吡啶并吡唑类化合物与蛇毒蛋白的相互作用

运用荧光猝灭的原理在p H 7.6的生理条件下,眼镜蛇毒蛋白与系列6-氨基-4-芳基-5-氰基-3-甲基-1-苯基吡啶[2,3-c]并吡唑化合物之间的相互作用被研究,并且筛选出6-氨基-4-对羟基苯基-5-氰基-3-甲基-1-苯基吡啶[2,3-c]并吡唑（I）进行了详细研究。猝灭常数KSV、结合常数K以及结合位点n被获得。该实验证明眼镜蛇毒蛋白与I之间生成了新的化合物,而这一过程是静态猝灭的过程,并且它们之间存在着一定的结合。     

Eindeutige Synthese des 4,7-Dihydro-4-oxo-1 H-pyrazolo[3,4-b]pyridins – Bemerkungen zur „(N?C)-Umlagerung”︁ von (2-Alkoxycarbonyl-vinyl-amino)pyrazolen

Unambiguous Synthesis of 4,7-Dihydro-4-oxo-1H-pyrazolo[3,4-b]pyridine — Further Comments on the “(N C)-Rearrangement” of (2-Alkoxycarbonyl-vinyl-amino)pyrazols 4,7-Dihydro-4-oxo-1H-pyrazolo[3,4-b]pyridine 1a is synthesized by decarboxylation of 1-benzyl-5-carboxy-4-hydroxy-pyrazolo[3,4-b]pyridine 4b and debenzylation of 1-benzyl-4,7-dihydro-4-oxo-pyrazolo[3,4-b]pyridine 1b with sodium in liquid ammonia. The product from 3-amino-pyrazol and methyl propiolate, formerly described as 1a , obviously is the 6-oxo isomer 2a . Use of the parameter δ¹³(CO) for the structural assignment of pyrazolo[3,4-b]pyridones is only permitted, if in the corresponding media mainly the oxo-tautomer is existing. It is again demonstrated that DMSO is often an insufficient medium. Debenzylation of 1b and similar compounds with SeO₂ is only possible, if the α-position of CO is blocked by a substituent. Otherwise diselenids of type 6 are formed. This obviously is a general reaction of cyclic lactames. The cyclisation of (2-alkoxycarbonyl-vinyl-amino)pyrazols 7 in acidic media, and with catalytical amounts of the corresponding amino-pyrazols gives 6,7-dihydro-6-oxo-pyrazolo[3,4-b]pyridines 2 via amino 4-(2-alkoxycarbonyl-vinyl)pyrazols 8 , i.e. via products of an “(N C)-rearrangement”, while by thermal cyclisation of 7 4,7-dihydro-4-oxo-pyrazolo[3,4-b]pyridines 1 are formed.     

Allgemeine Synthesen und rationelle Strukturparameter isomerer Derivate von [3,4]-kondensierten Pyrazolen

General Syntheses and Rational Parameters for Structural Assignment of Isomeric Derivatives of [3,4]-fused Pyrazoles 4 isomeric 1- or 2-methyl-, and 1- or 2-benzyl-pyrazolo[3,4-b]pyridones, i.e. the 4-oxo-types 17a, b or 11a, b and the 6-oxo-types 16a, b or 10a, b , are synthesized unambiguously. Cyclisation of 1-substituted 3- or 5-(1-methyl-2-ethoxycarbonyl-vinylamino)-pyrazoles 9a, b or. 15a, b , which were synthesized from 1-substituted 3- or 5-amino-pyrazoles and ethyl acetoacetate yields 11a, b or 17a, b in downtherm, but 10a, b or 16a, b in presence of acidic catalysts. The acidic cyclisation is preceded by a new rearrangement of 9 or 15 into 1- substituted 3- 27 or 5-amino-4-(1-methyl-2-ethoxycarbonyl-vinyl)-pyrazoles 30 ; mechanism and concurring reactions are explained. Because of their higher electron densities at C-4 it is easier to cyclise derivatives of 5-amino-pyrazoles compared to 3-amino-pyrazoles. All isomeric 1- or 2-substituted 4(6)-chloro-6(4)-methyl-pyrazolo-[3,4-b]pyridines are formed with POCl₃ from the corresponding oxo-compounds. The position of a substituent at N-1 or N-2 of [3,4]-fused pyrazoles can be assigned using the significant ¹H-n.m.r.-parameter Δ = δ — − δ_HMPT (conc. HC—3). If solvent influences are considered, δ(C  O) is a useful ¹³C-n.m.r.-parameter to distinguish the 4-oxo-types ( 11a, b; 17a, b ) from the 6-oxo-types ( 10a, b; 16a, b ) of pyrazolo[3,4-b]pyridones. Further own and lit. dates conc. structural assignment (n.m.r., i.r., u.v.) are discussed critically.     

