Hydroxy ethyl carbamate

The first reported synthesis of hydroxyurea (24) consists of the condensation of hy-droxylamine with potassium cyanate (Scheme 7.14) [87]. Condensation of hydroxy-lamine with ethyl carbamate also gives pure hydroxyurea in good yield after recrystallization (Scheme 7.14) [88]. Nitrogen-15 labeled hydroxyurea provides a useful tool for studying the NO-producing reactions of hydroxyurea and can be prepared by the condensation of N-15 labeled hydroxylamine with either potassium cyanate or trimethylsilyl isocyanate followed by silyl group removal (Scheme 7.14) [89, 90]. Addition of hydroxylamine to alkyl or aryl isocyanates yields alkyl or aryl N-hydroxyureas (Scheme 7.14) [91, 92]. The condensation of amines with aromatic N-hydroxy carbamates also produces N-substituted N-hydroxyureas (Scheme 7.14) [93]. 

Acetyluracil — Ethyl 2-hydroxy-4-methyl-5-pyrimidinecarboxylate (XXXVI), which is prepared by the cyclization of the ureidomethylene derivative of aceto-acetic ester, can be caused to rearrange into 5-acetyluracil (XXXVII) in dilute alkali [304]. Compound (XXXVII) can also be prepared from diketene and ethyl carbamate, followed by treatment with ethyl orthoformate and cyclization with ammonia [305]. 

H- Benzimidazole, 2,2-pentamethylene-reduction, 5, 423 Benzimidazole-2-carbaldehyde oximes, 5, 436 Benzimidazolecarbaldehydes oxidation, 5, 437 Benzimidazole-2-carbamates 5-substituted as anthelmintics, I, 202 Benzimidazole-l-carboxylic acid, 2-amino-methyl ester reactions, 5, 453 Benzimidazole-2-carboxylic acid decarboxylation, 5, 435 Benzimidazole-3-carboxylic acid, 1-hydroxy-ethyl ester synthesis, 6, 407 Benzimidazoles acidity, 5, 50, 385, 386 acylation, 5, 71, 391, 402, 417 N-alkyl-... 

Ethylenediamine, Al,/V,A, A -tetramethyl- 1,2-Ethanediamine,, V,N.N1, h -tetramethyl-[110-18-9], 61,116 Ethylene glycol, 61, 65, 103 Ethyl ether, compared with boron fluoride (BF3)(1 1), 61, 116 Ethylmagnesium bromide, 60, 83 ETHYL threo-[ 1 -(2-HYDROXY-l, 2-DIPHENYL)ETHYL]CARBAMATE, 61,93... 

Ethyl threo-[l-(2-hydroxy-1,2-diphenyl)ethyl]carbamate Carbamic acid (2-hydroxy-1,2-diphenylethyl)-, ethyl ester, (/ , / )- (9) (73197-89-4) Ethyl carbamate Carbamic acid, ethyl ester (8, 9) (51-79-6)... 

Hydroxy tautomers of some types of 1,3-oxazinediones have been encountered in the previous section. Here, compounds normally represented as diketo compounds are described. Thus, aroyl-ketenes, generated through the thermolyses of 6-aryl-2,2-dimethyl-l,3-dioxin-4-ones, can be trapped by ethyl carbamate to give 7V-aroylacetylcarbamates (208). These products on heating give 6-aryl-... 

Amino-l-hydroxyethyl)phosphonic acid occurs in the plasma membrane of Acanthamoeba castellani and the 2R isomer is formed, in that organism, by the hydroxy-lation of (2-aminoethvl)phosphonic acid This biosynthesis step in vitro has been studied by Hammerschmidt" who synthesized various chiral deuterium-labelled derivatives of both compounds using the isotopically labelled 2-benzyloxyethanal in Abramov reactions to obtain, initially, the dimethyl (2-benzyloxy-l-hydroxyethyl)phosphonate (362). This ester was resolved through the diastereoisomeric carbamates 363 the separated carbamates were sequentially de-l-O-protected, silylated at the a-HO group, debenzylat-ed and, by means of the Mitsunobu reaction, converted into dimethyl [2-eizido- -(tert-butyldimethylsilyloxy)ethyl]phosphonates. Subsequently, standard reactions were used to transform the latter into the diastereoisomeric, isotopically labelled (2-amino-1-hydroxy-ethyl)phosphonic acid. 

