Indoles polycycliques. I. Synthèse de dérivés oxo-6 du benzo[a]pyrano-[4,3-b] indole et de l'indolo[3,2-c] quinoléine à partir d'acides aryl-2 indole carboxyliques-3

The tetracyclic indole derivatives were prepared by lactonisation of 1-methyl-2-(2-hydroxyphenyl)indole-3-carboxylic acid or by reductive cyclisation of 1-methyl-2-(2 nitrophenyl)indole-3-carboxylic acid, respectively. These acids were obtained, in good yields, by alkaline hydrolysis of 1-methyl-2-aryl-3-trifluoroacetyl-indoles. This last synthetic method seems of general use to prepare 2-arylindole-3-carboxylic acids in which the pyrrole nitrogen atom is substituted.     

Synthèses d'indoles par cyclisation réductrice. II Nouvelle mélhode de synthèse des indole carboxamides-3, donnant accés aux dérivés de la gramine

A new synthetic method for 3-indolecarboxamides, in two steps from 2-halogenonitrobenzenes, is reported. These benzene derivatives, reacting with sodium salts of cyanoacetamides in N,N-dimethylformamide, give 2-(2-nitrophenyl)cyanoacetamides. Catalytic hydrogenation of the nitro derivatives, at 80°, leads directly to 3-indolecarboxamides. Reduction of the amides by lithium aluminium hydride gives finally 3-aminomethylindoles (gramine and its derivatives), so obtained by a new synthetic route.     

Dioxo-2,5 pipérazines. 1. La synthèse des carboxythiazolo dioxo-2,5 pipérazines

A new and general synthesis of 2,5-dioxopiperazine condensed with the thiazolidine ring is described. The synthesis involves the use of N-ethoxy carbonyl-2-ethoxy-1-2-dihydroquinoleine (EEDQ) as activating agent to form the 2,5-diketopiperazine (EEDQ) as activating agent to form the 2,5-diketopiperazine ring. By this method 9-carbobutoxy-7,7-dimethyl-2,5-dioxo-8-this-1,4-diazabicyclo[4.3.0] nonane (6) and 9-carboxy-8,8 dimethyl-2,5-dioxo-7-thia-1,4-diazabicy clo [4.3.0] nonane (8) were obtained, with near quantitative yield, from 4-carboxy-2-carbobutoxy-5,5 dimethylthiazolidine (4). The former was transformed into acid 7 by hydrolysis with barium bydroxyde and the latter was esterified with diazornethane thus producing a methylester 9. The use of the ethy lester of N-(2-cabobutoxy-4-carboxy-5,5-dimethyl-thiazolidine)glycine (10) for synthesis of 6 was also successful. The spectromethric data were interpreted and confirm the proposed structure of the new compounds.     

A New Route for the Synthesis of Thymidylate Synthase Inhibitor Raltitrexed

Raltitrexed (8), a new quinazoline-based inhibitor of thymidylate synthase (TS), has been registered widely for the first-line treatment of advanced colorectal cancer. [1,2] As reported in the literature, [3,4] it can be prepared from 2-thiophenecarboxylic acid via 7 steps in 3% overall yield, but n-BuLi and the low temperature at - 78 ℃ was needed for the introduction of 5-carboxyl group into thiophene ring through lithiation of 2-(N-Boc-N-methylamino) thiophene followed by the addition of CO2. Here we wish to report a new route for the synthesis of Raltitrexed which was obtained from 2,5-thiophenedicarboxylic acid via 6 steps in 18.2% overall yield (Scheme 1). The mild conditions utilized in the synthetic route avoid the use of n-BuLi, NaH and the experimental conditions of low temperature at - 78 ℃ and strictly free of water, and are suitable for the large-scale preparation.     