The synthesis of fused and pendant pyrazole heterocyclic compounds from 5-amino-3-methyl-1-phenylpyrazole and their evaluation as fluorescent brightening agents

5-Amino-3-methyl-1-phenylpyrazole ( 1 ) has been condensed with EMME ( 2 a) and EMCA ( 2 b) and the resulting ethyl 5-aminoacrylates ( 3 a–b) cyclized to pyrazolo[3,4,-b]pyridines ( 4 a–b). 3-Methyl-1-phenylpyrazol-5-yl diazonium salt ( 7 ), prepared from ( 1 ) was coupled with tobias acid ( 8 ) and 2-methoxy-6-aminoquinoxaline ( 9 ) to get the corresponding O-aminoarylazo and heterylazo dyes ( 10 ) which were oxidatively cyclized to 2-N-(3-methyl-1-N-phenylpyrazol-5-yl)-1,2,3-triazolo[4,5-a] naphthalene and [4,5-f] quinoxaline derivative ( 11 ). The spectral properties of the compounds ( 4 a–b, 5 , 6 , 11 a–b) were studied.     

Synthesis of pyrazolo[4′,3′:5,6]pyrazino[2,3-c]pyrazoles and pyrazolo[4′,3′:5,6]pyrazino[2,3-d]pyrimidines and their application to polyester fibres

4-Nitroso-1-phenyl-3-methyl-5-aminopyrazole ( 1 ) was condensed with ethylcyanoacetate ( 2 ), malononitrile ( 4a ) and 2-cyanomethylbenzimidazole ( 4b ) to yield 6-hydroxy-5-cyano, 6-amino-5-cyano and 6-amino-5-(benzimidazol-2-yl)-3-methylpyrazolo [3,4-b]pyrazines 3, 5a and 5b , respectively. 5-Cyano-6-chloro derivative 6 obtained from 3 was converted to 3-aminopyrazolo[4′,3′:5,6]pyrazino[2,3-c]pyrazoles 8a and 8b by the treatment with hydrazin hydrate ( 7a ) and phenylhydrazine ( 7b ), respectively. Compound 5a was treated with formamide ( 9a ), urea ( 9b ) and thiourea ( 9c ) to give 4-aminopyrazolo[4′,3′:5,6]pyrazino[2′3′-d]pyrimidines 10a–10c. With refluxing acetic anhydride compounds 8a, 8b and 10a gave corresponding acetamido derivatives 8c, 8d and 10d. Compound 5a was treated with ethylorthoformate ( 11 ), acetic anhydride ( 12 ) or benzoylchloride ( 13 ) to give fused benzimidazopyrazolo[4′,3′:5,6]pyrazino[2′,3′-d]pyrimidines, viz., benzimidazol[1,2-c]pyrazolo[4,3-g]pteridines ( 14a–14c ). Some of the compounds 8, 10 and 14 were applied to polyester as disperse dyes and their fastness properties were studied.     

