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The hydrolysis of phenyl isocyanate is subject to general base catalysis by tertiary amines and the point for water falls on the Bronsted plot, which indicates that the uncatalysed reaction involves two molecules of water, one acting as a nucleophile and the other as a general base.The rather small solvent isotope effect, kw H2O/kw D2O = 1.65, and the proton inventory, are discussed.The hydrolysis of methyl isocyanate (unlike phenyl isocyanate) is acid-catalysed, probably proceeding with pre-equilibrium protonation.Methyl isocyanate reacts with hydrogenphosphate dianion and with hydrogensulphate ion, forming mixed anhydride species.The formal reaction with hydrogensulphate ion may proceed by pre-equilibrium protonation followed by nucleophilic attack by sulphate ion.

Gaseous methyl isothiocyanate (MITC), the principal breakdown product of the soil fumigant metam sodium (sodium N-methyldithiocarbamate), is an inhalation exposure concern to persons living near treated areas. Inhalation exposure also involves gaseous methyl isocyanate (MIC), a highly reactive and toxic transformation product of MITC. In this work, gas-phase hydroxyl (OH) radical reaction rate constants of MITC and MIC have been determined using a static relative rate technique under controlled laboratory conditions. The rate constants obtained are 15.36 × 10-12 cm3 molecule-1 s-1 for MITC and 3.62 × 10-12 cm3 molecule-1 s-1 for MIC. The average half-lives of MITC and MIC in the atmosphere are estimated to be 15.7 and 66.5 h, respectively. The molar conversion of MITC to MIC for OH radical reactions is 67% ± 8%, which indicates that MIC is the primary product of the MITC-OH reaction in the gas phase.

8-Carbamoyl-3-methylimidazo[5,1-d]-1,2,3,5-tetrazin-4(3H)-one (temozolomide, 1) is an anti-cancer prodrug. As part of investigations to probe its postulated mode of action using PET we have developed two rapid radiosynthetic routes for the preparation of temozolomide labeled with the short-lived positron emitter, carbon-11 (t1/2 = 20.4 min). Reaction of 5-diazoimidazole-4-carboxamide (7) with the novel labeling agent [11C-methyl] methyl isocyanate (8) gave [3-N- 11C-methyl]temozolomide (9) in 14-20% radiochemical yield from [11C-methyl] methyl isocyanate (8) (decay corrected). The position of radiolabeling in the 3-N-methyl group was confirmed by [11/13C]colabeling and subsequent carbon-13 NMR spectroscopy. Similarly, the reaction of 5-diazoimidazole-4-carboxamide (7) with [11C-carbonyl]methyl isocyanate (10) gave [4-11C-carbonyl]temozolomide (11) in 10-15% radiochemical yield from [11C-carbonyl]methyl isocyanate (10) (decay corrected). Apyrogenic samples of [3-N-11C-methyl]temozolomide (9) and [4-11C-carbonyl]temozolomide (11), with good chemical and radiochemical purities, have been prepared and used in human PET studies.

Atmospheric amides have primary and secondary sources and are present in ambient air at low pptv levels. To better assess the fate of amides in the atmosphere, the room temperature (298 ± 3 K) rate coefficients of five different amides with OH radicals were determined in a 1 m3 smog chamber using online proton-transfer-reaction mass spectrometry (PTR-MS). Formamide, the simplest amide, has a rate coefficient of (4.44 ± 0.46) × 10-12 cm3 molec-1 s-1 against OH, translating to an atmospheric lifetime of ～1 day. N-methylformamide, N-methylacetamide and propanamide, alkyl versions of formamide, have rate coefficients of (10.1 ± 0.6) × 10-12, (5.42 ± 0.19) × 10-12, and (1.78 ± 0.43) × 10-12 cm3 molec-1 s-1, respectively. Acetamide was also investigated, but due to its slow oxidation kinetics, we report a range of (0.4-1.1) × 10-12 cm3 molec-1 s-1 for its rate coefficient with OH radicals. Oxidation products were monitored and quantified and their time traces were fitted using a simple kinetic box model. To further probe the mechanism, ab initio calculations are used to identify the initial radical products of the amide reactions with OH. Our results indicate that N-H abstractions are negligible in all cases, in contrast to what is predicted by structure-activity relationships. Instead, the reactions proceed via C-H abstraction from alkyl groups and from formyl C(O)-H bonds when available. The latter process leads to radicals that can readily react with O2 to form isocyanates, explaining the detection of toxic compounds such as isocyanic acid (HNCO) and methyl isocyanate (CH3NCO). These contaminants of significant interest are primary oxidation products in the photochemical oxidation of formamide and N-methylformamide, respectively.

