Compounds with One Heteroatom

FIVE-MEMBERED HETEROCYCLES FUSED TO ONE BENZENE RING 

Compounds whose structures include a quinone moiety have been intensively investigated as potential antitumor agents. At least two quinones, mitomycin C and diaziquone, that have found their way to the clinic. These compounds in addition include a reactive aziridine ring. A recent entry that incorporates both those features, apaziquone (135), also known as E09, may be viewed as an oxidized indole. In the key reaction of a succinct synthesis to this agent, quinone 129 is allowed to react with 

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The first group consists of monocyclic heteroaromatic compounds with one heteroatom and without strongly electron-donating substitutents (OH, NH2). Pyrrole, furan, and thiophene are better electron donors than benzene. The order of their reactivities in azo coupling is thiophene > pyrrole > furan > benzene. 

After the compounds with one heteroatom in the ring, the second group of heteroaromatics are the heteroaromatic compounds with two or more heteroatoms in the same ring, but without electron donor substituents. 

Compounds with one heteroatom in each heterocyclic ring... 

Compounds with one heteroatom in each heterocyclic ring 10.23.9.1.1(1) Synthesis of the heterocyclic ring... 

Equally interesting is the situation in the second class of compounds studied (analogues of non-alternant hydrocarbons), which is best divided into two sub-groups analogues of the tropylium ion and analogues of azulene. The empirical correlation of experimental and theoretical excitation energies studied requires a further subdivision into compounds with one heteroatom (e.g. thiopyrylium ion) and two heteroatoms, either adjacent (e.g., 1,2-dithiolium ion) or non-adjacent (e.g., 1,3-dithiolium ion). Experimental and theoretical data are presented in Table VII. Table VIII summarizes data for the derivatives of dithiolia. Figure 15 shows the absorption curves of 1-benzo-... 

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