Ethyl imine

A 1 2 mixture of MejSiNEt2 and Mel induces the ring cleavage of oxazolidines to afford the corresponding A-[2-(trimethylsiloxy)ethyl]imine <02JOC5170>. 

Ethylamine is not as readily metabolized as methyla-mine, and portions are excreted unchanged from the lung and in the urine. The metabolism of ethylamine is believed to occur in two stages. The amino group is initially dehydrogenated to an intermediate imine (ethyl imine), which reacts spontaneously with water, forming the corresponding aldehyde (acetaldehyde) and ammonia. The final metabolic products of acetic acid and urea are excreted in the urine. Ethylamine is a normal constituent of mammalian and human urine. 

Poly[ethylene-N-(P-trimethylsilyl ethyl)imine] Bisphenol-A polycarbonate Poly(P-propiolactone)... 

The method of determination by means of the alkyl iodides does not, as a rule, distinguish between ethyl imine and methyl imine in doubtful cases it is necessary to distil a considerable quantity of the hydriodide of the base, and purify and identify the alkyl iodide which is evolved. A second method consists in distilling the base with potassium hydroxide, evaporating the distillate to dryness with hydrochloric acid, separating the organic hydrochlorides from ammonium chloride by means of absolute alcohol and chloroform, and converting the former into pic rates, chloroplatinates, etc., which may then be identified the method must however, be used with caution, as it may lead to errone ous results. 

Allylic phosphates are used for carbonylation in the presence of amines under pressure. Carbonylation of diethyl neryl phosphate (389) affords ethyl homonerate (390), maintaining the geometric integrity of the double bond[244]. The carbonylation of allyl phosphate in the presence of the imine 392 affords the /3-lactam 393. The reaction may be explained by the formation of the ketene 391 from the acyl phosphate, and its stereoselective (2 + 2] cycloaddition to the imine 392 to give the /3-lactam 393(247],... 

Write an equation showing how you could prepare ethyl phenyl ketone from propanenitrile and a Grignard reagent What is the structure of the imine intermediate ... 

Similar intermediates including o-ethoxycarbonyl-, o-cyano- and o-dimethyl-aminomethylene-piperidones or their imines have been used to give partially reduced analogues, e.g. (244), in the [2,3-. 

The assumed transition state for this reaction is shown in Scheme 5.5. The two bulky t-butoxy groups are expected to locate at the two apical positions. One of the 3,3 -phenyl groups would effectively shield one face of an imine, and consequently, a diene attacks from the opposite side. Judging from this model, similar selectivities were expected in the Mannich-type reactions of imines with silyl eno-lates. Actually, when ligand 10 was used in the reaction of imine la with S-ethyl-thio-l-trimethylsiloxyethene, the corresponding / -amino thioester was obtained in 84% ee (Scheme 5.6). As expected, the sense of the chiral induction in this case was the reverse of that observed when using catalyst 6 [12, 25]. 

One of the standard methods for construction of the basic heterocyclic ring was elaborated not long after the turn of the century. Thus, condensation of ethyl lactate with guanidine leads to the imine of the desired ring system (47), possibly by a reaction scheme such as that outlined below. Hydrolysis affords the oxazolidinedione (48). Methylation in the presence of base gives 49. 

One of the earliest preparations of this ring system starts with displacement of the hydroxyl of benzaldehyde cyanohydrin (125) by urea. Treatment of the product (126) with hydrochloric acid leads to addition of the remaining urea nitrogen to the nitrile. There is thus obtained, after hydrolysis of the imine (127), the hydantoin (128). Alkylation by means of ethyl iodide affords ethotoin (129)... 

Benzaldehyde cyanohydrin is reacted with urea to displace the hydroxyl group of the cyanohydrin. That intermediate is treated with HCI to convert the urea nitrogen to a nitrile. The resultant imine is hydrolyzed to the phenylhydantoin. Alkylation with ethyl iodide gives ethotoin, as described by A. Pinner in Chem. Ber. 21, 2325 (1888). 