Synthesis and Antimicrobial Evaluation of Some Novel Bis-α,β-Unsaturated Ketones,Nicotinonitrile, 1,2-Dihydropyridine-3-carbonitrile,Fused Thieno[2,3-b]pyridine and Pyrazolo[3,4-b]pyridine Derivatives

The title compounds were prepared by reaction of 1,1′-(5-methyl-1-phenyl-1H-pyrazole-3,4-diyl)diethanone (1) with different aromatic aldehydes 2a–c, namely Furfural (2a), 4-chlorobenzaldehyde (2b) and 4-methoxybenzaldhyde (2c) to yield the corresponding α,β-unsaturated ketones 3a–c. Compound 3 was reacted with malononitrile, 2-cyanoacetamide or 2-cyanothioacetamide yielded the corresponding bis[2-amino-6-(aryl)nicotinonitrile] 4a–c, bis[6-(2-aryl)-2-oxo-1,2-dihydropyridine-3-carbonitrile] 5a–c or bis[6-(2-aryl)-2-thioxo-1,2-dihydropyridine-3-carbonitrile] 6a,b, respectively. The reaction of compound 6a with each of 2-chloro-N-(4-bromophenyl) acetamide (7a), chloroacetamide (7b) in ethanolic sodium ethoxide solution at room temperature to give the corresponding 4,4′-(5-methyl-1-phenyl-1H-pyrazole-3,4-diyl)bis-6-(2-furyl)thieno[2,3-b]pyridine-2-carboxamide] derivatives 9a,b. While compound 6a reacted with hydrazine hydrate yielded the 4,4′-(5-methyl-1-phenyl-1H-pyrazole-3,4-diyl)bis[6-(2-furyl)-1H-pyrazolo[3,4-b]pyridin-3-amine] 11. The structures of the products were elucidated based on their spectral properties, elemental analyses and, wherever possible, by alternate synthesis. Antimicrobial evaluation of the products was carried out.     

Reactions with 5,6-Diphenyl-2,3-dihydro-imidazo[2,1-b]thiazol-3-ones and 6,7-Diphenyl-2,3-dihydro-4H-imidazo[2,1-b]1,3-thiazin-4-one

2-Methyl-5,6-diphenyl-2,3-dihydro-imidazo[2,1-b]thiazol-3-one 5 and 6,7-diphenyl-2,3-dihydro-4H-imidazo[2,1-b]1,3-thiazin-4-one 6 are prepared from 4,5-diphenyl-2-mercapto-imidazole 1 . Compounds 5 and 6 react with amines or hydrazines to give the 2-(4,5-diphenyl-imidazol-2-ylthio)acet(or propan) amides (hydrazides) 7a – g and the 3-(4,5-diphenyl-imidazol-2 ylthio) propanamides(hydrazides) 8a – e , respectively. The hydrazides 7a, 7b and 8a are condensed with aromatic aldehydes to the hydrazones 9a – h and 10a – d . Compound 5 couples with aryldiazonium salts to give 2-arylazo-2-methyl-5,6-diphenyl-2,3-dihydro-imidazo[2,1-b]thiazol-3-ones 11a – d .     

6-甲基-4-羟基-噻嗯并[2,3-b]噻喃-2-磺酰胺的合成

以2-巯基噻吩和巴豆酸为起始原料,经加成缩合制得3-(2-噻吩巯基)丁酸;在P2O5催化下环合制得6-甲基-4-氧-噻嗯并[2,3-b]噻喃;再用氯磺酸进行氯磺化、氨水氨解制得6-甲基-4-氧-噻嗯并[2,3-b]噻喃-2-磺酰胺;最后用硼氢化钠还原得到盐酸杜塞酰胺的中间体6-甲基-4-羟基-噻嗯并[2,3-b]噻喃-2-磺酰胺,合成总收率为16.0%。其化学结构经IR,1H NMR,MS得以确证。     

Novel derivatives of methyl hexahydro-3-methyl-6-thioxo-1,2,4,5-tetrazine-3-nonanoate

Methyl hexahydro-3-methyl-6-thioxo-1,2,4,5-tetrazine-3-nonanoate (I) on treatment with reagents such as chloroacetic acid, 1,2-dibromoethane and 2-mercaptoethanol under different reaction conditions afforded methyl 3,4,6,7-tetrahydro-3-methyl-6-oxo-2H-thiazolo[3,2-b]-1,2,4,5-tetrazine-3-nonanoate (II), methyl 3,4,6,7-tetrahydro-3-methyl-2H-thiazolo[3,2-b]-1,2,4,5-tetrazine-3-nonanoate (III) and methyl 8-methyl-1-oxa-4-thia-6,7,9,10-tetraazaspiro-[4.5]-decane-8-nonanoate (IV) in good yields. The structures of compounds II–IV were established by elemental analysis, infrared (IR), nuclear magnetic resonance (NMR), and mass spectral data.     

