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Ethyl Azidoformate

Wear leather gloves, goggles, heavy face shield, and laboratory coat. Work from behind body shield. Avoid unnecessary heat, friction, or impact. Mop up with wet paper towels. In the fume hood and behind a shield, place paper towels in a beaker containing 6 M hydrochloric acid (prepared by adding concentrated acid to an equal volume of cold water about 150 mL for each 1 g of azide). Follow waste disposal procedure.2 [Pg.262]

Reactions for Spillage and Waste Disposal NjCOOCH,CHj + Sn + 2HC1 - N2 + H,NCOOCH CHj + SnCI2 [Pg.262]

Armour, M.A., Laboratory methods for disposal of toxic inorganic and organic chemicals, Hazardous Waste Control in Research and Education, Korenaga, T. et al., Eds., Lewis Publishers, Boca Raton, FL, 1994, p. 100. [Pg.263]

Yellow oil, pungent odor, very volatile bp5, 42°C bp72o, 140-141X.1 Explosive distillation, even under reduced pressure, is dangerous. [Pg.264]


Among the less widely exploited interconversion processes are those involving thermal reactions with ethyl azidoformate, which convert furan into A-ethoxycarbonyl-A -pyrrolin-2-one, and thiophenes into A-ethoxycarbonylpyrroles (Scheme 96a) (64TL2185). The boron trifluoride catalyzed reaction of l,3-diphenylbenzo[c]furan with A-sulfinylaniline results in the replacement of the oxygen by an iV-phenyl group (Scheme 96b) 63JOC2464). [Pg.142]

The photolytic and thermolytic decomposition of azides in the presence of olefins has been applied to aziridine synthesis. However, only a limited number of steroid aziridines have been prepared in this manner. The patent literature reports the use of cyanogen azide at ca. 50° for 24 hours in ethyl acetate for the preparation of an A-nor- and a B-norsteroidal aziridine. The addition is believed to proceed via a triazoline. The reaction of cholest-2-ene with ethyl azidoformate takes place in a nonselective manner to produce a mixture of substances, including C—H insertion products. [Pg.30]

Analogously to ynamines and o, /3-acetylenic ketones, 4-aminobut-3-yn-2-ones react with 1,3-dipoles (68HCA443 73HCA2427 92KGS867). The reaction of 4-dimethylaminobut-3-yn-2-one with diphenylketene follows a route of [2-1-21-cycloaddition (30°C, THF, 1 h) to give 2-acetyl-3-dimethylamino-4,4-diphenyl-cyclobut-2-en-l-one (377) in 15% yield. With ethyl azidoformate (30°C, THF, 3 h), the tiiazole 378 is formed in 82% yield, whereas with phenyl isocyanate, the quinoline 379 is the product (by a [2- -4] scheme) in 70% yield (68HCA443). [Pg.246]

On the other hand, poly(ethoxycarbonylimino-4-vi-nylpyridinium ylide) (Scheme 13) was prepared essentially by the same method from 1-ethoxycarbonylimino-pyridinium ylide, as described by Hafner [15] from the reaction of poly (4-vinylpyridine) with nitrene, generated from the pyrolysis of ethyl azidoformate. [Pg.375]

A solution of ethyl azidoformate (10 g, 87 mmol) in anhyd benzene (250 mL) was photolyzed at 60-70 C for 60 h, using a high-pressure Hg ultraviolet lamp, whereupon N2 was evolved and the solution became yellow. The benzene and remaining azido ester were removed under reduced pressure, and the yellow-brown oily residue distilled under high vacuum to give a yellow oil yield 8.35 g (67%) bp 46-47 C/5 x 10"3 Torr bp 130 C/0.2 Torr. [Pg.138]

Careful chromatographic and detailed HNMR spectroscopic analysis of the products from the thermolyses of ethyl azidoformate in o-, m- and p-xylene revealed in all cases a mixture of 1 //-azepines.80 In o-xylene, only two of the four possible isomers were separated and characterized, namely, ethyl 4,5-dimethy 1-1 //-azepine-1 -carboxylate (9 %) and ethyl 3,4-dimethyl-l H-azepine-1-carboxylate (7 %). w-Xylene yielded a 2 3 mixture of ethyl 3,5-dimethyl-l//-azepine-1-carboxylate and ethyl 2,4-dimethyl-l//-azepine-l-carboxylate. The 2,4-dimethyl isomer (20 %) can be isolated from the mixture by removal of the 3,5-dimethyl isomer as its Diels-Alder cycloadduct with ethenetetracarbonitrile. p-Xylene gave a mixture of the two possible isomeric azepines which were partially separated by column chromatography. A pure sample of ethyl 2,5-dimethyl-1//-azepine-1-carboxylate (26%) was obtained from the mixture by selective decomposition of the 3,6-dimethyl isomer with refluxing alcoholic potassium hydroxide. [Pg.139]

