Preparation of 2-amino-2-deoxy-3,4,5,6-tetra-O-methyl-d-gluconic acid hydrochloride, an intermediate in the preparation of polypeptide-type polyamides (original) (raw)
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Carbohydrate Research, 2006
2-Amino-2,3-dideoxy-D D-manno-heptonic acid (7) has been synthesized from 2,5,6,7-tetra-O-acetyl-3-deoxy-D D-gluco-heptono-1,4-lactone (1), which was readily prepared from D D-glycero-D D-gulo-heptono-1,4-lactone. O-Deacetylation of 1 followed by treatment with 13:1 (v/v) 2,2-dimethoxypropane/acetone in the presence of p-toluenesulfonic acid gave methyl 3-deoxy-4,5:6,7di-O-isopropylidene-D D-gluco-heptonate (3) as a crystalline product (80% yield). The free hydroxyl group (OH-2) of 3 was mesylated and substituted by azide to give the corresponding azide derivative 5. Hydrogenolysis and further hydrolysis of the ester function of 5 afforded a-amino acid 7 (43% overall yield from 1). Compound 7 is an analog of L L-alanine having a polyhydroxy chain attached to C-3. The diastereoisomer of 7 at C-2, 2-amino-2,3-dideoxy-D D-gluco-heptonic acid (12) was also prepared from 3, by a route that involved 2,3-dideoxy-2-iodo derivative 8 as a key intermediate.
Arkivoc, 2005
Methyl 6-azido-6-deoxy-2,3:4,5-di-O-isopropylidene-D-galactonate (1), prepared in two steps from D-galactono-1,4-lactone, was hydrolyzed to the corresponding acid 2, which was esterified with phenol (PhOH) in the presence of dicyclohexylcarbodiimide (DCC) to give the phenyl ester 3. Hydrogenolysis of the azide function of 3 yielded the hydrochloride derivative of the amino acid 4. Compound 4 is conveniently substituted for the polycondensation; therefore, this reaction was conducted using DMF as solvent and N,N-diisopropylethylamine as a basic catalyst. The MALDI-TOF mass spectrum of the isolated product (5) indicated that this was a mixture of the cyclic trimer (M + Na + , 793.7) and linear oligomers (from the tetramer to the tetradecamer). To favor the linear polymerization the dimeric amino acid 10 was prepared starting from 2. Thus, hydrogenation of 2 gave the amino acid 6, and treatment of 2 with pentachlorophenol-DCC gave the pentachlorophenyl ester 7. Coupling of 6 with 7 in the presence of DCC gave the dimer 8, which was converted (PhOH, DCC) into 9. Hydrogenolysis of 9 afforded the dimeric amino acid 10, which was polymerized under the conditions employed for 4. The resulting polyamide 11 was highly soluble in common organic solvents, and its molecular weight was established by MALDI-TOF MS and size exclusion chromatography (M w = 2700).
Arkivoc, 2003
The chiral monomer N-(1´-amino-2´-(S)-propyl)-5-oxo-2-(S)-tetrahydrofurancarboxy-amide hydrochloride (11), a precursor of a AABB-type stereoregular polyamide, has been synthesized from pentachlorophenyl 5-oxo-2-(S)-tetrahydrofurancarboxylate (2) and 2-(S)-amino-1-propanol (3). Compounds 2 and 3 are derivatives of the natural amino acids L-glutamic acid and L-alanine, respectively. The regioselective attack of the amino group of 3 to the ester function of 2 led to N-(1´-hydroxy-2´-(S)-propyl)-5-oxo-tetrahydrofurancarboxyamide (4) in 80% yield. However, the tosylation of the primary hydroxyl group of 4, and the subsequent substitution by azide to give 6, took place with low yields. Therefore, an alternative route was conducted starting from 3, which was selectively N-protected as the tert-butyloxycarbonyl derivative (N-Boc), O-tosylated and substituted by azide to afford 1-azido-2-(S)-N-(tert-butyloxycarbonyl)aminopropane (9) in 41% yield from 3. The amino group of 9 was deprotected by acid hydrolysis and the resulting amine 10 was regioselectively condensed with 2 to give the azide derivative 6. Hydrogenolysis of 6 afforded the desired monomer 11 in 69% yield from 2 and 10.
