Synthesis and biological activity of (S)-2-amino-3-(2,5-dihydro-5-oxo-4-isoxazolyl)propanoic acid (TAN-950 A) derivatives.

(S)-2-Amino-3-(2,5-dihydro-5-oxo-4-isoxazolyl)propanoic acid (TAN-950 A (1)) is a novel amino acid antibiotic which shows a high affinity for glutamate receptors of the central nervous system. To improve the affinity for glutamate receptors, the structure-activity relationships of TAN-950 A derivatives 6a--o, 15a--o were investigated. Optically active TAN-950 A analogs 15a--h were synthesized starting with methyl (S)- and (R)-N-Boc-pyroglutamate (8) via acylation at the C-4 position followed by isoxazolone formation with hydroxylamine and subsequent deprotection reactions. The lactam 16, prepared from (RS)-aminoadipic acid, and dimethyl esters 19 of (R)- and (S)-aspartic acid were converted to (RS)-3-methyl-homo-TAN-950 A (15i) and optically active nor-TAN-950 A derivatives 15j--o, respectively, utilizing a similar sequence of reactions. Most of TAN-950 A derivatives 6a--o, 15a--o showed an affinity for glutamate receptors. The 3-alkyl derivatives 15b, d--g, especially, showed a high affinity for the quisqualate subtype-receptor and had a strong activating effect on the hippocampal neurons (glutamate agonistic activity). The (R)-enantiomer 15a of TAN-950 A had increased selectivity for the N-methyl-D-aspartate (NMDA) subtype-receptor. This selectivity was further enhanced by removal of the methylene group in the amino acid moiety of 15a. The most potent and selective NMDA agonistic activity was observed with (R)-3-methyl-nor-TAN-950 A (15m).     

3-(Hetarylamino)- and 3-[(hetarylmethyl)amino]-isoquinolin-1(2H)-ones

The reaction of 2-(cyanomethyl)benzoic acid with amines RNH₂ (R = Ar, Het, CH₂Ar, CH₂Het) leads to the formation of the corresponding 3-NHR-isoquinolin-1(2H)-ones. When R = CH₂Ar and CH₂Het, there is a side reaction involving hydrolysis of the hydrolytically-unstable intermediates, derivatives of 2-(2-amino-2-iminoethyl)benzoic acid, leading to 2-R-isoquinoline-1,3(2H,4H)-diones.     

Reactivity of 3,5-bis-(4-amino-1,2,5-oxadiazol-3-yl)-1,2,4-triazole

Alkylation of 3,5-bis(4-amino-1,2,5-oxadiazol-3-yl)-1,2,4-triazole with haloalkanes afforded N-CH₂R derivatives, and nitration furnished the corresponding bis-N-nitramine isolated as a trisodium salt. Treatment of the latter with CH₃I resulted in denitration. Diazotization and oxidation of 3,5-bis(4-amino-1,2,5-oxadiazol-3-yl)-1,2,4- triazole, its N-methyl and N-carboxy derivatives gave rise to the corresponding azido and nitro derivatives. Salts of 3,5-bis(4-amino-1,2,5-oxadiazol-3-yl)-1,2,4-triazol-5-acetic acid with nitrogen-containing bases were synthesized. It was established that the character of reaction products of 3,5-bis(4-amino-1,2,5-oxadiazol-3-yl)-1,2,4-triazole with formaldehyde depended on the acid-base properties of the medium.__________Translated from Zhurnal Organicheskoi Khirmii, Vol. 41, No. 2, 2005, pp. 270–276.Original Russian Text Copyright © 2005 by Sergievskii, Romanova, Mel’nikova, Tselinskii.     

Synthesis and Crystal Structure of 3-（4-Ethoxyphenyl）-6-（phenoxymethyl）-1,2,4-triazolo[3,4-b][1,3,4]thiadiazole

The title compound C18H16N4O2S has been synthesized by the reaction of 4-amino-3-(4-ethoxyphenyl)-5-mercapto-1,2,4-triazole with phenoxyacetic acid in phospho- rus oxychloride, and characterized by IR, NMR spectra and elemental analysis. Its structure was determined by single-crystal X-ray diffraction. It crystallizes in monoclinic, space group P21/c with a = 1.4903(3), b = 1.5230(2), c = 0.9615(16) nm, Z = 4, V = 1.7769(5) nm3, Dc = 1.317 g/cm3, μ = 0.201 mm-1, F(000) = 736, R = 0.0795 and wR = 0.2233. In the title compound, all rings are essentially planar.     

