Abstract:Reaction of a-bromobenzyl cyanide and ethyl xanthamidate, NH,*CS*OEt, in benzene or without a solvent yields a-carbamylthiobenzyl cyanide (VI), whereas in alcohol the ethyl xanthamidate is isomerized to ethyl thiolcarbamate (IV). The reaction in benzene in the presence of sodium acetate gives 2 : 5-di-(2-ethoxy-5-phenyl-4-thiazolylimino)-3 : 4-diphenylpyrroline (VIII), a brilliant red pigment, of which the structure has been proved by hydrolysis. The synthesis of similar pigments also occurs when methyl and n-… Show more
“…Methyl cyanate was generated according to Pasinszki & Westwood (1995) by gas-solid reaction of the evaporated O-methyl thiocarbamate (CH 3 OC(S)NH 2 ) with yellow mercury oxide (HgO, Sigma Aldrich) packed into a tube in half-section in a vacuum line (0.3 mbar pressure). A sample of O-methyl thiocarbamate was prepared according to the method given in Davies & Maclaren (1951). To remove the water, which is a by-product, the reaction products were passed through a short tube (15 cm) filled in half-section with phosphorus pentoxide (P 2 O 5 , Sigma Aldrich).…”
Aims. The recent discovery of methyl isocyanate (CH 3 NCO) in Sgr B2(N) and Orion KL makes methyl cyanate (CH 3 OCN) a potential molecule in the interstellar medium. The aim of this work is to fulfill the first requirement for its unequivocal identification in space, i.e. the availability of transition frequencies with high accuracy. Methods. The room-temperature rotational spectrum of methyl cyanate was recorded in the millimeter wave domain from 130 to 350 GHz. All rotational transitions revealed A-E splitting owing to methyl internal rotation and were globally analyzed using the ERHAM program. Results. The data set for the ground torsional state of methyl cyanate exceeds 700 transitions within J = 10−35 and K a = 0−13 and newly derived spectroscopic constants reproduce the spectrum close to the experimental uncertainty. Spectral features of methyl cyanate were then searched for in Orion KL, Sgr B2(N), B1-b, and TMC-1 molecular clouds. Upper limits to the column density of methyl cyanate are provided.
“…Methyl cyanate was generated according to Pasinszki & Westwood (1995) by gas-solid reaction of the evaporated O-methyl thiocarbamate (CH 3 OC(S)NH 2 ) with yellow mercury oxide (HgO, Sigma Aldrich) packed into a tube in half-section in a vacuum line (0.3 mbar pressure). A sample of O-methyl thiocarbamate was prepared according to the method given in Davies & Maclaren (1951). To remove the water, which is a by-product, the reaction products were passed through a short tube (15 cm) filled in half-section with phosphorus pentoxide (P 2 O 5 , Sigma Aldrich).…”
Aims. The recent discovery of methyl isocyanate (CH 3 NCO) in Sgr B2(N) and Orion KL makes methyl cyanate (CH 3 OCN) a potential molecule in the interstellar medium. The aim of this work is to fulfill the first requirement for its unequivocal identification in space, i.e. the availability of transition frequencies with high accuracy. Methods. The room-temperature rotational spectrum of methyl cyanate was recorded in the millimeter wave domain from 130 to 350 GHz. All rotational transitions revealed A-E splitting owing to methyl internal rotation and were globally analyzed using the ERHAM program. Results. The data set for the ground torsional state of methyl cyanate exceeds 700 transitions within J = 10−35 and K a = 0−13 and newly derived spectroscopic constants reproduce the spectrum close to the experimental uncertainty. Spectral features of methyl cyanate were then searched for in Orion KL, Sgr B2(N), B1-b, and TMC-1 molecular clouds. Upper limits to the column density of methyl cyanate are provided.
“…A mixture of gaseous ethyl cyanate and water was generated by passing O -ethyl thiocarbamate over solid yellow mercury(II) oxide (FERAK Laborat GMBH) packed into a small Pyrex tube (Scheme ). , The CH 3 CH 2 OCN/H 2 O mixture from the reaction zone was led directly into the IR spectrometer or condensed in a U-trap inserted between the reaction tube and the spectrometer. 1 …”
Gaseous ethyl cyanate, CH3CH2OCN, has been generated from the gas/solid reaction of O-ethyl thiocarbamate
with mercury oxide and characterized in the gas phase by infrared spectroscopy for the first time. Experimental
data indicate the presence of two conformers in the gas phase, the gauche (synclinal) and the trans
(antiperiplanar) form. The molecular geometries and energetics of the possible conformers are obtained from
DFT calculations at the B3LYP level and from ab initio calculations at the MP2, MP3, MP4, QCISD, and
CCSD(T) levels of theory. The assignment of the gas-phase infrared spectrum is assisted by normal coordinate
calculations based on the scaled computed force field of the two conformers. The kinetic instability of CH3CH2OCN toward isomerization is studied at the B3LYP level, in a vacuum and in solutions. Solvent effects
are modeled using the polarized continuum model (PCM). Calculations show that the isomerization is not a
unimolecular process at ambient temperatures, and bimolecular processes are responsible for the instability.
In polar solvents, the OCN- anion plays a key role in the isomerization, being an effective catalyst for the
cyanate-isocyanate rearrangement.
“…Na@ + ClCHZ-C-CH, -++ C H~N H -C -S C H Z C O This was confirmed by Humphlett and Lamon[1371 in analo-gous investigations on the reactions of ammonium dithiocarbamate with chloroacetaldehyde, chloroacetone, ethyl chloroacetate, and phenacyl bromide. These reactions again lead, not to the primary dithiocarbamates, as had previously been assumed[13*-1401, but to the 4-hydroxythiazolidinethiones (58), which lose water within a few days to form thiazoline-Zthiones(57).…”
The methods suitable for the preparation of thiocarbamates are described and illustrated by examples and procedures. They are grouped under the following headings:
Addition of Alcohols and Thiols to Isothiocyanates
Thioacylation of Amines
with chlorothioformates
with O,S‐diesters of dithiocarbonic acid
with trithiocarbonates
Thioacylation of Alcohols, Phenols, and Thiols
with thiocarbamoyl chlorides
with N,N‐dialkylmercaptochloroformimidium chlorides
with N,N′‐thiocarbonyldiimidazole
Reaction of Thiocyanates and Cyanates with Hydrogen Sulfide
Alkylation of Metal Dithiocarbamates
Additions to Thiocyanic Acid
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