Naphtho -thiadiazole

Brombosz SM, Appleton AL, Zappas AJ n, Bunz UHF (2010) Water-soluble Benzo- and Naphtho-thiadiazole-based bisbiazoles and their metal sensing propt es. Chem Commun 46 1419-1421... 

ITVTVis data have also recently been reported for 3,4-diphenyl-l,2,5-thiadiazole 1,1-dioxide 10 <2000JP0272, 2003JP0220, 2004JP01091> and for the fused phenanthro[9,10-c]-l,2,5-thiadiazole 1,1-dioxide 51 and ace-naphtho[l,2-f]-l,2,5-thiadiazole 1,1-dioxide 53 analogues <2000JP0272>. 

The fusion of a second aromatic ring results in subtle changes in reactivity. Halogenation of naphtho[l,2-c]-l,2,5-thiadiazole (42) occurs either by 4,5-addition of chlorine (43a) or by 5,6-substitution (44) by bromine. This heterocyclic analog of phenanthrene behaves like phenanthrene in that it gave the 4,5-addition product (43b) when treated with Br2 in glacial acetic acid (Scheme... 

The PPP configuration analysis technique and the mo ecules-in-molecules/localized configuration interaction (MIM/LCI) method can provide an explanation of the fact that some cyclic sulfur diimides are colorless, while others are not. Thus, while 1,2,5-thiadiazoles 231 and 232 are colorless, naphtho[l,8- /][l 4,2,6]thiadiazine 229 is colored (low intensity absorption at 642 nm). The energy level of the color band appears to be largely determined by frontier orbital interactions. By considering the overlap between the two fragments, (i) the NSN group and (ii) the... 

Attack at the heteroatoms was observed in the reactions of (1) and (2) with dimethyl acetylenedicarboxylate and with benzyne (78JCS(P1)1006). Compound (2) behaves as a heterodiene toward the acetylene ester, producing the quinoxaline (25) and selenium. The diester (25) was obtained only in trace amounts from (1). These reactions, and the failure of (1) and (2) to react with maleic anhydride, contrast with the behavior of naphtho[2,3-c] [l,2,5]thiadiazole which reacts with maleic anhydride across the center ring (64TL3815). 

There have been few studies of the reactivity of molecules in this class. Calculations (ir density) indicate that the positional order in naphtho-[2,3-c]-l,2,5-thiadiazole (8.129 X = S), is 4 > 6 > 5, whereas localization energies and frontier electron densities predict 4 > 5 > 6 [66TCA(5)401] the high reactivity of the 4-position follows from the benzenoid character generated in the transition state (8.130). CNDO/2 calculations for naph-tho[2,3-c]-l,2,5-oxa-, -thia-, and -selena-diazoles (8.129, X = O, S, Se) predict the order 6 > 4 5 (73CHE1331). For the corresponding [1,2-c]... 

The effect of fusion of another ring to benzofuroxan is rather variable. Naphtho[l,2-c]furoxan (16) and some of its derivatives show AG 83 kJ mol-1.100 Accurate data are available for two fused benzofuroxans, 10 and 11 (see Table V),72 and qualitative Tc measurements have been made on a number of related compounds.100,101,344,345 The slowest interconversions were noted for the furoxano- and furazano-fused compounds (83,84).101 The (heavily biased) isomeric JV-methyltriazole derivatives 85 and 86 were, qualitatively, rather more rapidly isomerized than were compounds 10 or 16,344 while the fused thiadiazole 87344 (AG1 72 kJ mol-1), thiophene 88345 (69 kJ), and thiazole 89344 (64 kJ mol - ) had still lower barriers. The fastest furoxan yet to be measured is the linear-fused example 90 (AG ... 

Physical Properties. - Naphtho[2,3-c][1,2,5]thiadiazol-4,9-dione and its selenium analogue have been studied by X-ray crystallography. Both show significant ir interaction of the chalcogen diimide with the it system of the naphthoquinone. ... 

Cumulative Index of Heterocyclic Systems Naphtho [2,3 -d ] -1,2,3-thiadiazole (1265)... 

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