2-(3-ethyl-2,2-dimethylcyclobutyl-methyl)-4(3H)-quinazolinones

Anthranilic acid and its 5-bromo and 4-chloro derivatives react with pinanoic and pinonoic acid chlorides to give the corresponding N-acyl derivatives. The pinanoyl derivatives give the corresponding 2-(3-ethyl-2,2-dimethyl-cyclobutylmethyl)-4-(3H)-quinazolinones when refluxed in formamide. Pinanoylanthranilic acid reacts with dicyclohexylcarbodiimide to give 2-(3-ethyl-2,2-dimethylcyclobutylmethyl)benz-3,1-oxazin-4(H)-one and subsequently with hydrazine hydrate to give 3-amino-2-(3-ethyl-2,2-dimethylcyclobutylmethyl)-4(3H)-quinazolinone. Refluxing of the pinanoyl- and pinonoylanthranilic acids with acetic anhydride gives acetylanthranilic acid, and pinonoylanthranilic acid gives 4(3H)-quinazolinone with formamide.Riga Technical University, Riga LV-1658, Latvia; e-mail: marina@osi.lanet.lv. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 811–817, June, 1999.     

An efficient procedure for the preparation of (1S,3R)- and (1S,3S)-1-amino-3-(hydroxymethyl)cyclopentanes

Enantiomerically pure (1S,3S)- and (1S,3R)-1-amino-3-(hydroxymethyl)cyclopentanes have been efficiently synthesized from L-aspartic acid. The title compounds are isosteres of ribose and may be used to construct nucleoside analogs with important antiviral and antineoplastic activities as demonstrated by a concise total synthesis of (+)-4'-deoxycarbapentostatin nucleoside.     

Synthese von 3-(2-Carboxy-4-Pyridyl)- und 3-(6-Carboxy-3-pyridyl)-DL-alanin

Synthesis of 3-(2-Carboxy-4-pyridyl)-and 3-(6-Carboxy-3-pyridyl)-DL-alanine As starting materials for potential photochemical approaches to betalaines C(R = COOH) and to muscaflavine F(R = COOH), β-(2-carboxy-4-pyridyl)- and β-(6(carboxy-3-pyridyl))-DL-alanine ( A and D with R = COOH or 4 and 11 ), respectively, were prepared (Scheme 1). The synthesis of 4 (= A, R = COOH) started with the 2-[(4-pyridyl)methyl]malonate 1 and proceeded via the N-oxide 2 , cyanation and hydrolysis (Scheme 2). Amino acid 11 was obtained from (3-pyridyl)methyl-bromide ( 6 ) via the malonate 7 by an analogous sequence of reactions (Scheme 3).     

Synthesis and biological evaluation of novel 9-heteroaryl substituted 7-chloro-4,5-dihydro-4-oxo-1,2,4-triazolo[1,5-a]quinoxaline-2-carboxylates (TQX) as (R,S)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) receptor antagonists

In this paper, we report a study on some new 4,5-dihydro-4-oxo-1,2,4-triazolo[1,5-a]quinoxaline-2-carboxylate derivatives (TQXs), bearing a nitrogen-containing heterocycle at position-9, and designed as (R,S)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) receptor antagonists. These compounds ensue from the structural modification of previously reported 8-heteroaryl-TQXs which were endowed with high affinity and selectivity for the AMPA receptor. All the newly synthesized compounds were biologically evaluated for their binding at the AMPA receptor. Gly/N-methyl-D-aspartic acid (NMDA) and kainic acid (KA) high-affinity binding assays were performed to assess the selectivity of the reported derivatives toward the AMPA receptor. This study produced some new TQXs which are less potent than the reference compounds, and endowed with a mixed AMPA and Gly/NMDA receptor binding affinity. To rationalize the experimental findings, a molecular modeling study was performed by docking some TQX derivatives to the AMPA receptor model.     

