Synthèse d'analogues bihétérocycliques du phénanthrène: Les méthyl-1-[1]benzothinéo,benzoséléno[2,3-b ]pyrroles,et méthyl-1-[1]benzofuro,benzothiéno et benzoséléno[3,2-b ]pyrroles

The condensation of ethyl sarcosinate on 2- or 3-halogeno 3- or 2-formyl[1]benzofuran. benzothiophene or benzoselenophene, and on the related 2h-[1]-3-benzoheteroyclanones is described. In the last instances the resulting compounds were formylated in teh 2-position with subsequent. After hydrolysis and decarboxylation, the I1methy][1]benzothieno-, benzoseleno [2,3-b]pyrroles were were thus obtained.     

Propriétés de la benzopyranno[1][2,3-b]quinoxalinone-12

Under basic conditions. [1]benzopyrano[2,3-b]quioxakin-12-one leads to 3-(i-hydroxybenzoy1)-1H-quinoxalin-2-one. This ketone reacts with hydroxylamine and phenylhydrazine to give the expected derivatives or those of [1]benzopyrano92,3-b]quinoxalin-12-one. The reduction of [1]benzopyrano[2,3-b]quinoxalin-12-one was unsucessful by chemical means. However, electrochemical reduction leads to a dihydropyrazine nucleus.     

Synthése de la benzopyranno[1][2,3-b]quinoxalinone-12

3-Benzyl-2-quinoxalinones were obtained by condensation of o-phenyl-enediamine with phenylpyruvic acids. These quinoxalinones were easily substituted in position 2 and which permitted the preparation of many derivatives, however, cyclisation of these compounds into 12H-[1]benzopyrano[2,3-b]quinoxalines failed. This new heterocycle might be synthesized from ethyl 2-phenoxy-3-quinoxalinecarboxylate.     

Nouvelles synthèses de thiéno[3,2-c] - et thiéno[2,3-c]pyridines

A new method for the synthesis of thieno[2,3-c]-and [3,2-c]-pyridines and of their tetrahydro derivatives is described. The process is based on some modifications of the Pomeranz-Fritsch reaction leading to isoquinolines.     

Synthèse des pyrido[2,3-d] el [3,2-d] -s-triazolo[3,4-f] pyrimidines el de (pyrazolyl-1')-4 pyrido[2,3-d] et [3,2-d] pyrimidines

The synthesis of two new heterocycles is described: pyrido-[2,3-d]-.s-triazolo[ 3,4-f] pyrimidine and pyrido[3,2-d]-.s-triayzolo-[3,4-f] pyrimidine. 4-[I'-Pyrazolyl]pyrido[2,3-d]pyrimidines and 4-[1′-pyrazoly1] pyrido[ 3,2-d] pyrimidine are obtained by the action of 4-hydrazinopyrido[2,3-d]pyrimidine and 4-hydrazinopyrido-[3,2-d]pyrimidine with several β-diketones.     

Synthèse de la diméthyl-4,4-dihydrofuranedione-2,3

4,4-Dimethyl-dihydro-2,3-furanedione ( 4 ), an intermediate in the synthesis of (+)-D -pantothenic acid, is obtained in good yield from readily available substances such as isopropyl chloride, diethyl oxalate and formaldehyde, without oxidative conditions.     

Pyrrolothienopyrazines: Synthèse de la pyrrolo[1,2-a]thieno[3,2-e]pyrazine et de la pyrrolo[1,2-a]thieno[2,3-e]pyrazine

The synthesis of pyrrolo[1,2-α]thieno[3,2-e]pyrazine and pyrrolo[1,2-α]-thieno[2,3-e]pyrazine is described. These syntheses could be achieved by intramolecular cyclization of 2- (and 3-) (1-pyrrolyl)-3- (and -2)-thienyl-amines obtained by hydrolysis of carbamates or by cleavage of the corresponding ureas. An original way giving better results was also studied via a Curtius rearrangement by reaction between the azide and aldehyde groupings. The synthesis of 2- (and -3)-2-formyl-1-pyrrolyl)-2- (and -3)-thenoylazide is described.     