Amino-thieno[2,3–c]pyrazole und Amino-thieno[2,3–b]pyrrole

Amino-thieno[2,3–c]pyrazoles and Amino-thieno[2,3–b]pyrroles The synthesis of thieno[2,3–c]pyrazoles and thieno[2,3–b]pyrroles is described. From the dithioliumsalt ( 1 ) and potassium hydroxide the potassium-(2,2-dicyan-1-methylthio-ethen-1-yl)-thiolate ( 2 ) is formed. This reacts with hydrazine hydrate to form the 3-amino-5-thioxo-pyrazol-4-carbonitrile ( 3 ) S-Alkylation with α-chlorocarbonyl compounds yielding ( 6a–c ) leads via Thorpe-Ziegler-cyclization to 3,4-diamino-thieno[2,3–c]pyrazoles ( 9 ) if the position 1 is alkylated ( 8 ). Acetyl acetone yields 2-mercapto-pyrazolo[1,5–a]pyrimidine ( 5 ). After S-alkylation ( 10a–d ) are immediately cyclized to thieno [2′,3′:3,4]pyrazolo[1,5-a]pyrimidine ( 11a–d ). The ketone ( 6a ) can be cyclized to the pyrazolo [5,1–b]thiazole ( 12 ). 3 reacts with oxalyl chloride to form the 2,3-dioxo-6-thioxo-imidazo[1,2-b]pyrazole ( 13 ) of which S-phenacyl derivative ( 14 ) because the NH-proton cannot be cyclized. The 5-amino-3,4-dicyano-pyrrol-2-thiolate ( 16 ) shows the analogous behaviour. The S-alkylation is followed by cyclization, and 3,5-diamino-thieno[2,3–b]pyrroles ( 18a–b ) arise. Reaction of 5-amino-2-alkylthio-pyrrol-3,5-dicarbonitrile ( 17 ) with acetyl acetone provides pyrrolo[1,2-a]pyrimidine ( 20a–c ) which can be cyclized to form thieno[3′,2′:4,6]pyrimidines ( 21a–c ) very easily.     

COMPARATIVE METABOLISM OF PHENANTHRO[3,4-B]THIOPHENE,PHENANTHRO[4,3-B]THIOPHENE AND THEIR CARBON ANALOG BENZO[C]PHENANTHRENE BY RAT LIVER MICROSOMES

Phenanthro[3,4-b]thiophene (P[3,4-b]T) and phenanthro[4,3-b]thiophene (P[4,3-b]T) are thiasters of weakly mutagenic benzo[c]phenanthrene (B[c]P). These polycyclic sulfur heterocycles (thia-PAHs) represent a group of chemicals which have been identified in cigarette smoke. P[3,4-b]T is a potent mutagen in Salmonella typhimurium strain TA100 in the presence of rat liver S9, whereas its isosteric isomer P[4,3-b]T is a nonmutagenic compound. In order to understand the mechanism underlying the differences in the mutagenic activity of P[3,4-b]T and P[4,3-b]T, we have investigated the metabolism of P[3,4-b]T, P[4,3-b]T, and their carbon analogue B[c]P by rat liver microsomes. The liver microsomes from rats treated with Aroclor 1254 metabolized P[3,4-b]T, P[3,4-b]T, and B[c]P at a rate nearly 7- to 9-fold greater than of the control liver microsomes. High-performance liquid chromatography (HPLC) analysis of the metabolites formed showed that B[c]P was metabolized almost exclusively to its dihydrodiols which comprised predominantly K-region diol as noted in the previous studies. Our preliminary studies on the metabolism of P[3,4-b]T, P[4,3-b]T and B[c]P by liver microsomes from control and Aroclor 1254-treated rats have shown a significant reduction in the formation of 6,7-diol (K-region diol) and 8,9-diol (diol with a bay-region double bond) of the two thia-PAHs compared to the formation of analogous 5,6-diol (K-region diol) and 3,4-diol (diol with a bay-region double bond) from B[c]P. Both P[3,4-b]T and P[4,3b]T produced a major, relatively nonpolar metabolite(s) (80–96% of total metabolites). These studies indicate that the highly mutagenic P[3,4-b]T is not metabolized to dihydrodiol with a bay-region double bond to any greater extent than the weakly or nonmutagenic B[c]P or P[4,3-b]T, suggesting that the metabolite(s) other than P[3,4-b]T8,9-diol is likely to be involved in the mutagenicity of P[3,4-b]T.     

