Déplacements Chimiques induits en RMN par un Réactif Lanthanidique: II—Analyse Conformationnelle de Sulfinamates Cycliques: Oxo-2 Oxathiazannes-1,2,3 et Oxo-2 Benzo-5,6 Dihydro-3,4 Oxathiazines-1,2,3

Re-examination of recent results in the literature about 2-r-substituted 5-c-tert-butyl-1,3,2-dioxaphosphorinanes and 3,3-dimethyl-1-oxothiethan made us select, under the indicated conditions, the static model because it is easier to use than the dynamic one. Its application to 17 cyclic sulphinamates belonging to two series—the 2-oxo-1,2,3-oxathiazans (I) and the 5,6-benzo-3,4-dihydro-2-oxo-1,2,3-oxathiazins (II)—confirms, in the presence of Eu(fod)₃, the structures established without the shift reagent, from chemical shifts and coupling constants only, and shows their conformational diversity. For the series (I) the following conformations are found: (i) standard chairs with an axial S?O group (CA) when the molecule is not substituted in the 4 and 6 positions or when the substituents are equatorial (with the exception of 3-tert-butyl-4-t-methyl-2-r-oxo-1,2,3-oxathiazan); the substituents R?Me, iPr or tBu on the nitrogen atom are preferentially axial; (ii) strained chairs with axial Me-4 and S?0 groups (CA); in this conformation R?Ph may be partially conjugated and R?Me or tBu may prefer the more favourable axial orientation; (iii) twist conformations with a 1,4-axis and an axial S?O group (COA) for the two 4-c,6-c- and 4-t,6-c-di-tert-butyl-2-r-oxo-3-phenyl-1,2,3-oxathiazans; (iv) the twist conformation with a 3,6-axis and an axial S?O group (CNA) for trans-3-tert-butyl-4-methyl-2-oxo-1,2,3-oxathiazan because of the 4-methyl—3-tert-butyl 1,2-interaction. For the series (II) half-chair forms with an axial S?O group are proposed.     

Synthesis of new halo-substituted pyrazolo[5,1-c][1,2,4]triazines

Ethyl 3-tert-butyl-4-oxo-7-X-4,6-dihydropyrazolo[5,1-c][1,2,4]triazine-8-carboxylates (X = H, Cl, Br) were synthesized for the first time by diazotization of 7-amino-3-tert-butyl-4oxo-8-ethoxycarbonyl-6H-pyrazolo[5,1-c][1,2,4]triazines with tert-butyl nitrite in the presence of trimethylsilyl halides. A new method was developed: a reaction between 7-amino-3-tert-butyl-4-oxo-6H-pyrazolo[5,1-c][1,2,4]triazine-8-carboxylic acid and I₂/TEA followed by treatment with NaBH₄ led to a mild decarboxylation. The acid reacts with N-halosuccinimides to give novel 8-halo-substituted derivatives. The amino groups of the latter were acylated by treatment with trifluoroacetic anhydride to give monoacylation products.

     

Beiträge zur Chemie des Phosphors. 224. Zur Thermolyse von 1,2-Di-tert-butyldiphosphan, 1,2,3-Tri-tert-butyltriphosphan und Tetra-tert-butylcyclotetraphosphan

Contributions to the Chemistry of Phosphorus. 224. On the Thermolysis of 1,2-Di-tert-butyldiphosphane, 1,2,3-Tri-tert-butyltriphosphane, and Tetra-tert-butylcyclotetraphosphane On disproportionation of 1,2-di-tert-butyldiphosphane, H(t-Bu)P? P(t-Bu)H (1) , 1,2,3-tri-tert-butyltriphosphane, H₂(t-BuP)₃ (2) , is formed which reacts further at temperatures above 100°C to give 1-(tert-butylphosphino)-2,3,4-tri-tert-butylcyclotetraphosphan, P₅(t-Bu)₄H (4) . Compound 4 reacts with 1 or 2 with lengthening of the P-sidechain to furnish the corresponding 1-(1,2-di-tert-butyldiphosphino)-2,3,4-tri-tert-butylcyclotetraphosphane, P₆(t-Bu)₅H (5) . At temperatures above 170°C, 5 disproportionates into the tetra-tert-butylcyclotetraphosphane, (t-BuP)₄ (3) which is stable up to about 200°C, and the bicyclo[3.1.0]hexaphosphane P₆(t-Bu)₄ from which the polycyclophosphanes P₉(t-Bu)₃ and P₈(t-Bu)₆ arise during the further course of the thermolysis. These products are finally converted through even more phosphorus-rich and more highly condensed t-butylcyclophosphanes into elemental phosphorus. In each reaction step, varying amounts of the monophosphane derivatives t-BuPH₂, (t-Bu)₂PH, and (t-Bu)₃P are formed. The proposed course of the reaction is further substantiated by the pyrolysis products of pure 2 and 3 .     