The title compound, C9H12N2O3, crystallizes with two molecules in the asymmetric unit. There is extensive hydrogen bonding which results in the formation of a two-dimensional corrugated sheet. This supramolecular structure is determined by the formation of hydrogen-bonded chains resulting from the presence of a 6-amino group and an ethoxycarbonyl group as substituents on a pyridine ring in relative para positions which constitute a π-electron 'push-pull' system.

The invention discloses a preparation method of methyl isocyanate. The preparation method comprises the following steps: under the protection of nitrogen, dissolving methylamine hydrochloride and triphosgene in an organic solvent, stirring and cooling, dropwise adding an organic alkali solution, carrying out heat preservation reaction after dropwise adding, carrying out atmospheric distillation after reaction, controlling the top temperature, and collecting fractions to obtain the methyl isocyanate. The method avoids the use of phosgene in the traditional process, adopts the reaction of triphosgene and methylamine, has high safety, is beneficial to operator protection, is convenient to operate, is not limited to laboratories, does not need special pressure-resistant and high-temperature-resistant equipment, has the capacity of 100 kilograms, and is suitable for fine chemical enterprises such as pharmaceutical enterprises.

Mutations in oncogenes and tumor suppressors contribute to the development and progression of cancer. The present disclosure describes compounds and methods to recover wild-type function to p53 mutants. The compounds of the present disclosure can bind to mutant p53 and restore the ability of the p53 mutant to bind DNA and activate downstream effectors involved in tumor suppression. The disclosed compounds can be used to reduce the progression of cancers that contain a p53 mutation.

Reaction of N-Alk-N′-(trimethylsilyl)carbodiimides (Alk = Me, But) with nitrating agents (N2O5, (NO2)2SiF6) affords alkyl(nitro)cyanamides and N-alkyl-N′-nitrocarbodiimides. The product ratio depends on the reaction conditions. N-(tert-butyl)-N′-nitrocarbodiimide can be obtained in almost pure form. This compound is stable at temperatures below 10 °C. Its structure was confirmed by 1Н, 13C, and 14N NMR. The reaction of N-(tert-butyl)-N′-nitrocarbodiimide with amines provides a new route to N-alkyl(aryl)-substituted N′-(tert-butyl)-N″-nitroguanidines.

The products formed during exposure of the CH3CONHOH/Ar (AHA/Ar) matrices to the full output of the Xe lamp and to 225 nm OPO radiation are studied. The irradiation promotes the isomerization, 1Z → 1E, and AHA photodissociation reactions. Four

The invention relates to a single-isocyanate preparation method and system, the method using an excess of phosgene with the corresponding [...] phosgenation reaction, the obtained reaction solution through the mentioned after the hydrogen chloride escapes the carbonyl chloride, phosgene with the isocyanate to realize the complete separation of, excess phosgene can achieve the goal of recycling. In the phosgene escapes after cracking of the reaction liquid obtained by the pyrolysis gas inert solvent for [...], obtaining the corresponding isocyanate solution, follow-up separation can obtain the qualified isocyanate. The method for preparing the single isocyanate process with high yield and low solid the characteristics of the product waste. (by machine translation)

The present invention provides a genus of polycyclic amines that are useful as opioid receptor modulators. The compounds of the invention are useful in both therapeutic and diagnostic methods, including for treating pain, neurological disorders, cardiac disorders, bowel disorders, drug and alcohol addiction, drug overdose, urinary disorders, respiratory disorders, sexual dysfunction, psoriasis, graft rejection or cancer.

The present invention provides compounds, compositions thereof, and methods of using the same.

