Amino acetal

Glycine or amino-acetic acid, NHjCHjCOOH tyrosine, />-HOC<.H4CH2CH(NH2)COOH cystine, [ SCH2CH(NH2)COOH]2. 

The facile formation of cyclobutane products is indeed another important contribution of enamine chemistry (302-306). The formation of cyclobutanes has also been found in the closely related reactions of amino acetal derivatives of ketenes with acrylic esters (307). 

The configuration of the amine was retained, except in the case of amino acid derivatives, which racemized at the stage of the pyridinium salt product. Control experiments showed that, while the starting amino acid was configurationally stable under the reaction conditions, the pyridinium salt readily underwent deuterium exchange at the rz-position in D2O. In another early example, optically active amino alcohol 73 and amino acetate 74 provided chiral 1,4-dihydronicotinamide precursors 75 and 76, respectively, upon reaction with Zincke salt 8 (Scheme 8.4.24). The 1,4-dihydro forms of 75 and 76 were used in studies on the asymmetric reduction of rz,>S-unsaturated iminium salts. 

The Pomeranz-Fritsch-Bobbitt cyclisation of activated amino-acetal 38 yielded the desired 4-hydroxyquinoline 39 in acceptable yield. The non-obvious regioselectivity of the cyclisation can be attributed to the overriding para-directing effect of alkoxy groups. ... 

Acid-catalyzed hydrolysis of the latter followed by Jones oxidation furnished racemic peshawarine (43) (Scheme 12). Simanek et al. (59) transformed the same amino acetal 47, obtained in optically active form from the Emde degradation of rhoeadine methiodide (48), to ( )-43, also by hydrolysis and oxidation. However, the optical activity was lost during hydrolysis (Scheme 12). 

Using the chiral a-amino acetal 1-120 ion and two different N-nucleophiles 1-122 and 1-123, the pyrrolidines 1-124 and 1-125, respectively, are obtained in good di-... 

The treatment of (2-benzoylamino-5-iodobenzoyl-amino)acetic acid ethyl ester 88 with hydrazine hydrate for 4h yielded hydrazine derivative 2-benzoylamino-iV-hydrazinocarbonylmethyl benzamide 89, which on refluxing with sodium acetate and acetic acid for 8 h resulted in the formation of 6-iodo-10-phenyl-3//-3,4,9,10a-tetra-azaphenanthren-2-one 90 <2000IJH59> (Scheme 5). 

Glycine H2N—CH2—COOH (a-amino acetic acid i.e., and aliphatic amino acid) ... 

Oxidation of sulphonamides in the presence of bromide or iodide ions and sodium methoxide in methanol also leads to formation of the N-halogeno intermediate. The nitrogen-halogen bond in these intermediates is weak and will undergo themiolysis. At -10 °C, reaction proceeds by base catalysed elimination of hydrogen halide and ftirther steps lead to an a-amino acetal 20. The reaction is carried out in an undivided cell and renders a-aminoacetals readily available for the iso-... 

A. Methyl a-[(methoxyethylidene)amino]acetate (1). A flame-dried, 500-mL, twonecked, round-bottomed flask is equipped with a stir bar, rubber septum, eind an argon inlet. The flask is charged with methyl acetimidate hydrochloride (10.0 g, 91 mmol) (Note 1) and dry dichloromethane (140 mL) (Note 2). The stirred suspension is cooled to 0°C and solid methyl glycinate hydrochloride (11.5 g, 91 mmol, Note 1) is added in one portion with a powder funnel under a stream of Ar. After the mixture is stirred for 45 min at 0°C, a solution of dry triethylamine (12.7 mL, 91 mmol) (Note 2) in dry dichloromethane (11 mL) is added via syringe pump during 2.5 hr. Stirring is continued for 5 hr while the mixture is... 

Methyl a-[(methoxyethylidene)amino]acetate Glycine, N-(l-methoxyethylidene)-, methyl ester (10) (64991-38-4)... 

Substrates include benzyl (2 g) and cinnamyl (2.7 g) alcohols to acids cyclopentanol (1 g), benzhydrol (3.9 g), benzoin (4 g), pantolactone (2.6 g) to ketones (RuCy TCCA/( Bu N)Br/aq. Kj(C03)/CH3CN) (Fig. 2.14) [25] [[2-[2-hydroxypropyl) amino]-l,2-dioxoethyl]amino]acetic acid ethyl ester (6.21 kg) to [(l,2-dioxo-2-oxopropyl)amino]ethyl)amino] acetic acid ethyl ester, part of the industrial-scale synthesis of thrombin inhibitor (RuCyaq. Na(BrOj)/CH3CN) [166] (H-)-dihydroc-holesterol (8 g) to cholest-3-one (RuO /aq. K(10 )/(BTEAC)/CHCl3) [308] ... 

Table 1. a-Substituted x-Amino Acetates (Glycine Derivatives) by Alkylation of 3.6-Dialkoxy-2,5-dihy-dropyrazines. Followed by Hydrolysis... 

Ausbeuteangabe mit Stem betrilTl isoliertes, reines Produkt. b Gesaratausbeute der beiden Stufen, ohne Reinisolierutig des Amino-acetals. 

John L. LaMatMna and R. T. Suleske 19 a-AMINO ACETALS 2.2-DIETH0XY-2-(4-PYRIDYL)ETHYLAMINE... 

Amlnochrysammlc or Amlnochrysammlnlc Acid. See 2,4,5,7-Tetranitro-8-amino-1-hydroxy-anthraquinone, described under Aminohydtoxyanthraquinone and Derivatives Aminocompounds are described individually, such as amino acetic acid, aminobenzoic acid, aminocarbazole, aminotetrazole, aniline, etc... 

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