A convenient synthesis of optically active 5,5-disubstituted 4-amino- and 4-hydroxy-2(5H)-furanones from (S)-ketone cyanohydrins

(S)-Ketone cyanohydrins (S)-2 are accessible by enantioselective HCN addition to ketones 1 by using hydroxynitrile lyase from Manihot esculenta ((S)-MeHNL) as a biocatalyst. Acylation of (S)-2 gave the corresponding (S)-acyloxynitriles (S)-3, which can be cyclized by LHMDS to give 5,5-disubstituted (S)-4-amino-2(5H)-furanones (S)-4 and (S)-5. Different substituents (H. Me, OBn, OH) in the 3-position of the furanones were introduced by selecting the appropriate acylating agent, which in the case of benzyloxyacetyl chloride led to the novel structure type of 4-amino-3-hydroxyfuranones (S)-5. For the synthesis of 5,5-disubstituted (S)-tetronic acids (S)-8, ketone cyanohydrins (S)-2 were first transformed into the corresponding 2-hydroxy esters (S)-6. Acylation of (S)-6 gave 2-acyloxy esters (S)-7, which, by treatment with LHMDS or LDA, afforded tetronic acids (S)-8 in high yields and enantiomeric excesses. By debenzylation of benzyloxy acetoxy derivatives (S)-8e,f, the new vitamin C analogues (S)-9a,b were generated. All the described tetronic acid and aminofuranone derivatives were obtained in good chemical yields and without racemization with respect to the starting cyanohydrins (S)-2. In many cases the enantiomeric purity could be enriched by simple recrystallization (e.g. (S)-4a from 69% ee to > 99% ee).     

A new route to 7-substituted derivatives of n-[4-(2-[2-amino-3,4-dihydro-4-oxo-7H-pyrrolo(2,3-d)pyrimidin-5-yl]ethyl)benzoyl]-L-glutamic acid [ALIMTA (LY231514, MTA)

Alkylation of various primary amines with crotyl bromide, followed by DMAP-promoted acylation with methyl malonyl chloride to 4 and then manganic triacetate dihydrate/cupric acetate induced radical cyclization, gave 1-substituted-4-vinyl-3-carbomethoxy-2-pyrrolidinones (5). Thiation to the thiolactams 6 and guanidine cyclization then gave a series of 2-amino-3,4-dihydro-4-oxo-5-vinyl-7-substituted pyrrolo[2,3-d]pyrimidines (7). Palladium-catalyzed C-C coupling with diethyl 4-iodobenzoylglutamate led in one step via an unexpected redox reaction to the diethyl esters 9 of a series of 7-substituted derivatives of ALIMTA (LY231514, MTA), from which the target analogues 10 were readily prepared by saponification. Attempted deprotection at position 7 was successful in only one case (9d, R = CH(2)C(6)H(3)(OMe)(2)(-3',4'), which resulted in a known pentultimate precursor (9, R = H) of ALIMTA. The 7-substituted derivatives 10 proved to be inactive in vitro as inhibitors of cell division.     

Synthesis and Crystal Structure of 4-（4,6-Dimethoxylpyrimidin-2-yl）- 3-thiourea Carboxylic Acid Ethyl Ester

4-（4,6-Dimethoxyl-pyrimidin-2-yl）-3-thiourea carboxylic acid ethyl ester was synthesized by the reaction of 2-amino-4,6-dimethoxyl pyrimidine, potassium thiocyanate and methyl chloroformate in ethyl acetate. Single crystals suitable for X-ray measurement were obtained by recrystallization with the solvent of dimethyl formamide at room temperature. The crystal structure was determined by X-ray diffraction analysis. Crystallographic data： C10H14N4O4S, M, = 286.31, monoclinic, space group C2/c with a = 2.5309（3）, b = 0.67682（6）, c = 1.74237（19） nm, β = 114.744（3）°, V= 2.7106（5） nm3, Dc = 1.403 g/cm3, p = 0.225 mm-1, F（000） = 1200, Z= 8, R= 0.0514 and wR= 0.1529.     

Hantzsch reaction of 3-(2-bromoacetyl)tropolone. Synthesis of 3-(4-thiazolyl)tropolones

3-Acetyltropolone was brominated with phenyltrimethylammonium tribromide to afford 3-(2-bromoacetyl)-tropolone ( 2 ), whose reactions with thiourea, thioformamide, and ammonium dithiocarbamate gave respectively 3-(2-amino-4-thiazolyl)-, 3-(4-thiazolyl)-, and 3-(2-mercapto-4-thiazolyl)tropolone. In a similar manner, compound 2 was treated with six 1-substituted 2-thioureas and three thioamides to give the corresponding 3-(4-thiazolyl)tropolone derivatives.     