Methyl [2-[4-hydroxy-2-[2-(4-hydroxyphenyl) ethenyl]phenyl]ethyl]carbamate, see G-30056... 

A mixture of 24.1 g (0.10 mol) of 3-o-methoxyphenoxy-2-hydroxy-1 -propyl carbamate and 6.0 g (0.10 mol) of urea was heated rapidly to the temperature range of 180°C to 200°C, and maintained there for five hours. The reaction melt was poured into 50% ethyl alcohol, from which the product crystallized as a white solid. The crude yield was 18.3 g (82%) melting point 131.5°C to 137 t. Crystallization from water and 95% alcohol gave 9.0 g (40.3%) of pure 5-o-methoxyphenoxymethyl-2-oxazolidone melting point 141°Cto 143. This melting point was not depressed when the material was mixed with an authentic sample. In additional runs acetone was used Instead of ethyl alcohol with equivalent results. 

The hydroxy derivatives on reaction with ethyl isocyanate in the presence of CuCl in THF gave the corresponding carbamate lactones. 

Ethyl -3 -hydroxy-A- (2 -methoxy-1 -methy lethy 1) -2 -oxo-l,2,3,4-tetrahydroquinoline, see Metolachlor Ethyl-A- (3-hydroxyphenyl)carbamate, see Desmedipham... 

Carbamate esters also produced 2-oxo compounds, e.g., the esters of 3-aminopropanol88 and of 3-halogenopropanol.87 A few compounds have thus been prepared from carbamates, e.g., 20, with an aromatic substituent88 [Eq. (10)] or a heterocyclic one.89 Ethyl 7V-(3-hydroxy-propyl) urethanes cyclize to 2-oxo compounds with sodium methoxide.78 An interesting novel approach was to react an A-(chloromethyl)-carbamate with olefins to yield 2190 [Eq. (11)]. 

The cyclohexene 121, which was readily accessible from the Diels-Alder reaction of methyl hexa-3,5-dienoate and 3,4-methylenedioxy-(3-nitrostyrene (108), served as the starting point for another formal total synthesis of ( )-lycorine (1) (Scheme 11) (113). In the event dissolving metal reduction of 121 with zinc followed by reduction of the intermediate cyclic hydroxamic acid with lithium diethoxyaluminum hydride provided the secondary amine 122. Transformation of 122 to the tetracyclic lactam 123 was achieved by sequential treatment with ethyl chloroformate and Bischler-Napieralski cyclization of the resulting carbamate with phosphorus oxychloride. Since attempts to effect cleanly the direct allylic oxidation of 123 to provide an intermediate suitable for subsequent elaboration to ( )-lycorine (1) were unsuccessful, a stepwise protocol was devised. Namely, addition of phenylselenyl bromide to 123 in acetic acid followed by hydrolysis of the intermediate acetates gave a mixture of two hydroxy se-lenides. Oxidative elimination of phenylselenous acid from the minor product afforded the allylic alcohol 124, whereas the major hydroxy selenide was resistant to oxidation and elimination. When 124 was treated with a small amount of acetic anhydride and sulfuric acid in acetic acid, the main product was the rearranged acetate 67, which had been previously converted to ( )-lycorine (108). 

C22HmNj05 171504-92-0) see Indinavir sulfate [3S-[2(lS, 2S ),3a,4aP,8aPIH3-I3- (l,l-dimethyl-ethyl)amino carbonyl)octahydro-2(l//)-isoquinolinyl -2-hydroxy-l-((phcnylthio)mcthyl propyl carbamic acid phenylmethyl ester... 

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