Synthèse de flavones et de xanthones dans la série du benzo[4,5]thiophène

We describe the first synthesis of 2-arylbenzo[4,5]thieno-[2,3-b]pyran-4-one and of 2-arylbenzo [4,5] thieno [3,2-b] pyran-4-one, from benzo [4,5] thiophene and we have extended these cyclizations to obtain the heterocyclic analogs of the xanthones.     

Synthèse dc la pyrido[2,3-f] phtalazine et des diformyl-6,7; -4,6; -4,7; -2,4 quinoleines

This article describes the synthesis of a new heterocycle, pyrido[2,3,f]phtalazine and three new diformylquinolincs.     

Synthesis and Diels-Alder reactions of the benzo[4,5]thieno [2,3-c]pyrrole ring system

The first synthesis of the parent compound of the benzo[4,5]thieno[2,3-c]pyrrole ring system and its derivatives, as well as their Diels-Alder reactions with DMAD and N-phenylmaleimide are reported. A new synthesis of the benzo[4,5]thieno[2,3-d]pyridazine ring system is also described.     

Synthèse et propriétés photochromiques de 1, 3-dihydrospiro[2H-indole-2,3′-[3H]pyrimido[5,4-f][1,4]benzoxazines] et de 1,3-dihydrospiro[2H-indole-2,7′-[7H]thiazolo[5,4-f][1,4]benzoxazines]

Synthesis and Photochrmic Characteristics of 1,3-Dihydrospiro[2H-indole-2,3′-[3H-]pyrimido[5,4-f][1,4]benzoxazines] and 1,3-Dihydrospiro[2H-indole-2,7′[7H]thiazolo[5,4-f][1,4]benzoxazines] Two new series of 1,3-dihydrospiro[2H-indole-ozazine] derivatives were synthesized, the 1,3-dihydrospiro[2H-indole-2,3′-[3H]pyrimido[5,4]pyrimido[5,4-f][1,4]benzoxaines] 4-10 and the 1,3-dihydrospiro[2H-indole2,7′-[7H]thiazolo-[5,4-f][1,4]benzoxaines] 11–17 . These series extend the available range of photochromic properties (rate constant of thermal bleaching, UV/VIS spectrum of the opened coloured form, and photocoloration yield), an interesting feature of variable-transmission materials. The synthesis of these compounds (Scheme 1) required the preliminary synthesis of intermediate β-hydroxy-α-nitrosotherocycles 18 and 19 (Scheme 2). Important amounts of a coloured, non-photochromic, stable secondary product (See 20 ) were found in the condensation in the spiro[indole-thiazolobenzoxazine] series. The photochromic characteristics of the new derivatives were determined using a flash-photolysis apparatus coupled to a fast-scanning spectrometer. The role of the heteroatoms in the oxazine moiety and the role of substitutents in the indole moiety were investigated quantitatively through the study of the photochromic properties and the solvent effects. The presence of an S-atom gives rise to interesting properties which open up new prospects for synthesis and application.     

Synthèse énantiospécifique de la (+)-(R)-éthyl-6-dihydro-2,3-méthyl-2-4H-pyranone-4, phéromone de la mite Hepialus hecta L

Enantiospecific Synthesis of (+)-(R)-6-Ethyl-2,3-dihydro-2-methyl-4H-pyran-4-one, Sex-pheromonal Component of the Male Swift Moth Hepialus hecta L . A new synthesis of (+)?(R)-6-ethyl-2,3-dihydro-2-methyl-4H-pyran-4-one ((R)- 8 ), sex-pheromonal component of the male swift moth Hepialus hecta L., has been performed from (?)-(R)-1-(1,3-dithian-2-yl)propan-2-ol with an enantiomeric excess of ? 97%.     

[1]Benzothieno[2,3-d]pyridazines V. Etude des Réactions de substitution des Benzothiéno[2,3-d]pyridazinethiones

The substitution and addition reactions of the 2H[1]benzothiéno[2,3-d]phyridazinethione-1 and the 3H[1]benzothiéno[2,3-d]pyridazinethione-4 gave N- or S-substituted derivatives whose structures were identified by 1R and NMR spectroscopy.     