The invention provides a preparation method of methyl isocyanate. A reaction product synthesized at the high temperature is directly fed into a first organic solvent for treatment at the temperature of 200-300 DEG C, effective separation of the methyl isocyanate and hydrogen chloride is realized, the fact that the methyl isocyanate reacts with the hydrogen chloride to produce methyl carbamyl chloride is avoided, the once-through yield of the methyl isocyanate is increased, repeated heating and condensation are not required, energy consumption and production of by-products are reduced, meanwhile, multiple decomposition reactors are not required and the number of condensers is decreased in the aspect of devices, and the investment cost and the production cost are greatly reduced.

Silyl group at the nitrogen atom in the O-silylurethanes drastically affects the thermolysis processes and allows one to simplify the synthesis of methyl- and trimethylsilyl isocyanates.

Gaseous methyl isothiocyanate (MITC), the principal breakdown product of the soil fumigant metam sodium (sodium N-methyldithiocarbamate), is an inhalation exposure concern to persons living near treated areas. Inhalation exposure also involves gaseous methyl isocyanate (MIC), a highly reactive and toxic transformation product of MITC. In this work, gas-phase hydroxyl (OH) radical reaction rate constants of MITC and MIC have been determined using a static relative rate technique under controlled laboratory conditions. The rate constants obtained are 15.36 × 10-12 cm3 molecule-1 s-1 for MITC and 3.62 × 10-12 cm3 molecule-1 s-1 for MIC. The average half-lives of MITC and MIC in the atmosphere are estimated to be 15.7 and 66.5 h, respectively. The molar conversion of MITC to MIC for OH radical reactions is 67% ± 8%, which indicates that MIC is the primary product of the MITC-OH reaction in the gas phase.

Provided herein are compounds, compositions and methods for the treatment of Flaviviridae infections, including HCV infections. In certain embodiments, the compounds are according to Formula 2001: where PD, Base, RA and RB are as provided herein. In certain embodiments, compounds and compositions of nucleoside derivatives are disclosed, which can be administered either alone or in combination with other anti-viral agents.

A series of novel push-push I and push-pull II carbene-stabilized complexes of phosphorus(V) fluorides bearing substituents with liquid-crystalline properties were synthesized by the oxidative addition of difluoroamines to phosphorus(III) halides. These octahedral complexes were characterized by NMR spectroscopy and X-ray analysis.

Matrix photolysis of N,N-dialkyldiazoacetamides 1a-d at 7-10 K results in either the formation of C-H insertion products (in case of N,N-dimethyl and N,N-diethyl diazoamides) or almost exclusive Wolff rearrangement to ketenes (in the case of the cyclic di

This present invention provides an improved process for preparing Temozolomide (TMZ) stable at room temperature for at least 18 months. This present invention also relates to Temozolomide stable at room temperature for at least 18 months.

The present invention provides a process for the preparation of a tetrazine derivative of formula (I), or a pharmaceutically acceptable salt thereof wherein R1 represents a hydrogen atom, a straight or branched C1-C6 alkyl group, C2-C6 alkenyl group or C2-C6 alkynyl group, which C1-C6 alkyl group, C2-C6 alkenyl group and C2-C6 alkynyl group is unsubstituted or substituted with 1, 2 or 3 substituents selected from halogen atoms, straight or branched C1-C4 alkoxy groups, C1-C4 alkylthio groups, C1-C4 alkylsulphinyl groups, C1-C4 alkylsulphonyl groups and phenyl groups, which phenyl groups are unsubstituted or substituted with one or more substituents selected from C1-C4 alkyl groups, C1-C4 alkoxy groups and nitro groups; or R1 represents a C3-C8 cycloalkyl group; and R2 represents a group of formula —(C═O)NR3R4, wherein R3 and R4 are independently selected from hydrogen atoms, C1-C4 alkyl groups, C2-C4 alkenyl groups and C3-C8 cycloalkyl groups, which process comprises: i) providing a compound N of formula (III), wherein R1 is as defined; R1—N═C═O ii) absorbing the compound of formula (III) into a solvent to obtain a solution of the compound of formula (III); iii) adding to the thus obtained solution a compound of formula (II), to obtain a compound of formula (I), as defined above, wherein R2 is as defined above; iv) decomposing any excess compound of formula (III) remaining by addition of water; and v) optionally salifying the thus obtained compound with a pharmaceutically acceptable acid, or base.

