Hydrazides s. Carboxylic acid

Hydration of carbon-carbon double bonds s. a. Alcohols from ethylene derivatives —, preferential 16, 194 19, 183 —, stercospecific 16, 194 Hydrazides s. Carboxylic acid... 

Carboxylic acid hydrazides from carboxylic acid esters GOOR -v CONHNHg with cis-frans-rearrangement s. 17, 413... 

Carboxylic acid hydrazides from carboxylic acids—Hydroxamic acids from 1-acylimidazoles—Carboxylic acid amides s. 18, 441... 

Hexokinase, 287 Homoarginine, 552, 553 Homobiotinyl p-nitrophenyl ester, 615 Homoserino, 156, 414 Hydrazides as inhibitors, 38 test for, 211 Hydrazines, 210 synthesis of, 210 Hydrazones, test for, 211 Hydrocinnamaldehyde, 125 Hydrocinnamic acid, 123 Hydrofluoric acid, 201 Hydrogenation, 200 Hydrogen peroxide, 49-51, 315 Hydrophobic probes, 191 3/S-Hydroxy-5-androstene-17/S-carboxylic acid, 477... 

Subst. carboxylic acid hydrazides from carboxylic acids GOOH GONHNHR via carboxylic acid chlorides s. 13, 462... 

Subst. carboxylic acid amides from carboxylic acid hydrazides via carboxylic acid azides s. 14-, 486 CONHNH2 CON<... 

Thiazole carboxylic acid hydrazides were prepared in a similar way (444, 445). Thus by refluxing thioacetamide or thiobenzamide with y-bromoaceto acetic ester arylhydrazones (83) for several hours in alcohol the 4-carboxythiazole derivatives (84) listed in Table II-ll were obtained (Scheme 36) (656). This reaction is presumed to proceed via dehydration of the intermediate, thiazoline-S-oxide. 

Claisen ester condensation, 6, 279 Thiazolecarboxylic acid chlorides reactions, 6, 279-280 Thiazolecarboxylic acid hydrazides synthesis, 6, 280 Thiazolecarboxylic acids acidity, 6, 279 decarboxylation, 6, 279 reactions, S, 92 6, 274 Thiazole-2-carboxylic acids decarboxylation, S, 92 Thiazole-4-carboxylic acids stability, S, 92 Thiazole-5-carboxylic acids decarboxylation, S, 92 Thiazole-4,5-dicarboxylic acid, 2-amino-diethyl ester reduction, 6, 279 Thiazole-4,5-dicarboxylic acids diethyl ester saponification, 6, 279 Thiazolediones diazo coupling, 5, 59 Thiazoles, 6, 235-331 ab initio calculations, 6, 236 acidity, S, 49 acylation, 6, 256 alkylation, S, 58, 73 6, 253, 256 analytical uses, 6, 328 antifogging agents... 

Amino-S-hy droxy-1,2,3-triazole-4-carboxylic acid hydrazide 1 A218... 

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 reaction was applied to model dipeptides exemplified by the y-phenyl-hydrazide of N-carbobenzoxy-a-L-glutamyl-L-methionine methyl ester (4) and found to afford the carboxylic acid (S) in good yield without disturbance of the carbo-benzoxy and ester protective groups. The results suggest use of the phenylhydrazide group for protection of carboxyl groups in peptide chemistry. 

The products of the reaction between carboxylic acid hydrazides and carbon disulfide cyclize very readily to Zl4-l,3,4-oxadiazoline-2-thiones (LXXXIII) (see Section II.7). The intermediates, the acyl- or benzoyl-dithiocarbazic acids may, however, also be isolated and reacted with alkyl halides to give S-alkyl dithiocarbazates (LXXXVIIIa) which also cyclize easily either to thiadiazoline or oxadiazoline rings according to the reaction circumstances (see Section II.7). 

RESOLUTION Dehydroabietylamine. d- and /-Of-Methylbenzylamine. (S)-l-Nitroso-2-methylindoline-2-carboxylic acid. /.-Tyrosine hydrazide. 

The synthesis of carbohydrazides from the corresponding 1-acylimidazoles by Staab s method703,1166 proceeds under very mild conditions an equimolar mixture of carboxylic acid and l,Tcarbonyldiimidazole is heated in anhydrous tetrahydrofuran until evolution of carbon dioxide ceases and is then treated with the requisite hydrazine derivative. Hydrazine hydrate can be used to provide unsubstituted hydrazides since hydrazinolysis of the acylimidazole is faster than its hydrolysis.703,1166... 

Chemicals Required. Benzaldehyde 80 g Ethanol [95% (v/v)] 750 ml 5-Methyl-3-isoxazole-carboxylic acid hydrazide 72 g l-Benzylidene-2-(5-methyl-3-isoxazolylcarbonyl) hydrazine 11.5 g Anhydrous Solvent Ether 500 ml Pure LiAlH 1.85 g Ethyl acetate 25 ml Benzene 20 ml Methanol q.s. 

---