Heterocyclic compounds condensed

R] Simpson, ]. C. E. Cinnolines. In The Chemistry of Heterocyclic Compounds. Condensed Pyridazine and Pyrazine rings (Cinnolines, Phthalazines, and Quinoxalines)-, Weissberger, A. Ed. Interscience Publishers New York-London, 1953 p3. 

R] Singerman, G. M. Cinnolines. In Heterocyclic Compounds. Condensed Pyridazines Including Cinnolines and Phthalazines-, Weissberger, A., Taylor, E. C. Eds. John Wiley Sons New York-London, 1973 pi. 

It is well known that in nitrogen-containing heterocyclic compounds the reactivity of alkyl groups is enhanced. In the thiazole series, alkyl groups in the 2-position are reactive towards carbonyl compounds and condensations may be realized. 

Thiophenealdehydes have been condensed with aliphatic aldehydes, methyl ketones,cyclic ketones, " benzyl cyanides,and aliphatic nitro compounds to the corresponding vinylthiophenes. By the use of potassium methylate, 2-thiophenealdehyde has been condensed with the reactive methyl groups of iV-heterocyclic compounds. Thiophenealdehydes have... 

C. F. H. Allen, The Chemistry of Heterocyclic Compounds—Six Membered Heterocyclic Nitrogen Compounds with Four Condensed Rings. Interscience, New York, 1951. 

Synthetically, vicinal functionally substituted aryl- and hetarylacetylenes are promising intermediates for preparing different condensed heterocyclic compounds, taking into account the fact that these polyfunctional groups can be selectively involved in cyclization processes. 

In a recent review of heterocyclic compounds no further mention is made of the three-membered ring structures for the condensation products from hydrazine and carbonyl compounds. However, the products obtained from azodicarbonyl derivatives with aliphatic diazo compounds were formulated as diaziridines [Eq. (1)]. Recent investi-... 

Miscellaneous reactions in neutral ionic liquids Kitazume et al. have also investigated the use of [EDBU][OTf as a medium in the formation of heterocyclic compounds [58]. Compounds such as 2-hydroxymethylaniline readily condense with... 

The final chapter is by M. R. Grimmett of Otago, New Zealand, and is the third and final part of his survey of the halogenation of heterocyclic compounds. It deals with the halogenation of condensed heterocycles. The first two parts of this series appeared in Volumes 57 and 58 of Advances. 

Cormier and Dure (1963) found another type of luciferin and called it protein-free luciferin. Protein-free luciferin was found in the vapor condensate of freeze-drying whole animals, and also in the 3 5-56 % ammonium sulfate fraction of the crude extract noted above. The protein-free luciferin behaved like an aromatic or heterocyclic compound and it was strongly adsorbed onto Sephadex and other chromatography media, requiring a considerable amount of solvent to elute it. The luminescence reaction of protein-free luciferin in the presence of luciferase required a 500-times higher concentration of H2O2 compared with the standard luciferin preparation. Both types of the luciferin preparation had a strong odor of iodoform. 

These observations indicated that an intermolecular double condensation to give a bis N-(methylene-4-oxocoumarinyl)-l,4 aromatic diamine had occurred. Data from the elemental analysis indicated that the calculated and observed values were within the acceptable limits ( 0.4%) and in conformity with the assigned structure. In the addition of molar equivalents of 1,4-aromatic binucleophilic compounds to compound 72 we did not observe any heterocyclic compounds resulting from the further intermolecular nucleophilic attack on the single condensation product. Since the condensation of 3-(dimethylaminomethylene)-chromane-2,4-dione with aromatic binucleophilic compounds is the only route to the new coumarinic compounds, this represents a useful synthetic method. 

Narasimhan, N. S., Mali, R. S. Heteroatom Directed Aromatic Lithiation Reactions for the Synthesis of Condensed Heterocyclic Compounds, 138, 63-147 (1986). 

Spironaphthooxazines are generally prepared by condensation of 2-alkylidene heterocyclic compounds with an o-nitrosonaphthol in methanol or ethanol, as shown in Scheme 18.73... 