Nouvelles syntheses de la thieno[2,3-b] pyrazine

Two new syntheses of thieno[2,3-b]pyrazine are reported with methylpyrazine as the starting material. One of the methods consists of an original method to form a thiophene ring in condensed systems.     

Quelques réactions nuclé ophiles et électrophiles de la thiéno[2,3-b]pyrazine. Comparaison de sa réactivite avec celles de thiéno diazines et de la thiényl-2 pyrazine dans le cas de la nitration

We studied the action of nbutyllithium, the action of chlorine and the action of nitric acid in sulfuric acid medium on thieno-[2,3-b]pyrazine, These reactions led us to comparethe behaviour of thieno[2,3-b]pryazine with that of thieno[2,3-d]pyrimidine and of thieny1-2pyrazine under the same consitions.     

Pyrrolothiénopyrazines: Etude chimique de la pyrrolo[1,2-a]thiéno[2,3-e]pyrazine

The reactivity of pyrrolo[1,2-a]thieno[2,3-e]pyrazine towards quaternisation, bromination, nitration, Friedel-Crafts, Vilsmeier-Haack and Reissert reactions was studied. Assignment of structures to the product is based upon ir, nmr and mass spectral studies.     

Synthesis of 2,3-dihydrospiro[benzofuran-2,4′ -piperidines] and 2,3-dihydrospiro[benzofuran-2,3′-pyrrolidines]

The synthesis of 2,3-dihydrospiro[benzofuran-2,4′-piperidines] 3 and 2,3-dihydrospiro[benzofuran-2,3′]-pyrrolidine] 6 is described. The synthesis was achieved by a Grignard reaction of a 2-fluorobenzylhalide with an appropriate cycloazaalkyl ketone to yield the tertiary alcohols 1 and 4 . Subsequent intramolecular displacement of the aromatic fluoride by the derived alkoxides provided the novel system. Nitration of 1′-acetyl-2,3-dihydrospiro[benzofuran-2,4′-piperidine] 7 resulted in a 5-nitro derivative.     

Synthesis of thieno[2,3-d]thia[1]pyrano[4,3-b]pyrrole derivatives

It is shown that 2-methyl-3-carbethoxy-4H,8H,5,6-dihydrothieno[2,3-d]thia[1]pyrano [4,3-b]pyrrole and 8-methyl-9-carbethoxy-10H,5,6-dihydrothieno[2,3-d]thia[1]chromeno[4,3-b]pyrrole and their S,S-dioxides, respectively, are obtained in the reaction of 2-methyl-3-carbethoxy-4-thienylhydrazine with tetrahydro-4-thiopyrone, tetrahydro-4-thiopyrone S, S-dioxide, 4-thiochromanone, and 4-thiochromanone S,S-dioxide in the presence of an acid catalyst.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 195–196, February, 1979.     

Synthese de nouvelles 1H,3H pyrido[2,3-d] pyrimidinediones-2,4

The synthesis and spectroscopic properties of a series of new substituted 2,4-dioxopyrido[2,3-d]pyrimidines are reported.     

Benzofuro[2,3-d]pyridazines IV. Etude de la chloro-4 benzofuropyridazine

[1] Benzofuro[2,3-d] pyridazone was synthesized by three methods namely8: catalytic dehalogenation of the 4-chlorobenzofuro [2,3-d] pyridazone; removal of the hydrazono group of 4-hydrazinobenzofuro [2,3-d] pyridazine and desulphurization of benzofuro [2,3-d] pyridazine and desulphurization of benzofuro [2,3-d] pyridazine-4(3H) thione. The 4-substituted derivatives were obtained by nucleophilic attack of the 4-chlorobenzofuro[2,3-d] pyridazine. Tetrazolo[1,5-b]- and s-triazolo-[1,2-b] benzofuro [2,3-d] pyridazones. The structural assignment of the benzofuro[2,3-d]pyridazones was made by the Noe effect.