-oxo-4-phenylbuatonic 4-Oxo-4-phenylbutanoic acid was investigated. All of the newly synthesized compounds were evaluated as antitumor (cytotoxic) agents. Most of these compounds have shown significant antitumor activities.

In this study, the coupling of 2-phenylpyridine derivatives and potassium cyanate through C–H bond functionalization in the presence of a copper salt is developed for the first time. By this protocol, various heteroarylated acetanilide derivatives are synthesized in good yields. 2-Phenylpyridines containing electron-donating and -withdrawing groups appear to be well-tolerated by this transformation.

The addition of carbon (Grignard and organolithium reagents) and hydride nucleophiles (Schwartz reagent) to isocyanates and isothiocyanates constitutes a versatile, direct and high yielding approach to the synthesis of functionalized (thio)amide derivatives including haloamides and formamides. The chemoselective delivery of a nucleophilic (eventually configurationally stable) organometallic species to a given iso(thio)cyanate is the crucial parameter for the success of the strategy. Thus, the influence of the factors governing classical methodologies (e.g. dehydrative condensation) such as steric hindrance and electronic properties of the reactants become practically negligible.

A new method for the asymmetric synthesis of β-arylalanines (X) is developed involving the Pd-catalyzed cross-coupling of chiral allyl alcohols (I) with arylboronic acids and the Ichikawa sigmatropic rearrangement of allyl cyanates to isocyanates [ (VIII)] as key steps.

Since Becker and co-workers isolated the 2-phosphaethynolate anion (PC–O−) in 1992, the phosphorus-containing analogue of the cyanate ion (NC–O−), the 2-phosphaethynolate anion has gained much attention because this anion is isoelectronic to small molecules such as OCS and F–CP as well as the thiocyanate anion SCN−. This paper highlights the recently reported methods for the synthesis of 2-phosphaethynolate anions and its utilization in the synthesis of organophosphorus compounds, especially the interesting work reported by two independent groups of J. M. Goicoechea and H. Grutzmacher.

Unprecedented magnetic borohydride exchange (mBER), magnetic Wang aldehyde (mWang) and magnetic amine resins were prepared from highly magnetic polymer-coated cobalt or iron nanoparticles. Microwave irradiation was used to obtain excellent degrees of functionalization (>95 %) and loadings (up to 3.0 mmol g−1) in short reaction times of 15 min or less. A small library of ureas and thioureas was synthesized by the exclusive application of these magnetic resins. As a first step, a reductive amination of aromatic and aliphatic aldehydes was carried out with mBER. The excess of primary amine needed to complete the reaction was subsequently scavenged selectively by mWang. Simple magnetic decantation from the resins resulted in secondary amines in good to excellent yields and purities. The used magnetic resins were efficiently regenerated and reused for the next run. In a second step, the secondary amines were converted to trisubstituted (thio)ureas in excellent yields and purities by stirring with an excess of iso(thio)cyanate, which was scavenged by addition of the magnetic amine resin after completion of the reaction. The whole reaction sequence is carried out without any purification apart from magnetic decantation; moreover, conventional magnetic stirring can be used as opposed to the vortexing required for polystyrene resins.

The reaction of Grignard reagents with 2-pyridyl cyanate affords to give nitrites in high yields.

The reaction of B 6 vitamins 1-3 with cyanate, in the presence of equivalent amounts of hydrochloric acid, yields different adducts according to the structure of the starting material. Regiospecific attack on the amino group or the phenolic hydroxy group was found for 2a,b and 3a,b, respectively.From the aldehydes 1a,b, the 2H-pyrido[3,4-e]-1,3-oxazin-2-ones 7a,b were obtained through an attack on both the phenolic and aldehyde group

The microwave spectrum of phenyl cyanate was observed in the frequency ranges 15-18 and 30-40 GHz. Rotational constants were obtained for the ground and first eight excited states of the torsional vibration of the cyanate group with respect to the phenyl ring. The values of the inertia defect indicate the planar equilibrium conformation of phenyl cyanate. The torsional frequency was 42 cm−1 estimated from the inertia defects. The torsional motion of the OCN group in this molecule is discussed.

