5-Benzyl-3-methoxycarbonyl

The N-atoms of 1,2,4-triazole and of the 1,2,4-triazolyl anion are preferentially attacked by electrophiles. The reaction of dimethyl sulfate with sodium 1,2,4-triazolide in acetonitrile gives a 100% yield of a mixture of 1-methyl- and 4-methyl-1,2,4-triazole in a proportion of 8.8 1. Similarly, benzylation, methoxycarbonylation and trimethylsilylation can be carried out, again leading mainly to 1-substituted compounds [159]. Quatemization of 1-methyl-1,2,4-triazole with trimethyloxonium tetrafluoroborate proceeds stepwise ... 

Chemical Name 2,6-Oimethyl-4-(3-nitrophenyl)-3-methoxycarbonyl-1 /4-dihydropyridine-5-carboxylic acld-2(N-benzyl-N-methylamino)ethyl ester hydrochloride... 

Athyl- 650, 652 1-Benzyl- 650, 652 l-Benzyl-3-aminocarbonyl- 650 1-Benzyl- -chlorid 593 l-Benzyl-4-methoxycarbonyl- -jodid 593... 

Similarly, tri-O-benzyl-glucal affords the corresponding manno-configurated methoxycarbonyl cyclopropanes upon treatment with methyl diazoacetate under... 

Dimethylcarbonate, in presence of K2CO3, has been found to react with benzyl aryl and alkyl aryl sulfones RCH2S02Ar at 180-210 °C to form the corresponding mono-C-methyl derivative selectively and in high yield. The monomethylation has been attributed to a methoxycarbonylation-methylation-demethoxycarbonylation sequence via ArS02C(Me)(C02Me)R. 

The amidic group in methyl A -acetyl-p-aminobenzoate was reduced preferentially to an ester group with borane in tetrahydrofuran (1.5-1.8 mol per mol of the amide), giving 66% yield of methyl p-A -ethylaminobenzoate. Similarly l-benzyl-3-methoxycarbonyl-5-pyrrolidone afforded methyl l-ben2yl-3-pyr-rolidinecarboxylate in 54% yield and l,2-diethyl-5-ethoxycarbonyl-3-pyra-zolidone gave ethyl l,2-diethylpyrazolidine-3-carboxylate in 60% yield. 

Alkylation of 2-methoxycarbonyl-l-oxoindane with these sugar-substituted sulfonium salts gives the (/f)-2-alkyl derivatives with enantiomeric excesses up to 12%, while alkylation of ethyl 2-methyl-3-oxobutanoate with allyl or benzyl(aryl)sulfonium perchlorates gives 2-allyl-(or benzyl)-substituted ethyl 2-methyl-3-oxobutanoates 5 with enantiomeric excess up to 25%12. 

Brom-5-formyl-l-( 4-methoxy-henzyl)-imidazol l-Benzyl-4-brom-5-carboxy-...946 /-Benzyl-4-brom-5-mercapto-...946 4-Brom-5-methoxycarbonyl-]-methyl-...1047 1033 50% 67% 68% 50% ... 

Analog erhalt man Brom- und Alkoxycarbonyl-substituierte Produkte wie z.B. 1-( 2-Brom-4-methoxycarbonyl-benzyl)-6,7-dimethoxy-2-methyl-1,2,3,4-tetrahydro-isochinolin (61%). Ein Beispiel aus der Steroid-Chemie ist die Herstellung von / 7fi-Dimelhylamino-3-hydroxy-17a-methyl-5-androsten aus einem Iminium-Salz2 ... 

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