Condensed pyridazines. Part III. Rearrangement and ring cyclization during the thermolysis of (z)-methyl 3-(6-azido-3-chloro-1-methyl-4-oxo-1,4-dihydropyridazin-5-yl)-2-methylacrylate

The thermolysis of (Z)-methyl 3-(6-azido-3-chloro-1-methyl-4-oxo-1,4-dihydropyridazin-5-yl)-2-methylacrylate ( II ) provides a new synthetic route to pyrrolo[2,3-c-]pyridazines, specifically, methyl 3-chloro-1,6-dimethyl-4-oxo-1,4-dihydro-7H-pyrrolo[2,3-c]pyridazine-5-carboxylate ( III ) in 91% yield. Treatment of III with ozone provides an entry into the novel pyridazino[3,4-d][1,3]oxazine ring system, specifically, 3-chloro-1,7-dimethylpyridazino[3,4-d][1,3]oxazine-4,5-dione ( IV ) in 73% yield. Compound IV is smoothly hydrolyzed into 6-acetylamino-3-chloro-1-methyl-4-oxo-1,4-dihydropyridazine-5-carboxylic acid ( V ) which is readily recyclized into IV by dehydration with acetic anhydride. Furthermore, IV undergoes a facile reductive ring opening reaction with sodium borohydride to give 3-chloro-6-ethylamino-1-methyl-4-oxo-1,4-dihydropyridazine-5-carboxylic acid ( VI ) in 95% yield.     

Synthesis of two naturally occurring 3-methyl-2,5-dihydro-1-benzoxepin carboxylic acids

[structures: see text] Two naturally occurring 3-methyl-2,5-dihydro-1-benzoxepin carboxylic acids, 6-hydroxy-3-methyl-8-(phenylethyl)-2,5-dihydro-1-benzoxepin-9-carboxylic acid (radulanin E) (1) and 9-hydroxy-3-methyl-2,5-dihydro-1-benzoxepin-7-carboxylic acid (2), were synthesized using Stille coupling followed by Mitsunobu cyclization.     

Synthesis of 4,12-dihydro-4-oxoquino-[1,8a,8-a,b]quinoxaline-5-carboxylic acid derivatives

The synthesis and antibacterial activity of 1-substituted amino-2-fluoro-4,12-dihydro-4-oxoquino[1,8a,8-a,b]quinoxaline-5-carboxylic acid derivatives are described. The synthetic route includes a carbon homologation and two intramolecular nucleophilic displacement cyclization reactions leading to the novel 4,12-dihydro-4-oxoquino[1,8a,8-a,b]quinoxaline-5-carboxylic acid heterocycle.     

Synthesis of novel poly(hydroxyether terephthalate) via polyaddition of 2,5-difluoroterephthalic acid with aromatic bis(epoxide)s

A novel and more reliable synthetic route to 2,5-difluoroterephthalic acid was developed. A series of new poly(hydroxyether terephthalate) were prepared by the polyaddition of 2,5-difluoroterephthalic acid with various aromatic bis(epoxide)s catalyzed by tetrabutyl ammonium bromide.     

Incorporating distinct metal clusters to construct diversity of 3D pillared-layer lanthanide-transition-metal frameworks

Three novel 3D pillared-layer heterometallic lanthanide-transition-metal (hetero-Ln-TM) compounds, namely, Ln2Cu7I6(ina)7(H2O)6.H2O [ina=isonicotinic acid; Ln=Ce (1), Sm (2)] and Er4(OH)4Cu5I4(ina)6(na)(2,5-pdc).0.3H2O (3; na=nicotinic acid, 2,5-pdc=2,5-pyridinedicarboxylic acid), have been obtained by incorporating different metal clusters as building blocks under hydrothermal conditions. Compounds 1 and 2 are isostructural and consist of two distinct building units of dimeric [Ln2(ina)6] cores and inorganic 2D [Cu8I7]nn+ layers based on the [Cu3I3] and [Cu4I3]+ clusters. Compound 3 is constructed from decanuclear [Cu10I8]2+ clusters and inorganic 1D [Er4(OH)4]n8n+ cluster chain-based layers, which represent the first example of a 3D hetero-Ln-TM constructed by the combination of two distinct types of metal cluster units of a 1D [Er4(OH)4]n8n+ cluster polymer and a transition-metal cluster. It is interesting that decarboxylation occurred in the ortho position and 2,5-pdc2- was partially transformed into na- under hydrothermal conditions. Compounds 1-3 represent good examples of using different metal cluster units to construct fascinating 3D hetero-Ln-TM frameworks.     