Synthesen mit 1, 3-Dithietanen. XIII. Synthesen von kondensierten Heterocyclen aus substituierten 5-Thioxo-Δ3-pyrazolin-4-carbonsäureestern

Syntheses with 1, 3-Dithietanes. XIII. Syntheses of Condensed Heterocycles from 5-Thioxo-3-pyrazoline-4-carboxylates 3-Amino-2-aroyl-5-thioxo-3-pyrazoline-4-carboxylates 1d – f react with bromoacetal-dehydediethylacetale, phenacyl bromides, ethyl bromopyruvate, ethyl α-chloro-acetate or chloro-acetylacetone to give ethyl dihydropyrazolo[5,1-b]thiazolecarboxylates 2 , 4 , 5 or 7 . The derivatives of ethyl tetrahydropyrazolo [5,1-b]thiazolecarboxylates 8 or 9 are obtained by reaction of 1d – f with ethyl β-anilino-α-chloro-crotonate and oxalylchloride, respectively. The ethyl methylthiopyrazoline-carboxylate 10d and an excess of hydrazine hydrate afford pyrazolo[3,4-c]pyrazole 11 . Compounds 10 react with phenyl isocyanate to give pyrazolo[3,4-d][1,3]oxazin-6-ones 13 . The dithietanes 12 and cinnamohydrazide yield pyrazolo[1,2-a]pyrazolecarboxylates 15 .     

Condensation of 4-phenyl-3,5-dicarboethoxycyclopentane-1,2-dione with primary amines

Condensation of the title compound ( 1 ) with primary aromatic amines gave the dianilides ( 2 ), which cyclized to cyclopenta[1,2-c:4,3-c′]diquinolines ( 3 ). Treatment of 1 with o-phenylenediamine or 2,3-diaminopyridine afforded cyclopenta[2,1-b:3,4- b ′]bis[1,5]benzodiazepine ( 4 ) and bis[1,5]pyrido[b]diazepine derivative ( 5 ), respectively. Whereas, with o-aminophenol a mixture of 2c and cyclopenta[2,1- b :3,4- b ′]bis[1,5]benzoxazepine ( 7 ) was obtained. Pechmann reaction of 1 with m-cresol gave the bis[1]benzopyrane ( 9 ). Mannich reaction of 1 with benzylamine afforded the 3-azabicyclo[3.2.1]octane system ( 10 ).     

Phenolation of (+)-Catechin with Mineral Acids. II. Identification of New Reaction Products

To investigate the reactions that occur in the flavanoid unit during the liquefaction of tannin in phenol, the phenolysis of (+)-catechin was studied using either H₂SO₄, HCl, or BF₃ 2H₂O as acid catalyst. In addition to 2-[3-(3,4-dihydroxyphenyl)-2-hydroxy-3-(4-hydroxyphenyl)propyl]-1,3,5-benzenetriol (1) and 2-[(3,4-dihydroxyphenyl)(4-hydroxyphenyl)methyl]-2,3-dihydro-4,6-benzofurandiol (3) that have been described previously, eight additional reaction products were isolated, four of which were compounds that have not been described previously. The novel compounds described here are: 2-[3-(3,4-dihydroxyphenyl)-2-hydroxy-3-(2-hydroxyphenyl)propyl]-1,3,5-benzenetriol (2), 2-[(3,4-dihydroxyphenyl)(2-hydroxyphenyl)methyl]-2,3-dihydro-4,6-benzofurandiol (4), 2-[(3,4-dihydroxyphenyl)(4-hydroxyphenyl)methyl]-2,3-dihydro-7-(4-hydroxyphenyl)methyl-4,6-benzofurandiol (5), and 2-(1,3,5-trihydroxyphenyl)methyl-3-(3,4-dihydroxyphenyl)-6-[(3,4-dihydroxyphenyl)(4-hydroxyphenyl)methyl]-2,3,5,6-tetrahydrobenzo[1,2-b:5,4-b′]-difuran-4-ol (6). The structures of these and other previously described products are consistent with opening of the pyran ring of catechin and reaction at C-2 by either the para or the ortho position of phenol. Additional products resulting from reaction between pyran ring cleavage products and catechin, and from reaction of cleavage products were found. Similar reactions would be expected to take place during the phenolysis of condensed tannins.     

