3-Methyl-4-nitrophenyl carbamate

Alternatively, two phosgene equivalents were studied, methyl chloroformate and p-nitrophenyl chloroformate. When methyl chloroformate was used for the end game, N-carbamate 54 was obtained smoothly but subsequent cyclization to ben-zoxazinone 1 was sluggish. Furthermore, removal of the unreacted intermediate methyl carbamate 54 from Efavirenz was not trivial, thus we did not pursue this method. On the other hand, reaction of 53 and p-nitrophenyl chloroformate initially provided the corresponding p-nitrophenyl carbamate 55 under mild basic conditions (KHC03). Carbamate 55 was smoothly cyclized to 1 upon increasing... 

Loudwig, S. and Goeldner, M., N-methyl-N-(o-nitrophenyl)carbamates as photolabile alcohol protecting groups. Tetrahedron Lett., 42, 7957-7959, 2001. 

Crich and Rumthao reported a new synthesis of carbazomycin B using a benzeneselenol-catalyzed, stannane-mediated addition of an aryl radical to the functionalized iodocarbamate 835, followed by cyclization and dehydrogenative aromatization (622). The iodocarbamate 835 required for the key radical reaction was obtained from the nitrophenol 784 (609) (see Scheme 5.85). lodination of 784, followed by acetylation, afforded 3,4-dimethyl-6-iodo-2-methoxy-5-nitrophenyl acetate 834. Reduction of 834 with iron and ferric chloride in acetic acid, followed by reaction with methyl chloroformate, led to the iodocarbamate 835. Reaction of 835 and diphenyl diselenide in refluxing benzene with tributyltin hydride and azobisisobutyronitrile (AIBN) gave the adduct 836 in 40% yield, along with 8% of the recovered substrate and 12% of the deiodinated carbamate 837. Treatment of 836 with phenylselenenyl bromide in dichloromethane afforded the phenylselenenyltetrahydrocarbazole 838. Oxidative... 

Importantly, TV-carbamoyl derivatives of primary amines obtained from photolabile benzoins exist in varying proportions as cyclic hydroxyoxazolidinone tautomers. Therefore, the preparation of TV-carbamoyl derivatives of benzoins is applicable only for secondary amines and TV-alkylated amino acids. 244 At basic pH unsymmetrical benzoins, such as 3,5-dimethoxybenzoin, their mixed carbonate and carbamate derivatives, tend to equilibrate to the isomeric forms. Nevertheless, in TFA and aqueous solutions at pH 8 the structural integrity is fully maintained. 244 Preparation of 3,5-dimethoxybenzoin-derived carbamates of secondary amines and amino acids can be mediated by either CDI/methyl triflate in ni-tromethane 246 or 4-nitrophenyl chloroformate/DMAP in dry THF. 244 ... 

As alternatives to 4-nitrophenyl chloroformate, carbonyl diimidazole [100-102] or di-A-succinimidyl carbonate [103,104] can be used to convert polymeric alcohols into alkoxycarbonylating reagents suitable for the preparation of support-bound carbamates. Polystyrene-bound alkoxycarbonyl imidazole is less reactive than the corresponding 4-nitrophenyl carbonate, and sometimes requires heating to undergo reaction with amines. Additional activation of these imidazolides can be achieved by N-methylation (Entry 9, Table 14.7). 

Photooxidation of parathion also occurred on leaf surfaces (18), together with isomerization and other reactions. Fenitro-thion (j),O-dimethyl 0-3-methyl-4-nitrophenyl phosphorothionate) and other phosphorothionate insecticides behaved similarly (19). Some pesticides do not require external reagents for photodegradation on surfaces carbamate insecticides such as carbaryl (1-naphthyl li-methylcarbamate), aminocarb (4-dimethylamino-3-methylphenyl li-methylcarbamate), and mexacarbate (4-dimethylamino-... 

The 0,0-diethyl-o-p-nitrophenyl phosphorothioate (parathion) was obtained from the American Cyanamid Co., and the 1-naphthyl-N-methyl-carbamate (Sevin) was obtained from the R. A. Taft Sanitary Engineering Center, U. S. Public Health Service. The Dow Chemical Co. provided... 

CARBAi nC ACID, METHYL-, o-ISOPROPYLPHENYL ESTER see i nA250 CARBAMIC ACID, METHYL-, 2-(l-METHYLETHYL)PHENYL ESTER see MIA250 CARBAMIC ACID, METHYL-, 3-METHYLPHENYL ESTER (9CI) see MIB750 CARBAMIC ACID, METHYL((4-NITROPHENYL)THIO)-, 2,3-DIHYDRO-2,2-DIMETHYL-7-BENZOFURANYL ESTER see DLH870 CARBAMIC ACID, METHYL-, SPIRO(l,3-BENZODIOXOLE-2,l -CYCLOHEXAN)-4-YL ESTER see SLD550... 

There are five papers on carbamate chemistry of interest. The mechanism of the reaction in MeCN of (V-methyl-iV-phenylcarbamoyl chlorides (94) with benzyl-amines is believed to be 5n2 based on Hammett p values, a cross-interaction constant Pxy of —0.14, h/ d values for the iV-deuteriated benzylamines all <1, and low activation enthalpies. The aminolysis of / -nitrophenyl W-phenylcarbamates in acetonitrile involving the T (7) was discussed earher. Solvolysis-decomposition of iV-l-adamantyl-iV-/ -tolylcarbamoyl chloride (95) in hydroxy he solvents involves a facile slow ionization (5n 1 mechanism) giving a cation which eliminates ArNCO to... 

C8H8N204 carbamic acid, (4-nitrophenyl)-, methyl ester 1943-87-9 499.15 43.802 2 13476 C8H803 4-hydroxy-2-methoxybenzaldehyde 18278-34-7 522.32 46.033 2... 

This group was developed as a water soluble carbamate in peptide synthesis. It is prepared hy methylating (2-phenylthio)ethylcarbamates of amino acids with methyl iodide and AgBp4. Amines may also be protected using Pms-4-nitrophenyl carbonate as a stable crystalline reagent that can be stored. The Pms group was cleavable with NaHCOi, hut Na2C03 was proved to be more efficient. ... 

Methyl 1)7-2,1,4-benzothiadiazine-3-carbamates 3 can be prepared from 2-nitroanilines and methyl isothiocyanatoformate via the (2-nitrophenyl)thioureas 1 by reductive ring closure effected by sodium dithionite.135... 

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