The invention relates to 3-substituted-1H-indole, 3-substituted-1H-pyrrolo[2,3-b]pyridine, and 3-substituted-1H-pyrrolo[3,2-b]pyridine compounds of the Formula (I): or a pharmaceutically acceptable salt thereof, wherein the constituent variables are as defined herein, compositions comprising the compounds, and methods for making and using the compounds.

The present invention provides a process for the preparation of a tetrazine derivative of formula (I), or a pharmaceutically acceptable salt thereof wherein R1 represents a hydrogen atom, a straight or branched C1-C6 alkyl group, C2-C6 alkenyl group or C2-C6 alkynyl group, which C1-C6 alkyl group, C2-C6 alkenyl group and C2-C6 alkynyl group is unsubstituted or substituted with 1, 2 or 3 substituents selected from halogen atoms, straight or branched C1-C4 alkoxy groups, C1-C4 alkylthio groups, C1-C4 alkylsulphinyl groups, C1-C4 alkylsulphonyl groups and phenyl groups, which phenyl groups are unsubstituted or substituted with one or more substituents selected from C1-C4 alkyl groups, C1-C4 alkoxy groups and nitro groups; or R1 represents a C3-C8 cycloalkyl group; and R2 represents a group of formula -(C=O)NR3R4, wherein R3 and R4 are independently selected from hydrogen atoms, C1-C4 alkyl groups, C2-C4 alkenyl groups and C3-C8 cycloalkyl groups, which process comprises: i) providing a compound of formula (III), wherein R1 is as defined; R1-N=C=O ii) absorbing the compound of formula (III) into a solvent to obtain a solution of the compound of formula (III); iii) adding to the thus obtained solution a compound of formula (II), to obtain a compound of formula (I), as defined above, wherein R2 is as defined above; iv) decomposing any excess compound of formula (III) remaining by addition of water; and v) optionally salifying the thus obtained compound with a pharmaceutically acceptable acid, or base.

1,4,2-diazaphospholidine-3,5-diones and related compounds and unpredictability in catalysis was studied. The five-membered ring species 4 6, which are all readily accessible by the McCormack reaction, optionally with subsequent hydrogenation, were selected for this study. The use of saturated species of type 4 (1-organyl-phospholanes) as catalysts led to a complete reverse in the selectivity of the reaction, in favor of the formation of the isocyanate trimers. Owing to the high activity of the corresponding P-oxides in carbodiimidization reactions, it can be assumed that the findings can be attributed to partial air oxidation of the trivalent phosphorus species applied. The symmetrical species 6, in total contrast to the other two members of the series, do not exhibit any catalytic activity with respect to isocyanates and instead react cleanly with two equivalents of isocyanate to effect the extrusion of 1,3-diene.

A general procedure for the synthesis of alkyl and aryl alkylcarbamates starting from the corresponding 5-methyl N-alkylthiocarbamates is described. This procedure consists of three steps that are carried out in a one-pot fashion, without isolating the intermediate N-alkylcarbamoyl chlorides or alkyl isocyanates. All the target products were obtained in high yields (16 examples, average yield 91%). To be noted is the recovery of a co-product of industrial interest, dimethyl disulfide, in a half mole amount for each mole of thiocarbamate, with complete exploitation of the reagent. The alkyl isocyanates, if required, can also be isolated in high yields. Georg Thieme Verlag Stuttgart.

(Chemical Equation Presented) Time-resolved infrared (TRIR) spectroscopy, product studies, and computational methods were applied to the photolysis of sulfilimines derived from dibenzothiophene that were expected to release acetylnitrene, trifluoroacetylnitrene, mesylnitrene, and tosylnitrene. All three methods provided results for acetylnitrene consistent with literature precedent and analogous experiments with the benzoylnitrene precursor, i.e., that the ground-state multiplicity is singlet. In contrast, product studies clearly indicate triplet reactivity for trifluoroacetylnitrene, though TRIR experiments were more ambiguous. Product studies suggest that these sulfilimines are superior sources for sulfonylnitrenes, which have triplet grounds states, to the corresponding azides, and computational studies shed light on the electronic structure of the nitrenes.