Carbohydrate Research, 1989
Acetylation of 2-amino-2-deoxy-D-&conic acid (1) with acetyl chloridepyridine gave 2,3-unsaturated six-and five-membered lactones (2 and 3). Their benzoylated analogs (4 and 5) were obtained by benzoylation of 1 with benzoyl chloride-pyridine. Reaction of 1 with hot acetic anhydride-sodium acetate gave a-1:2 mixture of(E)-and (Z)-2-acetamido-6-acetoxyhexa-2,4-dien-4-olide (6-E and 6-Z). Treatment of 3 with 1,8-diazabicyclo[5.4.0]undec-7-ene also gave as the main product 6-Z, which was isolated crystalline from the reaction mixture. The same reaction applied to compound 5 gave selectively the Z-isomer of the benzoylated furanone 7. Partial and total hydrogenation (Hz-Pd-C) of the mixture 6-E,Z gave, respectively, a racemic monounsaturated lactone (8) and a dideoxy lactone (9), for which the three-configuration for the chiral centers at C-2 and C-4 was determined. Acidic removal of the acetyl groups from 9 afforded the 2-amino-6-hydroxy-1,4lactone hydrochloride 10. On the other hand, acetylation at high temperature of the 4,6-0-benzylidene derivative of l(l1) gave the 2,3-unsaturated, six-membered lactone (l2), precursor of 2-acetamido-6-acetoxyhexa-2,4-dien-5-olide (14).
Facile Synthesis of (R, R) and of (R, S) Tricarballylic Acid Anhydride and Imide Derivatives
Molecules, 2000
The diastereomeric mixture of (R)-2-(methoxycarbonylmethyl)-N-(R)-1-(1phenylethyl) succinimide 11s and (S)-2-(methoxycarbonylmethyl)-N-(R)-1-(1-phenylethyl) succinimide 11a was synthesized by reaction of 2-(carboxymethyl)succinic anhydride 6 with (R)-(α)-methylbenzylamine in dry THF/room temperature/24 hrs. The diastereomeric mixture of 1-[(R)-(α)-Methylbenzylamideformyl)]propane-2,3-dicarboxylic acid anhydride 9s and 1-[(R)-(α)-methylbenzylamideformyl)]propane-2,3-dicarboxylic acid anhydride 9a was isolated as an intermediate under the reaction conditions. This diastereomeric mixture 9s/9a was also prepared by a different route via reaction of 1-(chloroformyl)propane-2,3dicarboxylic acid anydride 12 with (R)-(α)-methylbenzylamine in the presence of DMA at 0 o C for 24 hrs.
Syntheses and properties of polyamides from glucosamine and glucose derivatives
1993
Starting from D-glucosamine, the synthesis of various differently modified methyl and benzyl 2,6-diaminosaccharides 11,12,17 and 18 was accomplished. Interfacial and solution polycondensation of those diamino derivates with aromatic and aliphatic acyl chlorides yielded polyamides 34, 35, 36 and 37a-d which were characterized by 'H NMR spectroscopy and their inherent viscosities. The presence of an anomeric benzyl group in 12 did not decrease the reactivity of the 2-amino function. The free hydroxy functions in polyamides 35a-b were acetylated to give polyamides 39ab. Partially blocked polyamides 36a-d had similar properties as unprotected polyamides 34-35 ad. Under corresponding conditions di-0-acylated diaminosaccharide 18 gave only oligomers. Number-average molecular weights were obtained from gel-permeation chromatography to be 10300 < a,, < 24000 (interfacial polycondensation), corresponding to number-average degrees of polymerization up to P,, = 64, whereas polycondensation in solution afforded only an values between 2000 and 3000. Starting with D-glucose the synthesis of a Cglycosidic diaminosaccharide 28 was developed. This reacted to polyamides 38 ad which showed thermal stability up to 280 "C.