In order to determine the complete rs structure of methyl cyanate, the microwave spectra of 13CH3OCN, CH318OCN, CH3O13CN, sym-CH2DOCN, and asym-CH2DOCN have been observed in the frequency range from 7.5 to 50.0 GHz. From these data together with the already reported molecular constants of normal and 15N isotopic species, the following structural parameters [bond lengths in A(1 A = 0.1 nm) and angles in degrees] are obtained: r(C1 H1) = 1.074(12), r(C1 H2) = 1.075(25), r(C1 O) = 1.455(1), r(O C2) = 1.302(3), r(C2 N) = 1.146(3), 〈H1 C1 H2 = 110.4(22). 〈H2 C1 H2 = 110.7(35), 〈H1 C1 O = 106.5(11), 〈H2 C1 O = 109.4(14), 〈C1 O C2 = 113.8(3), and 〈O C2 N = 178.4(6). The rs structure of methyl cyanate indicates that the bond length of r(O C2) is much shorter than that of r(O C1) and that the OCN chain is slightly bent. The obtained structural parameters were very similar to those of methoxyethyne (CH3OCCH), which is an isoelectric molecule of methyl cyanate.

A carbene 5″ derived from N-fluoropyridinium cation is the suggested intermediate in the novel synthesis of pyridotriazines 3.

Addition of arylisothiocyanates to active methylene compounds leads to a variety of compounds depending on the structure of the starting material and conditions used to conduct the addition. Addition of arylisothiocyanate to ethyl 4,4-dicyano-3-methylbut-2-enoate (1c) leads to a pyrido[2,3-d]pyrimidine resulting from addition of a second mole of cyanate to the initial adduct. Addition of arylisothiocyanate to diethyl 2-cyano-3-methylpent-2-enedioate (1b) led to a mixture of pyridine and thiopyran adducts, while addition to diethyl 3-amino-2-cyanopent-2-enedioate (1a) led to open chain structures

The microwave spectra of ethyl selenocyanate, CH 3 CH 2 SeCN ( 80 Se and 78 Se species), have been observed in the frequency range from 8000 to 27 000 MHz. The rotational constants are determined to be A = 3922.92(18), B = 2898.00(8), and C = 1789.82(2) MHz for 80 Se species and A = 3960.25(28), B = 2898.17(13), and C = 1796.27(2) MHz for 78 Se species. Only one rotational isomer was identified as having the synclinal ( gauche ) form. The dihedral angle is found to be about 590 from the synperiplanar ( cis ) position. The dipole moments of this rotamer are determined to be μ a = 4.37(10), μ b = 0.80(5), μ c = 0.50(5). and μ total = 4.47(10) D for the 80 Se species. The rotational conformer of ethyl selenocyanate was similar to that of ethyl thiocyanate hut was different from that of ethyl cyanate.

The stereochemistry of an allyl cyanate-to-isocyanate rearrangement has been investigated by employing a chiral allyl carbamate. The rearrangement has been found to be stereospecific and the chirality of an allyl cyanate is transformed into that of an allyl isocyanate. This result shows that an allyl cyanate-to-isocyanate rearrangement is a concerted reaction involving a cyclic transition state.

During crystallization of the pyridinium N-phenolate dye 1 from a saturated aqueous solution of urea, 1-(4-hydroxyphenyl)-2,4,6-triphenylpyridinium cyanate (4) is formed unexpectedly as verified by IR, 1H-NMR and X-ray structural analysis. Such a course of reaction can be explained by the strong nucleophilic character of the betaine dye 1. The anion of 4, [NCO]−, is disordered between two positions; one of them can be assigned to an isocyanate and the other to a cyanate group. The nitrogen atom of the anion is involved in an intermolecular, nearly linear hydrogen bond with the hydroxy group of the cation whereas its oxygen atom is pointing towards the pyridinium ring of an adjacent pyridinium cation.

A new method for the synthesis of 4-amino-D-hex-2-enopyranosides and 2-amino-D-hex-3-enopyranosides has been developed. The key feature in this method involves construction of the allylamine moiety in the pyranose framework by employing an allyl cyanate-to-isocyanate rearrangement.

