• V V Ghaisas

      Articles written in Proceedings – Section A

    • Sulphur isosters of carcinogenic hydrocarbons - Part II. 6∶12-Dimethylbenzo (1∶2-b, 5∶4-b′) dithionaphthene and thionaphtheno (4∶5∶4′∶5′) thionaphthene

      V V Ghaisas K Rabindran B D Tilak

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      With the view to study the significance of the 9∶10-phenanthrene double bond (“phenanthrene bridge”) in 9∶10-dimethyl-1∶2∶7∶8-dibenzanthracene (II), 6∶12-dimethylebenzo (1∶2b, 5∶4-b′)dithionaphthene (V) was prepared where both the phenanthrene bridges in (II) are removed by isosteric replacement with thiophene rings and themeso-positions are blocked by methyl groups. Compound (V) should prove noncarcinogenic.

      2∶7-Dimethoxyethylmercaptonaphthalene (IX) on cyclization gave thionaphtheno(4∶5∶4′:5′-)thionaphthene (VIII). The constitution (VIII) follows from the favoured α-cyclization in the naphthalene series and the similarity of its absorption spectrum with that of 3∶4-benzphenanthrene.

    • Thiophenes and thiapyrans - Part XII. Synthesis of thiophthenes

      V V Ghaisas B D Tilak

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      Thieno(3:2-b)thiophene (I) and thieno(2:3-b)thiophene (II) were prepared starting from 3- and 2-thiophenethiols and bromoacetaldehyde dialkoxy acetals. Condensation of the latter with the thiols gave 3-thienyl 2:2-diethoxyethyl sulphide (IV) and 2-thienyl 2:2-dimethoxyethyl sulphide (V) which on cyclization gave (I) and (II).

      Thieno(3:2-b)thionaphthene (IX) was prepared starting from 3-thiophenethiol and 2-bromocyclohexanone. Condensation of the latter compounds gave 2-(3′-thienylmercapto)cyclohexanone which on cyclization gave 5: 6: 7: 8-tetrahydro-thieno(3: 2-b)thionaphthene (VIII). Dehydrogenation of (VIII) gave (IX). 4: 5: 6: 7-Tetrahydrothieno(2: 3-b)thionaphthene (XI) was prepared similarly starting from 2-thiophenethiol. Attempts to dehydrogenate (XI) to thieno (2:3-b) thionaphthene (XII) were unsuccessful.

      We are deeply indebted to the Socony-Vacuum Oil Co. for the gift of 3-thiophenethiol used in the present and in subsequent work. Our thanks are also due to Dr. T. S. Gore for the microanalyses.


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