Synthesis of carbohydrate-containing polyamides and study of their properties
European Polymer Journal, 1990
Carbohydrate-containing polyamides were prepared using low-temperature solution polycondensation of 2,3,4,5-tetra-O-acetylgalactaroyl dichloride (3) with various aromatic and aliphatic diamines viz. ; m-phenylenediamine; benzidine; 4,4′-diaminodiphenylmethane; 1,5-diaminoanthraquinone; 2,6-diaminoanthraquinone; 4,4′-diaminodicyclohexylmethane; hexamethylenediamine; and ethylenediamine (12). The four O-acetyl groups in 3 protect the hydroxyl functions and give good solubility as a result of increasing lipophilicity. The optimum conditions for the best yield and viscosity of the polyamide were determined by study of the factors affecting the polycondensation. These conditions for reaction of 3 with 4 were reached with reactant concentrations of 0.5 mol/l at −10°. On the other hand, the optimum conditions for reaction of 3 with 12 involved concentrations of 1.0 mol/l at 0°. Polyamides containing the unacetylated carbohydrate chains were obtained by de-O-acetylation of the synthesized acetylated carbohydrate-containing polyamides. Structures of the acetylated and de-O-acetylated carbohydrate-containing polyamides were confirmed by elemental analysis, i.r. and 1H-NMR spectroscopy. Their thermal degradations were studied by differential thermal analysis and thermogravimetric analysis.
Lipase-Catalyzed Ring-Opening Polymerization of the O-Carboxylic Anhydride Derived from Lactic Acid
Biomacromolecules, 2009
Lipases from porcine pancreas and from Pseudomonas cepacia catalyze the ring-opening polymerization of lactones. Polymerization of the four-membered-butyrolactone yielded poly(3hydroxybutyrate) in up to 89% yield with a degree of polymerization of 3-12. Polymerization of the four-membered-propiolactone, the five-membered γ-butyrolactone, and the seven-membered-caprolactone also yielded the corresponding polyesters in good yields with degrees of polymerization up to 25. Coordination catalysts, such as alumoxanes, fail in the homopolymerization of γ-butyrolactone; thus this lipase route is the first homopolymerization of γ-butyrolactone. To characterize the product polyesters, we used the method of MALDI-TOF mass spectroscopy to determine both the true molecular weight of the components and the mass of the repeat unit.
Synthesis of 3,3-dimethylazetidine-2-carboxylic acid and some derivatives
1998
~,-Chloro-a-(N-alkylimino)esters were reduced by sodium cyanoborohydride in methanol in the presence of acetic acid with complete selectivity to give rise to either ~,-chloro-a-(N-alkylamino)esters (reaction at 0°C) or 1-alkyl-3,3-dimethylazetidine-2-carboxylic esters (reaction at reflux). The isolable ~,-cMoro-a-(N-alkylamino)esters are suitable sources for l-(N-alkylamino)-2,2-dimethylcycloprupane-1-carboxylic esters via base-induced 1,3-dehydrochlorination, while the former substrates as transient species undergo 1,4-dehydrocMorination to the corresponding azetidines. The latter process was used for the synthesis of 3,3-dimethylazetidine-2-carboxylic acid, a new non-proteinogenic sterically hindered c~-amino acid, via hydrogenolysis of methyl 1-benzyl-3,3-dimethylazetidine-l-carboxylate and subsequent acidic hydrolysis. Reduction of alkyl 4-chloro-3,3-dimethyl-a-(N-alkylimino)butanoates with lithiumaluminiumhydride in diethyl ether afforded 1-alkyl-3,3-dimethyl-2-(hydroxymethyl)azetidines. © 1998 Elsevier Science Ltd. All rights reserved.