A new approach for the synthesis of amino sugars using an allyl cyanate-to-isocyanate rearrangement has been developed. The key feature in this method involves introduction of the nitrogen substituent into the pyranose framework by [3,3] sigmatropic rearrangement of an allyl cyanate. Subsequent functionalization of the allylamine moiety by either hydroxylation or cyclofunctionalization completes the synthesis of two amino sugars, D-perosamine and D-vicenisamine.

A 2-deoxyisomaltose analogue of acarbose was stereoselectively synthesised in 11 steps with a total yield of 7% starting from 2,6-dibromo-2, 6-dideoxy-D-mannono-1,4-lactone (6). The latter was reduced to the lactol, converted to the methyl glycoside (7) and hydrogenated to the methyl 6-bromo-2,6-dideoxyglycoside (8). Benzylation of the hydroxy groups, elimination of bromine to a 5-ene and Ferrier carbocyclisation gave (2S, 3R)-2,3-bisbenzyloxycyclohex-5-enone (12). 1, 2-addition of benzyloxymethyl lithium at –110°C gave a 6:1 mixture of tertiary alcohols 13; the (1S) isomer was the major one. Reaction with trichloroacetyl isocyanate gave a carbamate 19, which, when dehydrated to the cyanate, spontaneously underwent [1,3] sigmatropic rearrangement to an isocyanate, which on addition of methanol gave the methylcarbamate 20. Basic hydrolysis of this compound gave (2R, 3R,5R)-5-amino-1-benzyloxymethyl-2,3

An effective interaction model is presented linking high-level quantum chemistry to a structured environment via semiclassical interaction operators resembling effective core potentials. The model gives transferable results equivalent to a quantum chemical treatment of the complete system. This is applied to calculations of the reaction pathway for carbonic anhydrase in which a zinc hydroxide species attacks CO2. The reaction path is shown to be compressed by the substrate−peptide contacts so that the end point structures have partial chemical bonds. The controversial binding structure for cyanate inhibitor was found to be closely related to the CO2 bound state due to a proton abstraction facilitated by the enzyme. A mutation to link carbonic anhydrase with other hydrolysis metalloenzymes is also examined. The model accuracy for large systems is confirmed by reproductions of crystal structures as local energy minima and by the approximate agreement of the reaction energetics with known free energies.

Metal doping was adopted to modify TiO 2 (P-25) and enhance the photocatalytic degradation of harmful cyanides in aqueous solution. Ni, Cu, Co, and Ag doped TiO 2 were found to be active photocatalysts for UV light induced degradation of aqueous cyanides generating cyanate, nitrate and ammonia as main nitrogen-containing products. The photoactivity of Ni doped TiO 2 was greatly affected by the state of Ni, that is, the crystal size and the degree of reduction of Ni. The modification effects of some mixed oxides, that is, Ni-Cu/ TiO 2 were also studied. The activity of Ni-Cu/TiO 2 for any ratio of Cu/Ni was higher than that of Ni- or Cu-doped TiO 2 , and the catalyst at the Cu/Ni ratio of 0.3 showed the highest activity for cyanide conversion.

The C2-symmetric building block 1,2:5,6-di-N,O-carbonyl-1,6-diamino-3,4-O-isopropylidene- d -mannitol can be synthesized from d -mannitol in four steps using a nucleophilic substitution with cyanate and a subsequent cyclization in the final key step. The direct electrochemical oxidation of the resulting dioxazolidinone at 40 mA/cm2 in methanol at graphite electrodes with sodium benzene sulfonate as supporting electrolyte leads to the dimethoxylated product, which can be used in various diastereoselective amidoalkylation reactions. In all cases di-trans-stereoselectivity is observed.

A one-pot procedure for the conversion of mono-substituted arenes into the ortho-cyano derivatives was accomplished through directed lithiation followed by electrophilic cyanation with phenyl cyanate.