Synthesis and X-ray single crystal structure of first aromatic ortho-di-tert-butyl azolo[1,2,4]triazine

Oxidation of 3,4-di-tert-butyl-8-methyl-1,4-dihydropyrazolo[5,1-c][1,2,4]triazine with NBS/K₂CO₃ furnished 3,4-di-tert-butyl-8-methylpyrazolo[5,1-c][1,2,4]triazine, a mildly strained heteroaromatic compound. X-Ray single crystal diffraction analysis indicated that the conjugated 1,2,4-triazine ring adopts a twist-boat configuration, while the two t-Bu substituents are located on the opposite sides of the azole plane. The related 3-tert-butyl-4-(o-C-carboranyl)-8-methyl-1,4-dihydropyrazolo[5,1-c][1,2,4]triazine was also synthesized, however, its oxidative aromatization was unsuccessful.     

Diastereoselective synthesis of 3-tert-butyl-3,4-dihydropyrazolo[5,1-c][1,2,4]triazine-3,4-diyl dicarboxylates

The reactions of 3-tert-butyl-7-R¹-8-R²-pyrazolo[5,1-c][1,2,4]triazines (R¹ = H, Br; R² = Me, n-Bu) with N-bromosuccinimide in the presence of R³CO₂H (R³ = Me, t-Bu, Ph) afforded novel diastereomerically pure 3-tert-butyl-7-R¹-8-R²-3,4-dihydropyrazolo[5,1-c][1,2,4]triazine-3,4-diyl dicarboxylates. The structures of the isolated products were established on the basis of IR, ¹H, ¹³C, 2D NOESY NMR, high resolution mass spectrometry and X-ray single-crystal analysis. The steric and mechanistic origins of the observed regio- and stereoselectivity were also discussed.     

Synthesis of 8-tert-Butyl-9-oxo-1,2,4-triazolo[4,5-b]-1,2,4-triazolo[3,4-c]-1,2,4-triazine

8-tert-Butyl-9-oxo-1,2,4-triazolo[4,5-b]-1,2,4-triazolo[3,4-c]-1,2,4-triazine has been synthesized by the interaction of 6-tert-butyl-3-hydrazino-1,2,4-triazolo[3,4-c]-1,2,4-triazin-5-one with formic acid. The conditions of carrying out the reaction are discussed. Spectral characteristics are given.     

Trimethylsilyl- und Trimethylstannylester der Trithiophosphonsäuren; Darstellung,Protolyse und weitere Reaktionen

Trimethylsilyl and Trimethylstannyl Esters of the Trithiophosphonic Acids; Preparation, Protolysis, and Further Reactions The organotrithiophosphonic acid bis(trimethylsilyl) esters RP(S)(SSiMe₃)₂, R = Ph ( 1a ), R = t-Bu ( 1b ) and R = Me ( 1c ) are formed in high yield from the organo-bis(trimethylsilyl)-phosphanes RP(SiMe₃)₂ by the addition of three sulfur atoms (3/8 S₈) in toluene solution. 1b has also been prepared by reacting disodium tert-butyltrithiophosphonate, Na₂t-BuP(S)S₂ ( 2 ) with SiMe₃Cl. Analogous reactions can be used for the preparation of the stannyl esters RP(S)(SSnMe₃)₂, R = t-Bu ( 5a ) and R = Me ( 5b ). More favorable, however, these compounds are synthesized from the corresponding silyl esters 1b, c and SnMe₃Cl or, as has been shown in the case of 5a , by reacting dithiophosphonic acid anhydrides (RP(S)S)₂ with (SnMe₃)₂S. Low temperature solvolysis of the silyl esters 1b, c with water or methanol results in the free organotrithiophosphonic acids RP(S)(SH)₂, R = t-Bu ( 6a ) and R = Me ( 6b ), which can be isolated as white solids at —30°C. Contrary to the sodium salt 2 and the stannyl esters 5a, b , the acids 6a, b , and, to a smaller extent, the silyl esters 1a—c are thermally not stable towards decomposition into the thioanhydrides (RP(S)S)₂. The silyl and stannyl esters 1a—c and 5a, b , respectively, are capable of cleaving the ether linkage of tetrahydrofuran, which in the case of 1b leads to the quantitative formation of t-BuP(S)[S(CH₂)₄OSiMe₃]₂ ( 9 ). 1b, c and 5a, b react with Cl₂ and Br₂ forming the 3,6-diorgano-3,6-dithio-1,2,4,5,3,6-tetrathiadiphosphorinanes (RP(S)S₂)₂, R = t-Bu ( 7a ) and R = Me ( 7b ).     