Ring-closing metathesis-based synthesis of (3R,4R,5S)-4-acetylamino-5-amino-3-hydroxy- cyclohex-1-ene-carboxylic acid ethyl ester: a functionalized cycloalkene skeleton of GS4104

(3R,4R,5S)-4-Acetylamino-5-amino-3-hydroxy-cyclohex-1-ene-carboxylic acid ethyl ester, a functionalized cyclohexene skeleton of GS4104, was diastereoselectively synthesized. A major advantage of this synthesis is the use of readily available L-serine to replace frequently used (-)-shikimic acid or (-)-quinic acid as the starting material. Ring-closing metathesis and diastereoselective Grignard reactions successfully served as the key steps. Absolute configurations of the key intermediates were confirmed by corresponding two-dimensional NMR studies.     

Synthesis and Crystal Structure of 4-(4,6-Dimethoxylpyrimidin-2-yl)-3-thiourea Carboxylic Acid Ethyl Ester

4-(4,6-Dimethoxyl-pyrimidin-2-yl)-3-thiourea carboxylic acid ethyl ester was synthesized by the reaction of 2-amino-4,6-dimethoxyl pyrimidine,potassium thiocyanate and methyl chloroformate in ethyl acetate.Single crystals suitable for X-ray measurement were obtained by recrystallization with the solvent of dimethyl formamidc at room temperature.The crystal structure was determined by X-ray diffraction analysis.Crystallographic data:C10H14N4O4S,Mr=286.31,monoclinic,space group C2/c with a=2.5309(3),b=0.67682(6),c=1.74237(19)nm,β=114.744(3)°,V=2.7106(5)nm3,Dc=1.403 g/cm3,μ=0.225mm-1,F(000)=1200,Z=8,R=0.0514 and wR=0.1529.     

Preparation of optically active threo-2-amino-3-hydroxy-3-phenylpropanoic acid (threo-beta-phenylserine) via optical resolution

To obtain optically active threo-2-amino-3-hydroxy-3-phenylpropanoic acid (1), (2RS,3SR)-2-benzoylamino-3-hydroxy-3-phenylpropanoic acid [(2RS,3SR)-2] was first optically resolved using (1S,2S)- and (1R,2R)-2-amino-1-(4-nitrophenyl)-1,3-propanediol as the resolving agents to afford (2R,3S)- and (2S,3R)-2 in yields of 73% and 66%, based on half of the starting amount of (2RS,3SR)-2. Next, the racemic structures of ammonium and some organic ammonium salts of (2RS,3SR)-2 were examined based on melting point, solubility, and infrared spectrum, with the aim of optical resolution by preferential crystallization. The benzylammonium salt of (2RS,3SR)-2 was suggested to exist as a conglomerate at room temperature, although it forms a racemic compound at the melting point. The optical resolution by preferential crystallization of the racemic salt afforded the (2R,3S)- and (2S,3R)-salts with optical purities of 90-97%. The (2R,3S)- and (2S,3R)-2 obtained from the purified salts were hydrolyzed by reflux in hydrochloric acid to give (2R,3S)- and (2S,3R)-1.     

Synthesis and Crystal Structure of 4-（4,6-dimethoxyl -pyrimidin-2-yl）-3-thiourea Carboxylic Acid Methyl Ester

1 INTRODUCTION Pyrimidinyl thioureas have been studied for many years because of their broad antibiosis and sterilibza- tion properties. Recent years’ study shows that pyri- midinyl thioureas not only can be used to kill insects and adjust plant growth, but also have anti-viral ac- tivities[1, 2]. From our early quantum study on these compounds, we find that they have several active cen- ters and can form polyligand complexes with metals easily[3]. These complexes are widely used as ant…     

On triazoles. I. The reaction of N-cyanocarbonimidodithioic acid diesters with hydrazines