An enantioselective synthesis of new 12-amino alkylidenecyclopentenone prostaglandins is reported. The key step of the synthesis involved a [3.3] sigmatropic rearrangement of an asymmetric allylic cyanate to elaborate an asymmetric 5-amino-1,6-diene which was further transformed into cyclopentenone by successive ring-closing metathesis reaction catalyzed by the Grubbs reagent and one-pot oxidation. A palladium-catalyzed cross-coupling reaction on a 5-iodo-1,5-diene allowed the synthesis of prostanoids with variable Rw side chains. These new compounds exhibit high cytotoxic activities.

A series of 7-amino- and 7-oxo-5-aryl-6-cyanopyrido[2, 3-d]pyrimidines, 4 and 11, respectively, and pyrimido [5', 4':5, 6]pyrido[2, 3-d]pyrimidine derivatives 6 and 7 was synthesized and investigated as antiviral agents. Different synthetic strategies for the preparation of the target compounds were explored. A synthetic procedure for 4 and 11 starting with 6-amino-1, 2, 3, 4-tetrahydro-2, 4-dioxopyrimidine, proper aldehyde, and malononitrile or ethyl cyanoacetate, respectively, in a one-pot reaction proved to be the method of choice for preparation of compounds of such type. Construction of another pyrimidine ring on the pyridine nucleus of compound 4 was achieved either by reaction with phenyl iso(thio)cyanate or with formic acid to yield 6 and 7, respectively. The structure of the prepared compounds was confirmed through elemental analysis and spectral investigation. Most of the newly synthesized compounds were subjected to antiviral activity testing against herpes simplex virus (HSV) where some of them show good activities.

Evolution and development of the synthesis and rearrangement ofallyl cyanate is described. Allyl cyanate-to-isocyanate rearrangement is a concerted [3.3]-sigmatropic process involving highly selective [1,3]-chirality transfer to the newly formed asymmetric center bearing nitrogen. The usefulness of this rearrangement is manifested by the synthesis of natural products containing nitrogen-substituted quaternary carbon atoms.

The reactivity, fate, and toxicity of cyanide in water and soil is highly dependent on the chemical speciation of the cyanide. As outlined in Chapter 2, many different soluble and solid forms of cyanide exist. The simplest form of soluble cyanide is the negatively charged cyanide ion, CN−, which is composed of a carbon atom triple bonded to a nitrogen atom (–C≡N). The nature of this triple bond controls the reactivity of the cyanide anion, including complexation with other metal cations,CYWS “L1666_C005” — 2005/10/12 — 17:36 — page 58 — #2(HCN), oxidation of cyanide to cyanate, and adsorption onto clays and other soil components.

A stereocontrolled route via allyl 1,2-diols to vicinal diamines based on the [3.3] sigmatropic rearrangement of allyl cyanate has been developed. Our approach consists of two consecutive steps: stereoselective construction of allyl anti- and syn-1,2-diols followed by [1,3]-chirality transfer by sigmatropic rearrangement, which allow an access to anti-(2R,3R)- and syn-(2R,3S)-2,3-diaminobutanoic acids. [reaction: see text]

Over the last few years, we have embarked on the development of the synthesis of allyl cyanate and its rearrangement. This reaction offers an efficient transformation of the allyl alcohols into the allyl amines with high stereospecific manner even when the allyl alcohols are highly substituted at the γ-positions. Applications of this rearrangement in the context of the natural product synthesis have realized a new approach to the synthesis of amino-sugars, a new protocol for stereocontrolled allyl amine synthesis, and the first total synthesis of the peptidyl nucleoside antibiotic, blasticidin S.

Par photolyse de cyanato-1- et isocyanato-1 triaryl-1,2,2 ethylenes, on obtient respectivement des diaryl-3,4 dihydro-1,2 isoquinolones-1 et -isoquinoleinethiones-1

The microwave spectra of ethyl cyanate (CH3CH2OCN) and its 15N species generated by reacting O-ethyl thiocarbamate or O-ethyl thiocarbamate-15N with mercury (II) oxide have been observed in the frequency range from 8 to 40 GHz. The rotational constants for normal and 15N species have been determined. The dipole moments (debye) obtained for normal species are μa = 4.70 ± 0.18, μb = 0.38 ± 0.15, and μtotal = 4.72 ± 0.33. The observed reaction product was concluded to be antiperiplanar(trans)-ethyl cyanate.