On the amination of 1,2,4-triazines by potassium amide in liquid ammonia and by phenyl phosphorodiamidate. A 15n-study

The amination of 5-R- and 6-R-3-X-1,2,4-triazines (R = C₆H₅, t-C₄H₉, X = SCH₃, SO₂CH₃, N⁺ (CH₃)₃, Cl) by potassium amide in liquid ammonia has been studied. In all reactions the formation of the corresponding 3-amino-1,2,4-triazines takes place; in some reactions by-products were found: from 5-phenyl- and 5-t-butyl-3-(methylthio)-1,2,4-triazine a ring contracted product i.e. 5-phenyl and 5-t-butyl-3-(methylthio)-1,2,4-triazole, from 6-phenyl-3-(methylthio)-1,2,4-triazine the dimer 3,3′-bis-(methylthio)-6,6′-bisphenyl-5,5′-bi-1,2,4-triazine and from 5-t-butyl-3-(trimethylammonio)-1,2,4-triazine chloride compound bis-(5-t-butyl-1,2,4-triazin-3-yl)- amine. Furthermore the conversion of 5-phenyl- and 5-t-butyl-1,2,4-triazin-3-one into the corresponding 3-amino compound by treatment with phenyl phosphorodiamidate (PPDA) was studied. A ¹⁵N study of these aminations showed that nearly all compounds undergo substitution according to both S_N(AE) and S_N(ANRORC) processes. The contribution of each of the competitive mechanisms to the amination is strongly influenced by the character of the leaving group.     

2-取代氨基-6-甲基-5-氧代-4-正丁基-4,5-二氢-1,2,4-三氮唑并[1,5-a]嘧啶类衍生物的合成

以2-溴丙酸甲酯、α,α-二氯甲基甲醚和胍唑为原料, 经缩合以及环化反应制得2-氨基-6-甲基-5-氧代-4,5-二氢-1,2,4-三氮唑并[1,5-a]嘧啶. 为了提高其在有机溶剂中的溶解性, 该化合物再同1-溴丁烷发生亲核取代反应得到了2-氨基-6-甲基-5-氧代-4-正丁基-4,5-二氢-1,2,4-三氮唑并[1,5-a]嘧啶, 然后与芳基醛和叔丁基异氰发生Ugi多组分反应, 合成了一系列具有潜在催吐活性的2-取代氨基-6-甲基-5-氧代-4-正丁基-4,5-二氢-1,2,4-三氮唑并[1,5-a]嘧啶类衍生物, 产品结构经质谱、核磁共振谱及元素分析确认.     

Beiträge zur Chemie des Phosphors. 138. P5(t-Bu)4H – das erste Derivat von iso-P5H5

Contributions to the Chemistry of Phosphorus. 138. P₅(t-Bu)₄H — the First Derivative of iso-P₅H₅ The thermolysis of 1,2-di-tert-butyldiphosphane, H(t-Bu)P? P(t-Bu)H, yields under suitable conditions the compound P₅(t-Bu)₄H ( 1 ) as the main product. Besides, the tert-butylphosphanes t-BuPH₂, P₆(t-Bu)₅H ( 2 ), H₂(t-BuP)₃, and (t-BuP)₄ are formed. 1 has been isolated in the pure state and structurally characterized as 1-(tert-butylphosphino)-2,3,4-tri-tert-butyl-cyclotetraphosphane. Hence, compound 1 is a derivative of iso-P₅H₅ with a branched phosphorus skeleton built up by a four-membered ring and a phosphorus side chain.     

