Hydrazine carboxylate, methyl

Phenyl isocyanate, with ethyl hydrazine-carboxylate to give 4-phenyl-l-car-bethoxysemicarbazide,51,122 Phenylmercuric acetate, with methallyl alcohol to yield 2-methyl-3-phenyl-propionaldehyde, 51, 17 1-PHENYL-1,3-PENTADIYNE, 50, 97 1-PHENYL-1,4-PENTADIYNE. 50, 97 a-Phenylpentanal, from 2-benzyl-4,4,6-trimethyl-5,6-dihydro-l,3(4H)-... 

In a dry flask containing 4.2 ml of 1.89 M phosgene in toluene was added a solution of 9H-fluoren-9-yl-methyl hydrazine carboxylate (3.91 mmol) dissolved in 40 ml of CH2CI2 and 40 ml of saturated aqueous NaHC03 solution. The mixture ws stirred 15 minutes and 58 mg of product isolated. IR data supplied. 

For the mechanism of this reaction, see Robinson and Robinson,1918, H3i 639 1924, 145, 827.) The reaction is of wide application for example, the use of methyl-phenyl-hydrazine, CsH5(CHj)> -iN H, in the above reaction gives i-methyl-2-phenylindole, whereas pyruvic acid, CH CO COOH, when converted to its phenylhydrazone and then indolised, gives indole-2-carboxylic... 

The aminolysis of esters of pyrimidine occurs normally to yield amides. The reagent is commonly alcoholic ammonia or alcoholic amine, usually at room temperature for 20-24 hours, but occasionally under refiux aqueous amine or even undiluted amine are used sometimes. The process is exemplified in the conversion of methyl pyrimidine-5-carboxylate (193 R = Me) or its 4-isomer by methanolic ammonia at 25 °C into the amide (196) or pyrimidine-4-carboxamide, respectively (60MI21300), and in the butylaminolysis of butyl ttracil-6-carboxylate (butyl orotate) by ethanolic butylamine to give A-butyluracil-5-carboxamide (187) (60JOC1950). Hydrazides are made similarly from esters with ethanolic hydrazine hydrate. 

Phenylpyrido[4,3-d]pyrimidin-o(677)-ones (145) have been prepared from 7-phenylpyrano[4,3-d]pyrimidin-5(6/7)-ones (144) by treatment with ammonia, hydroxylamine, or hydrazine at room temperature. The utility of the route lies in the rapid preparation of 4-methyl-2-phenylpyrimidine-5-carboxylic acid (143) from cheap... 

Electrophilic substitution of the ring hydrogen atom in 1,3,4-oxadiazoles is uncommon. In contrast, several reactions of electrophiles with C-linked substituents of 1,3,4-oxadiazole have been reported. 2,5-Diaryl-l,3,4-oxadiazoles are bromi-nated and nitrated on aryl substituents. Oxidation of 2,5-ditolyl-l,3,4-oxadiazole afforded the corresponding dialdehydes or dicarboxylic acids. 2-Methyl-5-phenyl-l,3,4-oxadiazole treated with butyllithium and then with isoamyl nitrite yielded the oxime of 5-phenyl-l,3,4-oxadiazol-2-carbaldehyde. 2-Chloromethyl-5-phenyl-l,3,4-oxadiazole under the action of sulfur and methyl iodide followed by amines affords the respective thioamides. 2-Chloromethyl-5-methyl-l,3,4-oxadia-zole and triethyl phosphite gave a product, which underwent a Wittig reation with aromatic aldehydes to form alkenes. Alkyl l,3,4-oxadiazole-2-carboxylates undergo typical reactions with ammonia, amines, and hydrazines to afford amides or hydrazides. It has been shown that 5-amino-l,3,4-oxadiazole-2-carboxylic acids and their esters decarboxylate. 

Carboxylic acids 6,7-Dimethoxy-1 -methyl-2(l H)-quinoxalinone-3-propionylcarboxylic acid hydrazine 70... 