A practical preparation of methyl 2-methoxy-6-methylaminopyridine-3-carboxylate from 2,6-dichloro-3-trifluoromethylpyridine.

An effective and practical synthetic route to methyl 2-methoxy-6-methylaminopyridine-3-carboxylate (7), the key intermediate of 5-bromo-2-methoxy-6-methylaminopyridine-3-carboxylic acid (1), from 2,6-dichloro-3-trifluoromethylpyridine (12) was undertaken. Process improvements were highlighted by regioselectivity of 12 with a nitrogen nucleophile and conversion of the 3-trifluoromethyl group into the methoxycarbonyl group. The reaction of 12 with N-benzylmethylamine provided the 6-(N-benzyl-N-methyl)aminopyridine 26a and the regioisomer 26b in >98:<2 ratio in a quantitative yield. Treatment of 2-methoxy-6-methylamino-3-trifluoropyridine (14a) with a large excess of sodium methoxide followed by acid hydrolysis gave the pyridine-3-carboxylic ester 7 in an excellent yield. The potential application of this reaction is also described.     

Pyrazolo[1,5-d]triazines-1,2,4. I. Dérivés pyrazoliques

Pyrazole hydrazides and hydrazines were synthesized from pyrazole-5-carboxylic acid, 4-bromopyrazole-5-carboxylic acid and pyrazole-5-carboxaldehyde. The 5-pyrazolyloxadiazoles and 5-pyrazolylthiadiazoles were obtained by cyclising the pyrazole hydrazides with phosphorus oxychloride and tetraphosphorus decasulphide. Cyclisations in 1,2-dihydro-1-oxo- (or l-thioxo)pyrazolo[1,5-d]-1,2,4-triazines were eventually observed. The structures were assignated by nmr.     

Formation of novel polycyclic cage compounds through ‘uncaging’ of readily accessible higher cage compounds

The synthesis of the novel cage compounds 7-halomethyl-8-(carbomethoxy)tetracyclo[4.2.1.1^4,7.0^2,5]deca-3-(11)-ene-10-ones, methyl-4-methylene-6-oxopentacyclo[5.4.0.0.^2,5.0^3,10.0^7,9]undecane-9-carboxylate, 3-chloromethyl-4-(carbomethoxy)tetracyclo[4.2.1.1.^3,8.0^2,5]deca-7(11)ene-10-one, 2-bromo-5-methyl-8-methylene-6-oxotricyclo[5.3.0.0^3,9]decane-4-carboxylic acid and 2-bromo-5-methyl-8-methylene-6-oxotricyclo[5.3.0.0^3,9]decane-4-methyl carboxylate, achieved through base catalyzed rearrangement, is described.     

Fluorénacènes et fluorénaphènes synthèses dans la série des indéno-fluorènes,XVII. Dérivés méthylés du cis-fluorénacène,du trans-fluorénacène et du trans-fluorénaphène

By condensation of the chlorides of the three 9-oxo-fluorene-2-, -3-, and -4-carboxylic acids with 4-bromo-1,2-xylene on one side, and of the chlorides of o-bromobenzoic acid, 2-bromo-4-methyl-benzoic acid and 2-bromo-4,5-dimethyl-benzoic acid with fluorene, 2-methylfluorene and 3-methylfluorene on the other side, followed by direct or indirect cyclisation and by final reduction, several new methyl derivatives of the indenofluorenes I, II and IV are synthesized.     