Facile synthesis of 6-hetaryl[1,2,4]triazolo[3,4-<Emphasis Type="Italic">b</Emphasis>][1,3,4]thiadiazoles and 7-hetaryl[1,3,4]thiadiazolo[2,3-<Emphasis Type="Italic">c</Emphasis>][1,2,4]triazines with fungicidal activity

Condensation of 4-amino-4H-1,2,4-triazole-3-thiol and 4-amino-6-methyl-3-sulfanyl-1,2,4-triazin-5(4H)-one with ethyl cyanoacetate gave ethyl [1,2,4]triazolo[3,4-b][1,3,4]thiadiazol-6-ylacetate and ethyl 3-methyl-4-oxo-4H-[1,3,4]thiadiazolo[2,3-c][1,2,4]triazin-7-ylacetate, respectively. Reactions of the condensation products with 1,3-diphenylprop-2-en-1-one, aromatic aldehydes, and carbon disulfide or N,N-dimethylformamide dimethyl acetal (followed by treatment with hydrazine hydrate) gave the corresponding 6-hetaryl-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazoles and 7-hetaryl-3-methyl-4H-[1,3,4]thiadiazolo[2,3-c][1,2,4]triazin-4-ones. Preliminary tests revealed fungicidal activity of the pyrazolyl-substituted derivatives. Published in Russian in Zhurnal Organicheskoi Khimii, 2007, Vol. 43, No. 12, pp. 1813–1818. The text was submitted by the authors in English.     

Recherches en série triazépine-1,2,4: II — Etude de la réaction de l'acétylacétate d'éthyle avec les diamino-3,4 oxo-5 dihydro-4,5 triazines-1,2,4

The reaction of 3,4-diamino-5-oxo-4,5-dihydro-l,2,4-triazine or its 6-methyl or 6-phenyl substituted derivatives and ethyl acetoacetate gave three compounds: 4,7-dioxo-9-methyl-1,4,6,7-tetrahydro-as-triazino[4,3-b]-1,2,4-triazepine in poor yield, isomeric 4,9-dioxo-7-methyl-1,4,8,9-tetrahydro-as -triazino[4,3-b]-1,2,4-triazepine and by competitive cyclisation, 2-methyl-7-oxo-3,7-dihydro-s-triazolo[3,2-c]-1,2,4-triazine. By condensation of 3-methylamino-4-amino-5-oxo-4,5-dihydro-1,2,4-triazine with ethyl acetoacetate, the formation of 4,9-dioxo-7,10-dimethyl-4,8,9,10-tetrahydro-as-triazino[4,3-b]-1,2,4-triazepine was strongly favored.     

Beiträge zur Chemie des Phosphors. 142. P6(t-Bu)5H – das erste Cyclotetraphosphan mit P2-Seitenkette

Contributions to the Chemistry of Phosphorus. 142. P₆(t-Bu)₅H – the First Cyclotetraphosphane with a P₂ Side Chain The thermolysis of 1, 2-di-tert-butyldiphosphane, H(t-Bu)P? P(t-Bu)H, leads to formation of the hitherto unknown hexaphosphane P₆(t-Bu)₅H ( 1 ). In the first instance the iso-P₅H₅ derivative P₅(t-Bu)₄H [3] is formed, which reacts further with H₂(t-BuP)₂ or H₂(t-BuP)₃ yielding 1 . Compound 1 has been isolated in the pure state and structurally characterized as 1-(1,2-di-tert-butyldiphosphino)-2, 3, 4-tri-tert-butyl-cyclotetraphosphane, i. e. as a four-membered ring compound with a P₂ side chain. Due to the chirality of the P atoms in the side chain, 1 exists as a mixture of two configurational isomers, the threo-and the erythro-form.     

Synthesis of substituted pyrido[3´,2´:4,5]thieno[3,2-c]isoquinolin-5(6H)-ones and their sulfinyl and sulfonyl derivatives

A method for the synthesis of previously unknown pyrido[3´,2´:4,5]thieno[3,2-c]isoquinolin-5(6H)-ones was suggested, which includes a condensation reaction of substituted 3-cyanopyridine-2(1H)-thiones with methyl 2-(chloromethyl)benzoate and subsequent treatment of the condensation products with potassium tert-butoxide. The oxidation of the condensation products to sulfoxides or sulfones and subsequent treatment of these compounds with potassium tert-butoxide led to substituted pyrido[3´,2´:4,5]thieno[3,2-c]isoquinolin-5(6H)-one 11-oxides or substituted pyrido[3´,2´:4,5]thieno[3,2-c]isoquinolin-5(6H)-one 11,11-dioxides.