Some degree of regioselectivity can be imposed on l//-azepine formation if the arene has substituents of high steric demand.63 For example, the thermolysis of ethyl azidoformate in a tenfold molar excess of 1,4-di-fert-butylbenzene yields a 95 5 mixture of the di-zerr-butyl-l//-azcpincs 3 and 4, crystallization of which yields the pure 3,6-di-/er/-butyl isomer 3. [Pg.139]

Thermolysis of ethyl azidoformate in a mixture of ethylbenzene and dichloromethane, a known singlet nitrene stabilizer, failed to improve the yield of the 1//-azepine.148... [Pg.140]

Surprisingly, in view of the use of hexafluorobenzene as an inert solvent for (ethoxycar-bonyljnitrene insertions into alicyclic C —H bonds,149 the thermolysis, or photolysis, of ethyl azidoformate in an excess of hexafluorobenzene yields hexafluoro-1//-azepine 7.150... [Pg.140]

The metalloporphyrin-catalyzed decomposition of ethyl azidoformate in the presence of an arene has been investigated but with little success in improving the yields of the 1 //-azepines.151 The nickel and copper complexes had no effect, whereas the cobalt-tetraphenylporphyrin complex accelerated the decomposition rate of the azido ester but produced more A-arylurethane rather than 1//-azepine. [Pg.140]

The triazoles previously obtained from jS-keto-ylides and acyl azides or ethyl azidoformate are the 2-acyltriazoles (80) formed by isomerization under the basic conditions of the initially formed 1-substituted triazoles (79). The latter can be isolated in some cases if the reactions are interrupted. Aryl mono- and bis-azides have also been used in the preparation of the triazolcs (81). [Pg.163]

The preparation of N-carbethoxy-8-azabicyclo [5.1.0] oct-3-ene (158) from ethyl azidoformate (157) and 1,4-cycloheptadiene through a photolytic reaction, and its palladium(II)-catalyzed multistep rearrangement to N-carbethoxynortropidine (159), has been presented by Wiger and Retting as a new route to the 8-azabicyclo[3.2.1]octene skeleton (87) (Scheme 8). [Pg.35]

See Ethyl azidoformate See Diethyl azoformate See other azo compounds... [Pg.516]

The pyranofurooxazoline 109 can be prepared by a nitrene insertion reaction of the corresponding furan 110 upon treatment with ethyl azidoformate at — 50 °C under photolysis conditions. Compound 109 is moisture sensitive, and upon treatment with wet acidic THF was converted quantitatively to the more polar furanopyran 111. The structure and stereochemistry of 109 were proved unambiguously by X-ray diffraction, showing that the nitrene inserted anti to the bridgehead methyl group <1999JOC736> (Scheme 30). [Pg.792]

The reaction of ethyl azidoformate (93) with tetramethylallene yielded triazoline 94 and oxazoline 95 [88]. The triazoline 94 was formed by [3 + 2]-cycloaddition of azide 93 to the allene. The oxazoline 95 may result from [3 + 2]-cycloaddition of car-bethoxynitrene (96), which is formed from 93 by nitrogen evolution, to the allene or by the [2 +1] addition of the nitrene and subsequent rearrangement. [Pg.758]

Ethyl azidoformate, 1193 Fluorothiophosphoryl diazide, 4308 2-Furoyl azide, 1821 Glutaryl diazide, 1874... [Pg.25]

The thione group of dithiazolethiones is a very reactive heterodipolarophile. In Scheme 18 are given cycloadditions with nitrile oxides <67BSF2239>, diphenylnitrilimine, and ethyl azidoformate <85JCS(P1)1205>. The primary adducts are spiro derivatives, but only compound (131), which is obtained from nitrile oxides is isolable at low temperature. All are decomposed to give respectively compounds (132)-(134) and occasionally nitriles and sulfur. Compound (134) reacts further with nitrilimine affording compound (135) which is also isolated. [Pg.517]