From the sulfonyl-urethane described above and N-amino-hexamethylene-imine, there is obtained, in a yield of 70%, the compound 4-[[4-[)3-[5-methyl-isoxazolyl-(3)-carboxamido]-ethyl]-benzene-sulfonyl] ]-1,1-hexamethylene-semicarbazide in the form of colorless crystals of MP 189°C. 

Cl Compound of Code No. CM 6912 25 g of the imine obtained under (B), dissolved in 400 ml of acetic acid, are heated at the reflux temperature for 1 hour. After evaporating the solvent in vacuo, the residue is taken up in methylene chloride. The solution is washed with a dilute sodium bicarbonate solution and then with water. After evaporating the solvent, the residue is chromatographed on silica, elution being carried out with an 80/20 mixture of ether and ethyl acetate. 9 g of benzodiazepine are thus obtained. Melting point 196. ... 

However, valence isomerism in some l//-azepinc-4,5-dicarboxylates, e.g. 3, which is undetectable by NMR spectral measurements, has been confirmed by trapping out the benzene imine tautomers 4, as their bisdipolar cycloadducts 5, with diazomethane.233,234 In contrast, ethyl l//-azepine-l-carboxylate and diethyl l-acetyl-l//-azcpinc-3,5-dicarboxylate, with diazomethane, yield only the C4-C5 dipolar cycloadducts. 

The suggested reaction mechanism involves a nucleophilic attack of the imine nitrogen at the activated triple bond, followed by a proton exchange, to give a benzimidazolinium system which, by intramolecular attack at the carbonyl group, leads to an epoxide that ring opens to the observed product. For the ethyl derivative (R = Et) a tub conformation could be established by X-ray crystallographic analysis.33... 

Synthesis of aziridines by treatment of carbenes with imines was reported by Jacobsen [56]. A metallocarbene 104 derived from ethyl diazoacetate and copper fluorophosphate was treated with N-arylaldimines to form aziridines with reasonable diastereoselectivities (>10 1 in favor of cis) but with low enantioselectivities (about 44% ee). This was shown to result from a competitive achiral reaction path-... 

The most successful approach in this reaction category has been the use of chiral boron Lewis acid catalysts, in the addition of ethyl diazoacetate to imines reported by Wulff (Scheme 1.33) [59-60]. 

Reactions between imines and a-diazo carboxylates afford aziridine-2-carboxylates [55]. An asymmetric version of this reaction using chiral nonracemic catalysts has been described [53, 56-58]. As an example, catalytic aziridination of inline 44 (Scheme 3.14) with ethyl diazoacetate in the presence of 10% catalyst generated... 

This area of research has only recently attracted the attention of synthetic organic chemists, but there has been a flurry of impressive activity in the area. Simple (i. e., unstabilized) carbenes suffer from many of the problems of nitrenes (vide infra) and most reported synthetically useful procedures use carbenoids the majority of recent reports have focussed upon reactions between a-diazoesters and imines in the presence of a range of catalysts. In one of the earliest reports of enantioselective carbene-imine reactions, for instance, Jacobsen and Finney reported that ethyl diazoacetate reacts with N-arylaldimines in the presence of cop-per(i) hexafluorophosphate with mediocre stereoselectivity to give N-arylaziridine carboxylates. Though the diastereoselectivities of the reaction were often acceptable (usually >10 1, in favor of the cis isomers) the observed enantioselectivity was low (no more than 44% ee Scheme 4.27) [33],... 

Probably the most widely applicable asymmetric imine aziridination reaction reported to date is that of Wulff et al. These workers approached the reaction from a different perspective, utilizing the so-called vaulted , axially chiral boron Lewis acids VANOL and VAPOL [35] to mediate reactions between ethyl diazoacetate and N-benzhydrylimines (Scheme 4.29) [36]. The reactions proceed with impressive enantiocontrol, but there is a requirement that the benzhydryl substituent be present since this group is not an aziridine activator there is, therefore, a need for deprotection and attachment of a suitable activating group. Nonetheless, this method is a powerful one, with great potential for synthesis, as shown by the rapid synthesis of chloroamphenicol by the methodology [37]. 

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