     

Synthesis and conversions of 3-(4-amino-5-methyl-4H-1,2,4-triazol-3-ylmethylene)-2-oxo-1,2,3,4-tetrahydroquinoxaline

The reaction of the hydrazone 3a with hydrazine hydrate in DBU/ethanol conveniently gave 3-(4-amino-5-methyl-4H-1,2,4-triazol-3-ylmethylene)-2-oxo-1,2,3,4-tetrahydroquinoxaline 6 . The reactions of 6 with an equimolar and 2-fold molar amount of nitrous acid afforded 3-(α-hydroxyimino-4-amino-5-methyl-4H-1,2,4-triazol-3-ylmethyl)-2-oxo-1,2-dihydroquinoxaline 9 and 3-(α-hydroxyimino-5-methyl-2H-1,2,4-triazol-3-ylmethyl)-2-oxo-1,2-dihydroquinoxaline 10 , respectively, which were converted into the 3-heteroarylisoxazolo[4,5-b]quin-oxalines 13a,b and 11 , respectively. Compound 9 was also cyclized into the 8-quinoxalinyl-1,2,4-triazolo-[3,4-f][1,2,4]triazines 14a,b .     

Intramolecular cyclization of 4-amino-3-alkylsulfanyl-1,2,4-triazoles as a method for annelation of thiadiazine and thiadiazole rings

4-Amino-5-(pyridin-4-yl)-4H-1,2,4-triazole-3-thiols reacted with N-substituted isatins to give 2-oxo-3-[5-(pyridin-4-yl)-3-sulfanyl-4H-1,2,4-triazole-4-ylimino]-2,3-dihydro-1H-indoles which were treated with phenacyl bromides to obtain the corresponding S-phenacyl derivatives. The latter underwent base-catalyzed intramolecular cyclization with formation of 6,7-dihydro-5H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines spiro-fused to 2-oxo-2,3-dihydro-1H-indole fragment at C³. Analogous cyclization of 2,6-di-tert-butyl-4-[5-hetaryl-3-(2-aryl-2-oxoethylsulfanyl)-4H-1,2,4-triazole-4-ylimino]cyclohexa-2,5-dienones involved the imino nitrogen atom to produce the corresponding 6-aroyl-5-(3,5-di-tert-butyl-4-hydroxyphenyl)-3-hetaryl-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazoles.     

Reactivity of 7-amino-3-tert-butyl-4-oxo-4,6-dihydropyrazolo[5,1-c][1,2,4]triazine-8-carbonitrile

By reaction of carbonyl compounds with 7-amino-3-tert-butyl-4-oxo-4,6-dihydropyrazolo[5,1-c]-[1,2,4]triazine-8-carbonitrile 3-tert-butyl-8-R-4,6,9,10-tetrahydropyrimido[4′,5′:3,4]pyrazolo[5,1-c][1,2,4]-triazine-4,10-diones and (3-tert-butyl-4-oxo-8-cyano-4,6-dihydropyrazolo[5,1-c][1,2,4]triazin-7-yl)acetamide were obtained.     

The Detection of tert-Butylthiosulfoxylic Acid,t-BuSSOH,and 1-Oxatrisulfane,HSSOH, in the Gas Phase – Experimental Results and Ab Initio Calculations

