Methyl-urethan

There is obtained from 4-[)3-[5-methyl-isoxazolyl-(3)-carboxamido]-ethyl]-benzene-sulfonamide (prepared from 5-methyl-isoxazole-(3)-carboxylic acid chloride and 4-()3-aminoethyl)-benzene-sulfonamide hydrochloride, MP 213° to 214°C in pyridine) and chloroformic acid methyl ester, in a yield of 69%, the compound N-[ [-4-[)3-[5-methyl-isoxazolyl-(3)-carbox-amido] -ethyl] ] -benzene-sulfonyl] ] -methyl-urethane in the form of colorless crystals of MP 173°C. 

N 36.83%, OB to C02 -42.1% colorless needles from ether nip 38° d 1.243 at 49/4° RI 1.4616 at 48,6°. V sol in cold w, ale, chlf and benz less sol in eth and still less sol in petr eth. Can be prepd by nitrating n-methyl-urethane with abs nitric acid. The resulting soln of methyl nitrourethane is drowned in w, neutralized with Na carbonate, and extrd with eth to remove methyl nitrourethane. On passing ammonia gas thru the eth extract, a white ppt of the ammonium salt of methylnitramine is deposited and sepd by filtration. It is disd in ale and boiled to drive off the ammonia, and... 

Condensation of methyl urethane, H2NC06CH3j with CH20 gives rise to the methylene diurethane (III) and this compd, under different specific conditions of refluxing, resulta in the various specific linear (IV V) and cyclic products (I II) as shown. The observations of relevance here are that the various products, both linear and cyclic, are interconvertible under acid catalysis including / into IF and conversely. The... 

Among the agricultural chemicals used for the cultivation of tobacco crops we find several amines, amides and carbamates. These include dimethyldodecylamine acetate (Penar), maleic hydra-zide-diethanolamine (MH-30), and carbaryl (Sevin) as a representative of the methyl urethanes (Figure 3 , 14), It is known that small quantities of these agents are found as residues in harvested tobacco (15). To date, only diethanolamine (DELA), the water-solubilizer for maleic hydrazide in MH-30, has been studied as a possible precursor for nitrosamines in tobacco and in tobacco smoke. In 1976, more than 1,400 metric tons of maleic hydrazide had been used on U.S. tobacco (16), most of which had been applied as the MH-30 formulation with diethanolamine (14,16). 

The original method of preparing diazomethane is as follows. Methyl-urethane, formed by the interaction of methylamine and chloroformic ester, is converted into the nitroso compound by the action of nitrous acid, the latter yielding diazomethane on treatment with alcoholic potash. 

Methyl urethane, ml81 Methyl valerate, m340... 

SYNS ETHYLESTER KYSELINY METHYLKARBAMINOVE ETHYL METHYLCARBAMATE METHYLCARBAiMIC ACID, ETHYL ESTER N-METHYL URETHAN METHYLURETHANE N-METHYLURETHANE... 

Sodium azide, NaN3, is a white salt which dissolves readily in water (28% w/w at 0°C 29.5% at 2rC 34% at 80°C and 35.5% at 100°C [87]) and less readily in 1,2-ethanediol, 2-methoxyethanol, and formamide. The azide crystallizes from these solvents as the rhombohedral beta form [88] for other modifications, see Chapter 3. It is practically insoluble in alcohol, ether, acetone, tetrahydrofuran, toluene, chloroform, 2-butanone, methyl acetate, and methyl urethane [88]. 

Dunzelt concluded in his 1896 Inaugural Dissertation (34) that although this correlation seemed to be generally correct, it did not hold for two compounds. Bromal hydrate was found to be very soluble in water and produce narcosis in fish at low concentrations. By contrast, methyl urethane was found to produce only a slight narcotic effect, even though it was only slightly soluble in water. This finding of Dunzelt may have provided Meyer with the impetus to search for another chemical property that better correlated with narcotic potency. Meyer further... 

Since diethyl carbonate may be a teratogenic agent and ethyl urethane is a carcinogen, the use of diethyl pyrocarbonate is discussed under toxicological aspects. The compound should be replaced by dimethyl pyrocarbonate, since methyl urethane, unlike ethyl urethane, is not carcinogenic. 

Ramage, R., Raphy, G. Design of an affinity-based N -amino protecting group for peptide synthesis Tetrabenzo[a,c,g,f]fiuorenyl-17-methyl urethanes (Tbfmoc). Tetrahedron Lett., 33, 385-388 (1992). 

---