The present invention relates to a process for preparing temozolomide.

Silylation of a series of aliphatic, carbocyclic, and fatty-aromatic amines gave the corresponding silyl derivatives whose yield depended on the electronic and steric structure of the substrate and the nature of the silylating agent. The yield of isocyanates obtained by phosgenation of the silyl derivatives under mild conditions decreased in going from aliphatic amines to benzylamines and rose as the length of the alkyl chain in fatty-aromatic amines extended. The most convenient procedure for the synthesis of low-boiling alkyl isocyanates was found to be based on the transformation of amines or ammonium salts into silyl or silyl silyl-carabamates, followed by pyrolysis of the latter in the presence of trichloro(phenyl)silane. Pleiades Publishing, Inc., 2006.

A novel compound of the formula (I): wherein R1 is alkoxycarbonyl or the like, R2 is alkyl or the like; R3 is hydrogen or the like; R4 is alkylene or the like; R5 is optionally substituted heterocyclic group; R6, R7, R8 and R9 are independently hydrogen; alkyl, alkoxy, or the like; R10 is optionally substituted aromatic ring, or the like; or a pharmaceutically acceptable salt thereof, which has an inhibitory activity against cholesteryl ester transfer protein (CETP).

The 1,2,4-dithiazolidine-3,5-dione heterocycle, also referred to as a dithiasuccinoyl (Dts)-amine, serves as a readily removable amino protecting group for building blocks used in syntheses of peptides, glycopeptides, and PNA; it is also useful as a masked isocyanate and (inversely) as a sulfurization reagent for trivalent phosphorus. Bis(chlorocarbonyl)disulfane, the two-sulfur analogue of succinyl chloride, has been envisioned as a reagent for facile single-step elaboration of the heterocycle. However, reactions of bis(chlorocarbonyl)disulfane directly with primary amines fail to yield Dts-amines for reasons that are discussed. Inspired by several precedents from the organosilicon chemistry literature that a trimethylsilyl group may serve as a "large proton," a successful, high-yield preparation of Dts-amines through reactions of bis(chlorocarbonyl)disulfane with bis(trimethylsilyl)amines has been developed. Studies aimed at elucidating mechanistic reasons for these observations are also presented. Copyright

Bis(chloromethyl)phosphinic chloride reacts with trimethylsilyl methylcarbamate in benzene in the presence of a base to give trimethylsilyl bis(chloromethyl)phosphinate. The same reaction performed without a solvent and in the absence of a base yields trimethylsilyl bis(chloromethyl)phosphinate and bis(chloromethyl)phosphinic anhydride. Reaction of bis(chloromethyl)phosphinic chloride with trimethylsilyl diethylcarbamate yields N,N-diethylbis(chloromethyl)phosphinic amide. The reaction of bis(chloromethyl)phosphinic (-phosphinothioic) chlorides with trimethylsilyl N-trimethylsilylacetimidoate was studied.

The reaction of nitroethane with NO in the presence of O2 was investigated over Cu-MFI catalyst. Nitroethane reacted readily in NO/O2 over Cu-MFI with initial conversion to CO2 and N2. Deactivation due to deposited material was observed below 330°C with the eventual emergence of isocyanates, mainly CH3NCO by dehydration, but with some HNCO, by deposit decomposition. Nitromethane reacted in a similar way but deactivation was slower. While HNCO was then the only isocyanate formed, significant amounts of HCN and NH3 were also observed. With both systems, nitrogen rose either by hydrolysis of isocyanate to amine (or ammonia) on Broensted sites and subsequent SCR reactions involving transition metal ions or through reaction of NO2 with deposits. The rates of these processes were sufficiently fast for nitroethane to be feasible as an intermediate during the SCR of NO by ethane on Cu-MFI.