Flash vacuum pyrolysis (FVP) of tert-butylthiosulfinic acid S-tert-butylester, t-BuS(O)St-Bu, at a temperature of 500 °C and a pressure of 0.07 hPa leads to the formation of tert-butylthiosulfoxylic acid, t-BuSSOH ( 1 ), and 2-methylpropene as byproduct. 1 has been identified in the gas phase by its IR absorption bands at ν(OH) = 3598 cm^–1, δ(SOH) = 1149 cm^–1 and ν(SO) = 718 cm^–1. At higher temperatures (700 °C) the elimination of a second mole of 2-methylpropene and the shift of ν(SO) to higher wavenumbers (750 cm^–1) indicate the formation of 1-oxatrisulfane, HSSOH. Different sulfenic acids RSOH (R = Me, i-Pr, t-Bu) were synthesized by FVP in order to study the influence of the substituent R on the vibrational wavenumbers ν(OH), ν(SO) and δ(SOH) observed in the gas phase. The strongest effect results for δ(SOH) leading to a decrease by 6 wavenumbers if the methyl group is substituted by a tert-butyl group. The assignment of the experimental wavenumbers has been supported by theoretical values obtained from ab initio calculations at the MP2(fc)/6-311G** level. Furthermore, the theoretical studies show that of all compounds RS₂OR′ (R = R′ = H, Me; R = Me (H), R′ = H (Me)) the unbranched chain isomers RSSOR′ are energetically favored over the branched chain isomers. Relaxed potential energy surface scans at the MP2(fc)/6-311G** level have been carried out to study the rotational isomers of the branched molecules RS(Y)XR′ (R = R′ = H, Me; R = Me (H), R′ = H (Me); X = O (S), Y = S (O)). Of the three conformations (+)syn-clinal, (–)syn-clinal, and anti-periplanar resulting from molecular model considerations only the two latter ones correspond to local minima on the calculated potential curve. The (–)syn-clinal conformation is slightly favored for all other constitutional isomers except for HS(O)SH and MeS(O)SH, which prefer the anti-periplanar conformation.     

Synthesis of certain N- and C-alkyl purine analogs

A number of N- and C-alkyl derivatives of selected guanine analogs have been synthesized as potential antiviral agents. n-Pentyl, n-hexyl and 6-hydroxyhexyl derivatives in the imidazo[1,2-α]-s-triazine, 9–11 , imid-azo[1,2-α]pyrimidine, 13–17 , and thiazolo[4,5-d]pyrimidine, 19–21, ring system have been prepared by the direct alkylation of the sodium salt of the appropriate aglycon with the respective alkylbromides. Dehydra-tive coupling of 3-amino-6-hydrazino-1,2,4-triazin-5(4H)-one ( 22 ) with either hexanoic acid or heptanoic acid, and further ring closure of the reaction products 24a and 24b provided the n-pentyl and n-hexyl derivatives of 6-amino-1,2,4-triazolo[3,4-f][1,2,4]triazin-8(7H)-one 25a and 25b , respectively. A similar condensation of 3-amino-6-aminomethyl-1,2,4-triazin-5(4H)-one ( 23 ) with heptanoic acid, followed by ring annulation, readily gave 2-amino-7-n-hexylimidazo[5,1-f][1,2,4]triazin-4(3H)-one ( 25c ). Bromination of 25c with N-bromosuccini-mide afforded the corresponding 5-bromo derivative 26 . Alkylation of the in situ generated sodium salt of 4-methoxycarbonylmethyl-5-methoxycarbonyl-2-oxo-1H,3H-imidazole ( 27 ) with 1-bromohexane gave the N-1 alkylated product 31 . Manipulation of the functional groups in 31 and further hydrazine mediated ring annulation furnished 5,6-diamino-1-n-hexyl-3-methylimidazo[4,5-c]pyridine-2,4-dione ( 39 ). Catalytic hydrogena-tion of 39 gave 7-methyl-8-oxo-9-hexyl-3-deazaguanine ( 40 ), a congener of the immunostimulator 7-methyl-8-oxoguanosine.     

Synthesis of some fused triazoloquinolines

The reaction of 3 -amino-1,2,4-triazolo[4,3-a]quinoline ( II ) with diethyl ethoxymethylenemalonate and ethyl acetoacetate/ethyl trifluoroacetoacetate afforded 10-carboethoxy-9-oxo-9H-pyrimido[1′,2′:1,5][1,2,4]triazolo-[4,3-a]quinoline ( III ) and 11-methyl/trifluoromethyl-9-oxo-9H-pyrimido[1′,2′:1,5][1,2,4]triazolo[4,3-a]quinoline ( IV/V ) respectively. 2-Chloropyridine-3-carboxylic acid chloride reacted with II to yield 5-oxo-5H-pyrido-[3″,2″:5′,6′]pyrimido[1′,2′:1,5][1,2,4]triazolo[4,3-a]quinoline ( VII ), a new ring system.