Benzyl methylester

N-Benzyl- -methylester 213 N,N-Diacetyl- -iithylester 240 N,N-Dimethyl- -athylester 205, 238 Phenyl- 614... 

A mixture of 4.98 g of acetoacetic acid N-benzyl-N-methylaminoethyl ester, 2.3 g of aminocrotonic acid methyl ester, and 3 g of m-nitrobenzaldehyde was stirred for 6 hours at 100°C in an oil bath. The reaction mixture was subjected to a silica gel column chromatography (diameter 4 cm and height 25 cm) and then eluted with a 20 1 mixture of chloroform and acetone. The effluent containing the subject product was concentrated and checked by thin layer chromatography. The powdery product thus obtained was dissolved in acetone and after adjusting the solution with an ethanol solution saturated with hydrogen chloride to pH 1 -2, the solution was concentrated to provide 2 g of 2,6-dimethyl-4-(3 -nitrophenyl)-1,4-dihydropyridlne-3,5-dicarboxylic acid 3-methylester-5- -(N-benzyl-N-methylamino)ethyl ester hydrochloride. The product thus obtained was then crystallized from an acetone mixture, melting point 136°Cto 140°C (decomposed). 

Benzoyl- 313 Natrium-Salz 316 4-Benzoyl- 159, 313 4-Benzoyl- -(-)-mcnthylester 324 4-Benzoyl- -methylester 289 4-Benzyl- 313 -benzylester 184,69/... 

Oxo-3-(2-nitro-phenyl)- -methylester 477 3-Oxo-3-phenyl-2-benzyl- -nitril 562 3-Oxo-3-phenyl- -nitril 562 Pentafluor- 147... 

Amidocarbonylation methodology can also be applied to the synthesis of N-acclyl- (D,L)-phenylalanine, a key intermediate for aspartame (1-aspartyl-l-phenylalanine methylester), from styrene oxide (via isomerization to phenac-etaldehyde) [24] or benzyl chloride [25] in good yields. 

The variety of educts and products of the higher MCRs is illustrated here. Product 72 (Scheme 1.18) is formed from the five functional groups of lysine, benzaldehyde, and tert-butylisocyanide. The synthesis of 73 is achieved with hydrazine, furanaldehyde, malonic acid, and the isocyano methylester of acetic acid, compound 74 results from the reaction of benzylamine, 5-methyl-2-furanaldehyde, maleic acid mono-ethylester, and benzylisocyanide. ° Zhu et al. prepared a variety of related products, such as, 75, from (9-amino-methyl cinnamate, heptanal, and a-isocyano a-benzyl acetamides. 

On the basis of this pioneering work, Rubenbauer and Bach developed a Bi(OTf)3-catalyzed highly diastereoselective benzylation of silyl enol ethers [65]. Various cyclic and acyclic silyl enol ethers were amenable to this protocol (Scheme 24). Various a-substituted benzyl acetates were tested with terf-butyl-substituted silyl enol ether 31a, and the use of only 1 mol% of Bi(OTf)3 was enough to obtain the desired benzylated ketones 32 in high yields and with excellent diastereoselectivities (up to 95 5). Whereas a-nitro- (30a), ot-cyano- (30b) and a-methylester-substituted (30d) benzyl acetates gave the anti diastereoisomer as the major product, the phosphonate-substituted benzyl acetate (30c) exclusively resulted in the syn isomer (Scheme 24). 

Als basische Katalysatoren fur die Michael-Addition konnen auch Benzyl-trimethyl-am-moniumhydroxid (Methode ) oder Natronlauge (Methode ) verwendet werden. Die Reaktion von Propensaure-methylester mit Nitro-alkanen kann je nach Substitutionsgrad der Nitro-Verbindung und Verhaltnis der Edukte zu Mono(I)-, Bis(II)- oder Tris(III)-Ad-ditionsprodukten fiihren2,3. 

Die Addition von 7-Nitro-4-oxo-heptansaure-methylester an Acrylnitril in methanolischer Benzyl-trimethylammonium-hydroxid (Triton B)-Losung fuhrt zu 7-/Vitro-4-oxo-decandi-saure-methylester-nitril (40% )4 ... 

S. 5S>H-Ile-OMe H5C6-CIIa-Br H2C = CH - CH2 - Br 94 87 88 75 (S) (S) (S) -2-Amino-2-benzyl-3-methyl-pent an-saure-methylester (S) -2-Amino-2- (1-methyl-propyl) -4-penlensaure-methyl-esler 1... 

Amin Reaktionszeit [h]. .. -S-Benzyl-N-phthaloyl-cystein-methylester opt. Ausbeute [%ee]... 

Thus, the N-protected indoline 211 (Scheme 33), on regiospecific metallation followed by bromination with dibromotetrafluoroethane provided the 7-bromoindoline 212. Removal of the urethane functionality and subsequent benzylation of the free amine formed, furnished the tertiary amine 213. Addition of oxazoline 214 derived from 2,4,5-trimethoxybenzaldehyde to the Grignard reagent prepared from 213, followed by acid hydrolysis of the resulting biaryl 215 afforded the 2-substituted isobutylbenzoate 216. Catalytic N-debenzylation of the methylester 217 obtained by transesterification of 216 yielded oxoassoanine (203). 

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