Gallagher and co-workers (11) reported the cycloadditions of electron-dehcient azides with the ketene-(5, 5)-acetals (46) (Scheme 9.11). Reaction of p-toluenesul-fonyl azide with 46 gave the unstable cycloadducts 47, which underwent rearrangement to afford compounds 48 in 24—89% yield. In the case of ethyl azidoformate. [Pg.629]

The stereoselective intermolecular cycloaddition of azides to chiral cyclopenta-none enamines was reported, but both product yields and enantiomeric excesses (ee) were low (24) (Scheme 9.24). Ethyl azidoformate (115) and A-mesyl azido-formamimidate (116) underwent 1,3-dipolar cycloaddition with the monosubsti-tuted chiral enamine 114 to give products 117 and 118 in low yields with ee of 24 and 18%, respectively. Intermolecular cycloaddition of the A-mesyl azidoforma-mhnidate 116 with the disubstituted C2-symmetric chiral enamine 119 proceeded with good diastereoselectivity to give compound 120 in 18% yield. On cleavage of the enamine unit, compound 120 afforded 118 with low ee. [Pg.636]

The ring expansion of arenes by electron-deficient singlet nitrenes is by far the most versatile synthetic route to 1H -azepines. The first l//-azepines were prepared independently in 1963 by Hafner, and by Lwowski, and their coworkers. They found that ethoxycarbonyl-nitrene (Scheme 26, path a R=C02Et), generated by photolysis of ethyl azidoformate, adds to benzene to give initially the unstable azanorcaradiene (227), electrocyclic ring... [Pg.536]

Thermal decomposition of ethyl azidoformate in the presence of 4-phenyl-l,2-dithiole-3-thione leads to 1,2,3-dithiazine (400 Scheme 51) (76CJC3879). [Pg.591]

Photochemical decomposition of ethyl azidoformate in cyclohexene gives 7-carbethoxy-7-azabicyclo[4.1.0]heptane (108) as main product (56% at 38° and 75% at —75°) together with the three isomeric cyclohexenylurethans.82>83M>8 A nitrene mechanism for the reaction is supported by the fact that the same products in almost the same ratio are obtained in the base-induced cleavage of N-p-nitrobenzenesulfonoxyurethan (107). All evidence indicates that the second reaction yields the carbethoxynitrene by an a-elimination mechanism. The aziridine isomerizes at 140° into 2-ethoxy-4,5-cy clo hexano-A2-oxazoline (109). [Pg.18]

When ethyl azidoformate, cyanogen azide, or/CO(Ns)j is decomposed in benzene solution, no aziridipes/but azepines 111 are obtained.83M 98 101 324 32 The 7-azanorcaradienes (110) are most probably formed as unstable intermediates but rearrange immediately into the more stable azepines. [Pg.18]

Brown and Edwards have studied the photochemical reaction of ethyl azidoformate with dihydropyran and have isolated in good yield the very reactive aziridine 115. The thermal reaction between the two compounds, however, takes a completely different course via triazoline to imino lactone. [Pg.18]

Irradiation of ethyl azidoformate in the presence of enol acetates also leads essentially to the corresponding very reactive N-carbethoxyaziridines.97 Structures 116 and 117 have been obtained from isopropenyl acetate and 1-acetoxycyclo-hexene. [Pg.18]

The reaction of /3-enamino-A5-phosphanes with dimethyl acetylenedi-carboxylate gives l-aza-4A5-phosphinines (244) [89JCS(P1)2273]. Six-membered ring phosphorus-containing heterocycles were obtained by the reaction of enaminophosphines (245) with ethyl azidoformate (87TL2875). [Pg.337]

Thermal decomposition of ethyl azidoformate in the presence of 4-phenyl-l,2-dithiole-3-thione leads to the rare 1,2,3-dithiazine system (254) (76CJC3879). The reaction presumably involves initial attack of the nitrene at S-l, followed by a [1,2] rearrangement of the resulting ylide (Scheme 34). [Pg.1082]


See other pages where Ethyl Azidoformate is mentioned: [Pg.161]    [Pg.684]    [Pg.137]    [Pg.138]    [Pg.138]    [Pg.138]    [Pg.151]    [Pg.27]    [Pg.428]    [Pg.72]    [Pg.91]    [Pg.259]    [Pg.618]    [Pg.79]    [Pg.80]    [Pg.684]   
See also in sourсe #XX -- [ Pg.262 ]

See also in sourсe #XX -- [ Pg.225 ]




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