Propyl formate, hydrolysis

The mechanism of the acid-catalyzed decomposition of 1-alkyltriazolines has been studied <93JOC2097>. The hydrolytic decomposition of these triazolines in aqueous buffers leads predominantly to 1-alkylaziridines with lesser amounts of 2-(alkylamino)ethanol, alkylamines, and acetaldehyde. The rate of hydrolysis of 1-alkyltriazolines is about twice as fast as that of the analogous acyclic 1,3,3-trialkyltriazenes and varies in the order t-butyl > isopropyl > ethyl > butyl > methyl > propyl > benzyl <92JOC6448>. The proposed mechanism, involving rate-limiting formation of a 2-(alkylamino)ethyldiazonium ion, is shown in Scheme 65. A theoretical study ab initio calculation) of the acid-induced decomposition of 4,5-dihydro-l,2,3-triazolines has also been reported <91JA7893>. 

The first enzymatic polymerizations of substituted lactones were performed by Kobayashi and coworkers using Pseudomonas fluorescens lipase or CALB as the biocatalyst [90-92]. A clear enantiopreference was observed for different lactone monomers, resulting in the formation of optically active polymers. More recently, a systematic study was performed by Al-Azemi et al. [93] and Peelers et al. [83] on the ROP of 4-alkyl-substituted CLs using Novozym 435. Peelers et al. studied the selectivity and the rates as a function of the substituent size with the aim of elucidating the mechanism and the rate-determining step in these polymerizations. Enantio-enriched polymers were obtained, but the selectivity decreased drastically with the increase in substituent size [83]. Remarkably for 4-propyl-e-caprolactone, the selectivity was for the (R)-enantiomer in a polymerization, whereas it was S)-selective in the hydrolysis reaction. Comparison of the selectivity in the hydrolysis reaction (Fig. 10b) with that of the polymerization reaction (Scheme 8a) revealed that the more bulky the alkyl substituent, the more important the deacylation step becomes as the rate-determining step. 

The presence of surface OH groups or H2 O molecules can play a primary role in adsorption. For example, a microcalorimetric study of the adsorption of stearic acid, from heptane solution, on ferric oxide (Husbands et al., 1971) revealed that preadsorbed water enhanced adsorption of stearic acid. When adsorption takes place from a dry organic liquid, residual surface water may act as special agent. This was shown for the adsorption of a silane coupling agent (y-amino-propyl-triethoxysilane) on silica covered with water molecules for 6 < 1 (Trens and Denoyel, 1996). By the simultaneous determination of adsorption isotherms and the enthalpies of displacement (of heptane by various silanes) it was demonstrated that the amine function was able to displace some of the surface water and make it available for the hydrolysis of the silane into trisilanol, whereas the residual water was able to promote the formation of siloxane bonds between the trisilanol molecules and the surface. 

In contrast, the intermediately formed methylenecyclopropane 44 reacts with electron-rich alkenes to give cycloadducts, e.g. 45, with the bis(acceptor)methylenecyclopropane reacting as a heterodiene. This hetero-Diels-Alder reaction is also applicable to electron-rich alkynes, e.g. formation of 46. Thus, a solution of 3-acetoxy-5,5-dimethyl-2-(l-piperidinocyclo-propyl)cyclohexen-2-enone (47) and 1 equivalent of alkyne was reacted at 36°C for 4 hours. Alkyl-substituted alkynes, although applied in great excess, did not form any products. Depending on the substituents, further acidic hydrolysis opens up a method for the preparation of acetates or lactones. 

Hydrolysis of the ester with NaOH and p-lactone formation gave the propyl analogue 206 of 113 in >20% yield from simple starting materials over ten steps. 

The etherification of 4-mercaptoacetanilide with w-propyl bromide gives rise to the formation of 2-nitro-4 (propylthio) acetanilide with the elimination of one mole of HBr. The resulting product upon hydrolysis converts it to an amine, reduction with SnCl2 to a diamine, and finally interaction with S-methyl thiourea affords eyelization to yield carbamie aeid [5-(propylthio)-IH benzimidazol-2-amino]. This upon acetylation with methyl ehloroformate affords the offieial eompound albendazole. 

Fused Azepines.—Formation. A convenient route to benzazepinones (25) in which the aryl ring has an electron-donating substituent (R) is provided by the cyclization of y-(aryl)propyl isocyanates, using phosphorus oxychloride and stannic chloride.The benzazepine-l,3-dione (27) was synthesized by ring-closure of (26) and hydrolysis of the chloroimide (28) that was formed irradiation of (27) produced mainly dimers at the alkene bond. ... 

Derivatives of carboxylic acids such as amides are relatively stable to hydrolysis and can exist in aqueous solutions, at least at pH 7. However, the important modification of this reaction, namely rapid one-step formation of amides in aqueous media at room temperature, has been proposed only in 2007. " Besides the selected amine, 2,2,2-trifluoroethylamine hydrochloride (TFEA), special catalyst should be used ethyl-[3-(dimethylamino)propyl]carbodiimide, C2H5-N=C=N-... 

Write a balanced chemical equation using condensed structural formulas for (a) foe formation of propyl acetate from foe appropriate acid and alcohol (b) the saponification (base hydrolysis) of methyl benzoate. 

Generally, esters are actually derived from a reaction between a carboxylic acid and an alcohol (accompanied by the loss of water) and the reaction of water with an ester ( hydrolysis ) produces the carboxylic acid and the alcohol. Thus, as shown in Scheme 5.6, the formation of the ester propyl propanoate and its hydrolysis to... 

Reaction of ethyl crotonate and nitroethane in the presence of the basic 1,8-diaza-bicyclo[5.4.0]undec-7-ene (DBU) led to nitro-ester 3.49 in 74% yield.31 Catalytic hydrogenation of the nitro group and acid hydrolysis produced 3-methyl-4-amino-butanoic acid, 3.50. Choosing different conjugated esters as starting materials led to formation of 3-ethyl- (59% overall yield) 3-propyl- (51% overall yield) 3-isopropyl-(62% overall yield) 3-butyl- (56% overall yield) 3-sec-butyl- (60% overall yield) 3-isobutyl- (58% overall yield) and, 3-r-butyl-4-aminobutanoic acid (31% overall yield).31 The yields observed in this study clearly show that conjugate addition of nitro enolates is a synthetically useful process. 

Trifluoromethylpurines have been prepared mainly through formation of the pyrimidine ring starting from highly functionalised imidazoles. 5-Amino-4-(cyanoformimidoyl)imidazole 29 reacted rapidly with neat trifluoroacetic anhydride to give the 6-cyano-2-trifluoromethylpurine 30 (20 °C, 10 min, 52 %) [55] (Scheme 13). However, hydrolysis to the 6-carboxamidopurine 31 was observed when the reaction was carried out over several days [55,56]. This latter transformation has been applied to prepare 9-(3-hydroxy-propyl)-2-trifluoromethyl-9H-purine-6-carboxamide [57]. 

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