Δ3-1,3,4-Oxadiazolines spiro-fused at C2 to C2 to oxazolidines (12) or to C2 of tetrahydro-1,3-oxazines (13) were synthesized. The oxadiazolines undergo thermolysis in benzene at 90°C with first-order rate constants of (1.6-50) × 10-5 s-1. The dependence of these rate constants on the nature of the substituents present on the oxadiazoline ring is consistent with a mechanism involving a carbonyl ylide intermediate. Substituents on N of the oxazolidine or tetrahydro-1,3-oxazine moieties play a major role in determining the fragmentation pathways. Oxadiazolines with N-carbonyl groups (12c-j, 13d,e) afford essentially quantitative yields of the corresponding aminooxycarbenes, while other fragmentation reactions compete with carbene generation in the case of oxadiazolines with N-methyl (12b, 13c) or N-sulfonyl (12k) groups.

Matrix-isolated 4-methyl-1,2,4-triazolinedione la and 4-phenyl-1,2,4-triazolinedione 1b were photolyzed at λ335 nm and λ≥310 nm, respectively. The reactions induced by photolysis were monitored by FT-IR spectroscopy. The isocyanates 2a and 2b are always the more abundant products with carbon monoxide. Methyl- and phenylaziridine-2,3-diones (3a and 3b) were detected as minor, but well-identified reaction products. The IR experimental absorption bands were assigned by comparison with literature data and with simulated infrared spectra obtained by ab initio calculation at the 6-31G* level. Stable at the matrix temperature (10 K), 3a and 3b photolyzed to isocyanates and CO when irradiated at λ≥230 nm. Irradiation of 2b at this wavelength induces its decomposition. The kinetic data show that the rate constant process 1a→2a is faster than the 1a→3a process (3.29×10-3 and 2.35×10-4 min-1 respectively).

The electronic structure of the 1,4-dicarbonyl-substituted 1,4-dimethyltetraz-2-enes 1-4 has been studied by He(I) photoelectron (PE) spectroscopy and semiempirical quantum chemical calculations.The compounds are characterized by five ionization potentials with energies less than 12 eV which are assigned to the molecular orbitals ?3 (HOMO), n+, ?2, n+OO, and n-OO.Gas-phase thermolysis of these compounds was investigated by variable temperature PE spectroscopy.The thermolysis commences by loss of molecular nitrogen and formation of short-lived amidyl CH3-N.-CO-R or carbamyl CH3-N.-CO-OR radicals which decompose by cleavage of the CO-R or CO-OR bond, respectively, (β scission).Thus, the former radicals disproportionate to methyl isocyanate and N-methylformamide (R=H) or loose a methyl radical affording methyl isocyanate (R=CH3), and the latter decompose to methyl isocyanate and an aldehyde.

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The present invention relates to novel cyano-containing pyrimidine derivatives of the general formula (I) wherein R1represents halogen, C1 4-alkyl, C1 4-alkoxy, halogeno-C1 4-alkyl, or halogeno-C1 4-alkoxy, R2represents halogen, C1 4-alkoxy, halogeno-C1 4-alkyl, or halogeno-C1 4-alkoxy, R3represents halogen, hydroxy, or an oxo group formed together with R4 or R3represents one of the following groups represented by and-O-SO2-R6, R4represents hydrogen or an oxo group formed together with R3, R5represents hydrogen or in each case an optionally substituted or unsubstituted C1 20 -alkyl, C2 20-alkenyl, C2 20-alkynyl, C1 4-alkoxycarbonyl, C3 7-cycloalkyl, or carboxyl or phenyl, R5represents an optionally substituted or unsubstituted five- or six-membered heterocyclic ring, or an optionally substituted bicyclic group formed by condensation of a five or six-membered heterocyclic ring with phenyl, and R6represents in each case an optionally substituted or unsubstituted C1 20-alkyl, C2 20-alkenyl, C2 20-alkynyl or phenyl; to processes for their preparation and to their use as herbicides.