The reaction of N-cyanocarbonimidodithioic acid di(alkyl and aralkyl)esters with different alkyl-, aralkyl- and arylhydrazines to yield 1-substituted-3-R-thio-5-amino-1H-1,2,4-triazoles ( 3 ) and 2-substituted-3-R-thio-5-amino-2H-1,2,4-triazoles ( 4 ) was studied. Isolation of the different types of isomeric pairs of 3 and 4 helped to prove the structure of products obtained which made possible correction of some confusion in the literature. The 3 (R = H) tautomeric structure of the non-substituted derivatives was supported by comparison of their uv and cmr spectra with those of the alkylated and aralkylated derivatives 3 and 4 , respectively, again correcting confusion in the literature. An hplc determination of the ratio of products 3 and 4 formed in the above reactions with different hydrazines made it possible to prove the mechanism of the reaction.     

Synthesis of Novel New 2-(2-(4-((3,4-Dihydro-4-oxo-3-aryl quinazolin-2-yl)methyl)piperazin-1-yl)acetoyloxy)-2-phenyl Acetic Acid Esters

Stereoselective diazotization of (S)-2-amino-2-phenyl acetic acid (L-phenyl glycine) (4) with NaNO₂ in 6% H₂SO₄ in a mixture of acetone and water gave optically pure (S)-2-hydroxy-2-phenyl acetic acid (L-mandelic acid) (5). Esterification, gave (S)-2-hydroxy-2-phenyl acetic acid esters (6). The latter was treated with chloroacetyl chloride in the presence of triethylamine (TEA) in dichloromethane (DCM) to yield (S)-2-chloroacetyloxy phenyl acetic acid ester (2). In another sequence, the reaction of 2-(chloromethyl)-3-arylquinazolin-4(3H)-one (9) treated with N-Boc piperazine, followed by deprotection of the Boc group, to obtain 3-aryl-2-((piperazin-1-yl)methyl) quinazolin-4(3H)-one (3). Reaction of 2 with 3 in the presence of K₂CO₃ and KI gave the title compound, 2-(2-(4-((3,4-dihydro-4-oxo-3-arylquinazolin-2-yl)methyl)piperazin-1-yl) acetoyloxy)-2-phenyl acetic acid esters (1). The structures of all the new compounds obtained in the present work are supported by spectral and analytical data.     

Lithiation of 2-Alkyl-3-amino- and 2-Alkyl-3-(methylamino)-4(3H)-quinazolinones(1)

3-Amino-2-methyl-4(3H)-quinazolinone has been doubly lithiated, on nitrogen and in the 2-methyl group, with n-butyllithium. The lithium reagent thus obtained reacts with a variety of electrophiles (D(2)O, benzophenone, cyclohexanone, cyclopentanone, acetophenone, benzaldehyde, tetraisopropylthiuram disulfide (TITD)) to give the corresponding 2-substituted derivatives in very good yields. Reactions of the dilithio reagent with 2 molar equiv of methyl iodide or phenyl isocyanate give disubstituted derivatives. Double lithiation of the 2-ethyl and 2-propyl analogues have been achieved using LDA, and subsequent reactions with most electophiles are then similar. In the reaction of the dianion of the 2-ethyl compound with TITD, deamination from position 3 takes place with the formation of the 2-substituted derivative. In reactions with prochiral ketones, the dianion of the 2-ethyl compound gives very high diastereoselectivity. Lithiation and subsequent reactions of 3-(methylamino) analogues take place in a similar manner, thus providing access to a range of substituted 3-(methylamino)-2-alkyl-4(3H)-quinazolinones by a general procedure. Lithiation of 3-(dimethylamino)-2-ethyl-4(3H)-quinazolinone did not take place under similar conditions. Lithiation of 3-amino-2-unsubstituted-4(3H)-quinazolinone was also unsuccessful.     

非对映消旋体2-氨基-3-氰基-1-苯基-4-(3,4-亚甲二氧苯基)-2-环戊烯-1-醇的合成和晶体结构

用低价钛试剂(Ticl₄-Zn)与3-氧代-1-(3',4'-亚甲二氧苯基)-3-苯基丙基-1-丙二腈反应合成了非对映消旋体(1S,4R;1R,4S)和(1S,4S;1R,4R)2-氨基-3-氰基-1-苯基-4-(3,4-亚甲二氧苯基)-2-环戊烯-1-醇,用X射线衍射分析确定了这两个异构体的相对构型.