Ethyl carbamate, structure

URETHANE. [CAS 51-79-6], CO(NH2)OC2H5, also referred to as ethyl carbamate or ethyl urethane. Its structure is typical of the repeating unit in polyurethane resins. Colorless crystals or white powder, odorless, saltpeterlike taste. D 0.9862. mp 49C, bp 180C solutions neutral to litmus, soluble in w ater, alcohol, ether, glycerol, and chloroform slightly soluble in olive oil. Formed by the heating of ethanol and urea nitrate to 120-130% or by the action of ammonia on ehtyl carbonate or ethyl chloroformate. 

Second-generation juvenoids incorporate more substantial structural departures from neotenin and are more resistant to metabolic and environmental degradation. Epiphenonane, 2-ethyl-3-[3-ethyl-5-(4-ethylphenoxy)-pent-3-en-yl] 2-methyloxirane (131), has a rat oral LD50 of 4000 mg/kg. It and similar juvenoids are used in China and Japan to prolong the last larval instar of the silkworm so that silk production is increased 10—15%. Fenoxycarb, ethyl [2-(4-phenoxyphenoxy)ethyl] carbamate (132) (mp 53°C, vp 0.0078 mPa at 20°C), is soluble in water to 6 mg/L. The rat oral LD50 is >16,800 mg/kg. Fenoxycarb has a wide spectrum of activity, interfering with the developmental processes of fleas, cockroaches, and ants. 

Goto(121 125) has prepared (+)-morphine and related structures from (—)-sinomenine. More recently, (+)-opioids have been required, not for their gross pharmacological actions, although these have been examined/126 but as research tools for probing opioid receptors/67 (+)-Codeine and (+)-morphine were synthesized 128 from (+)-dihydrocodeinone (60) derived in one step from sinomenine/124 Conversion of 60 to the ethyl carbamate (61) facilitated the... 

This chapter is divided into seven main sections. The first of these sections is focused on technological contaminants, namely heterocyclic amines, acrylamide, furan, chloropropanok and their fatty acid esters, polycycKc aromatic hydrocarbons, monocyclic aromatic hydrocarbons, nitroso compounds, and ethyl carbamate. Other sections deal with microbial toxins (mycotoxins and bacterial toxins), persistent organohalogen contaminants (such as polychlorinated biphenyls, dibenzodioxins and dibenzofurans), chlorinated ahphatic hydrocarbons, pesticides (persistent chlorinated hydrocarbons and modem pesticides), veterinary medicines and contaminants from packaging materials. Presented for each of these contaminants are structures, properties, occurrence and the main sources of dietary intake, mechanisms of formation, possibilities of food contamination, prevention and mitigation and health and toxicological evaluations. 

Cobalt(III) complexes of formula cis- and trans-[Co(dtc)L4]2+ and [Co(dtc)2L2]+ where dtc = dimethyl-, diethyl- or piperidino-dithiocarbamate were prepared with phosphites P(OMe)3, P(OEt)3 and 4-ethyl-2,6,7-trioxa-l-phophabicyclo[2.2.2]octane as ligands L.1048 Whereas Co—P bonding is found, as defined in the crystal structures of each of the two forms of complexes isolated, a linkage isomer in which the phosphite is O bound was detected for the bis(dithio-carbamate) compounds. 

To verify such a steric effect a quantitative structure-property relationship study (QSPR) on a series of distinct solute-selector pairs, namely various DNB-amino acid/quinine carbamate CSPpairs with different carbamate residues (Rso) and distinct amino acid residues (Rsa), has been set up [59], To provide a quantitative measure of the effect of the steric bulkiness on the separation factors within this solute-selector series, a-values were correlated by multiple linear and nonlinear regression analysis with the Taft s steric parameter Es that represents a quantitative estimation of the steric bulkiness of a substituent (Note s,sa indicates the independent variable describing the bulkiness of the amino acid residue and i s.so that of the carbamate residue). For example, the steric bulkiness increases in the order methyl < ethyl < n-propyl < n-butyl < i-propyl < cyclohexyl < -butyl < iec.-butyl < t-butyl < 1-adamantyl < phenyl < trityl and simultaneously, the s drops from -1.24 to -6.03. In other words, the smaller the Es, the more bulky is the substituent. The obtained QSPR equation reads as follows ... 

Another useful reagent for alcohols is Pirkle s (-)-(/ )-l-(l-naphthalenyl)ethyl isocyanate (14)161. For example, it was used to separate the two diastereomeric carbamates obtained from rue-13. The carbamate shown by X-ray analysis to have structure 15 was cleaved162 to furnish (+ )-strigol (13), the witchweed germination factor, thus confirming the absolute configuration of 13163. 

In the first step, the tertiary amide structure is reduced to hemiaminal 31 with the aid of the at complex (30) from D1BAH and butyl-lithium The hemiaminal opens selectively to aminoaldehyde 32 In a second step the ring nitrogen atom is protected as carbamate 11 with ethyl ehloroformate. 

Two vanadium(iv) ethylxanthate complexes have been prepared 440 their e.p.r. parameters are practically identical with those of the corresponding diethyldithio-carbamate complexes and on this basis analogous structures were proposed, i.e. a dodecahedral eight-co-ordinate structure with four bidentate ethylxanthate ligands and a distorted tetrahedral structure with four unidentate ligands. Addition of phosphorus(iii) ligands (L) such as trialkylphosphites to solution of the ethyl xanthate... 

Chemically, retigabine (D-23129) is ethyl N-(2-amino-4-(4-fluorobenzlamino)phenyl-carbamate (59), and is structurally unrelated... 

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