4- Methyl-2-aminopentanoic acid

Fischer and Bergmann 75 adapted the method of Hinsberg 76 for the N-methylation of benzenesulfonamides in the synthesis of Sar, 5-aminopentanoic acid, and racemic Orn. Two years later Fischer and Lipschitz 73 succeeded in the synthesis of optically active, N-methylated derivatives of Ala, Leu, Phe, and Tyr. TV-Tosyl amino acids were N-methylated with two equivalents of iodomethane at 65-68 °C in a sealed pressure tube. The tosyl group was then deprotected either with sodium in liquid ammonia or with hot hydrochloric acid, but partially racemic products were obtained that were purified by crystallization with optically active bases. 77 Cheung and Benoiton did not observe racemization during deprotection with sodium in liquid ammonia. 78 ... 

S,4S,5 E,7E)-3-Amino-4-hydroxy-6-methyl-8-(4-bromophenyl)-octa-5,7-dienoic acid [Aboa = Br-Ahmp, Br-Apoa], (2S,3S,8S,9S)-3-Amino-9-methoxy-2,6,8-trimethyl-10-phenyl-deca-4,6-dienoic acid (Adda). 3-Amino-2,4-dimethylpentanoic acid (Admpa). (2S,3R,5S)-3-amino-2,5,9-trihydroxy-10-phenyldecanoic acid (Ahda). j3-Aminoisobutyric acid (jS-AiB). (3S,4S,5E,7E)-3-Amino-4-hydroxy-6-methyl-8-phenylocta-5,7-dienoic acid [Ahmp (Faulkner) or Apoa (Fusetani)]. (2S,3R,5R)-3-Amino-2,5-dihydroxy-8-phenyloctanoic acid (Ahoa). 3-Aminopentanoic acid (Apa /5-Apa). (2R,3R)-3-Amino-2-methylbutanoic add (Amba). 3-Amino-2-methylhexanoic acid (Amha). 3-Amino-2-methyl-7-octynoic add (Amoa, Amoya). 3-Amino-7-octynoic add (Aoya). (2S,3R)-3-Amino-2-methylpentanoic acid (Map). http // www.ncbi.nlm.nih.gov/ Taxonomy/ tax.html... 

Using the lithium enolate of a-bromopropionate, trans and cis /V-(p-toluenesul-finyl)-2-methyl-2-carbomethoxy aziridines 191 were prepared from (S)-47.101-103 The -isomers predominate. Regio- and stereoselective aziridine ring-opening leads to efficient asymmetric syntheses of (-)-a-methylphenylalanine (192),102 (+)-a-methyl-p-phenylserine (193),102 (+)-2-methyl-3-phenylpropanoic acid (194a),103 and (-)-2-methyl-3-aminopentanoic acid (194b).103... 

C5H11N02 5-aminopentanoic acid 660-88-8 23.46 0.9308 2 5930 C5H12S methyl butyl sulfide 628-29-5 -97.85 1.0943 2... 

Methyl-l-nitrobutane, A"33.8 Valine, A4.19, A"15 Norvaline, A10.15, A"8 2-Amino-2-methylbutyric acid, A40.9 4-Amino-2-methylbutyric acid, A34.5 4-Amino-3-methylbutyric acid, A27.16 4-Aminopentanoic acid, A 14.14, A"6, A"8 [4- C]Valine, D 3.10... 

There are other amine surrogates that can be used to prepare amino acids by reaction with halides or other electrophilic species. Most are rather specific, but one shows some generality. Effenberger showed that reaction of methyl 5-bromohexan-oate 1.19) with potassium isocyanate gave 1.81. In this case, the isocyanate is the amine surrogate, and hydrolysis with concentrated HCl at 100°C gave 6-amino-hexanoic acid, 1.82, as its HCl salt. 4-Aminobutanoic acid, 3-aminopropanoic acid and 5-aminopentanoic acid were prepared in an identical manner.47... 

The hydrolysis of lactams is rather stndghtforward and most of the variety in this table results from different structural features and different synthetic manipulations of the lactams. Reaction I shows a simple hydroly of 3-methyl-2-pyrrolidinone 2.48) to give 2-ethyl-4-aminobutanoic acid 2.49). Several substituted derivatives were prepared, including 2-methyl-4-aminobutanoic acid, 3-ethyl-4 aminobutanoic acid, 3-propyl-4-aminobutanoic acid, 3-(l-methylethyl)-4-aminobutanoic acid, 2,3-diethyl-4-aminobutanoic acid, 2-ethyl-S-aminopentanoic acid, 3-methyl-5-amino-pentanoic acid, 3-ethyl-5-aminopentanoic acid, 3-propyl-5-aminopentanoic acid, and 3-( 1 -methylethyl)-5-aminopentanoic acid. l... 