A series of di- and trinuclear copper(II) complexes containing N,N,N′,N′-tetramethylethylenediamine(tmen), N,N-diethylethylenediamine(deen), 2,2′-bipyridyl(bpy) or 1,10-phenanthroline(phen) and azide, thiocyanate or cyanate ions have been prepared and characterized by their magnetic susceptibilities, infrared, electronic, and ESR spectra, and electric conductances. Magnetic susceptibility data for the dimeric complex [Cu2(tmen)2(N3)2] (ClO4)2 shows the presence of a ferromagnetic interaction (Weiss constant θ=+30 K) above 150 K, whereas the two copper(II) ions are apparently non-coupled below 150 K. On the other hand, the dimeric complex [Cu2(bpy)2(N3)2] (ClO4)2 shows the presence of a large antiferromagnetic exchange interaction (μeff

From the Cu(II)NCO−3(5)-methylpyrazole (mpz) system two compounds Cu(NCO)2(mpz)2 and four compounds Cu(mpz·NCO)2 were isolated. The latter compounds contain carbamoylmethylpyrazolate anions as chelate ligands and are coligand isomers of the cyanate compounds. According to the results of indirect structural methods, the Cu(NCO)2(mpz)2 complexes have pseudooctahedral structures and differ in their polyhedron distortions. The Cu(mpz·NCO)2 complexes show tetragonally distorted six or five coordinate structures, possibly differing also by the methyl group position on the pyrazole ring.

The complex [Mo(CO)3(η-C5Me5)(PPh3)]BF4(1) reacts with NaN3 in methanol solution to give a mixture of cis-[Mo(CO)2(η-C5Me5)(PPh3)(N3)](2) and cis-[Mo(CO)2(η-C5Me5)(PPh3)(NCO)](3), which were separated as pure products by column chromatography. Pure (3) was also obtained by an independent route, i.e. by treating a methanol solution of (1) with cyanate ion. The solid-state structures of complexes (2) and (3) were determined by single-crystal X-ray diffraction: they are isomorphous, space group P21/c(no. 14); for (2), a= 8.625(2), b= 18.655(9), c= 17.573(5)A, β= 92.29(2)°, Z= 4,3 315 independent data [Io > 2.5σ(Io)] refined to R= 0.032, R′= 0.034; for (3), a= 8.641 (1), b= 18.547(3), c= 17.52(1)A, β= 91.15(3)°,Z= 4, 2 045 independent data [Io > 2.5σ(Io)] refined to R= 0.044, R′= 0.046. Differences in the co-ordination geometry of the N3– and NCO– ligands are discussed.

ON alkyl shifts are observed in the dipoles 3, 13 from tosyl isocyanate (2a) and imido(thio)carbonates 1 (12) to give (thio)allophanates 5 (14). Similarly, addition of tosyl isothiocyanate (2b) to isourea 24a leads to the product 28 of an O S methyl shift. A cross-over experiment involving 2a and imidothiocarbonates 12b,c gives the four products 14a–d proving the intermolecular nature of the rearrangement. However, on mixing 2a and isoureas 24a,b or 2b and imido(thio)carbonates 1 (12), the reaction stops at the stage of dipoles 8, 19, 25a,b. Die Dipole 3, 13 aus Tosylisocyanat (2a) und Imido(thio)kohlensaureestern 1 (12) geben O N-Alkyl-Verschiebungen zu (Thio)Allophansaureestern 5 (14). ahnlich fuhrt die Addition von Tosylisothiocyanat (2b) an den Isoharnstoff 24a zum Produkt 28 einer OS-Methyl-Verschiebung. Ausgehend von 2a und den Imidothiokohlensaureestern 12b,c ergab ein Kreuzungsversuch die vier Produkte 14a–d und bewies so den intermolekularen Verlauf der Umlagerung. Beim Zusammengeben des Isothiocyanats 2b und der Imido(thio)kohlensaureester 1 (12) oder von 2a und der Isoharnstoffe 24a,b bleibt die Reaktion jedoch auf der Stufe der Dipole 8, 19, 25a, b stehen.