Ethyl 3-methyl-5-oxopyrazoline-4-carboxylate and its I-methyl derivative were prepared in the reaction of diethyl acetylmalonate and hydrazine hydrate, and methylhydrazine in acetic acid at 95-100°C for 3 hr in 83% and 95% yields, respectively (89SC2087). 

The hydroxymethyl and carboxyl group of Ser can participate in pyrazole-ring formation, as shown in the transformation of A -protected L-Ser with the Mitsunobu reagent into a /3-lactone which afforded the N-protected serine hydrazide upon treatment with methyl hydrazine. Cyclization to 25 was achieved by diisopropyl azodicarboxylate (DIAD) and TPP [90H(31)79]. 

Isocarboxazid Isocarboxazid, 2-benzylhydrazid-5-methyl-3-isoxazolecarboxylate (7.2.6), can be synthesized from acetylacetone, which on nitrosation with nitrous acid gives 5-methyl-isoxazol-3-carboxyhc acid (7.2.2). Esterification of this product gives the ethyl ester of 5-methyl-isoxazol-3-carboxyhc acid (7.2.3). The synthesized ester (7.2.3) is further reacted with benzylhydrazine, to give isocarboxazide (7.2.6), or with hydrazine, which forms 5-methyl-isoxazol-3-carboxylic acid hydrazide (7.2.4). Reacting the latter with benzaldehyde gives hydrazone (7.2.5), which is further reduced to the isocarboxazide (7.2.6) [46,47]. 

Ring transformation of ethyl 2,4-dioxo-l,2,3,4-tetrahydropyrido[2,3- pyrimidine-5-carboxylates 317 with 80% hydrazine hydrate in boiling ethanol gave a mixture of 5-methyl/allyl/benzylamino-l,2,3,4-tetrahydro-l,4-dioxopyr-ido[3,4-i/ pyridazines 318, pyrido[2,3,4-< <7]pyridazino[3,4-/ [l,2,4]triazepines 319, and a low yield of 2,3,4,6,7-penta-azaphenalene 320. The reaction of 317 with hydrazine hydrate was also performed without a solvent in an oil bath at 125 °C for 1 h to give the same products, but higher yields of 318 and lower yield of 319 as well as traces of 320 were obtained (Equation 25) <1997FA657>. 

The synthesis of a triptan with a chiral side chain begins by reduction of the carboxylic acid in chiral 4-nitrophenylalanine (15-1). The two-step procedure involves conversion of the acid to its ester by the acid chloride by successive reaction with thionyl chloride and then methanol. Treatment of the ester with sodium borohy-dride then afford the alanilol (15-2). Reaction of this last intermediate with phosgene closes the ring to afford the oxazolidone (15-3) the nitro group is then reduced to the aniline (15-4). The newly obtained amine is then converted to the hydrazine (15-5). Reaction of this product with the acetal from 3-chloropropionaldehyde followed by treatment of the hydrazone with acid affords the indole (15-6). The terminal halogen on the side chain is then replaced by an amine by successive displacement by means of sodium azide followed by catalytic reduction of the azide. The newly formed amine is then methylated by reductive alkylation with formaldehyde in the presence of sodium cyanoborohydride to afford zolmitriptan (15-7) [15]. 

Meszaros, Hermecz et al. transformed the quaternary 6,7.8,9-tetrahydro-pyrido[1.2-u]pyrimidinium salts (204) with acid to the carboxylic acids (205 R1 = H)257 and with sodium hydrogen carbonate solution to the l,6,7,8-tetrahydropyrido[l,2- ]pyrimidines (205 R = alkyl).7x2 8 From the alkaline hydrolysis reaction mixture, compounds 206 and 207 were also isolated.133 The quaternary salt (204 R = Me) was transformed with hydrazine hydrate to 6-methylpiperidone and with ammonia to 6-methyl-4-oxo-6.7,8,9-tetrahydro-4//-pyrido[1.2- ]pyrimidine-3-carboxamide and its A-methyl derivative.133... 

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