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An investigation of methods to efficiently prepare activated N-methylcarbamates is reported. N-(Methylcarbamoyloxy)succinimide (3a), aryl N-methylcarbamates 3b-d and 2,2,2-trifluoro-1-(trifluoromethyl)ethyl N-methylcarbamate (3e) have been prepared in 70-80% yields from the corresponding chloroformates 5a-e, which were prepared as crystalline solids by the condensation of trichloromethylchloroformate (1) or bis(trichloromethyl)carbonate (2) with hydroxy compounds 4a-e in high yields.

The reactions of (CF3)2BNMe2 (D1) and (CF3)2BNEt2 (D2) with isocyanates and isothiocyanates have been studied.At or near room temperature the C=N bonds of RN=C=O and RN=C=S enter into cycloadditions with the B-N bond of D1 to yield the four-membered rings ; R = Me (I), tBu (II), Ph (III), CF3 (IV), and ; R = Me (V), Et (VI), tBu (VII), Ph (VIII), and p-FC6H4 (IX) respectively.I, V, VI, VIII and IX rearrange at ca. 60 deg C to form the isomers (XI) and ; R = Me (XII), Et (XIII), Ph (XIV) and p-FC6H4 (XV), respectively.At room temperature D2 reacts with MeN=C=O to yield (X) directly.X and XI reversibly incorporate MeN=C=O to form the six-membered heterocycles ; R = Me (XVI) and Et (XVII).The structures of II, VII, XIV and XVII have been established by single-crystal X-ray diffraction studies.The bond distances indicate that the ?-bonding is delocalized over OCN (sp2), SCN (sp2) and SCN2 (sp2) fragments in II, VII and XIV, respectively.Furthermore, the ?-character of the exocyclic C-N bonds in XIV and XVII, while considerable, is lower than that of the exocyclic C-O(S) bonds in II, VII and XVII.The other structural assignments were based on mass spectrometry and vibrational and multinuclear NMR spectra.

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The structures, physical properties, and reaction chemistry of isoelectronic alkyl complexes of osmium(VI) are compared. The three, five-coordinate alkyl complexes [NBun4][Os(N)(CH2SiMe3) 4], Os(NMe)(

Reactions of oxygen atoms and acetonitrile have been investigated in solid argon at 14-17 K.Primary photoproducts include hydroxyacetonitrile (HOCH2CN) and acetonitrile N-oxide (CH3CNO).Hydroxyacetonitrile forms hydrogen-bonded complexes with acetonitrile and acetonitrile N-oxide as the secondary products.Acetonitrile N-oxide is suggested to be formed by a simple bimolecular addition reaction of atomic oxygen with the nitrile nitrogen.The participation of O(1D) atoms is considered to increase the yield of hydroxyacetonitrile as compared to acetonitrile N-oxide via H-atom abstraction or insertion reactions.The spectral characteristics of hydroxyacetonitrile, acetonitrile N-oxide, and hydrogen-bonded hydroxyacetonitrile-acetonitrile complex isolated in argon matrices are given.

Siloxide ions undergo O/S exchange reactions with suitable sulfur-containing neutrals, e.g.H3SiO- + CS2 -> H3SiS- + COS.Silamide ions similarly undergo NR/O and NR/S exchange reactions together with nucleophilic displacement reactions, e.g.: .No simple correlation between rate and mechanism is observed for all the studied reactions.

Six 1,4-dihydro-5H-tetrazole (tetrazoline) derivatives have been photolysed in Ar and N2 matrices at 12 K.The dimethyltetrazolinone (1a) gave as the major product the same diaziridinone obtained previously from solution photolysis, but it also underwent a novel cleavage to MeNCO and, presumably, methyl azide.Iminotetrazolines (3a) and (3b) gave the corresponding carbodiimides (5a) and (5b), and iminodiaziridines (4a) and (4b); while the tetrazolinethiones (7a) and (7b) gave carbodiimides (8a) and (8b), respectively.Photolysis of the vinyl substituted tetrazolinone (9) proceeded differently in inert ambient-temperature solutions and low-temperature matrices.In the former an imidazolone (10) was the sole isolable product, while in the latter formation of diaziridinone (15) competed with an alternative cleavage giving t-butyl isocyanate and vinyl azide.THese results are best interpreted on the basis of an intermediate biradical, which, however, could not be detected directly by matrix ir. spectroscopy.

