Compounds containing Thiophen Rings

Macrocyclic Compounds containing Thiophen Rings.—Macrocyclic keto-lactones such as (193) and (194) have been prepared by electrophilic ring-closure, as were the ketones (117) and (118) mentioned previously. The lactam (195) has 

Kauffmann, B. Greving, J. Konig, A. Mitschker, and A. Woltermann, Angew. Chem., 1975 87, 745. 

---

Thiaisatoic anhydrides have been considered as precursors for the synthesis of tricyclic compounds containing thiophene ring. Syntheses of these anhydrides have a major problem owing to the instability of their precursors thiophene o-aminoacids, which easily decarboxylate at room temperature. Under MWI, alkaline hydrolysis of... 

When studying the carcinogenic activity of polycyclic hydrocarbons and their antdogs containing thiophene rings (cf. Tilak "), Tilak et al synthesized both thienothiophene 1 and its isomer 2 in low yield from 2-thienyl dimethoxyethyl sulfide (23) and 3-thienyl diethoxyethyl sulfide (24), respectively, by the method developed for synthesis of thiophenes and thiopyrans - [Eqs. (10) and (11)]. The compounds 23 and 24 were prepared from 2- and 3-mercaptothiophenes. ... 

Dihydrothienocoumarins that have analgesic activity without anti-inflammatory activity have been synthesized. Compounds of type (154), with antibacterial, antifungal, and other activities, have been synthesized. Some NN N"-trisubstituted guanidines that contain thiophen rings and have anti-inflammatory properties have been synthesized. " Nitrosation of methapyrilene in vitro has been studied. 

Ch. 8 Condensed Thiophene Compounds Containing Nitrogen Ring Systems... 

Compounds with two mesogenic groups with and without terminal alkyl chains containing thiophene rings (cf. Sect. 1.2) are described [8-10,462]. The liquid crystalline behavior of the various compounds is dependent on the length of the... 

C. Electrophilic Substitution of Compounds Containing Several Thiophene Rings... 

Cyclizations of doubly unsaturated diazo compounds containing a thiophene ring within rather than at the end of the diene system to yield thicnodiazepines have also been reported. Thus, thermolysis of the sodium salt 7 gives the l//-thieno[3,2-r/]-2,3-diazepine 9. The intermediate 8 rearranges to the more stable product 9 by a symmetry allowed [1,5] shift of hydrogen.14,1... 

Fig. 8.24 Structures of suprofen and ticlopidine, compounds containing a thiophene ring and associated with diverse toxicities in patients.

The synthesis of photochromic compounds containing combinations of benzothiophene and thiophene 70 (04JPP(A)97, 09JMS100), indene 71 (06TL1267), or benzofuran rings 72 and 73 (06BCJ1100, 08BCSJ644) was documented (Scheme 22). 

An attractive approach toward the preparation of polycyclic systems containing a thiophene ring involves the intramolecular [3 - - 2] cycloaddition of thiocarbonyl ylides. A number of representative examples were reported using mesoionic compounds. Gotthardt et al. (151) used l,3-dithiolium-4-olates such as 89 bearing an olefinic side chain. Upon heating to 120 °C in xylene, the polycyclic tetrahy-drothiophene 90 was formed (Scheme 5.33). 

Thienopyridines, compounds 19-24 in Figure 3, contain a nitrogen atom in a six-membered pyridine ring fused to a five-membered thiophene ring. As with furopyridines, most emphasis has been placed on isomers 19-22, with little reported in the literature for isomers 23 and 24. 

Most of the heterocycles are known hy their trivial names, e.g. pyridine, indole, quinoline, thiophene and so on. However, there are some general rules to he followed in a heterocycle, especially in the use of suffixes to indicate the ring size, saturation or unsaturation as shown in the following table. For example, from the name, pyridine, where the suffix is -ine, one can understand that this heterocyclic compound contains nitrogen, has a six-memhered ring system and is unsaturated. 

Thiophene sulfones show no aromatic character, they behave as dienes and also show reactions of compounds containing a C = C bond conjugated with an electron-withdrawing group. Thiophene sulfone itself is highly unstable, but alkyl and aryl groups and fused benzene rings increase the stability. 

The known nonclassical A,B-diheteropentalenes consist of compounds containing an annelated thiophene or selenophene ring, the only uncharged nonradical representations of which contain a tetravalent sulfur or selenium, while the charged structures represent carbonyl, azomethine, thiocarbonyl or selenocarbonyl ylides. The parent systems have not yet been synthesized, only substituted compounds being known. The properties of these substituted derivatives provide a good measure of understanding of the reactivities of the parent systems. 

Kekule form does the thiophen ring contain two double bonds. To refer to the compound as 2, 3 -dihydrothieno(3, 2 l,2)indolizine is obviously unsatisfactory. Thus although for relatively simple molecules the Stelzner system is adequate, it would require modification to cover the more complex cases. Since the IUPAC system is capable of straightforward application to a much wider range of compounds, there seems... 

---