New Bioactive Fused Triazolothiadiazoles as Bcl-2-Targeted Anticancer Agents

A series of 3-(6-substituted phenyl-[1,2,4]-triazolo[3,4-b]-[1,3,4]-thiadiazol-3-yl)-1H-indoles (5a–l) were designed, synthesized and evaluated for anti-apoptotic Bcl-2-inhibitory activity. Synthesis of the target compounds was readily accomplished through a reaction of acyl hydrazide (1) with carbon disulfide in the presence of alcoholic potassium hydroxide to afford the corresponding intermediate potassium thiocarbamate salt (2), which underwent cyclization reaction in the presence of excess hydrazine hydrate to the corresponding triazole thiol (3). Further cyclisation reaction with substituted benzoyl chloride derivatives in the presence of phosphorous oxychloride afforded the final 6-phenyl-indol-3-yl [1,2,4]-triazolo[3,4-b]-[1,3,4]-thiadiazole compounds (5a–l). The novel series showed selective sub-micromolar IC₅₀ growth-inhibitory activity against Bcl-2-expressing human cancer cell lines. The most potent 6-(2,4-dimethoxyphenyl) substituted analogue (5k) showed selective IC₅₀ values of 0.31–0.7 µM against Bcl-2-expressing cell lines without inhibiting the Bcl-2-negative cell line (Jurkat). ELISA binding affinity assay (interruption of Bcl-2-Bim interaction) showed potent binding affinity for (5k) with an IC₅₀ value of 0.32 µM. Moreover, it fulfils drug likeness criteria as a promising drug candidate.     

Über neue Pyrazolverbindungen. IV Darstellung und Cyclisierungsverhalten einiger akzeptorsubstituierter N-(Pyrazol-3-yl)-thioharnstoffe

New Pyrazol Derivatives. IV. Preparation and Cyclization of Some Acceptor-Substituted N-(Pyrazol-3-yl)-thioureas . 3-Aminopyrazol-4-carboxylic acid derivatives ( 1 , 2 ) were transformed by reaction with different isothiocyanates R²NCS to N-(pyrazol-3-yl)-N^. -substituted thioureas ( 5 , 6 ). Ethyl 3-amino-1-benzylpyrazol-4-carboxylate reacts with CSCl₂ to form ethyl 1-benzyl-3-isothiocyanatopyrazol-4-carboxylate ( 3 ) which yields with amines the corresponding N-(pyrazol-3-yl)-N^. -substituted thioureas ( 5 ). As a byproduct in the reaction with CSCl₂ N,N^. -di-(pyrazol-3-yl)-thiourea ( 4 ) is formed. With hydrazine or phenylhydrazine N-(pyrazol-3-yl)-thiosemicarbazides ( 7a , b ) are obtained. The thioureas ( 5 , 6 ) can be cyclized in basic solution to 4,5,6,7-tetrahydropyrazolo[3,4-d]pyrimidin-4-on-6-thiones ( 8 ) which on alkylation form 6-alkylthio-4,5-dihydropyrazolo[3,4-d]pyrimidin-4-ones ( 9 ). Methyl-N-(pyrazol-3-yl)-N^.-benzoylisothiourea ( 10 ) reacts with ethylamine to form N-benzoyl-N^. -ethyl-N^‥-(pyrazol-3-yl)-guanidine derivative ( 11 ) which on treatment with NaH in dimethylformamide yields 6-benzoylamino-5-ethyl-4,5-dihydropyrazolo[3,4-d]pyrimidin-4-one ( 12 ). By treatment with sulfuric acid the N-(pyrazol-3-yl)-thiourea derivatives ( 5 , 6 ) form new 6-amino substituted pyrazolo[3,4-d][1,3]thiazin-4-ones ( 13 ).     