Gas-phase pyrolysis of methyl dimethylcarbamate (1), O-methyl dimethylthiocarbamate (2), S-methyl dimethylthiocarbamate (3), and methyl dimethyldithiocarbamate (4) has been carried out in the temperature range 1043-1404 K applying the gas-phase Curie-point pyrolysis technique.Real-time analysis of the pyrolyses were carried out by field ionization- and collision activation mass spectrometry. 1 and 4 were found to be thermally very stable even after pyrolysis at 1404 K.N-Methyl methanimine was found in moderate yield following pyrolysis of 2 and 3.The possible isomerization of the ester functions were studied by application of collision activation mass spectrometry in combination with 18O and 34S labeling.The results are discussed considering available data on the simple acetic acid esters with special emphasis on the effect of increasing sulfur content.

The kinetics of the decomposition of a series of aliphatic acyl azides have been investigated.The first-order rate constants and activation parameters have been determined and the influence of the substituents and of solvent polarity on the rate of decomposition has been established.

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The thermal decomposition of various salts of mono-N-methylcarbamoyl and bis-N-methylcarbamoyl phosphoric acid in aprotic and protic solvents (acetonitrile, trichloromethane, alcohols) and in the solid state has been studied in detail.Final products are mono-, di-, poly-, and cyclophosphates, in addition phosphoric acid esters if alcohols are used as solvents; and either sym. dimethylurea or methyl isocyanate and methylamine.The spontaneous decomposition of sparingly soluble N-methyl carbamoyl phosphates in aqueous suspensions to yield slightly soluble diphosphates demonstrates clearly that the reaction of calcium hydrogen phosphate with alkali cyanates via calcium carbamoylphosphate to give calcium diphosphate - which has been considered a prebiotic key reaction - is not a result of a special feature of the structure of the intermediate product. - Keywords: N-Methylcarbamoyl Phosphates, Decomposition

The flowing afterglow and selected ion-flow tube techniques have been used to study the reactions of H2N- with N2O, CO2, CS2, SO2, and OCS in the gas phase.Thermal energy rate coefficients and product branching ratios have been determined and are discussed in terms of detailed reaction mechanisms.With use of the SIFT-drift technique, the product distribution for the reaction of H2N- with N2O was measured as a function of the center of mass kinetic energy in the range of thermal energy to ca. 15 kcal mol1-.Qualitative studies were made of the reactions of HO-, CH3O-, and (CH3)2N- with N2O, CO2, CS2, SO2, and OCS, and the reactions of a variety of other ions with OCS were also examined.These reactions provide efficient synthetic routes for the gas-phase preparation of a variety of interesting negative ions containing nitrogen and sulfur.The basicities and heats of formation of three of these anions, H2NS-, NSO-, and NCS-, have been bracketed by proton-transfer reactions.The nucleophilicities of these three anions, as well as of H2N-, HO-, HO2-, F-, HS-, CN-, NCO-, N3-, Cl-, and Br- toward CH3I, have been measured.

The furandione 1 reacts with diaryl- or arylalkylcarbodiimides to yield 4--2,3-furandiones 5, which isomerize to 2,3-pyrrolediones 2 above 60 deg C. 1, 2, and 5 react with dimethylcarbodiimide under mild conditions (20 deg C, a few minutes) to give the so far unknown pyrrolooxazinediones 7 which reversibly can lose dimethylcarbodiimide to form again 2.Analogously 2,3-thiophenedione 3 and dimethyl- or diisopropylcarbodiimide yield the pyrrolothiazines 8.The basic skeletons of 7 and 8 were determined by X-ray structure analys is of 7a and 8b.On the other hand, the reaction of 1 with diethyl- or diisopropylcarbodiimide leads to furopyrimidines 10.The bicyclic compounds 7, 8, and 10 can be regarded as heteroanalogues of the 7-deazapurine system.The reaction pathways leading to 5, 7, 8, and 10 involve cycloadditions, cycloreversions or fragmentation reactions as well as some surprising new furandione-furandione rearrangements.