Other 3-aiyl aminopropanoic acid derivatives have been prepared using oxazoli dine derivatives derived from vinyl acetates and hydroxylamines.62 Nitrone 2.126 is more sterically encumbered than the nitrones shown previously, and reaction with vinyl acetate gave a poor yield of 2.727.62 Hydrolysis of 2.337, followed by oxidation and catalytic hydrogenation led to 4-methyl-3-aminopentanoic acid, 2.128. ... 

Pyrazoles such as 2.159 are formed by a [3+2]-cycloaddition reaction of an alkene with a diazoalkane7 Basic hydrolysis of such pyrazolines leads to an amino acid. Reaction of 2.159 with aqueous sodium hydroxide, for example, gave 2-methyl-3-aminopropanoic acid 2.160) Similarly, 2-methyl-3-aminobutanoic acid was prepared in 52% yield 2-ethyl-3-aminopropanoic acid in 81% yield and, 2-methyl-3-aminopentanoic acid in 52% yield, all from the appropriate pyrazoline. ... 

Acid hydrolysis of this dihydrouracil derivative led to cleavage of the ring and formation of 4-methyl-3-aminopentanoic acid, 2.171. Substituted dihydrouracils (such as 2.170 and also 2.172) have been converted to 2-alkyl, 2,3-dialkyl, 3-alkyl,... 

An example of this process is the reaction of nitromethane with sodium meth-oxide to give the nitro enolate. Subsequent reaction with methyl 3-bromopropanoate gave a nitro-ester, and catalytic hydrogenation led to 4-aminopentanoic acid (4.105) in 19% overall yield. O The enolate of nitroethane reacted similarly with methyl... 

A number of functionalized chiral, nonracemic amino acids can be prepared using ethyl pyroglutamale as a chiral template. Silverman reduced ethyl pyroglutamate (5.4J) to the alcohol (5.42) with lithium borohydride.23 This was followed by treatment with bromine and triphenylphosphine to give 5-bromomethyl-2-pyrrolidinone, 5.48. Similarly prepared were 5-chloromethyl-2-pyrrolidinone (5.50) 5-fluoro-methyl-2-pyrrolidinone (5.52) and, 5-cyanomethyl-2-pyrrolidinone.23 In all cases, reaction with HCl and isolation via ion exchange chromatography gave the 5-halo-4-aminopentanoic acid [5-bromo-4-aminopentanoic acid 5.49) 5-chloro-... 

The Wolff rearrangement classical method for the chain extension of acids via rearrangement of an a-diazoketone intermediate. This technique has been used to conversion a-amino acids to P-amino acids. When S-2-aminobutanoic acid (5.110) was first converted to the phthalimido derivative, the acid moiety was treated with thionyl chloride and then diazomethane to give diazoketone 5.111. Wolff rearrangement and esterification generated methyl ester 5.112, which was converted to 3-aminopentanoic acid, 5.773.54... 

Kessels, M. M. Qualmann, B. Facile enantioselective synthesis of (S)-5-(2-methyl-l,2-dicarha-ctoso-dodecaborane(12)-l-yl)-2-aminopentanoic acid (L-MeCBA) using the bislactim ether method, J. Prakt. Chem. 1996, 89. 

Thiouracil derivatives of l,2-C2BioHi2 have been prepared with the aim of producing compounds which may have potential application in the treatment of melanomas. The C2Bio-cage was attached to the S-, 6-, and N(l)-positions of thiouracil. Studies using S-(2-methyl-l,2-dicarbadodecaborane(12)-l-yl-2-aminopentanoic acid (protected as a Boc derivative) have... 

Several boron-containing species have been used as chiral NMR derivatizing agents for the analysis of primary amines or diols. " Most noteworthy among these is 2-for-mylphenylboronic acid 61, which is commercially available. Reaction of 61 with an amine and diol forms a borate-imine as shown in Scheme 50.1. The reaction can be run using an enantiomerically pure amine such as PEA to determine the enantiomeric purity of the diol, or using an enantiomerically pure diol such as BINOL to determine the enantiomeric purity of the amine.The system has been used to determine the enantiomeric purity of amines with remote chiral centers such as l-amino-4-5 ec-butylbenzene and the methyl ester of 2-methyl-5-aminopentanoic acid. 

The series of guineamides A-F, isolated from Lyn ya majuscula collected in Papua New Guinea, permitted the discovery of a new acid, 2,2-dimethyl-3-hydroxyhexanoic acid (Dmhha, guineamides E and F) as well as 2-methyl-3-aminopentanoic acid (Mapa, guineamide A), a P-amino acid already identified in various metabolites of the mol-lusk Dolabella auricularia (Tan, Sitachitta, and Gerwick, 2003). None of the guineamides has any notable biological adivity. 

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