2,3-Heterokondensierte Thiophene aus substituiertem 2-Aminothiophen-3-thiol

2,3-Heterocondensed Thiophenes from Substituted 2-Aminothiophen-3-thiole Ethyl 5-amino-4-mercapto-3-methyl-thiophen-2-carboxylate ( 2 ), obtainable from the appropriate thienylthiocyanate 1 by reduction, undergoes reactions in analogy to the 2-aminobenzenthiole. Thus, with formic acid or trimethylorthoacetat the thieno [2,3-d]thiazoles 4 and 5 are formed. Aromatic aldehydes yield the thieno[2,3-d]thiazolines ( 6 ) which can be dehydrogenated by sulphur to form 9 . From carbon disulfide and 2 the thieno[2,3-d]thiazol-2-thione ( 7 ) is formed. With phenacylbromide or ethyl bromoacetate 2 can be converted into the thieno[3,2-b] thiazine derivatives 11 or 12 . Diazotation of 2 yields the thieno[2,3-d]1,2,3-thiadiazole derivative ( 14 ).     

Quinoxaline derivatives as long wavelength photosensitizers in photoinitiated cationic polymerization of diaryliodonium salts

The present paper is focused on visible light initiated cationic polymerizations. Photoinitiated polymerization of representative vinyl ether and oxirane monomers using two quinoxaline derivatives; namely (2-(2,3-dihydrobenzo [b][1,4]dioxin-6-yl)-3-(2,3-dihydrobenzo[b]-[1,4]dioxin-7-yl)-5-(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-8-(2,3-dihydrothieno[3,4-b][1,4]dioxin-7yl) quinoxaline) (DBQEd) and 2,3,5,8-tetra(thiophen-2-yl)quinoxaline (TTQ) are studied. Novel dyes based on the quinoxaline skeleton are employed as efficient photosensitizers in cationic photopolymerizations. Polymerizations were initiated at room temperature upon irradiation with long-wavelength UV and visible lights in the presence of diphenyliodonium hexafluorophosphate (Ph₂I⁺PF₆^?). The progress of the polymerizations was monitored by optical pyrometry (OP). Solar irradiation is also employed to carry out the cationic polymerization of a diepoxide monomer in the presence of air.     

Reactions of hydrazonoyl halides 44 [1]: synthesis of some new 1,3,4-thiadiazolines, 1,3,4-selenadiazolines and triazolino[4,3- a ]pyrimidines

1,3,4-Thiadiazolines, 1,3,4-selenadiazolines and triazolino[4,3-a]pyrimidines have been synthesized from 3-aza-[2,4-dimethyl(1,3-thiazol-5-yl)-2-bromo-3-substituted-amino]prop-2-en-1-ones with potassium thiocyanate, potassium selenocyanate, alkyl carbodithioates and 6-methyl-2-methylthio-4-substituted 3,4-dihydropyrimidine-5-carboxylates. Structures of the newly synthesized compounds have been established by elemental analysis, spectral data and alternative synthesis whenever possible. Some of products have been tested towards bacteria.     

5,6,7,8-四氢吡啶并[3,4-b]吡嗪的合成

3,4-二氨基吡啶与乙二醛环化得到吡啶并[3,4-b]吡嗪,进一步与氯甲酸乙酯在硼氢化锂的作用下发生还原反应得到乙基5,6-二氢吡啶并[3,4-b]吡嗪-6(5H)-羧酸酯,然后经钯碳氢化得到乙基-5,6,7,8-四氢-二氢吡啶并[3,4-b]吡嗪-6(5H)-羧酸酯,最后在碱性条件下去保护基团合成了5,6,7,8-四氢吡啶并[3,4-b]吡嗪。对还原反应进行了工艺研究,确定优化反应条件:硼氢化锂为还原剂,反应时间为1 h,反应温度为-15℃。总收率为48.4%。产品结构经1H NMR确证。