A Novel Synthesis of 1-Aminocyclopropane-1-carboxylic Acid (ACC)

A novel synthetic route of 1-aminocyclopropane-1-carboxylic acid (ACC) has been built via cyclopropanedicarboxylic acid monohydrazide III in moderation to good yield.     

An efficient high-yield synthesis of D-ribo-phytosphingosine

[Structure: see text] [4R-[4alpha(S),5alpha]]-2,2-Dimethyl-4-(2-oxo-5-vinyl[1,3]dioxolan-4-yl)oxazolidine-3-carboxylic acid tert-butyl ester 5a, obtained in excellent yield and diastereoselectivity by the alpha-hydroxyallylation of the Garner aldehyde (4), is exploited in a novel high-yield synthesis of D-ribo-phytosphingosine (8), using microwave-enhanced cross metathesis as the key step in the chain elongation.     

Reaction of 2,5‐dimethylpyrroles with quinones. Synthesis of new pyrrolylquinones

The reaction of 1,4‐naphthoquinone ( 1 ) with 2,5‐dimethylpyrroles ( 7a‐7d ) gives only 3‐(1,4‐naphtho‐quinonyl)‐2,5‐dimethylpyrroles. Extending the reaction to other quinones: 5‐hydroxy‐1,4‐naphthoquinone ( 2 ), 1,2‐naphthoquinone ( 3 ), quinoline‐5,8‐dione ( 4 ) and quinoxaline‐5,8‐dione ( 5 ), of which nothing was known, allows the synthesis of new pyrrolylquinones.     

A novel synthesis of (±)-2-acetyl-5,8-dimethoxy-1,2,3,4-tetrahydro-2-naphthol,a key intermediate for the synthesis of anthracyclinones

The title compound((±)-3) was prepared from readily available 5,8-dimethoxy-3,4-dihydro-2-naphthoic acid(4), according to the novel synthetic route visualized in $\text{Scheme I}$.     

Sur les dérivés de la fluorénone VI Les acides bromo-3-fluorénonecarboxylique-2 et bromo-2-fluorénonecarboxylique-3 et la bromo-3-méthyl-4-fluorénone

Starting from 2-amino-3-bromo-9-oxofluorene and from 3-methylfluorene respectively the preparation of 3-bromo-9-oxofluorene-2-carboxylic acid and of 2-bromo-9-oxofluorene-3-carboxylic acid is described. A synthesis of 3-bromo-4-methyl-9-oxofluorene is also given.     

Synthèses dans la série des bis-indéno-fluorénes III [1]. Dihydro-14, 15-13H-bis-indéno[2,1-a;1′,2′,-i]fluorène et dihydro-14, 15-8H-bis-indéno [2, 1-a;2′,1′-h]fluorène

Starting from 2-bromo-9-oxo-fluorene-1-carboxylic acid the biangular bis-indenofluorene 14, 15-dihydro-13H-diindeno[2, 1-a; 1′, 2′-1]fluorene (VIII) and the monoangular 14, 15-dihydro-8H-diindeno[2, 1-a; 2′, 1′-h]fluorene (XI) have been synthesised in 6 resp. 7 steps (overall yield 22% resp. 18%). As intermediate compounds the 14-oxoderivatives of VIII and XI were also obtained.     

3,4-二氢-3-甲基-4-氧代咪唑[5,1-d]并[1,2,3,5]四嗪-8-甲酸苯磺酰基呋咱氮氧基酯的合成

以3,4-二氢-3-甲基-4-氧代咪唑[5,1-d]并[1,2,3,5]四嗪-8-甲酰胺和苯磺酰基呋咱氮氧化物为原料,通过肖滕-鲍曼法合成了5种新的咪唑四嗪衍生物——3,4-二氢-3-甲基-4-氧代咪唑[5,1-d]并[1,2,3,5]四嗪-8-甲酸苯磺酰基呋咱氮氧基酯,其结构经1H NMR,IR,MS和元素分析确证。