A variety of heterocyclic compounds has been synthesized via condensed rhodacyclopentadienes (the diyne reaction ) (see for example Scheme 86 in Section IV,C,2). An example of the application of this type of process leading to the formation of a tribenzothiepin in outlined in Scheme 176.245 The bisacetylene derivative 149 can also be converted into a dibenzo[h,/] azuleno[l,2-d]thiepin derivative by means of (PhCN)2PdCI2 (cf. Scheme 172 in Section VI,A). 

A number of other ring systems have been prepared by intramolecular bis-annulation procedures. Pyrrolothiadiazolines 174 were prepared by condensation between hydrazides and compound 173 (Equation 14) <1998JPR676>. The thermally induced intra-intermolecular criss-cross cycloaddition of azine 175 in the presence of phenyl isocyanate leads to heterocyclic compound 176 containing three fused five-membered rings (Equation 15) <2002TL6431>. 

Other heterocyclic compounds, precursors of C-nucleosides, were prepared by condensing D-glucono- 1,5-lactone with l-hydrazino-4-phen-... 

This condensation is completely analogous to that of ethyl diazoacetate, mentioned on p. 281, and, in general, azides and aliphatic diazo-compounds are strikingly similar in the manner in which they react with unsaturated substances like acetylenes, olefine derivatives, and hydrogen cyanide to yield heterocyclic compounds. 

Keywords Fluorescence, Heterocyclic compound, Knoevenagel condensation, Spectroscopy... 

Similarly in condensed polynuclear aromatic compounds and heterocyclic compounds, the magnitude of the coupling constants between protons in the aromatic rings reflects the relative position of the coupled protons. 

This type of nucleoside includes numerous simple derivatives of heterocyclic compounds. Only a few examples are given. Condensation of the chloro-methyl ethers 1053 with silylated 5-fluorouracil gave the two mono- and one disubsituted derivatives 1054,1055, and 1056, respectively (86MI3). 

Dithiazolidines containing o-quinonemethide structural units in the 3,5-positions (e.g. (99)) are converted by reagents with an activated CHj group into a range of condensed heterocyclic compounds not easily accessible otherwise (Scheme 14) <85S535,86PHA283>. 

This, after 1,3,6,8-tetraazapyrene, was only the second example of obtaining both a negative and a positive radical from the same heterocyclic compound. Attempts to generate radical-ions from other condensed thiophenes succeeded only with dithieno[2,3-d 2, 3 -radical-cation [HFSC 0.42 (2H), 2.36 (IH), and 2.98 (IH) Gauss]. 

In the majority of dehydration reactions, heterocyclic compounds are formed, rather than carbocyclic compounds. Many possibilities for formation of carbocyclic compounds exist, but these are important only if (a) the heterocyclic or acyclic tautomers cannot undergo further elimination reactions, or (b) the conditions of reaction greatly favor the formation of an acyclic tautomer capable of affording only the carbocyclic compound. Both five- and six-membered carbocyclic compounds have been isolated, with reductic acid being the compound most frequently reported. Ring closure occurs by an inter-molecular, aldol reaction that involves the carbonyl group and an enolic structure. Many examples of these aldol reactions that lead to formation of carbocyclic rings have been studied.47 As both elimination and addition of a proton are involved, the reaction occurs in both acidic and basic solutions. As examples of the facility of this reaction, pyruvic acid condenses spontaneously to a dibasic acid at room temperature in dilute solution, and such 8-diketones as 29 readily cyclize to form cyclohexenones, presumably by way of 30, either in acid or base. 

One of the earliest authentic eight-membered heterocyclic compounds to be described was 6,7-diphenyldibenzo[e,g][l,4]diazocine (212) prepared by Tauber in 1892 by condensation of 2,2 -diaminobiphenyl and benzil. The diazocine ring is opened hydrolytically under vigorous conditions and is reduced to the 5,6,7,8-tetrahydro compound with sodium amal-... 

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