Carbamic acid hydrazide

SYNS AMINOUREA CARBAMIC ACID HYDRAZIDE CARBAMOYLH T)RAZINE CARBAMYLHYDRA-ZINE CARBAZAMIDE SEMICARBAZIDE... 

CARBAMIC ACID HYDRAZIDE see HGUOOO CARBAvnC ACID, ISOPROPYL ESTER see lOJOOO CARBAiMIC ACID, N-METHYL-, 3-DIETHYLARSINOPHENYL ESTER, METHIODIDE see MID900... 

Experiments.—Being a primary hydrazide (of carbamic acid), semicarbazide reduces ammoniacal silver solutions and Fehling s solution. It reacts readily with aldehydes and ketones with the elimination of water and formation of semicarbazones, which, since they are more easily hydrolysed than are phenylhydrazones and oximes, are to be preferred to the latter for purposes of separation and purification of carbonyl compounds. Shake an aqueous solution of the hydrochloride (prepared as described above) with a few drops of benzaldehyde, isolate the semicarbazone and purify it by recrystallisation from alcohol. Melting point 214° decomp. Benzaldehyde semicarbazone is decomposed into its constituents by gentle warming with concentrated hydrochloric acid. 

Chiral aliphatic isocyanates 384, which are applied to aminopropyl columns to render them chiral for the resolution of racemic amines, alcohols, and acids as amide, urea, carbamate or hydrazide derivatives, have been prepared with triphosgene. The authors found that approximately 0.66 mol rather than 0.33 mol of triphosgene was required per mol of amine, presumably because of a loss of phosgene gas along with the HQ by-product [270]. 

Early attempts to prepare 4(5)-aminoimidazole (25 R = H) from the carbamates (34 R = Me, Et) [obtained from the hydrazide (35) using the Curtius method] by either acid- or base-catalyzed hydrolysis resulted in failure (30JCS268). 

An ester group at C-3 or C-5 is not different in function from any ester in aliphatic or aromatic compounds. The ester can be converted into an amide or a hydrazide, or it may be hydrolyzed. The hydrazide can be converted into an acid azide and rearranged to an isocyanate which in turn will form a carbamate or can be hydrolyzed to an amine. However, the amine group can be replaced with chlorine by diazotization in hydrochloric acid, not an ordinary pattern of behavior (76AHC(20)65) although similar reactions do occur in the 1,2,4-triazole ring system. 

Malathion phosphoro organic, phosphoro dithioate Maleic hydrazide heterocyclic nitrogen, pyridazinedione Mancozeb dithiocarbamate Maneb dithiocarbamate MCPA phenoxy carboxylic acid MCPA-Thioethyl (other) thioate MCPB phenoxy carboxylic acid Mecarbam phosphoro organic, phosphoro dithioate, carbamate... 

Carboxylic acids, protection of, 224-276 as amides and hydrazides, 270-276 as esters, 227-270 Reactivity Chart 6, 433-436 S-Carboxymethyl thioethers, to protect thiophenols, 294-295 Catechols, protection of, 170-174 as cyclic acetals and ketals, 170-172 as cyclic esters, 173-174 Reactivity Chart 4, 425-428 CBZ, see Benzyl carbamates Chloroacetamides, to protect amines, 352-353... 

The azide 465, obtained from the hydrazide 462 with sodium nitrite in 50% acetic acid, afforded the carbamates 466 in refluxing alcohol. The presence of traces of water resulted in the formation of the urea 467 as by-product. 

N-Carbethoxyamidines 10 Carbalkoxycyanamides Carbalkoxyhydrazones N-Carbamylnitrones 0-Carbamyloxi mes Oxime carbamates 20 N-Carbonylureas Carboxylic acid alkoxymethylene-hydrazides... 

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